Potent inhibitors of secretory phospholipase A2: Synthesis and inhibitory activities of indolizine and indene derivatives

3636

J . Med. Chem. 1996, 39, 3636-3658

P oten t In h ibitor s of Secr etor y P h osp h olip a se A2: Syn th esis a n d In h ibitor y

Activities of In d olizin e a n d In d en e Der iva tives

Sanji Hagishita,* Masaaki Yamada, Kazuhiro Shirahase, Toshihiko Okada, Yasushi Murakami, Yuji Ito,

Takaharu Matsuura, Masaaki Wada, Toshiyuki Kato, Masahiko Ueno, Yukiko Chikazawa, Katsutoshi Yamada,

Takashi Ono, Isao Teshirogi, and Mitsuaki Ohtani

Shionogi Research Laboratories, Shionogi & Co., Ltd., Fukushima-ku, Osaka 553, J apan

Received J une 3, 1996^X

Phospholipase A2 is an enzyme which hydrolyzes the sn-2 position of certain cellular

phospholipids. The liberated lysophospholipid and arachidonic acid are precursors in the

biosynthesis of various biologically active products. As human nonpancreatic sPLA2 is present

in high levels in the blood of patients in several pathological conditions, the potent sPLA2

inhibitors have been suggested to be useful drugs. Here we describe the synthesis, structure-

activity relationship, and inhibitory activities of indolizine and indene derivatives. 1-(Car-

bamoylmethyl)indolizine derivatives and 1-oxamoylindolizine derivatives exhibited very potent

inhibitory activity. The former was unstable to air oxidation, but the latter exhibited an

improvement both in stability and in potency. Some compounds approached the stoichiometric

limit of the chromogenic assay.

In tr od u ction

Phospholipase A2 (PLA2) is an enzyme that specifi-

cally hydrolyzes the sn-2-acyl ester bond of phospho-

glycerides of cell membranes and is distributed widely

in nature. Activation of PLA2 leads to the release of

fatty acids and lysophospholipid, which are then con-

verted to mediators of inflammation and allergy, such

as prostaglandins, leukotrienes, and platelet activating

factor.¹Therefore, blockade of PLA2 can result in the

suppression of three important classes of lipid mediators

and offers an attractive therapeutic approach to inflam-

mation. Over the past decade, a number of distinct

types of PLA2 have been isolated and characterized.

Pancreatic type I secretory PLA2, nonpancreatic 14-kDa

type II secretory PLA2 (sPLA2), and 85-kDa cytosolic

PLA2²are especially well-known in relation to pathol-

ogy. Among these types, mammalian nonpancreatic

sPLA2 has been detected in high levels in the blood of

patients with septic shock²and pancreatitis³and also

in the synovial fluid of those suffering from rheumatoid

F igu r e 1. Prepared compounds.

arthritis.⁴Because of this involvement of sPLA2 in such

inflammatory processes, it has been suggested that a

chemical similarity to indole, the indolizine system was

potent sPLA2 inhibitor can be a therapeutically useful

considered likely to show similar sPLA2 inhibitory

drug in the treatment of septic shock, acute respiratory

activity.

distress syndrome, pancreatitis, trauma, bronchial

In this paper, we describe the synthesis and evalua-

asthma, allergic rhinitis, rheumatoid arthritis, gout, and

tion of sPLA2 inhibitory activity of four types of indoli-

other diseases.

zine derivatives, I-IV, and the indene derivative de-

Various PLA2 inhibitors have been described by many

picted in Figure 1 (also see Table 1). These derivatives

research groups.⁵Researchers at Lilly have recently

have not only a (carbamoylmethyl) group or an oxamoyl

found a highly potent sPLA2 inhibitor⁶having a novel

group at the C-1 position but also a carboxylic acid to

co-ordinate with the Ca²⁺ion located in the hydrophilic

domain at the active site. Also chemical modification

of the hydrophobic part located in the hydrophobic

domain was carried out using SAR study to pursue the

effective substituents.

indole structure by using computer-aided drug design

and chemical modification of a lead compound, which

was discovered in the course of high-volume screening.

This information prompted us to study the structural

effects of the closely related indolizine and indene

compounds on sPLA2 activity. The indolizine nucleus

is similar to indole with a delocalized 10 π-electron

aromatic system. Owing to its electronic and stereo-

Syn th esis

(1) Syn th esis of Typ e I Com p ou n d (Sch em e 1).

The carbanion of 2-methyl-5-methoxypyridine⁷was

reacted with benzonitrile to produce 2.⁸The

^XAbstract published in Advance ACS Abstracts, August 15, 1996.

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3637

Ta ble 1. Substituents of Indolizine and Indene Derivatives

compd

11-15

a

b

c

d

R₂

R₃

compd

R₂

R₃

Et

Ph

e

f

g

cycloPr

Et

o-Ph-C₆H₄

Ph

1-Naphthyl

o-Ph-C₆H₄

m-Cl-C₆H₄

Et

18-20, 25-28, 31, 32

i

ii

Et

Ph

xxii

Et

Me

cycloPr

Et

Me

cycloPr

Me

cycloPr

iPr

tBu

trans-4-(m-n-pentyl)cyclohexyl

1-adamantyl

o-Ph-C₆H₄

Ph

Et

o-Ph-C₆H₄

m-Cl-C₆H₄

m-CF₃-C₆H₄

1-naphthyl

o-Ph-C₆H₄

Ph

p-Ph-C₆H₄

cyclohexyl

cyclopentyl

cycloheptyl

n-Bu

pent-4-yl

2-naphthyl

3,5-(t-Bu)₂-C₆H₃

Bn

o-Bn-C₆H₄

2-thienyl

xxiii

xxiv

xxv

xxvi

xxvii

xxviii

xxix

xxx

xxxi

xxxii

xxxiii

xxxiv

xxxv

xxxvi

xxxvii

xxxviii

xxxix

xl

iii

Et

iv

Et

v

Et

p-n-Bu-C₆H₄

cyclohexyl

cyclopentyl

cyclohexyl

o-Ph-C₆H₄

m-Ph-C₆H₄

cinnamyl

phenethyl

1-naphthyl

o-Ph-C₆H₄

Ph

vi

cycloPr

Me

Et

vii

viii

ix

Et

x

Et

xi

Et

xii

xiii

xiv

xv

xvi

xvii

xviii

xix

xx

xxi

38-43

a

Et

cyclopentyl

Et

cycloPr

OMe

SMe

Me

3-(thienyl-2-yl)thienyl-2-yl

m-MeO-C₆H₄

o-NO₂-C₆H₄

Et

xli

Me

cyclohexyl

Et

Ph

e

f

g

Et

o-Ph-C₆H₄

b

c

cycloPr

Et

o-Ph-C₆H₄

cyclohexyl

d

Et

61-65

a

Me

Et

Ph

f

Et

m-Cl-C₆H₄

o,m-Cl₂-C₆H₃

m-CF₃-C₆H₄

1-naphthyl

2-naphthyl

b

c

d

e

g

h

i

o-Ph-C₆H₄

o-Bn-C₆H₄

j

Sch em e 1^a

a

Reagents: (a) LDA, C₆H₅CN; (b) 1-bromo-2-butanone, NaHCO₃; (c) LiAlH₄; (d) (1) (COCl)₂, (2) NH₄OH; (e) BBr₃; (f) NaH,

Br(CH₂)₃COOEt; (g) LiOH.

Tschitschibabin reaction, that is, alkylation of the

nitrogen of 2 with 1-bromo-2-butanone to the N-alky-

lated intermediate, followed by cyclization with NaH-

CO₃gave 3.⁹Although indolizine is generally unstable

to air oxidation because of its electron-rich character,

electron-withdrawing groups on the indolizine nucleus

have the effect of making the compounds much less

susceptible to oxidation by air. The benzoyl group of 3

was reduced to the benzyl group with LiAlH₄to give

compound 4, which was very reactive to an electrophile

and was acylated with oxalyl chloride without any

catalyst. Sequential treatment with NH₄OH gave 5a

in excellent yield. Demethylation of 5a with BBr₃

yielded 5b, which was O-alkylated using NaH and ethyl

4-bromobutylate to form 6a .

(2) Syn th esis of Typ e II Com p ou n d (Sch em e 2).

Compound 7¹⁰was reduced by catalytic hydrogenation

until no starting material was detected to give a mixture

of compounds 8a and 8b. As ammonolysis of 8a gave

9b in poor yield, 8b was used instead to obtain 9a in

good yield. The hydroxy group of 9a was protected to

give 9b, and then cyclization by the Tschitschibabin

reaction was done with 1-bromo-2-butanone and chlo-

romethyl cyclopropyl ketone to obtain 10b accompanied

by 10c and 10d , respectively. Ester 8a was also cyclized

to furnish 10a . In order to modify the substituent at

3638 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

Sch em e 2^a,b

a

Reagents: (a) H₂, Pd-C: (b) NH₄OH; (c) BnCl, K₂CO₃; (d) XCH₂COR₂, NaHCO₃; (e) R₃COCl; (f) t-BuNH₂-BH₃, AlCl₃; (g) NaH,

BrCH₂COOR₈; (h) LiOH or H₂, Pd-C. ^bR₂and R₃of a -g: see Table 1.

the C-3 position of indolizine, 10 was acylated without

any catalyst with various hydrophobic acyl chloride:

o-phenylbenzoyl chloride, m-chlorobenzoyl chloride, ben-

zoyl chloride, and 1-naphthyl chloride. Selective reduc-

tion of the carbonyl group at the C-3 position of 11,

except for 10a , to methylene was carried out with

gave an N-alkylated pyridinium intermediate which was

cyclized to 24. Various kinds of hydrophobic acyl groups

were introduced at the C-3 position of indolizine by this

method. Ketone 19 was converted to the desired

compounds 28 by the same procedure from 20 or 28.

In order to shorten the synthetic steps, the processes

of protection and deprotection of the hydroxy group were

eliminated (Scheme 4). Hydroxypicoline 23a was O-

alkylated with methyl bromoacetate to produce 29,

which was cyclized by the same procedure cited above

to give 30. To also remove the step of reduction of the

carbonyl group at the C-3 position, 30 was treated with

various benzyl halides, which gave compounds alkylated

at the C-3 position, accompanied by 1,3-dialkylated

derivatives. The electrophilic substituent of the indoli-

zine nucleus has been established, and the most reactive

positions are the C-3 and C-1 positions, in that order,¹⁵

but the difference in reactivities seems to be small.

Alternatively, compound 31 was obtained by acylation

of 30, followed by selective reduction of the carbonyl

group with NaBH₄-AlCl₃. Although the method re-

quired reduction of the newly produced ketone, the yield

and procedure for purification of the product were

improved.

Chemical modification at the C-2 position was achieved

with a methoxy or a methylthio group (Scheme 5).

Treatment of 16b with excess methyl bromoacetate,

followed by cyclization with K₂CO₃, gave a hydroxy

compound that was difficult to isolate and was used

directly for the next O-methylation to furnish 17c.

Compound 17c was hydrolyzed and decarboxylated

thermally to give 24f, which was C-alkylated at the C-3

position with o-(iodomethyl)biphenyl and treated by a

procedure similar to that described above to yield

28xxxviii with a methoxy group at the C-2 position.

According to the procedure of Kakehi et al.,¹⁶2-ben-

zyloxypyridine 23a was converted to 33, which was also

11

t-BuNH₂-BH₃complex and AlCl₃to give 12, which

was converted to the desired type II compound 15 as

shown in Scheme 2 by deprotection of the benzyl group,

followed by alkylation at the C-8 position.

(3) Syn th esis of Typ e III Com p ou n d (Sch em es

3-5). Compound 16b, obtained by O-benzylation of

16a ¹²was N-alkylated with 1-bromo-2-butanone or

bromomethyl cyclopropyl ketone and cyclized by the

Tschitschibabin reaction to give 17. Although 17 has

an electron-withdrawing group at the indolizine nucleus,

the acylation was possible at the C-3 position in good

yield without any catalyst, and several acyl chloride

were used to vary the R₃group. Hydrolysis of 18

required a drastic condition, using KOH in DMSO at

140 °C. The carboxylic acid was thermally decarboxy-

lated to give 19, which was reduced with LiAlH₄to yield

20. Alternatively, 16b was treated with 3-bromo-4-

phenyl-2-butanone¹³21 under Tschitschibabin reaction

conditions to give 22, which was then converted to 20vii,

having a methyl group at the C-2 position, by the same

procedure cited above. Sequential treatment of 20 with

oxalyl chloride and NH₄OH formed 25, which was then

treated by the same procedure cited for the preparation

of 15 to give 28. The merit of this synthetic pathway

from 16 to 28 is that the compounds of each step, except

for 20, are stable to oxidation by air and can be treated

easily. Unfortunately, the starting material 16 is not

easily prepared by the reported method.¹²

We next tried using 3-hydroxypicoline¹⁴23a as a

starting material (Scheme 3). Heating the protected

compound 23b or 23c with 2-halo ketone compounds

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3639

Sch em e 3^a,b

a

Reagents: (a) NaH, BnCl; (b) XCH₂COR₈, NaHCO₃; (c) R₃COCl; (d) (1) KOH-DMSO; (2) 4; (e) LiAlH₄or NaBH₄-AlCl₃; (f) 16b, 4;

(g) BnBr, KOH, TBAB; (h) MeI, K₂CO₃; (i) (1) (COCl)₂, (2) NH₄OH (j) H₂, Pd-C or BBr₃; (k) BrCH₂COOMe, K₂CO₃, KI; (l) OH^-. ^bR₂and

R₃of i-xxix: see Table 1.

cyclized to give an ca. 10:1 mixture of 8- and 6-benzyloxy

derivatives 34a + 34b. Treatment of the mixture with

KOtBu eliminated ethyl acrylate¹⁶to form 35, the

isomers of which were separated from each other, and

the 6-benzyloxy derivative was then S-alkylated to give

35b. Hydrolysis of 35b with KOH in DMSO under

reflux for 8 h formed the dicarboxylic acid, which was

thermally decarboxylated to give 24g. Compound 24g

was treated with o-phenylbenzyl iodide as above to

furnish a C-3 alkylated compound with contamination

by a C-1 alkylated compound. Sequential treatment

with oxalyl chloride and then NH₄OH as above gave

25xxxix, which was separated from the C-1 alky-

lated derivative. Compound 25xxxix was converted to

28xxxix, having a methylthio group at the C-2 position

by the above-mentioned procedure.

(4) Syn th esis of Typ e IV Com p ou n d (Sch em e 6).

This type of compound was prepared by applying the

second method (Scheme 3) for the preparation of com-

pounds of type III to 4-methoxypicoline 36 to give 41

via several steps as shown in Scheme 6. O-Alkylation

of 41 was carried out with ω-bromoalkyl ester, Br(CH₂)_n-

COOEt (n ) 1, 3, and 4), to give 42a -f. In the case of

n ) 2, â-propiolactone¹⁷was used and 43g was obtained.

The oxamoyl group of 42 was selectively reduced with

t-BuNH₂-BH₃complex and AlCl₃to the (carbamoyl-

methyl) group to give 44a .

(5) Syn th esis of Am in o Der iva tives (Sch em e 7).

Aminopicoline 45a was converted to its N-Cbz derivative

45b, of which the anion was alkylated with methyl

bromoacetate to produce 46. Reaction of 46 with 21 or

3-bromo-4-cyclohexyl-2-butanone in the presence of

NaHCO₃furnished 32xl or 32xli, which was converted

to the desired compound 28 by treatment similar to that

described above. The oxamoyl group of 27xli was

selectively reduced as in the case of 42 to give 48a .

(6) Oth er Mod ifica tion s (Sch em e 8). Chemical

modification at the C-8 position was carried out. Com-

pound 26ii was O-alkylated with alkyl halide to give

basic compounds 49c-e and acidic compounds 49b and

49g, following by deprotection. The methylene chain

was also changed by addition of â-propiolactone as

above. Tetrazole derivative 50b was also prepared via

the cyano derivative 50a from 26iii.

After the reaction with (COCl)₂, 20i was treated with

methylamine or dimethylamine instead of NH₄OH to

3640 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

Sch em e 4^a,b

a

Reagents: (a) KOH, BrCH₂COOMe; (b) (1) XCH₂COR₂, (2) DBU; (c) R₃COCl; (d) NaBH₄, AlCl₃; (e) R₃CH₂X; (f) (1) (COCl)₂, (2) NH₄OH;

(g) OH^-. ^bR₂and R₃of ii, vi, xxiv, and xxx-xxxvii: see Table 1.

Sch em e 5^a,b

a

Reagents: (a) (1) BrCH₂COOMe, (2) K₂CO₃, (3) Me₂SO₄, K₂CO₃; (b) (1) KOH-DMSO, (2) 4; (c) (1) BrCH₂COOEt, NaH, (2) CS₂, (3)

CH₂dCHCOOEt; (d) BrCH₂COOEt, DBU; (e) KOtBu; (f) NaH, MeI; (g) o-Ph-Bnl; (h) (1) (COCl)₂, (2) NH₄OH; (i) H₂, Pd-C; (j) BrCH₂COOMe,

K₂CO₃, KI; (k) OH^-. ^bR₂and R₃of xxxviii and xxxix: see Table 1.

give mono- or dimethylglyoxylamide, which were then

converted to 51a or 51b via a synthetic procedure

similar to that cited in the Scheme 3.

and then debrominated using catalytic hydrogenolysis

to give 57c. Reaction of 57 with triethyl phosphono-

acetate produced 58a and/or 59b,c. Radical bromina-

tion of 59b,c gave 60, which on reduction catalytically

yielded 58b and 58c. Compound 58 was condensed with

benzaldehyde and its derivatives in the presence of

MeONa to give 61, which was converted to the amide

62 via the active ester. After demethylation of 62 with

BBr₃, the compound 63 formed was O-alkylated as

above to give 64, which was reduced by catalytic

hydrogenation to give 66 and 67.

(7) Syn th esis of In d en e Der iva tives (Sch em e 9).

To obtain 53, m- or p-anisaldehyde was treated with

propionic or butyric anhydride under the Perkin reac-

tion condition. Compound 53 was reduced by catalytic

hydrogenation to give 54. Acidic cyclization of 54

yielded 57. Alternatively, the position para to the

methoxy group of 54c was blocked by bromination to

give 55, which was cyclized to 56 by acidic treatment

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3641

Sch em e 6^a,b

a

Reagents: (a) (1) XCH₂COR₂, (2) DBU; (b) R₃COCl; (c) t-BuNH₂-AlCl₃; (d) (1) (COCl)₂, (2) NH₄OH; (e) BBr₃; (f) Br(CH₂)_nCOOEt,

NaH or propiolactone; (g) OH^-. ^bR₂and R₃of 38-43: see Table 1.

Sch em e 7^a,b

a

Reagents: (a) N-(benzyloxycarbonyl)succinimide; (b) NaH, BrCH₂COOMe; (c) 21 or 3-bromo-4-cyclohexyl-2-butanone, NaHCO₃; (d)

(1) (COCl)₂, (2) NH₄OH; (e) H₂, Pd-C; (f) OH^-; (g) (1) t-BuNH₂-BH₃, AlCl₃, (2) H₂, Pd-C. ^bR₂and R₃of xi and xli: see Table 1.

En zym e In h ibitor y Activity a n d Discu ssion

X-ray crystallography, which will be submitted for

publication in due course. However, as mentioned

above, these compounds were not stable to air oxidation.

The chromogenic screening assay procedure¹⁸using

a thiol substrate analogue was used to identify and

evaluate inhibitors of recombinant human sPLA2. IC₅₀

values of the prepared compounds are shown in Table

2. We also used a slightly modified phosphatidyl

choline/deoxycholate assay that had been developed for

the evaluation of patient samples of human sPLA2,^19,20

and IC₅₀values are shown in Table 2. As mentioned

above, for the structure-activity relationships study,

the indolizine derivatives were grouped into four cat-

egories according to their structure. Compound 6b of

type I did not exceed the micromolar order of inhibitory

activity. Compound 12d , bearing the hydroxyl group

at the C-8 position, also did not show potent activity.

But replacement of the substituent by methylene amide,

15b-g, at this position (type II) had a favorable effect

on the enzyme interaction. Crystals of human type II

PLA2 complexed with 15f were grown and analyzed by

Replacing the methylene amide by an oxamoyl group

(type III) made the derivative stable and also increased

the potency of PLA2 inhibition. Variation of the residue

at the C-2 position did not have a major influence on

the inhibitory activity. However, bulky substituents

such as t-Bu or cyclopentyl groups revealed an unfavor-

able influence on the ability to inhibit PLA2. The ethyl

group appeared to be best.

Efforts to optimize compounds of type III included

structural variation of the substituent at the C-3 posi-

tion. Chemical modification giving benzyl-type substit-

uents increased the potency in the following order,

depending on the position in the benzene ring: p- < m-

< o-position (28viii < 28xxxiv < 28ii), although the

difference was not statistically important. An electron-

withdrawing group, 28iv, seemed to be better than an

3642 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

Sch em e 8^a

activity in that order. Introduction of a methyl or a

dimethyl group seemed to disturb co-ordination of the

amide group with the calcium (51a and 51b).

We also examined whether the indolizine skeleton

could be replaced by an indene ring. Although indene

derivatives 65a -j having an exo-methylene group gen-

erally showed 10 times or more decreased potency,

compared with the corresponding indolizine derivatives

15b-g, 1-naphthyl derivative (65a ) showed an IC₅₀

value of 25 nM. Partially reduced compounds 67a and

67b showed further lower potency. The introduction of

an oxamoyl group to the indene ring was tried to

improve the activity but was fruitless. The skeleton

seems to need an electron-rich character for sPLA2

inhibition, in addition to the geometric 6-5 fused ring.

Su m m a r y

In this report, we have described the preparation of

indolizine and indene derivatives that are designed to

inhibit human nonpancreatic PLA2. 1-(Carbamoyl-

methyl)indolizine derivatives were potent inhibitors, but

were not stable to air oxidation. Introduction of an

oxamoyl group to the C-1 position made the derivative

stable and highly potent. By chemical modification at

the C-3 position with various hydrophobic substituents

and at the C-1 or C-8 position with hydrophilic substit-

uents, some compounds approached the stoichiometric

limit of the chromogenic assay.

a

Reagents: (a) R₈CH₂X, (b) (1) Me₃SnN₃, (2) HCl.

electron-donating group, 28xx, but compound 28xxi,

having a nitro group at the ortho-position, showed lower

potency. The electronic effect of the substituent is not

a major factor influencing the inhibitory activity. Other

benzyl-type compounds, such as 28v, 28xvii, and 28xxvi,

showed highly potent activity, and substituted benzyl

groups were potent except when the substituent was

very bulky (28xv). Elongation of the methylene de-

creased the activity, as demonstrated by 28xvi, 28xxxv,

and 28xxxvi. A 2-fold or greater decrease in potency

was observed in compounds with hydrophobic substit-

uents such as alkyl- (28xiii and 28xvi) and cycloalkyl-

(28ix, 28x and 28xxii) groups. Hydrophobic heteroaro-

matic substituents (27xviii and 28xix) helped retain

the activity.

Co-ordination of the substituents at the C-1 and the

C-7 or C-8 positions with the calcium ion is necessary

to produce the activity as pointed out by the Lilly

workers,⁶and chemical modification at the C-1 and the

C-8 positions of indolizine compounds of type III was

achieved. The inhibitory activity disappeared on chemi-

cal modification of the ether linkage at the C-8 position

to the amino function (28xl), probably due to a confor-

mational change caused by hydrogen bonding between

the NH group and the carbonyl group at the C-1

position. The activity was improved by reducing the

carbonyl group (28xli) but still the conformation did not

seem to be suitable for co-ordination with the calcium,

because of the hydrogen bonding of the amino group

with the amide group.

Exp er im en ta l Section

Gen er a l Meth od s. Melting points were not corrected. IR

spectra were recorded on a Nicolet 20SXB FT-IR spectrometer.

¹H NMR spectra were recorded on a Varian VXR-200 and VXR-

300 FT-NMR spectrometer with tetramethylsilane as internal

reference. Mass spectra were measured on a J EOL J MS-SX/

S102A or a HITACHI M-90 mass spectrometer. Column

chromatography was performed on Merck Kiesel gel 60 with

a medium pressure unless otherwise noted. Drying of an

organic phase over anhydrous Na₂SO₄is simply indicated by

the word “dried”. Solvents were removed by evaporation under

reduced pressure unless otherwise noted.

5-Meth oxy-2-p h en a cylp yr id in e (2). A solution of n-BuLi

in hexane (1.6 M, 11.4 mL, 18.2 mmol) was added dropwise to

a solution of diisopropylamine (1.81 g, 17.9 mmol) in THF (50

mL) at -60 to -70 °C under N₂. The mixture was stirred for

10 min. A solution of 5-methoxy-2-methylpyridine⁷(2.20 g,

17.9 mmol) in THF (4 mL) was added dropwise. The mixture

was stirred for 10 min. A solution of benzonitrile (1.84 g, 17.9

mmol) in THF (8 mL) was added dropwise at -70 °C. The

mixture was stirred at -78 °C for 1 h and at room temperature

for 2 h and poured to ice-cold aqueous NH₄Cl. The organic

phase was separated and the aqueous phase was extracted

with ether. The combined organic phases were extracted with

dilute HCl. The extracts were washed with ether, basified

with 10% aqueous NaOH, and extracted with ether. The

extracts were washed with water and dried. After removal of

the solvent, the residue was chromatographed by eluting with

hexane:AcOEt (3:2) and crystallized from benzene:hexane to

give 3, 2.32 g (57.0% yield). The NMR showed the product to

be a mixture of the keto and the enol tautomers: IR ν_max

1

(Nujol) 1685, 1630 cm^-1; H NMR (CDCl₃) δ 3.84-3.88 (3H,

m), 4.45 (2H, m), 7.0-7.3 (3H, m), 7.82 (1H, m), 8.07 (2H, m),

8.27 (1H, m). Anal. (C₁₄H₁₃NO₂) C, H, N.

1-Ben zoyl-2-eth yl-6-m eth oxyin d olizin e (3). A mixture

of the pyridine derivative 2 (2.146 g, 9.44 mmol), 1-bromo-2-

butanone (2.14 g, 14.2 mmol), and NaHCO₃(1.60 g, 19 mmol)

in acetone (50 mL) was heated under reflux for 20 h. The

insoluble materials were removed off by filtration. The filtrate

was concentrated. The residue was recrystallized from ben-

zene:hexane to give 3: 2.39 g (90.7% yield); mp 138-139 °C;

IR ν_max(Nujol) 1600, 1592, 1505 cm^-1; ¹H NMR (CDCl₃) δ 1.19

The tetrazole group provided an additional ligand for

the calcium, as shown in 49b and 50b. Pyridine and

quinoline rings still may co-ordinate with the calcium

(49c, 49d , and 49e), while the compound with a phenyl

group (25ii) did not show activity at all. Methylenic

homologation with one and two carbon units at the

carboxylic acid function of the C-8 position lowered the

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3643

Sch em e 9^a,b

a

Reagents: (a) (R₂CO)₂O, R₂COONa; (b) H₂, Pd-C; (c) Br₂; (d) PPA; (e) H₂, Pd-C, AcONa; (f) PPA or TFA; (g) (EtO)₂POCH₂COOEt,

b

NaH; (h) NBS, BPO; (i) H₂, PtO₂; (j) RCHO, MeONa; (k) (1) BPO, (2) NH₄OH; (l) BBr₃; (m) NaH, Br(CH₂)_nCOOEt; (n) NaOH. R₂and R₃

of 61-65: see Table 1.

(3H, t, J ) 7.5 Hz), 2.72 (2H, q, J ) 7.4 Hz), 3.80 (3H, s), 6.69

(1H, dd, J ) 2.0, 9.8 Hz), 7.10 (1H, s), 7.26 (1H, d, J ) 9.6

Hz), 7.35-7.55 (4H, m), 7.67 (2H, m). Anal. (C₁₄H₁₄NO₂) C,

H, N.

benzene to give 5a : 1.27 g (73.6% yield); mp 159-160 °C; IR

1

ν_max(Nujol) 3342, 3166, 1664, 1571 cm^-1; H NMR (CDCl₃) δ

1.51 (3H, t, J ) 7.4 Hz), 2.90 (2H, q, J ) 7.4 Hz), 3.84 (3H, s),

4.07 (2H, s), 5.83 (1H, br s), 6.55 (1H, br s), 6.96 (1H, dd, J )

9.4, 2.4 Hz), 7.1-7.3 (6H, m), 9.59 (1H, d, J ) 2.4 Hz). Anal.

(C₂₀H₂₀N₂O₃) C, H, N.

1-Ben zyl-2-eth yl-6-m eth oxyin d olizin e (4). The benzoyl

derivative 3 (1.37 g, 4.90 mmol) was added in small portions

to a slurry of LiAlH₄(1.03 g, 27.1 mmol) in ether (100 mL)

with cooling in ice under N₂. The mixture was then heated

under reflux for 4.5 h. After cooling, the mixture was poured

into ice-cold 5% aqueous NaOH and extracted with ether. The

extracts were washed with water and dried. The solvent was

removed to give 1.23 g (94.5% yield). The oily residue was

used in the next preparation without further purification

(1-Be n zyl-2-e t h yl-6-h yd r oxyin d olizin -3-yl)glyoxyl-

a m id e (5b). A solution of BBr₃(976 mg, 3.89 mmol) in CH₂-

Cl₂(5 mL) was added to a solution of the methoxy compound

5a (437 mg, 1.30 mmol) in CH₂Cl₂(50 mL) at -20 °C. The

mixture was stirred at room temperature for 24 h and poured

to ice water. A small amount of MeOH was added. The

organic phase was separated and washed with water. After

removal of the solvent, The residue was crystallized from CH₂-

Cl₂: mp 219-220 °C (dec); IR ν_max(Nujol) 3388, 3261, 3193,

owing to its unstability: IR ν_max(film) 1642, 1550, 1218 cm^-1

;

¹H NMR (CDCl₃) δ 1.18 (3H, t, J ) 7.6 Hz), 2.57 (2H, q, J )

7.5 Hz), 3.75 (3H, s), 4.06 (2H, s), 6.38 (1H, dd, J ) 9.6, 2.2

Hz), 7.0-7.3 (7H, m), 7.39 (1H, d, J ) 2.2 Hz).

1

1678, 1530 cm^-1; H NMR (CDCl₃:CD₃OD) δ 1.14 (3H, t, J )

7.6 Hz), 2.85 (2H, q, J ) 7.8 Hz), 4.06 (2H, s), 7.01 (1H, dd, J

) 9.4, 2.4 Hz), 7.05-7.25 (6H, m), 9.64 (1H, d, J ) 2.4 Hz).

Anal. (C₁₉H₁₈N₂O₃‚0.9H₂O) C, H, N.

(1-Be n zyl-2-e t h yl-6-m e t h oxyin d olizin -3-yl)glyoxyl-

a m id e (5a ). A solution of the indolizine compound 4 (1.288

g, 4.85 mmol) in THF (25 mL) was added dropwise to a solution

of (COCl)₂(3.18 g, 25 mmol) in THF (5 mL) with cooling in

ice. The mixture was stirred at 0 °C for 1 h and added

dropwise to 28% NH₄OH (50 mL) with cooling in ice. The

mixture was stirred for 1 h at room temperature. Water was

added. The mixture was extracted with CH₂Cl₂. The extracts

were washed with water and dried. After removal of the

solvent, the residue was crystallized from ethyl acetate:

(1-Ben zyl-6-[(3-car beth oxypr opyl)oxy]-2-eth ylin dolizin -

3-yl)glyoxyla m id e (6a ). NaH (60%, 52 mg, 1.32 mmol) was

added to a solution of the alcohol 5b (213 mg, 0.661 mmol)

and ethyl 4-bromo-2-butylate (283 mg, 1.45 mmol) in DMF (5

mL) with cooling in ice under N₂. The mixture was stirred at

room temperature for 8.5 h, poured to ice water and extracted

with ethyl acetate. The extracts were washed with water and

dried. After removal of the solvent, the residue was chro-

3644 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

Ta ble 2. Inhibitory Activity against Human sPLA2 and

3-(3-Hyd r oxy-2-p yr id in yl)p r op a n a m id e (9a ). A solution

of the ester 8b (7.47 g) in 28% NH₄OH (50 mL) was allowed

to stand at room temperature overnight, and the volatile

materials were removed by distillation. The residue was

crystallized from EtOAc to give 9a : 6.49 g (94.7% yield); mp

Arachidonic Acid^a

IC₅₀(µM)

chromogenic PC/DOC

compd

6b

12d

15b

15c

15e

15f

15g

28i

27ii

28ii

28iii

28iv

28v

28vi

assay

compd

assay

1

130-134 °C; IR ν_max(Nujol) 3292, 3112, 1682, 1632 cm^-1; H

1.1

19

28xxxiii

28xxxiv

28xxxv

28xxxvi

28xxxvii

28xxxviii

28xxxix

28xl

28xli

43a

43b

43c

43d

43e

43f

43g

44

48b

49b

49c

49d

0.28

NMR (CDCl₃:CD₃OD) δ 2.71 (2H, t, J ) 6.9 Hz), 3.06 (2H, t, J

) 6.6 Hz), 7.09 (1H, dd, J ) 4.8, 8.1 Hz), 7.23 (1H, dd, J )

1.5, 7.8 Hz), 8.00 (1H, dd, J ) 1.2, 4.5 Hz). Anal. (C₈H₁₀N₂O₂)

C, H, N.

0.009

0.038

0.051

0.023

0.015

0.016

>50

0.2

4.4

0.14

3.4

1.4

1.3

0.24

0.08

22

0.007

0.046

0.083

0.055

0.08

0.044

0.03

>50

0.91

0.42

0.16

0.1

0.0042

0.08

0.014

0.015

0.013

0.03

0.014

0.052

0.026

0.028

0.135

0.005

0.2

0.013

3-(3-(Ben zyloxy)-2-p yr id in yl)p r opa n a m ide (9b). A mix-

ture of the hydroxy compound 9a (4.85 g, 29.2 mmol), benzyl

chloride (4.06 g, 32.1 mmol), and K₂CO₃(8.07 g, 58.4 mmol)

in methyl ethyl ketone (100 mL) was heated under reflux for

9 h. The insoluble materials were removed by filtration. The

filtrate was concentrated. The residue was dissolved in CH₂-

Cl₂. The solution was washed with water and dried. After

removal of the solvent, the residue was crystallized from

benzene to give 9b: 5.10 g (68.2% yield); mp 126-127 °C; IR

0.008

0.017

0.006

0.009

0.005

0.009

0.008

0.018

0.021

0.019

0.023

0.062

0.017

6.6

0.003

0.024

0.006

0.003

0.013

0.03

28vii

28viii

28xi

28x

28xi

ν

_max(Nujol) 3412, 3270, 3090, 1665, 1614, 1283 cm^-1; ¹H NMR

(CDCl₃) δ 2.75 (2H, t, J ) 6.9 Hz), 3.23 (2H, t, J ) 7.5 Hz),

5.10 (2H, s), 5.34 (1H, br s), 6.54 (1H, br s), 7.10 (1H, dd, J )

4.2, 8.4 Hz), 7.16 (1H, dd, J ) 8.4, 1.5 Hz), 7.3-7.45 (5H, m),

8.10 (1H, dd, J ) 1.5, 4.5 Hz). Anal. (C₁₅H₁₆N₂O₂) C, H, N.

0.019

0.1

0.007

28xii

28xiii

28xiv

28xv

28xvi

28xvii

28xviii

28xix

28xx

28xxi

28xxii

28xxiii

28xxiv

28xxv

28xxvi

28xxvii

28xxviii

28xxix

28xxx

28xxxi

28xxxii

0.078

0.0073 49e

49g

E t h yl 2-(8-(Ben zyloxy)-2-et h ylin d olizin -1-yl)a cet a t e

(10a ). A mixture of the ester 8a (1.0 g, 3.51 mmol), 1-bromo-

2-butanone (0.79 g, 5.23 mmol), and NaHCO₃(0.70 g, 8.23

mmol) in methyl ethyl ketone (10 mL) was heated under reflux

for 20 h. The solid was filtered off. After removal of the

solvent of the filtrate, the residue was chromatographed by

eluting with hexane:AcOEt (5:1) to give 10a (283 mg, 23.9%

yield) as an oil: ¹H NMR (CDCl₃) δ 1.15 (3H, t, J ) 7.2 Hz),

1.25 (3H, t, J ) 7.5 Hz), 2.61 (2H, q, J ) 7.6 Hz), 3.97 (2H, s),

4.04 (2H, q, J ) 7.2 Hz), 5.11 (2H, s), 5.93 (1H, d, J ) 7.4 Hz),

6.23 (1H, t, J ) 7.0 Hz), 7.08 (1H, s), 7.3-7.5 (6H, m).

2-(8-(Ben zyloxy)-2-eth ylin d olizin -1-yl)a ceta m id e (10b)

a n d 2-(2-E t h yl-8-[(2-oxobu t yl)oxy]in d olizin -1-yl)a cet a -

m id e (10c). The residue was chromatographed by eluting

with hexane:EtOAc (1:2) and with EtOAc. The first fraction

was crystallized from benzene:hexane to give 10b: 2.32 g

(48.2% yield); mp 117-119 °C; IR ν_max(Nujol) 3384, 3188, 1655

cm^-1; ¹H NMR (CDCl₃) δ 1.25 (3H, t, J ) 7.5 Hz), 2.65 (2H, q,

J ) 7.4 Hz), 3.87 (2H, s), 5.15 (2H, s), 5.21 (1H, br s), 5.63

(1H, br s), 6.01 (1H, d, J ) 7.4 Hz), 6.29 (1H, t, J ) 7.1 Hz),

7.11 (1H, s), 7.3-7.5 (6H, m). Anal. (C₁₉H₂₀N₂O₂) C, H, N.

0.21

0.13

0.045

0.051

0.006

0.011

0.01

0.021

0.036

0.025

0.12

49h

0.0013 50b

0.013

0.011

0.03

0.12

0.02

51a

51b

65a

65b

65c

65d

0.42

0.13

0.008

0.046

0.011

0.01

0.029

0.014

0.043

0.035

0.1

0.0014 65e

0.4

0.2

0.049

0.005

0.015

0.088

0.022

0.16

65f

65g

65h

65i

65j

67a

67b

0.067

0.24

0.025

0.17

15

12

a

IC₅₀values are the means of at least two experiments.

matographed by eluting with hexane:EtOAc (1:2) and recrys-

tallized from benzene to give 6a : 162 mg (56.2% yield); mp

143-144 °C. Anal. (C₂₅H₂₈N₂O₅) C, H, N.

The second fraction was crystallized from AcOEt:hexane to

give 10c: 0.208 g (4.6% yield); mp 156-157 °C; IR ν_max(Nujol)

1

3390, 3167, 1717, 1682 cm^-1; H NMR (CDCl₃) δ 1.14 (3H, t,

(1-Ben zyl-6-[(3-ca r boxyp r op yl)oxy]-2-eth ylin d olizin -3-

yl)glyoxyla m id e (6b). A mixture of the ester 6a (125 mg,

0.286 mmol) in MeOH (1.2 mL) and 10% aqueous LiOH (1.2

mL) was stirred at room temperature for 3 h, acidified with

dilute HCl, and extracted with CH₂Cl₂. The extracts were

washed with water and dried. After removal of the solvent at

reduced pressure, the residue was chromatographed by eluting

with CHCl₃:MeOH (10:1) and recrystallized from EtOAc to give

6b: 58.4 mg (49.9% yield); mp 176-178 °C; IR ν_max(Nujol)

J ) 7.3 Hz), 1.28 (3H, t, J ) 7.6 Hz), 2.63 (2H, q, J ) 7.2 Hz),

2.72 (2H, q, J ) 7.6 Hz), 3.92 (2H, s), 4.69 (2H, s), 5.26 (1H, br

s), 5.80 (1H, d, J ) 7.2 Hz), 6.26 (1H, t, J ) 7.1 Hz), 6.28 (1H,

br s), 7.13 (1H, s), 7.51 (1H, d, J ) 6.8 Hz). Anal (C₁₆H₂₀

N₂O₃‚0.1AcOEt) C, H, N.

-

2-(8-(Be n zyloxy)-2-cyclop r op ylin d olizin -1-yl)a ce t a -

m id e (10d ): 30.8% yield; mp 128-131 °C; IR ν_max(Nujol) 3386,

3197, 1655 cm^-1; ¹H NMR (CDCl₃) δ 0.54 (1H, dd, J ) 4.2, 1.8

Hz), 0.55 (1H, dd, J ) 3.9, 2.1 Hz), 0.90 (1H, dd, J ) 1.5, 4.2

Hz), 0.93 (1H, dd, J ) 3.2, 2.1 Hz), 4.00 (2H, s), 5.15 (2H, s),

5.22 (1H, br s), 5.65 (1H, br s), 6.00 (1H, d, J ) 7.5 Hz), 6.27

(1H, t, J ) 6.9 Hz), 7.3-7.5 (6H, m). Anal. (C₁₉H₁₈N₂O₂

0.2C₆H₆‚0.1H₂O) C, H, N.

1

3391, 3203, 1722, 1663, 1569, 1263 cm^-1; H NMR (CDCl₃) δ

1.14 (3H, t, J ) 7.5 Hz), 2.13 (2H, m), 2.52 (2H, t, J ) 6.9 Hz),

2.87 (2H, q, J ) 7.8 Hz), 4.06 (2H, t, J ) 6.3 Hz), 7.00 (1H, dd,

J ) 9.3, 2.1 Hz), 7.05-7.3 (6H, m), 9.78 (1H, d, J ) 1.5 Hz).

Anal. (C₂₃H₂₄N₂O₅‚0.5H₂O) C, H, N.

3-(Su bstitu ted ben zoyl)in d olizin e (11). General proce-

dure: the indolizine derivative 10 (1 equiv) and substituted

benzoyl chloride (1.5 equiv) in benzene were heated under

reflux for 4 h and washed with aqueous NaHCO₃and dried.

After removal of the solvent, the residue was purified by

recrystallization or column chromatography.

Eth yl 2-(8-(Ben zyloxy)-2-eth yl-3-(o-p h en ylben zoyl)in -

d olizin -1-yl)a ceta te (11a ). Column chromatography (hexa-

ne:AcOEt (5:1)) yielded 73.2% of an amorphous solid: IR ν_max

(Nujol) 1736, 1589, 1545 cm^-1; ¹H NMR (CDCl₃) δ 0.80 (3H, t,

J ) 7.4 Hz), 1.08 (3H, t, J ) 7.2 Hz), 2.14 (2H, br s), 3.78 (2H,

s), 3.94 (2H, q, J ) 7.0 Hz), 5.10 (2H, s), 6.40 (1H, d, J ) 7.2

Hz), 6.59 (1H, t, J ) 7.3 Hz), 7.1-7.6 (14H, m), 9.32 (1H, d, J

) 6.6 Hz). Anal. (C₃₄H₃₁NO₄) C, H, N.

Eth yl 3-(3-(Ben zyloxy)-2-p yr id in yl)p r op a n oa te (8a ). A

mixture of (E)-ethyl 3-(3-(benzyloxy)-2-pyridinyl)propenoate¹⁰

(12.2 g, 43.0 mmol), and 10% Pd-C (0.5 g) in EtOAc (250 mL)

was stirred in an H₂atmosphere until no more starting

material remained. The catalyst was filtered and the filtrate

was concentrated. The residue was chromatographed by

eluting with hexane:AcOEt (2:1 and 1:2). The fraction with

the larger R_fvalue (6.0 g (48.8% yield)) was the title com-

pound: ¹H NMR (CDCl₃) δ 1.23 (3H, t, J ) 7.2 Hz), 2.80 (2H,

t, J ) 7.5 Hz), 3.22 (2H, t, J ) 8.1 Hz), 4.13 (2H, q, J ) 7.2

Hz), 5.10 (2H, s), 7.07 (1H, dd, J ) 4.5, 8.4 Hz), 7.13 (1H, dd,

J ) 1.5, 8.4 Hz), 7.3-7.5 (5H, m), 8.11 (1H, dd, J ) 1.5, 4.5

Hz). The fraction with the smaller R_fvalue (3.95 g, 47.0%

yield) was ethyl 3-(3-hydroxy-2-pyridinyl)propanoate (8b).¹⁰

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3645

2-(8-(Ben zyloxy)-2-eth yl-3-(o-p h en ylben zoyl)in d olizin -

1-yl)a ceta m id e (11b). Column chromatography (hexane:

AcOEt (1:2)) yielded 71.3% of an amorphous solid: ¹H NMR

(CDCl₃) δ 0.78 (3H, t, J ) 7.5 Hz), 2.05 (2H, br s), 3.65 (2H, br

s), 4.82 (1H, br s), 5.06 (1H, br s), 5.14 (2H, s), 6.42 (1H, d, J

) 7.5 Hz), 6.63 (1H, t, J ) 7.5 Hz), 6.95 (3H, m), 7.3-7.65

(11H, m), 9.14 (1H, d, J ) 6.9 Hz).

2-(3-Na p h t h yl-8-(b e n zyloxy)-2-e t h ylin d olizin -1-yl)-

a ceta m id e (12g): mp 166-169 °C (dec) (ether:hexane); 43.5%

yield. Anal. (C₃₀H₂₈N₂O₂) C, H, N.

8-Hyd r oxyin d olizin e Com p ou n d s (13). General proce-

dure: A mixture of the 8-(benzyloxy)indolizine derivative 12

and 10% Pd-C in EtOAc was stirred in hydrogen for 9h to 3

d.

2-(2-E t h yl-8-h yd r oxy-3-(o-p h en ylb en zyl)in d olizin -1-

2-(8-(Ben zyloxy)-3-(m -ch lor oben zoyl)-2-eth ylin d olizin -

1-yl)a ceta m id e (11c): mp 239-240 °C (dec) (benzene); 96.2%

1

yl)a ceta m id e (13b): amorphous solid; 59.6% yield; H NMR

1

yield; IR ν_max(Nujol) 3474, 3166, 1680, 1595 cm^-1; H NMR

(CDCl₃:CD₃OD) δ 1.10 (3H, t, J ) 7.5 Hz), 2.63 (2H, q, J ) 7.5

Hz), 3.89 (2H, s), 4.10 (2H, s), 5.84 (1H, d, J ) 7.2 Hz), 6.18

(1H, t, J ) 7.1 Hz), 6.67 (1H, d, J ) 7.6 Hz), 6.88 (1H, d, J )

6.8 Hz), 7.1-7.55 (8H, m).

(CDCl₃:CD₃OD) δ 0.90 (3H, t, J ) 7.6 Hz), 2.32 (2H, q, J ) 7.5

Hz), 3.84 (2H, s), 5.21 (2H, s), 6.54 (1H, d, J ) 7.8 Hz), 6.70

(1H, t, J ) 7.2 Hz), 7.35-7.6 (8H, m), 9.15 (1H, d, J ) 7.0 Hz).

2-(3-(m -Ch lor ob en zyl)-2-et h yl-8-h yd r oxyin d olizin -1-

yl)a ceta m id e (13c): amorphous solid; 58.3% yield.

2-(2-Cyclop r op yl-8-h yd r oxy-3-(o-p h en ylb en zyl)in d o-

lizin -1-yl)a ceta m id e (13e): amorphous solid; 55.8% yield.

2-(3-Be n zyl-8-h yd r oxy-2-e t h ylin d olizin -1-yl)a ce t a -

m id e (13f): mp 138-141 °C (ether:hexane); 45% yield. Anal.

(C₁₉H₂₀N₂O₂) C, H, N.

2-(3-Na p h t h yl-8-h yd r oxy-2-et h ylin d olizin -1-yl)a cet a -

m id e (13g): mp 138-142 °C (powder) (ether-hexane:AcOEt).

32% yield.

(In d olizin -8-yloxy)a ceta te Com p ou n d s (14 a n d 15).

General procedure: 60% NaH (1.5 equiv) was added in small

portions to a mixture of the 8-hydroxyindolizine compound 13

(1.0 equiv) and benzyl, ethyl, or methyl bromoacetate (3.0

equiv) in DMF. The mixture was stirred at room temperature

for 4-10 h. Dilute HCl was added. The mixture was extracted

with EtOAc. The extracts were washed with water and dried.

After removal of the solvent, the residue was purified by

chromatography or recrystallization.

2-(3-(m -Ch lor oben zoyl)-2-eth yl-8-[(2-oxobu tyl)oxy]in -

d olizin -1-yl)a ceta m id e (11d ): mp 191-192 °C (AcOEt:ben-

1

zene); 68.4% yield; IR ν_max(KBr) 1725, 1668, 1385 cm^-1; H

NMR (CDCl₃) δ 0.96 (3H, t, J ) 7.4 Hz), 1.18 (3H, t, J ) 7.2

Hz), 2.44 (2H, q, J ) 7.3 Hz), 2.61 (2H, q, J ) 7.4 Hz), 3.94

(2H, s), 4.81 (2H, s), 5.25 (1H, br s), 6.30 (1H, d, J ) 7.4 Hz),

6.49 (1H, br s), 6.65 (1H, t, J ) 7.3 Hz), 7.35-7.6 (3H, m),

7.64 (1H, m), 9.16 (1H, d, J ) 6.6 Hz). Anal. (C₂₂H₂₃

ClN₂O₄‚0.1C₆H₆) C, H, Cl, N.

-

2-(8-(Ben zyloxy)-2-cyclop r op yl-3-(o-p h en ylben zoyl)in -

dolizin -1-yl)acetam ide (11e). Column chromatography (hex-

ane:AcOEt (1:2)) yielded 56.6% of an amorphous solid.

3-(Su bstitu ted ben zyl)in d olizin e (12). General proce-

dure: BH₃-t-BuNH₂complex (6 equiv) was added in small

portions to a mixture of pulverized AlCl₃(3 equiv) in CH₂Cl₂

with cooling in ice. After stirring for 10 min, the mixture

became clear. A solution of the ketone 11 (1 equiv) in CH₂Cl₂

was added dropwise to the solution. The reddish orange

solution was stirred for 5 h. Dilute HCl was added dropwise.

The organic phase was separated, washed with aqueous

NaHCO₃and water successively, and dried. After removal of

the solvent, the residue was purified by chromatography or

recrystallization.

2-(8-[[(Ben zyloxyca r b on yl)m et h yl]oxy]-2-et h yl-3-(o-

p h en ylben zyl)in d olizin -1-yl)a ceta m id e (14b) a n d ca r -

boxylic a cid 15b: amorphous solid; 45.4% yield.

15b: mp 164-165 °C (AcOEt); 61.1% yield; IR ν_max(Nujol)

3410, 3228, 1732, 1666, 1603, 1265 cm^-^{1 1}H NMR (CDCl₃:

;

2-(8-(Ben zyloxy)-2-eth yl-3-(o-p h en ylben zoyl)in d olizin -

3-yl)eth a n ol (12a ). Column chromatography (hexane:AcOEt

(1:1)) gave viscous oil in 45.1% yield: ¹H NMR (CDCl₃) δ 1.09

(3H, t, J ) 7.6 Hz), 2.61 (2H, q, J ) 7.5 Hz), 3.16 (2H, t, J )

6.9 Hz), 3.73 (2H, q, J ) 6.3 Hz), 4.10 (2H, s), 5.11 (2H, s),

5.94 (1H, d, J ) 7.5 Hz), 6.16 (1H, t, J ) 7.2 Hz), 6.66 (1H, d,

J ) 7.8 Hz), 6.91 (1H, d, J ) 7.2 Hz), 7.1-7.6 (13H, m).

CD₃OD) δ 1.12 (3H, t, J ) 7.5 Hz), 2.69 (2H, q, J ) 7.5 Hz),

3.95 (2H, s), 4.11 (2H, s), 4.67 (2H, s), 5.86 (1H, d, J ) 7.2

Hz), 6.18 (2H, t, J ) 7.2 Hz) 6.67 (1H, d, J ) 7.5 Hz), 6.93

(1H, d, J ) 6.9 Hz), 7.12 (1H, m), 7.2-7.3 (2H, m), 7.3-7.5

(5H, m). Anal. (C₂₇H₂₆N₂O₄‚1.4H₂O) C, H, N.

2-(8-[[(Ben zyloxycar bon yl)m eth yl]oxy]-3-(m-ch lor oben -

zyl)-2-eth ylin d olizin -1-yl)a ceta m id e (14c) a n d ca r boxylic

a cid 15c: mp 157-158 °C (benzene); 38.8% yield.

2-(8-(Ben zyloxy)-2-eth yl-3-(o-p h en ylben zyl)in d olizin -

1-yl)a ceta m id e (12b): mp 134-136 °C (benzene:hexane);

15c: mp 216-219 °C (dec) (AcOEt); 57.5% yield; IR ν_max

(KBr) 3416, 3311, 1739, 1707, 1643, 1620, 1572, 1552, 1529,

1255 cm^-1; ¹H NMR (CDCl₃:CD₃OD) δ 1.16 (3H, t, J ) 7.5 Hz),

2.76 (2H, q, J ) 7.5 Hz), 3.98 (2H, s), 4.21 (2H, s), 4.70 (2H,

s), 5.92 (1H, d, J ) 7.5 Hz), 6.27 (1H, t, J ) 6.9 Hz), 6.89 (1H,

59.7% yield; IR ν_max(Nujol) 3451, 3171, 1677, 1526, 1259 cm^-1

;

¹H NMR (CDCl₃) δ 1.10 (3H, t J ) 7.5 Hz), 2.63 (2H, q, J )

7.8 Hz), 3.92 (2H, s), 4.11 (2H, s), 5.13 (2H, s), 5.20 (1H, br s),

5.65 (1H, br s), 5.99 (1H, d, J ) 7.5 Hz), 6.19 (1H, t, J ) 7.1

Hz), 6.67 (1H, d, J ) 7.5 Hz), 6.92 (1H, d, J ) 7.2 Hz), 7.13

(1H, dt, J ) 1.8, 7.2 Hz), 7.2-7.5 (12H, m). Anal. (C₃₂H₃₀N₂O₂)

C, H, N.

t, J ) 4.2 Hz), 7.04 (1H, s), 7.17 (3H, m). Anal. (C₂₁H₂₁

ClN₂O₄‚0.1H₂O) C, H, Cl, N.

-

2-(8-[(Ca r b om et h oxym et h yl)oxy]-2-cyclop r op yl-3-(o-

p h en ylben zyl)in d olizin -1-yl)a ceta m id e (14e) a n d ca r -

boxylic a cid 15e: amorphous solid; 43.8% yield.

2-(8-(Ben zyloxy)-3-(m -ch lor oben zyl)-2-eth ylin d olizin -

1-yl)a ceta m id e (12c): mp 167-168 °C (benzene:hexane);

15e: 65.5% yield; ¹H NMR (CDCl₃) δ 0.51 (2H, m), 0.89 (2H,

m), 1.76 (1H, m), 4.06 (2H, s), 4.22 (2H, s), 4.63 (2H, s), 5.82

(1H, d, J ) 7.5 Hz), 6.16 (1H, t, J ) 7.2 Hz), 6.56 (1H, d, J )

7.5 Hz), 6.88 (1H, d, J ) 7.2 Hz), 7.11 (1H, dt, J ) 7.5, 1.5

Hz), 7.26 (2H, m), 7.3-7.5 (5H, m).

1

69.7% yield; IR ν_max(Nujol) 3389, 3191, 1650, 1527 cm^-1; H

NMR (CDCl₃) δ 1.15 (3H, t J ) 7.6 Hz), 2.70 (2H, q, J ) 7.6

Hz), 3.94 (2H, s), 4.20 (2H, s) 5.16 (2H, s), 5.19 (1H, br s), 5.69

(1H, br s), 6.05 (1H, d, J ) 7.2 Hz), 6.27 (1H, t, J ) 7.1 Hz),

6.88 (1H, t, J ) 4.4 Hz), 7.05 (1H, s), 7.1-7.25 (3H, m), 7.3-

7.5 (5H, m). Anal (C₂₆H₂₅ClN₂O₂) C, H, Cl, N.

Met h yl

((3-b en zyl-1-(ca r b a m oylm et h yl)-2-et h ylin -

d olizin -8-yl)oxy)a ceta te (14f) a n d ca r boxylic a cid 15f: mp

2-(3-(m -Ch lor oben zyl)-2-eth yl-8-(2-h yd r oxybu tyloxy)-

in d olizin -1-yl)a ceta m id e (12d ): mp 131 °C (benzene:hex-

159-163 °C (ether:hexane); 42.2% yield. Anal. (C₂₂H₂₄

N₂O₄‚0.2H₂O) C, H, N.

-

ane); 73.0% yield; IR ν_max(Nujol) 3378, 3185, 1656, 1527 cm^-1

;

15f: mp 213-218 °C (dec) (ether:hexane); 79% yield; IR ν_max

¹H NMR (CDCl₃) δ 1.05 (3H, t J ) 7.5 Hz), 1.16 (3H, t, J ) 7.5

Hz), 1.64 (2H, m), 2.70 (2H, q, J ) 7.8 Hz), 3.8-4.05 (5H, m),

4.20 (2H, s), 5.55 (1H, br s), 5.68 (1H, br s), 5.93 (1H, d, J )

7.2 Hz), 6.30 (1H, t, J ) 7.2 Hz), 6.88 (1H, m), 7.04 (1H, s),

7.1-7.2 (3H, m). Anal. (C₂₃H₂₇ClN₂O₃) C, H, Cl, N.

1

(Nujol) 3418, 1735, 1718, 1638, 1618 cm^-1; H NMR (CDCl₃:

CD₃OD 7:1) δ 1.16 (3H, t, J ) 7.7 Hz), 2.77 (2H, q, J ) 7.7

Hz), 3.99 (2H, s), 4.24 (2H, s), 4.69 (2H, s), 5.89 (1H, d, J )

7.0 Hz), 6.23 (1H, t, J ) 7.0 Hz), 7.01-7.25 (6H, m). Anal.

(C₂₁H₂₂N₂O₄‚0.2H₂O) C, H, N.

2-(8-(Ben zyloxy)-2-cyclop r op yl-3-(o-p h en ylb en zyl)in -

d olizin -1-yl)a ceta m id e (12e): mp 208-210 °C (benzene);

37.9% yield. Anal. (C₃₃H₃₀N₂O₂) C, H, N.

2-(3-Ben zyl-8-(ben zyloxy)-2-eth ylin d olizin -1-yl)a ceta -

m id e (12f): mp 174-176 °C (ether:hexane); 77.3% yield. Anal.

(C₂₆H₂₆N₂O₂) C, H, N.

Met h yl ((3-n a p h t h yl-1-(ca r b a m oylm et h yl)-2-et h ylin -

d olizin -8-yl)oxy)a ceta te (14g) a n d ca r boxylic a cid 15g:

amorphous solid; 38% yield; IR ν_max(CHCl₃) 3498, 3384, 1754,

1

1671, 1596 cm^-1; H NMR (CDCl₃) δ 1.13 (3H, t, J ) 7.4 Hz),

2.77 (2H, q, J ) 7.4 Hz), 3.85 (3H, s), 4.04 (2H, s), 4.64 (2H,

s), 4.75 (2H, s), 5.37 (1H, br s), 5.84 (1H, d, J ) 7.2 Hz), 6.18

3646 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

(1H, t, J ) 7.2 Hz), 6.54 (1H + 1H, br s + d, J ) 7.2 Hz), 7.06

(1H, d, J ) 6.9 Hz), 7.19-7.27 (1H, m), 7.55-7.63 (2H, m),

7.71 (1H, d, J ) 7.8 Hz), 7.91 (1H, d, J ) 8.1 Hz), 8.24 (1H, d,

J ) 8.1 Hz).

stitu ted ben zoyl)in d olizin e (19). General procedure: To

a solution of the ester 18 (1.0 mmol) in DMSO (10 mL) was

added 50% aqueous KOH (3 mL). The mixture was heated at

140 °C for 2-24 h. After cooling, the mixture was acidified

with dilute HCl and extracted with EtOAc. The extracts were

washed with water and dried. After removal of the solvent,

the residue was purified by recrystallization to give the

carboxylic acid.

The acid in toluene was heated under reflux for 1 h and the

solvent was removed by distillation. The residue was purified

by recrystallization.

3-Ben zoyl-8-(ben zyloxy)-2-eth ylin dolizin e (19i): mp 92-

93 °C (AcOEt:hexane); IR ν_max(KBr) 2965, 1593, 1571, 1552,

1326, 1275, 1045 cm^-1; ¹H NMR (CDCl₃) δ 1.05 (3H, t, J ) 7.4

Hz), 2.42 (2H, q, J ) 7.4 Hz), 5.21 (2H, s), 6.47 (1H, d, J ) 7.4

Hz), 6.62-6.71 (2H, m), 7.25-7.52 (8H, m), 7.61-7.65 (2H,

m), 9.23 (1H, d, J ) 7.2 Hz); EIMS m/ z 355 [M⁺]. Anal.

(C₂₄H₂₁NO₂‚0.1H₂O) C, H, N.

8-(Ben zyloxy)-2-et h yl-3-(o-p h en ylb en zoyl)in d olizin e

(19ii): quantitative yield. Anal. (C₃₀H₂₅NO₂‚0.1H₂O) C, H,

N.

8-(Ben zyloxy)-3-(m -ch lor ob en zoyl)-2-et h ylin d olizin e

(19iii). mp 95.5-96.5 °C (ether:hexane); 87% yield. Anal.

(C₂₄H₂₀NO₂Cl) C, H, N, Cl.

8-(Ben zyloxy)-2-eth yl-3-(m -(tr iflu or om eth yl)ben zoyl)-

in d olizin e (19iv): mp 97-98 °C (ether:hexane); 84% yield.

Anal. (C₂₅H₂₀NO₂F₃) C, H, N, F.

8-(Ben zyloxy)-2-eth yl-3-(1-n a p h th oyl)in d olizin e (19v):

amorphous solid; 66.1% yield.

15g: mp 129-133 °C (hexane:AcOEt); 65% yield; IR ν_max

1

(Nujol) 3198, 1729, 1672, 1599, 1527 cm^-1; H NMR (CDCl₃:

CD₃OD 7:1) δ 1.12 (3H, t, J ) 7.6 Hz), 2.76 (2H, q, J ) 7.6

Hz), 4.03 (2H, s), 4.65 (2H, s), 4.73 (2H, s), 5.92 (1H, d, J )

7.6 Hz), 6.21 (1H, t, J ) 7.0 Hz), 6.54 (1H, d, J ) 6.8 Hz), 7.08

(1H, d, J ) 7.6 Hz), 7.23 (1H, t, J ) 7.0 Hz), 7.56-7.65 (2H,

m), 7.73 (1H, d, J ) 7.6 Hz), 7.92 (1H, d, J ) 7.4 Hz), 8.25

(1H, d, J ) 9.0 Hz).

Eth yl 3-Hyd r oxy-2-p yr id in ea ceta te (16b). NaH (60%,

2.69 g, 66.2 mmol) was added in small portions to a solution

of ethyl 3-hydroxy-2-pyridineacetate (16a ) (12.0 g, 66.2 mmol)¹²

in DMF (220 mL) at 0 °C. The mixture was stirred at 0 °C for

50 min. Benzyl chloride (8.4 mL, 72.8 mmol) was added

dropwise to the mixture, which was stirred overnight. EtOAc

was added. The mixture was washed with 5% aqueous

NaHCO₃and water and dried. After removal of the solvent,

the residue was chromatographed by eluting with AcOEt:

toluene (1:19 to 1:1) to give 16b (16.17 g, 90.0% yield) as an

1

oil: IR ν_max(film) 1736, 1446, 1278 cm^-1; H NMR (CDCl₃) δ

1.21 (3H, t, J ) 7.2 Hz), 3.93 (2H, s), 4.14 (2H, q, J ) 7.2 Hz),

5.10 (2H, s), 7.13-7.22 (2H, m), 7.32-7.43 (5H, m), 8.16 (1H,

dd, J ) 4.0, 3.0 Hz). Anal. (C₁₆H₁₇NO₃) C, H, N.

E t h yl 8-(Ben zyloxy)-2-et h ylin d olizin e-1-ca r b oxyla t e

(17a ). A mixture of pyridine derivative 16b (15.15 g, 55.8

mmol), NaHCO₃(23.45 g, 279 mmol), and 1-bromo-2-butanone

(11.4 mL, 113 mmol) in methyl ethyl ketone (250 mL) was

heated under reflux for 24 h, washed with water, and dried.

After removal of the solvent, The residue was chromato-

graphed by eluting with AcOEt:hexane (1:19 to 1:9) to give

17a (16.66 g, 92.0% yield) as an oil. Anal. (C₂₀H₂₁NO₃‚0.1H₂O)

C, H, N.

8-(Ben zyloxy)-2-cyclop r op yl-3-(o-p h en ylb en zoyl)in -

d olizin e (19vi): amorphous solid; 82% yield. Anal. (C₃₁H₂₅

-

NO₂0.1H₂O) C, H, N.

8-(Ben zyloxy)-3-(su bstitu ted m eth yl)-2-eth ylin d olizin e

(20). General procedure: (1) these compound were prepared

from 19, according to the procedure described for the prepara-

tion of 4 from 3.

Eth yl 8-(ben zyloxy)-2-cyclop r op ylin d olizin e-1-ca r box-

yla te (17b): oil; 78% yield; IR ν_max(film) 1693, 1525, 1304,

(2) A mixture of 19, NaBH₄(5 molar equiv), and pulverized

AlCl₃(3 molar equiv) in THF was heated under reflux for 45

min. Ice water was added. The mixture was extracted with

EtOAc. The extracts were washed with water and dried. After

removal of the solvent, the residue was purified by recrystal-

lization or column chromatography.

1

1227, 1094, 753 cm^-1; H NMR (CDCl₃) δ 0.55-0.62 (2H, m),

0.89-0.94 (2H, m), 1.16 (3H, t, J ) 7.2 Hz), 2.14-2.26 (1H,

m), 4.14 (2H, q, J ) 7.2 Hz), 5.16 (2H, s), 6.21 (1H, d, J ) 7.5

Hz), 6.43 (1H, t, J ) 7.2 Hz), 6.87 (1H, s), 7.28-7.42 (3H, m),

7.45-7.52 (3H, m). Anal. (C₂₁H₂₁NO₃‚0.1H₂O) C, H, N.

Eth yl 8-(Ben zyloxy)-2-eth yl-3-(su bstitu ted ben zoyl)-

in d olizin e-1-ca r boxyla te (18). General procedure: A mix-

ture of the indolizine 17 (1 equiv), substituted benzoyl chloride

(2.0 equiv), and Et₃N (5.0 equiv) was heated at 90 °C (bath

temperature) for 2-8h. EtOAc was added. The mixture was

washed with dilute HCl and water and dried. After removal

of the solvent, the residue was chromatographed by eluting

with AcOEt:hexane (1:2) and recrystallized.

3-Ben zyl-8-(ben zyloxy)-2-eth ylin d olizin e (20i): ¹H NMR

(CDCl₃) δ 1.28 (3H, t, J ) 7.4 Hz), 2.71 (2H, q, J ) 7.4 Hz),

4.22 (2H, s), 5.16 (2H, s), 5.99 (1H, d, J ) 7.4 Hz), 6.24 (1H,

dd, J ) 7.4, 7.4 Hz), 6.61 (1H, s), 7.02-7.51 (11H, m).

8-(Be n zyloxy)-2-e t h yl-3-(o-p h e n ylb e n zyl)in d olizin e

(20ii): quantitative yield; IR ν_max(CHCl₃) 1525, 1259 cm^-1

;

¹H NMR (CDCl₃) δ 1.25 (3H, t, J ) 7.5 Hz), 2.64 (2H, q, J )

7.5 Hz), 4.12 (2H, s), 5.15 (2H, s), 5.97 (1H, d, J ) 7.2 Hz),

6.20 (1H, t, J ) 7.1 Hz), 6.57 (1H, s), 6.69 (1H, d, J ) 7.4 Hz),

6.94 (1H, d, J ) 6.8 Hz), 7.06-7.55 (13H, m).

Eth yl 3-ben zoyl-8-(ben zyloxy)-2-eth ylin d olizin e-1-ca r -

boxyla te (18i): mp 124-125 °C (AcOEt:hexane); 79% yield;

IR ν_max(KBr) 2969, 1593, 1571, 1552, 1326, 1275, 1045 cm^-1

;

8-(Ben zyloxy)-3-(m -ch lor ob en zyl)-2-et h ylin d olizin e

¹H NMR (CDCl₃) δ 0.93 (3H, t, J ) 5.0 Hz), 1.12 (3H, t, J )

4.8 Hz), 2.43 (2H, q, J ) 5.0 Hz), 4.03 (2H, q, J ) 4.8 Hz), 5.18

(2H, s), 6.57 (1H, s, J ) 5.0 Hz), 6.72 (1H, dd, J ) 5.0 Hz),

7.3-7.6 (8H, m), 7.55-7.7 (2H, m), 8.99 (1H, d, J ) 4.8 Hz);

EIMS m/ z 427 [M⁺]. Anal. (C₂₇H₂₅NO₄‚0.1H₂O) C, H, N.

Eth yl 8-(ben zyloxy)-2-eth yl-3-(o-ph en ylben zoyl)in doliz-

in e-1-ca r boxyla te (18ii): mp 110-112 °C (ether:hexane);

46.0% yield. Anal. (C₃₃H₂₉NO₄) C, H, N.

(20iii): quantitative yield; IR ν_max(CHCl₃) 1551, 1258 cm^-1

;

¹H NMR (CDCl₃) δ 1.29 (3H, t, J ) 7.5 Hz), 2.70 (2H, q, J )

7.5 Hz), 4.20 (2H, s), 5.18 (2H, s), 6.03 (1H, d, J ) 7.5 Hz),

6.28 (1H, t, J ) 7.1 Hz), 6.61 (1H, s), 6.88-6.93 (1H, m), 7.06

(1H, br s), 7.19-7.23 (3H, m), 7.29-7.53 (5H, m).

8-(Ben zyloxy)-2-et h yl-3-(m -(t r iflu or om et h yl)b en zyl)-

in d olizin e (20iv): mp 73-75 °C (hexane); quantitative yield;

IR ν_max(Nujol) 1332, 1163, 1114 cm^-1; ¹H NMR (CDCl₃) δ 1.29

(3H, t, J ) 7.5 Hz), 2.71 (2H, q, J ) 7.5 Hz), 4.28 (2H, s), 5.18

(2H, s), 6.03 (1H, d, J ) 7.5 Hz), 6.29 (1H, t, J ) 7.2 Hz), 6.62

(1H, s), 7.09-7.18 (2H, m), 7.30-7.54 (8H, m).

8-(Ben zyloxy)-2-eth yl-3-(1-n a p h th ylm eth yl)in d olizin e-

1-ca r boxyla te (20v): mp 119-120 °C (hexane); 89.0% yield;

IR ν_max(Nujol) 1530, 1263, 735 cm^-1; ¹H NMR (CDCl₃) δ 1.26

(3H, t, J ) 7.5 Hz), 2.69 (2H, q, J ) 7.2 Hz), 4.65 (2H, s), 5.20

(2H, s), 6.03 (1H, d, J ) 7.2 Hz), 6.23 (1H, t, J ) 6.9 Hz), 6.59

(1H, d, J ) 6.9 Hz), 6.68 (1H, s), 7.10 (1H, d, J ) 6.9 Hz), 7.21

(1H, d, J ) 7.8 Hz), 7.3-7.65 (7H, m), 7.71 (1H, d, J ) 8.4

Hz), 7.91 (1H, d, J ) 8.1 Hz), 8.25 (1H, d, J ) 8.1 Hz). Anal.

(C₂₈H₂₅NO‚0.2H₂O) C, H, N.

E t h yl 8-(b en zyloxy)-3-(m -ch lor ob en zoyl)-2-et h ylin -

d olizin e-1-ca r boxyla te (18iii): mp 115.0-116.5 °C (ether:

hexane); 92% yield. Anal. (C₂₇H₂₄NO₄Cl) C, H, N, Cl.

E t h yl 8-(b en zyloxy)-2-et h yl-3-(m -(t r iflu or om et h yl)-

ben zoyl)in d olizin e-1-ca r boxyla te (18iv): mp 129.0-129.5

°C (ether:hexane); 82% yield. Anal. (C₂₈H₂₄NO₄F₃) C, H, N,

F.

Eth yl 8-(ben zyloxy)-2-eth yl-3-(1-n a p h th oyl)in d olizin e-

1-ca r boxyla te (18v): mp 169-170 °C (benzene:hexane);

59.3% yield. Anal. (C₃₁H₂₇NO₄) C, H, N.

Eth yl 8-(ben zyloxy)-2-cyclopr opyl-3-(o-ph en ylben zoyl)-

in d olizin e-1-ca r boxyla te (18vi): mp 143-145 °C (AcOEt:

hexane); 52% yield. Anal. (C₃₄H₂₉NO₄) C, H, N.

8-(Ben zyloxy)-2-eth yl-3-(su bstitu ted ben zoyl)in d oliz-

in e-1-ca r boxylic Acid a n d 8-(Ben zyloxy)-2-eth yl-3-(su b-

8-(Be n zyloxy)-2-cyclop r op yl-3-(o-p h e n ylb e n zyl)in -

d olizin e (20vi): 91% yield; IR ν_max(CHCl₃) 1527, 1448, 1259

1

cm^-1; H NMR (CDCl₃) δ 0.64-0.72 (2H, m), 0.83-0.93 (2H,

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3647

m), 1.85 (1H, tt, J ) 8.6 Hz, 5.0 Hz), 4.24 (2H, s), 5.13 (2H, s),

5.96 (1H, d, J ) 7.2 Hz), 6.19 (1H, t, J ) 7.2 Hz), 6.27 (1H, s),

6.80 (1H, d, J ) 7.5 Hz), 6.91 (1H, d, J ) 7.2 Hz), 7.14 (1H, td,

J ) 7.5 Hz, 2.1 Hz), 7.19-7.52 (12H, m).

8-(Ben zyloxy)-3-(cycloh ep t ylca r b on yl)-2-et h ylin d oli-

zin e (19xi): mp 85-86 °C (hexane); 74% yield. Anal. (C₂₅H₂₉

NO₂) C, H, N.

-

8-(Ben zyloxy)-2-eth yl-3-(2-oxopen tyl)in dolizin e (19xii):

mp 84 °C (hexane:EtOAc); 89% yield. Anal. (C₂₂H₂₅NO₂) C,

H, N.

8-(Ben zyloxy)-2-eth yl-3-(1-oxo-2-p r op ylp en tyl)in d oli-

zin e (19xiii): mp 137-138 °C (hexane:EtOAc); 25% yield.

8-(Ben zyloxy)-2-et h yl-3-(n a p h t h -2-ylca r b on yl)in d oli-

zin e (19xiv): amorphous solid; 70% yield. Anal. (C₂₈H₂₃NO₂)

C, H, N.

8-(Ben zyloxy)-3-(3,5-d i-ter t-b u t ylb en zoyl)-2-et h ylin -

d olizin e (19xv): mp 131 °C (hexane:EtOAc); 82% yield. Anal.

(C₃₂H₃₇NO₂) C, H, N.

8-(Ben zyloxy)-2-et h yl-3-(1-oxo-2-p h en ylet h yl)in d oli-

zin e (19xvi): mp 139-140 °C (hexane:EtOAc); 58% yield.

Anal. (C₂₅H₂₃NO₂) C, H, N.

E t h yl 3-b en zyl-8-(b en zyloxy)-2-m et h ylin d olizin e-1-

ca r boxyla te (22): A mixture of 3-bromo-4-phenyl-butan-2-

one¹³(1.3 equiv), ethyl pyridine-2-acetate (1.0 equiv), and

NaHCO₃(10 equiv) was heated at 165 °C for 1-4 h and

chromatographed by eluting with hexane:AcOEt (5-2:1): mp

117-118 °C (hexane); 47.4% yield; IR ν_max(Nujol) 1707, 1535,

1

1233 cm^-1; H NMR (CDCl₃) δ 1.15 (3H, t, J ) 7.5 Hz), 2.43

(3H, s), 4.13 (2H, q, J ) 7.2 Hz), 4.22 (2H, s), 5.16 (2H, s),

6.23 (1H, d, J ) 7.5 Hz), 6.39 (1H, t, J ) 6.6 Hz), 7.06 (2H,

m), 7.15-7.45 (7H, m), 7.48 (2H, m). Anal. (C₂₆H₂₅NO₃) C,

H, N.

3-Ben zyl-8-(ben zyloxy)-2-m eth ylin d olizin e-1-ca r boxy-

lic a cid : mp 132 °C (dec); 68.4% yield; IR ν_max(Nujol) 3295,

1

1670, 1535, 1259 cm^-1; H NMR (CDCl₃) δ 2.63 (3H, s), 4.25

3-(o-Ben zylb en zoyl)-8-(b en zyloxy)-2-et h ylin d olizin e

(19xvii): yellow oil; 58% yield. Anal. (C₃₁H₂₇NO₂‚0.5H₂O) C,

H, N.

(2H, s), 5.33 (2H, s), 6.51 (1H, d, J ) 0.8 Hz), 6.53 (1H, s),

7.0-7.1 (2H, m), 7.15-7.3 (2H, m), 7.35-7.50 (6H, m). Anal.

(C₂₄H₂₁NO₃) C, H, N.

8-(Ben zyloxy)-2-eth yl-3-th ien -2-ylin d olizin e (19xviii):

3-Ben zyl-8-(ben zyloxy)-2-m eth ylin dolizin e (20vii): quan-

titative yield; ¹H NMR (CDCl₃) δ 2.34 (3H, s), 4.22 (2H, s),

5.17 (2H, s) 6.00 (1H, d, J ) 7.6 Hz), 6.25 (1H, t, J ) 7.1 Hz),

6.56 (1H, s), 7.0-7.5 (11H, m).

mp 141-142 °C (hexane:EtOAc); 82% yield. Anal. (C₂₂H₁₉

NO₂S) C, H, N, S.

-

8-(B e n zylox y)-2-e t h yl-3-(3-t h ie n -2-y lt h ie n -2-y l)in -

d olizin e (19xix). 3-(Thiophene-2-yl)thiophene-2-carboxylic

acid was prepared by hydrolysis of the methyl ester:²¹mp 137-

3-(Ben zyloxy)-2-m eth ylp yr id in e (23b). A mixture of

2-methyl-3-pyridinol 23a ¹⁴(16.4 g, 0.15 mol), pulverized KOH

(12.72 g, 0.195 mol), tetrabutylammonium bromide (2.42 g, 7.5

mmol), and benzyl bromide (18.7 mL, 0.158 mol) in THF (380

mL) was stirred at room temperature for 1.5 h. Water was

added. The mixture was concentrated and then extracted with

EtOAc. The extracts were washed with water and dried. After

removal of the solvent, 28.3 g (90% yield) of the title compound

was obtained: ¹H NMR (CDCl₃) δ 2.56 (3H, s), 5.11 (2H, s),

7.04-7.16 (2H, m), 7.35-7.45 (5H, m), 8.08 (1H, dd, J ) 4.5,

1.5 Hz).

1

138 °C (hexane:EtOAc); H NMR (CDCl₃) δ 7.10 (1H, dd, J )

3.6, 5.0 Hz), 7.26 (1H, d, J ) 5.0 Hz), 7.39 (1H, dd, J ) 1.0,

5.0 Hz), 7.55-7.60 (2H, m); IR ν_max(KBr) 2845, 2606, 1671,

1273, 1245 cm^-1; The acid chloride was treated as above, but

the product could not be purified and used in the next

preparation without further purification.

8-(Be n zyloxy)-2-e t h yl-3-(m -m e t h oxyb e n zoyl)in d oli-

zin e (19xx): mp 64-67 °C; 77% yield. Anal. (C₂₅H₂₃NO₃) C,

H, N.

8-(Ben zyloxy)-2-eth ylin d olizin e (24a ). A mixture of 23b

(29.7 g, 0.149 mol) in EtOAc (17 mL) and 1-bromo-2-butanone

(22.5 g, 0.149 mol) was stirred at 70 °C for 0.5 h. EtOAc (23

mL) was added to the reaction mixture and the solid was

recrystallized from EtOAc to give the quaternary salt (47.04

g, 90.1%).

8-(Ben zyloxy)-2-eth yl-3-(1-oxo-2-(4-n -p en tylcycloh ex-

yl)eth yl)in d olizin e (19xxii): mp 64-65 °C (hexane); 41%

yield. Anal. (C₂₉H₃₇NO₂) C, H, N.

8-(Be n zyloxy)-2-m e t h y-3-(o-p h e n ylb e n zoyl)in d oli-

zin e (19xxiv): mp 114-116 °C; 66.9% yield.

8-(B e n zy lo x y )-3-b e n zo y l-2-c y c lo p r o p y lin d o lizin e

The quaternary salt (47.04 g, 0.134 mol) in benzene (150

mL) and DBU (44.2 mL, 0.295 mol) were refluxed for 0.75 h,

poured into ice water, and extracted with EtOAc. The extracts

were washed with water and dried. After removal of the

solvent, the title oily compound (46a ) (26.62 g, 79% yield) was

obtained: ¹H NMR (CDCl₃) δ 1.28 (3H, t, J ) 7.6 Hz), 2.70

(2H, q, J ) 7.6 Hz), 5.16 (2H, s), 5.99 (1H, d, J ) 7.5 Hz), 6.29

(1H, t, J ) 7.1 Hz), 6.48 (1H, s), 7.10-7.52 (7H, m).

8-(Ben zyloxy)-2-m eth ylin d olizin e (24b): 92% yield; oil;

¹H NMR (CDCl₃) δ 2.31 (3H, s), 5.16 (2H, s), 5.98 (1H, d, J )

7.6 Hz), 6.28 (1H, t, J ) 7.0 Hz), 6.44 (1H, s), 7.08 (1H, s),

7.34-7.55 (6H, m).

(19xxv): mp 144-146 °C; 81.4% yield. Anal. (C₂₅H₂₁

-

NO₂‚0.1H₂O) C, H, N.

3-(p -n -Bu t ylb e n zoyl)-2-e t h yl-8-m e t h oxyin d olizin e

(19xxvi): mp 90-91 °C (hexane); 72.8% yield. Anal. (C₂₂H₂₅

NO₂) C, H, N.

8-(Ben zyloxy)-2-m et h yl-3-(1-oxo-2-cycloh exylet h yl)-

lin d olizin e (19xxvii): mp 105-106 °C (hexane:EtOAc); 61%

yield. Anal. (C₂₃H₂₅NO₂) C, H, N.

8-(Be n zyloxy)-3-(cyclop e n t ylca r b on yl)-2-m e t h ylin -

dolizin e (19xxix): mp 93.5-94.5 °C; 24% yield. Anal. (C₂₂H₂₃

NO₂) C, H, N.

-

8-(Be n zyloxy)-2-e t h yl-3-(p -p h e n ylb e n zyl)in d olizin e

2-Cyclop r op yl-8-m eth oxyin d olizin e (24c): 72% yield; ¹H

NMR (CDCl₃) δ 0.60-0.68 (2H, m), 0.86-0.96 (2H, m), 1.83-

1.97 (1H, m), 3.89 (3H, s), 5.92 (1H, d, J ) 7.4 Hz), 6.25-6.34

(1H + 1H, m), 7.11 (1H, d, J ) 1.6 Hz), 7.47 (1H, d, J ) 7.0

Hz).

1

(20viii): quantitative yield; H NMR (CDCl₃) δ 1.26 (3H, t, J

) 7.2 Hz), 2.74 (2H, q, J ) 7.8 Hz), 4.28 (2H, s), 5.18 (2H, s),

6.02 (1H, d, J ) 7.2 Hz), 6.28 (1H, t, J ) 7.2 Hz), 7.11 (1H, d,

J ) 8.4 Hz), 7.23-7.71 (14H, m).

8-(Be n zyloxy)-3-(cyclop e n t ylm e t h yl)-2-e t h ylin d oli-

zin e (20x): ¹H NMR (CDCl₃) δ 1.15-1.34 (5H, m), 1.41-1.74

(6H, m), 2.18 (1H, quint, J ) 7.8 Hz), 2.65 (2H, q, J ) 7.4 Hz),

2.82 (2H, d, J ) 7.2 Hz), 5.17 (2H, s), 5.98 (1H, d, J ) 7.0 Hz),

6.34 (1H, dd, J ) 7.0, 7.4 Hz), 6.53 (1H, s), 7.3-7.5 (6H, m).

8-(Ben zyloxy)-2-eth yl-3-p en tylin d olizin e (20xii): IR ν_max

8-(Ben zyloxy)-2-cyclop r op ylin d olizin e (24d ): 69% yield;

¹H NMR (CDCl₃) δ 0.61-0.69 (2H, m), 0.86-0.96 (2H, m),

1.84-1.97 (1H, m), 5.15 (2H, s), 5.98 (1H, d, J ) 7.6 Hz), 6.25-

6.32 (1H + 1H, m), 7.12 (1H, d, J ) 2.0 Hz), 7.35-7.49 (6H,

m).

8-(Ben zyloxy)-2-et h yl-3-(su b st it u t ed ca r b on yl)in d o-

lizin e (19). General procedure: This compound was prepared

from 24, according to the procedure described for the prepara-

tion of 11 from 10.

(KBr) 2950, 2920, 1550, 1520, 1365, 1250 cm^{-1 1}H NMR

;

(CDCl₃) δ 0.90 (3H, br s), 1.20-1.66 (9H, m), 2.61 (2H, q, J )

7.4 Hz), 2.84 (2H, t, J ) 7.8 Hz), 5.16 (2H, s), 6.06 (1H, d, J )

7.2 Hz), 6.38 (2H, m), 7.3-7.5 (6H, m).

8-(Be n zyloxy)-2-e t h yl-3-(2-p r op ylp e n t yl)in d olizin e

(20xiii): 25% yield; ¹H NMR (CDCl₃) δ 0.82-0.88 (6H, m),

1.16-1.49 (12H, m), 1.64-1.86 (1H, m), 2.57-2.74 (4H, m),

5.16 (2H, s), 5.98 (1H, d, J ) 7.4 Hz), 6.34 (1H, dd, J ) 7.2,

7.4 Hz), 6.53 (1H, s), 7.31-7.50 (6H, m).

8-(Ben zyloxy)-2-et h yl-3-(p -p h en ylb en zoyl)in d olizin e

(19viii): mp 114-115 °C; 80% yield.

8-(Ben zyloxy)-3-(cycloh exylca r b on yl)-2-et h ylin d oli-

zin e (19ix): mp 88-89 °C (hexane:EtOAc); 77% yield. Anal.

(C₂₄H₂₇NO₂‚0.1H₂O) C, H, N.

8-(Ben zyloxy)-3-(cyclop en t ylca r b on yl)-2-et h ylin d oli-

zin e (19x): mp 63-64 °C (hexane); 68% yield. Anal. (C₂₃H₂₅

NO₂‚0.1H₂O) C, H, N.

-

8-(Be n zyloxy)-2-e t h yl-3-(n a p h t h -2-ylm e t h yl)in d oli-

zin e (20xiv): ¹H NMR (CDCl₃) δ 1.31 (3H, t, J ) 7.4 Hz), 2.76

3648 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

(2H, q, J ) 7.4 Hz), 4.39 (2H, s), 5.17 (2H, s), 6.00 (1H, d, J )

7.4 Hz), 6.22 (1H, dd, J ) 7.0, 7.4 Hz), 6.64 (1H, s), 7.22-7.8

(13H, m).

2-(3-Ben zyl-8-(ben zyloxy)-2-m et h ylin d olizin -1-yl)gly-

oxyla m id e (25vii): mp 212-214 °C; 96.2% yield. Anal.

(C₂₅H₂₂N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-2-eth yl-3-(p-p h en ylben zyl)in d olizin e-

1-yl)glyoxyla m id e (25viii): mp 196-199 °C; 61% yield.

Anal. (C₃₂H₂₈N₂O₃‚0.2H₂O) C, H, N.

2-(8-(Ben zyloxy)-3-(cycloh exylm eth yl)-2-eth ylin dolizin -

1-yl)glyoxyla m id e (25ix): mp 176 °C (hexane:EtOAc); 85%

yield. Anal. (C₂₆H₃₀N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-3-(cyclopen tylm eth yl)-2-eth ylin dolizin -

1-yl)glyoxyla m id e (25x): mp 161-162 °C (hexane:AcOEt);

77% yield. Anal. (C₂₅H₂₈N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-3-(cycloh eptylm eth yl)-2-eth ylin dolizin -

1-yl)glyoxyla m id e (25xi): mp 144-145 °C (hexane); 76%

yield. Anal. (C₂₇H₃₂N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-2-et h yl-3-(oxop en t yl)in d olizin -1-yl)-

glyoxyla m id e (25xii): mp 141-142 °C (hexane:EtOAc); 77%

yield. Anal. (C₂₄H₂₈N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-2-eth yl-3-(2-p r op ylp en tyl)in d olizin -1-

yl)glyoxyla m id e (25xiii): mp 159-160 °C (hexane:EtOAc);

82% yield. Anal. (C₂₇H₃₄N₂O₃‚1.6H₂O) C, H, N.

2-(8-(Ben zyloxy)-2-eth yl-3-(n aph th -2-ylm eth yl)in dolizin -

1-yl)glyoxyla m id e (25xiv): mp 209-210 °C (EtOAc); 77%

yield. Anal. (C₃₀H₂₆N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-3-(3,5-d i-ter t-bu tylben zyl)-2-eth ylin -

d olizin -1-yl)glyoxyla m id e (25xv): mp 230-231 °C (EtOAc);

59% yield. Anal. (C₃₄H₄₀N₂O₃‚0.2H₂O) C, H, N.

2-(8-(Ben zyloxy)-2-eth yl-3-(2-p h en yleth yl)in d olizin -1-

yl)glyoxyla m id e (25xvi): mp 188-189 °C (EtOAc); 79% yield.

Anal. (C₂₇H₂₆N₂O₃‚0.3H₂O) C, H, N.

2-(8-(Ben zyloxy)-3-(o-ben zylben zyl)-2-eth ylin d olizin -1-

yl)glyoxyla m id e (25xvii): mp 178-179 °C (hexane:EtOAc);

93% yield. Anal. (C₃₃H₃₀N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-2-et h yl-3-(t h iop h en e-2-ylm et h yl)in -

dolizin -1-yl)glyoxylam ide (25xviii): mp 191-192 °C (EtOAc);

73% yield. Anal. (C₂₄H₂₂N₂O₃S) C, H, N, S.

2-(8-(Ben zyloxy)-2-eth yl-3-((3-th ioph en e-2-ylth ioph en e-

2-yl)m eth yl)in d olizin -1-yl)glyoxyla m id e (25xix): mp 208-

209 °C (EtOAc); 10% Yield (two steps).

2-(8-(Ben zyloxy)-2-et h yl-3-(m -m et h oxyb en zyl)in d oli-

zin e-1-yl)glyoxyla m id e (25xx): mp 180-182 °C; 61% yield.

Anal. (C₂₇H₂₆N₂O₄‚0.1H₂O) C, H, N.

2-(8-(Ben zyloxy)-2-eth yl-3-(o-n itr oben zyl)in d olizin e-1-

yl)glyoxyla m id e (25xxi): mp 205-208 °C; 8% yield. Anal.

(C₂₆H₂₃N₃O₅) C, H, N.

2-(8-(Be n zyloxy)-2-e t h yl-3-((4-n -p e n t ylcycloh e xyl)-

m eth yl)in d olizin -1-yl)glyoxyla m id e (25xxii): mp 169-170

°C (EtOAc); 80% yield. Anal. (C₃₁H₄₀N₂O₃‚0.4H₂O) C, H, N.

2-(3-(Ad a m a n t -1-yl)-8-(b en zyloxy)-2-et h ylin d olizin -1-

yl)glyoxyla m id e (25xxiii): mp 225-226 °C (EtOAc); 21%

Yield (three steps). Anal. (C₂₉H₃₂N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-3-(bip h en yl-2-ylm et h yl)-2-m et h ylin -

d olizin -1-yl)-glyoxyla m id e (25xxiv): mp 198-200 °C; 82.7%

yield. Anal. (C₃₁H₂₆N₂O₃‚0.2H₂O) C, H, N.

8-(Be n zyloxy)-3-(o-b e n zylb e n zyl)-2-e t h ylin d olizin e

(20xvii): 91% yield; IR ν_max(neat) 2922, 1523, 1371, 1312 cm^-1

;

¹H NMR (CDCl₃) δ 1.19 (3H, t, J ) 7.4 Hz), 2.54 (2H, q, J )

7.4 Hz), 4.07 (2H, s), 4.18 (2H, s), 5.16 (2H, s), 5.97 (1H, d, J

) 7.4 Hz), 6.13 (1H, dd, J ) 6.6, 7.4 Hz), 6.48 (1H, d, J ) 7.8

Hz), 6.58 (1H, s), 6.69 (1H, d, J ) 6.8 Hz) 6.98-7.51 (13H, m).

8-(Ben zyloxy)-2-eth yl-3-((3-th iop h en e-2-ylth iop h en -2-

1

yl)m eth yl)in d olizin e (20xix): H NMR (CDCl₃) δ 1.22 (3H,

t, J ) 7.4 Hz), 2.63 (2H, q, J ) 7.4 Hz), 4.41 (2H, s), 5.06 (2H,

s), 5.92 (1H, d, J ) 7.0 Hz), 6.17 (1H, dd, J ) 7.0, 7.2 Hz),

6.51 (1H, s), 6.91-7.42 (11H, m).

8-(Be n zyloxy)-2-e t h yl-3-(m -m e t h oxyb e n zyl)in d oli-

zin e (20xx): quantitative yield; ¹H NMR (CDCl₃) δ 1.29 (3H,

t, J ) 7.5 Hz), 2.72 (2H, q, J ) 7.5 Hz), 3.72 (3H, s), 4.21 (2H,

s), 5.17 (2H, s), 6.01 (1H, d, J ) 7.2 Hz), 6.26 (1H, t, J ) 7.2

Hz), 6.58-6.75 (4H, m), 7.11-7.44 (5H, m), 7.46-7.63 (2H,

m).

8-(Ben zyloxy)-2-et h yl-3-(4-n -p en t ylcycloh exyl)m et h -

ylin d olizin e (20xxii): ¹H NMR (CDCl₃) δ 0.70-1.80 (24H,

m), 2.57-2.71 (4H, m), 5.17 (2H, s), 5.98 (1H, d, J ) 7.4 Hz),

6.34 (1H, dd, J ) 7.0, 7.4 Hz), 6.53 (1H, s), 7.26-7.51 (6H, m).

8-(Be n zyloxy)-3-(b ip h e n yl-2-ylm e t h yl)-2-m e t h ylin -

d olizin e (20xxiv): mp 98-99 °C; quantitative yield; ¹H NMR

(CDCl₃) δ 2.26 (3H, s), 4.11 (2H, s), 5.15 (2H, s), 5.97 (1H, d,

J ) 6.9 Hz), 6.19 (1H, t, J ) 7.1 Hz), 6.52 (1H, s), 6.72 (1H, d,

J ) 6.9 Hz), 6.93 (1H, d, J ) 6.9 Hz), 7.10-7.16 (1H, m), 7.23-

7.54 (12H, m).

3-Ben zyl-8-(ben zyloxy)-2-cyclopr opylin dolizin e (20xxv):

1

94% yield; H NMR (CDCl₃) δ 0.67-0.75 (2H, m), 0.87-0.97

(2H, m), 1.86-2.00 (1H, m), 4.34 (2H, s), 5.14 (2H, s), 5.98 (1H,

d, J ) 7.4 Hz), 6.21-6.31 (1H + 1H, m), 7.09-7.49 (11H, m).

3-(p -n -B u t y lb e n zy l)-2-e t h y l-8-m e t h o x y in d o lizin e

(20xxvi): oil; 67.9% yield; ¹H NMR (CDCl₃) δ 0.90 (3H, t, J )

7.3 Hz), 1.28 (3H, t, J ) 7.5 Hz), 1.32 (2H, m), 1.55 (2H, m),

2.54 (2H, t, J ) 7.6 Hz), 2.71 (2H, m), 3.92 (3H, s), 4.19 (2H,

s), 5.90 (1H, d, J ) 7.2 Hz), 6.28 (1H, t, J ) 7.1 Hz), 6.94 (1H,

d, J ) 8.2 Hz), 7.04 (1H, d, J ) 8.0 Hz), 7.23 (1H, d, J ) 7.0

Hz).

8-(Be n zyloxy)-2-e t h yl-3-(cycloh e xylm e t h yl)in d oli-

zin e (20xxvii): ¹H NMR (CDCl₃) δ 1.00-1.26 (5H, m), 1.55-

2.25 (6H, m), 2.25 (3H, s), 2.68 (2H, d, J ) 6.9 Hz), 5.16 (2H,

s), 5.98 (1H, d, J ) 7.2 Hz), 6.34 (1H, dd, J ) 6.9, 7.2 Hz),

6.47 (1H, s), 7.30-7.49 (6H, m).

2-(8-(Ben zyloxy)-2-eth yl-3-(su bstitu ted m eth yl)in d oli-

zin -1-yl)glyoxyla m id e (25). These compounds were pre-

pared from 20, according to the procedure described for the

synthesis of 5a from 4.

2-(3-Be n zyl-8-(b e n zyloxy)-2-e t h ylin d olizin -1-yl)gly-

oxyla m id e (25i): mp 188-189 °C; 63% yield; IR ν_max(Nujol)

3425, 3203, 2968, 2929, 1693, 1621, 1313 cm^-^{1 1}H NMR

;

(CDCl₃) δ 1.22 (3H, t, J ) 7.4 Hz), 2.85 (2H, q, J ) 7.4 Hz),

4.24 (3H, s), 4.78 (1H, br s), 5.13 (1H, s), 6.16 (1H, br s), 6.38

(1H, d, J ) 7.0 Hz), 6.49 (1H, dd, J ) 6.6, 7.4, Hz), 7.04-7.14

(2H, m), 7.20-7.49 (9H, m). Anal. (C₂₆H₂₄N₂O₃‚0.2H₂O) C,

H, N.

2-(8-(Ben zyloxy)-2-eth yl-3-(o-p h en ylben zyl)in d olizin -

1-yl)glyoxyla m id e (25ii): mp 183-185 °C (ether:hexane);

79.0% yield. Anal. (C₃₂H₂₈N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-3-(m -ch lor oben zyl)-2-eth ylin d olizin -

1-yl)glyoxyla m id e (25iii). mp 145-148 °C (ether:hexane);

80% yield; LSIMS m/ z 446 [M]^+•, 447 [M + H]⁺, 893 [2M +

H]⁺.

(8-(Ben zyloxy)-2-eth yl-3-(m -(tr iflu or om eth yl)ben zyl)-

in d olizin -1-yl)glyoxyla m id e (25iv): mp 182-185 °C (CH₂-

Cl₂:hexane); 76% yield.

2-(3-Ben zyl-8-(ben zyloxy)-2-cyclop r op ylin d olizin -1-yl)-

glyoxyla m id e (25xxv): mp 206-207 °C; 30% yield. Anal.

(C₂₇H₂₄N₂O₃‚0.3H₂O) C, H, N.

2-(3-(p -n -Bu t ylb en zyl)-2-et h yl-8-m et h oxyin d olizin -1-

yl)glyoxyla m id e (25xxvi): mp 195-196 °C (benzene); 96.8%

yield. Anal. (C₂₄H₂₈N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-3-cycloh exyl-2-m eth ylin d olizin -1-yl)-

glyoxyla m id e (25xxvii): mp 222-223 °C (EtOAc); 88% yield.

Anal. (C₂₅H₁₈N₂O₃) C, H, N.

2-(8-(Ben zyloxy)-3-cyclop en tylm eth yl-2-cyclop r op ylin -

d olizin -1-yl)glyoxyla m id e (25xxviii). Compounds 19xxviii

and 20xxviii were prepared by the above procedure and used

in the next preparation without further purification: mp 186-

187 °C; 28% yield. Anal. (C₂₆H₂₈N₂O₃) C, H, N.

(8-(Ben zyloxy)-2-eth yl-3-(1-n a p h th ylm eth yl)in d olizin -

1-yl)glyoxyla m id e (25v): mp 189-190 °C (benzene); 76.0%

yield. Anal. (C₃₀H₂₆N₂O₃) C, H, N.

(8-(Be n zyloxy)-2-cyclop r op yl-3-(o-p h e n ylb e n zyl)in -

d olizin -1-yl)glyoxyla m id e (25vi): mp 185-186 °C (CH₂Cl₂:

hexane); quantitative yield. Anal. (C₃₃H₂₈N₂O₃0.3H₂O) C, H,

N.

2-(8-(Ben zyloxy)-3-(cyclop en t ylm et h yl)-2-m et h ylin -

d olizin -1-yl)glyoxyla m id e (25xxix): Compound 20xxix was

prepared by the general procedure 2 cited above and used in

the next preparation without further purification: mp 174-

175 °C; 66% yield. Anal. (C₂₄H₂₆N₂O₃) C, H, N.

2-(3-(Su bstitu ted m eth yl)-8-h yd r oxy-2-eth ylin d olizin -

1-yl)glyoxyla m id e (26). General procedure 1: These com-

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3649

pounds were prepared from 25, according to the procedure

described for the synthesis of 12 from 13.

2-(3-Ben zyl-2-cyclop r op yl-8-h yd r oxyin d olizin -1-yl)gly-

oxyla m id e (26xxv): mp 188-190 °C; 96.7% yield. Anal.

(C₂₀H₁₈N₂O₃‚0.5AcOEt) C, H, N.

General procedure 2: A 1 M solution of BBr₃in CH₂Cl₂(3.3

molar equiv) was added to a solution of 25 in CH₂Cl₂. The

mixture was stirred for 3 h to 1 d. Ice water was added. The

organic phase was washed with water and dried. After

removal of the solvent, the residue was purified by recrystal-

lization or column chromatography.

2-(3-(p -n -Bu t ylb en zyl)-2-et h yl-8-h yd r oxyin d olizin -1-

yl)glyoxyla m id e (26xxvi): mp 145-148 °C (benzene); 59.3%

yield. Anal. (C₂₃H₂₆N₂O₃‚0.1H₂O) C, H, N.

2-(3-(Cycloh exylm eth yl)-8-h yd r oxy-2-m eth ylin d olizin -

1

1-yl)glyoxyla m id e (26xxvii): H NMR (CDCl₃) δ 1.00-1.80

2-(3-Ben zyl-2-eth yl-8-h yd r oxyin d olizin -1-yl)glyoxyla -

m id e (26i): mp 194-195 °C (AcOEt); IR ν_max(KBr) 3469, 3308,

2969, 1688, 1567, 1317 cm^-1; ¹H NMR (CDCl₃:CD₃OD) δ 1.23

(3H, t, J ) 7.8 Hz), 2.90 (2H, q, J ) 7.8 Hz), 4.22 (2H, s), 6.71

(1H, d, J ) 7.4 Hz), 6.78 (1H, dd, J ) 6.6, 7.4 Hz), 7.02-7.09

(2H, m), 7.18-7.33 (4H, m). Anal. (C₁₉H₁₈N₂O₃0.1H₂O) C,

H, N.

2-(2-E t h yl-8-h yd r oxy-3-(o-p h en ylb en zyl)in d olizin -1-

yl)glyoxyla m id e (26ii): mp 195-196 °C (dec) (ether:hexane);

95.0% yield. Anal. (C₂₅H₂₂N₂O₃‚0.1H₂O) C, H, N.

2-(3-(m -Ch lor ob en zyl)-2-et h yl-8-h yd r oxyin d olizin -1-

yl)glyoxyla m id e (26iii): mp 144-146 °C (AcOEt:hexane);

88% yield; LSIMS m/ z 356 [M]^+•, 357 [M + H]⁺, 713 [2M +

H]⁺.

2-(2-E t h yl-8-h yd r oxy-3-(m -(t r iflu or om et h yl)b en zyl)-

in d olizin -1-yl)glyoxyla m id e (26iv): mp 142-146 °C (AcOEt:

hexane); 96% yield.

2-(2-Eth yl-8-h yd r oxy-3-(1-n a p h th ylm eth yl)in d olizin -1-

yl)glyoxyla m id e (26v): mp 176-178 °C (benzene); 84.5%

yield. Anal. (C₂₃H₂₀N₂O₃‚0.5C₆H₆) C, H, N.

2-(2-Cyclop r op yl-8-h yd r oxy-3-(o-p h e n ylb e n zyl)in -

d olizin -1-yl)glyoxyla m id e (26vi): mp 189-191 °C (AcOEt:

hexane); 95% yield. Anal. (C₂₆H₂₂N₂O₃‚0.2H₂O) C, H, N.

2-(3-Be n zyl-8-h yd r oxy-2-m e t h ylin d olizin -1-yl)gly-

oxyla m id e (26vii): mp 189-192 °C; 94.9% yield. Anal.

(C₁₈H₁₆N₂O₃) C, H, N.

2-(2-E t h yl-8-h yd r oxy-3-(o-p h en ylb en zyl)in d olizin e-1-

yl)glyoxylam ide (26viii): quantitative yield; ¹H NMR (CDCl₃)

δ 1.25 (3H, t, J ) 7.5 Hz), 2.93 (2H, q, J ) 7.5 Hz), 4.25 (2H,

s), 5.76 (1H, br s), 6.39 (1H, br s), 6.70 (1H, d, J ) 7.2 Hz),

6.79 (1H, t, J ) 7.1 Hz), 7.08-7.78 (10H, m), 12.90 (1H, s).

2-(3-(Cyclop en tylm eth yl)-2-eth yl-8-h yd r oxyin d olizin -

1-yl)glyoxyla m id e (26x): ¹H NMR (CDCl₃) δ 1.1-1.3 (6H,

m), 1.46-1.76 (5H, m), 2.06-2.24 (1H, m), 2.78-2.91 (4H, m),

5.70 (1H, br s), 6.3 (1H, br s), 6.72 (1H, d, J ) 7.8 Hz), 6.91

(1H, dd, J ) 6.8, 7.8 Hz), 7.54 (1H, d, J ) 6.8 Hz), 12.93 (1H,

s).

2-(3-(Cycloh ep tylm eth yl)-2-eth yl-8-h yd r oxyin d olizin -

1-yl)glyoxyla m id e (26xi): ¹H NMR (CDCl₃) δ 1.13-1.9 (16H,

m), 2.67 (2H, d, J ) 7.4 Hz), 2.83 (2H, q, J ) 7.8 Hz), 5.70

(1H, br s), 6.30 (1H, br s), 6.72 (1H, d, J ) 7.5 Hz), 6.92 (1H,

dd, J ) 6.2, 7.8 Hz), 7.48 (1H, d, J ) 6.2 Hz), 12.94 (1H, s).

2-(2-Eth yl-8-h yd r oxy-3-oxop en tylin d olizin -1-yl)glyoxy-

la m id e (26xii). Anal. (C₁₇H₂₂N₂O₃) C, H, N.

2-(2,5-Di-ter t-bu tylben zyl)-8-h yd r oxy-2-eth ylin d olizin -

1-yl)glyoxyla m id e (26xv): ¹H NMR (CDCl₃) δ 1.18-1.80

(21H, m), 2.91 (2H, q, J ) 7.4 Hz), 4.20 (2H, s), 5.71 (1H, br

s), 6.31 (1H, br s), 6.70-6.88 (4H, m), 7.26-7.33 (2H, m), 12.90

(1H, s).

(11H, m), 2.33 (3H, s), 2.65 (2H, d, J ) 6.9 Hz), 5.7 (1H, br s),

6.24 (1H, br s), 6.71 (1H, d, J ) 7.8 Hz), 6.91 (1H, dd, J ) 6.3,

7.8 Hz), 7.46 (1H, d, J ) 6.3 Hz), 12.97 (1H, s).

2-(8-((Ca r b om e t h oxym e t h yl)oxy)-2-e t h yl-3-(su b st i-

tu ted m eth yl)in d olizin -1-yl)glyoxyla m id e (27). General

procedure: Compound 26 (1 mmol), methyl bromoacetate (1.1

mmol), K₂CO₃(3 mmol), KI (0.2 mmol), and DMF (3 mL) were

stirred for 5 h. Water was added. The mixture was extracted

with EtOAc. The extracts were washed with water and dried.

After removal of the solvent, the residue was purified by

recrystallization or column chromatography.

(8-((Ca r b oxym et h yl)oxy)in d olizin -1-yl)glyoxyla m id e

(28). General procedure: Aqueous KOH (1 N, 4 mL) was

added to a solution of the ester 27 (2 mmol) in MeOH (21 mL).

The solution was stirred at room temperature for 40 min,

washed with ether, acidified with 2 N HCl, and extracted with

EtOAc. The extracts were washed with water and dried. After

removal of the solvent, the residue was recrystallized.

(3-Ben zyl-8-((ca r beth oxym eth yl)oxy)-2-eth ylin d olizin -

1-yl)glyoxyla m id e (27i) a n d ca r boxylic a cid 28i: mp 191-

192 °C (AcOEt:hexane); 23% yield; IR ν_max(KBr) 3409, 3161,

1

2968, 1727, 1686, 1630, 1319, 1092 cm^-1; H NMR (CDCl₃) δ

1.20-1.32 (6H, m), 2.88 (2H, q, J ) 7.4 Hz), 4.18-4.29 (4H,

m), 4.72 (2H, s), 6.12 (1H, br s), 6.25 (1H, d, J ) 7.4 Hz), 6.49

(1H, dd, J ) 7.0, 7.4 Hz), 6.69 (1H, br s), 7.07-7.11 (2H, m),

7.20-7.35 (4H, m). Anal. (C₂₃H₂₄N₂O₅0.8H₂O) C, H, N.

28i: mp 244-245 °C (AcOEt:ether); 42% yield; IR ν_max(KBr)

3855, 2974, 2931, 1703, 1660, 1625, 1312, 1092 cm^-1; ¹H NMR

(CDCl₃:CD₃OD) δ 1.22 (3H, t, J ) 7.4 Hz), 2.90 (2H, q, J ) 7.4

Hz), 4.27 (2H, s), 4.73 (2H, s), 6.37 (1H, d, J ) 7.8 Hz), 6.73

(1H, dd, J ) 6.6, 7.8 Hz), 7.06-7.43 (6H, m); EIMS m/ z 380

[M⁺]. Anal. (C₂₁H₂₀N₂O₅0.7H₂O) C, H, N.

(8-((Car beth oxym eth yl)oxy)-2-eth yl-3-(o-ph en ylben zyl)-

in d olizin -1-yl)glyoxyla m id e (27ii) a n d ca r boxylic a cid

28ii: mp 127-129 °C (ether:hexane); 86.0% yield. Anal.

(C₂₉H₂₈N₂O₅) C, H, N.

28ii: mp 209-212 °C (dec) (ether:hexane); 93% yield. Anal.

(C₂₇H₂₄N₂O₅‚0.3H₂O) C, H, N.

(8-((Ca r beth oxym eth yl)oxy)-3-(m -ch lor oben zyl)-2-eth -

ylin d olizin -1-yl)glyoxyla m id e (27iii): mp 172-175 °C (AcO-

Et:hexane); 73% yield; LSIMS m/ z 442 [M]^+•, 443 [M + H]⁺,

885 [2M + H]⁺.

28iii: mp 230-233 °C (dec) (ether:hexane); 79% yield;

LSIMS m/ z 414 [M]^+•, 415 [M + H]⁺, 829 [2M + H]⁺.

(8-((Ca r b om et h oxym et h yl)oxy)-2-et h yl-3-(m -(t r iflu o-

r om eth yl)ben zyl)in d olizin -1-yl)glyoxyla m id e (27iv) a n d

ca r boxylic a cid 28iv: mp 136-137 °C (AcOEt:hexane); 59%

yield. Anal. (C₂₃H₂₁N₂O₅F₃‚0.2H₂O) C, H, N, F.

28iv: mp 235-237 °C (dec) (CH₂Cl₂:hexane); 97% yield.

(8-Car beth oxym eth yloxy-2-eth yl-3-(1-n aph th ylm eth yl)-

in d olizin -1-yl)glyoxyla m id e (27v) a n d ca r b oxylic a cid

28v: 37.8% yield.

2-(2-E t h yl-8-h yd r oxy-3-t h ie n -2-ylin d olizin -1-yl)gly-

oxyla m id e (26xviii): mp 163-164 °C (hexane:EtOAc); 40%

yield; MS m/ z 328 [M]⁺.

2-(2-Eth yl-8-h ydr oxy-3-((3-th ien -2-ylth ien -2-yl)m eth yl)-

in d olizin -1-yl)glyoxyla m id e (26xix): ¹H NMR (CDCl₃:CD₃-

OD) δ 1.28 (3H, t, J ) 7.4 Hz), 2.91 (2H, q, J ) 7.4 Hz), 4.50

(2H, s), 6.72 (1H, d, J ) 7.8 Hz), 6.80 (1H, dd, J ) 6.2, 7.8

Hz), 7.10-7.43 (6H, m).

28v: 68.4% yield.

(8-((Ca r b om e t h oxym e t h yl)oxy)-2-cyclop r op yl-3-(o-

ph en ylben zyl)in dolizin -1-yl)glyoxylam ide (27vi) an d car -

boxylic a cid 28vi: mp 178-179 °C (AcOEt:hexane); 69%

yield. Anal. (C₂₉H₂₆N₂O₅‚0.2H₂O) C, H, N.

2-(2-Eth yl-8-h yd r oxy-3-(m -m eth oxyben zyl)in d olizin -1-

yl)glyoxyla m id e (26xx): mp 140-143 °C; 86% yield.

2-(2-Eth yl-8-h yd r oxy-3-(o-n itr oben zyl)in d olizin -1-yl)-

glyoxyla m id e (26xxi): mp 174-178 °C (dec); 85% yield.

Anal. (C₁₉H₁₇N₃O₅) C, H, N.

8-Hyd r oxy-2-eth yl-3-(4-n -p en tylcycloh exyl)in d olizin -

1-yl)glyoxyla m id e (26xxii): mp 99-100 °C (hexane:EtOAc).

Anal. (C₂₄H₃₄N₂O₃) C, H, N.

28vi: mp 205-207 °C (dec) (AcOEt:hexane); 93% yield.

Anal. (C₂₈H₂₄N₂O₅‚0.3H₂O) C, H, N.

(3-Ben zyl-8-((car beth oxym eth yl)oxy)-2-m eth ylin dolizin -

1-yl)glyoxyla m id e (27vii) a n d ca r boxylic a cid 28vii: mp

193-195 °C; 41.4% yield. Anal. (C₂₂H₂₂N₂O₅) C, H, N.

28vii: mp 245-246 °C (dec); 86.7% yield. Anal. (C₂₀H₁₈N₂O₅

0.2H₂O) C, H, N.

2-(2-Eth yl-8-((ca r bom eth oxym eth yl)oxy)-3-(o-p h en yl-

ben zyl)in d olizin -1-yl)glyoxyla m id e (27viii) a n d ca r boxy-

lic acid 28viii: mp 221-222 °C, 54% yield. Anal. (C₂₈H₂₆N₂O₅)

C, H, N.

2-(3-(Biph en yl-2-ylm eth yl)-8-h ydr oxy-2-m eth ylin dolizin -

1-yl)glyoxyla m id e (26xxiv): mp 129-130 °C; 77.6% yield.

Anal. (C₂₄H₂₀N₂O₃‚0.2H₂O) C, H, N.

3650 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

28viii: mp 229-234 °C (dec); 84% yield. Anal. (C₂₇H₂₄

N₂O₅‚0.1H₂O) C, H, N.

-

2-(8-((Ca r b om et h oxym et h yl)oxy)-2-et h yl-3-((4-n -p en -

tylcycloh exyl)m eth yl)in dolizin -1-yl)glyoxylam ide (27xxii)

a n d ca r boxylic a cid 28xxi: mp 175-176 °C (hexane:EtOAc),

92% yield (two steps). Anal. (C₂₇H₃₈N₂O₅) C, H, N.

28xxii: mp 224-225 °C (EtOAc); 59% yield (from Na salt).

Anal. (C₂₆H₃₆N₂O₅‚0.7H₂O) C, H, N.

2-(3-(Ad a m a n t -1-yl-8-((ca r b om et h oxym et h yl)oxy)-2-

m eth ylin d olizin -1-yl)glyoxyla m id e (27xxiii) a n d ca r box-

ylic a cid 28xxiii: mp 191-192 °C (EtOAc); 38% yield (two

steps); MS m/ z 438 [M]⁺.

2-(8-((Car bom eth oxym eth yl)oxy)-3-(cycloh exylm eth yl)-

2-eth ylin d olizin -1-yl)glyoxyla m id e (27ix) a n d ca r boxylic

a cid 28ix: mp 149-150 °C, (hexane:EtOAc); 19% yield from

25ix. Anal. (C₂₂H₂₈N₂O₅) C, H, N.

28ix: mp 224-225 °C (AcOEt); MS m/ z 386 [M]⁺.

2-(8-((Car bom eth oxym eth yl)oxy)-3-(cyclopen tylm eth yl)-

2-eth ylin d olizin -1-yl)glyoxyla m id e (27x) a n d ca r boxylic

a cid 28x: mp 158-159 °C (AcOEt); quantitative yield. Anal.

(C₂₁H₂₆N₂O₅) C, H, N.

28xxiii: mp 237-238 °C (EtOAc); 60% yield; MS m/ z 424

[M]⁺.

28x: 43% yield. Anal. (C₂₀H₂₄N₂O₅‚0.4H₂O) C, H, N.

2-(8-((Car bom eth oxym eth yl)oxy)-3-(cycloh eptylm eth yl)-

2-eth ylin d olizin -1-yl)glyoxyla m id e (27xi) a n d ca r boxylic

a cid 28xi: mp 147-148 °C (AcOEt); 79% yield. Anal.

(C₂₃H₃₀N₂O₅) C, H, N.

2-(3-Ben zyl-8-(ca r b om et h oxym et h yl)oxy-2-cyclop r o-

p ylin d olizin -1-yl)-glyoxyla m id e (27xxv) a n d ca r boxylic

a cid 28xxv: mp 186-188 °C; 74.5% yield; IR ν_max(CHCl₃)

3502, 3390, 1759, 1737, 1697, 1642 cm^-1

. Anal. (C₂₃H₂₂-

28xi: 76% yield. Anal. (C₂₂H₂₈N₂O₅) C, H, N.

N₂O₅‚0.1H₂O) C, H, N.

28xxv: mp 235-237 °C; 74.6% yield. Anal. (C₂₂H₂₀N₂O₅‚

0.2H₂O) C, H, N.

2-(3-(p-n -Bu tylben zyl)-8-((ca r bom eth oxym eth yl)oxy)-

2-eth ylin d olizin -1-yl)glyoxyla m id e (27xxvi) a n d ca r box-

ylic a cid 28xxvi: mp 174-176 °C (EtOAc:benzene); 70.9%

yield. Anal. (C₂₃H₂₆N₂O₃‚0.1H₂O) C, H, N.

28xxvi: mp 217-220 °C (EtOAc); 92.4% yield. Anal.

(C₂₃H₂₆N₂O₃‚0.1H₂O) C, H, N.

2-(8-(Ca r bom eth oxym eth yoxy-3-(cycloh exylm eth yl)-2-

m eth ylin d olizin -1-yl)glyoxyla m id e (27xxvii) a n d ca r -

boxylic a cid 28xxvii: mp 177-178 °C (hexane:EtOAc); 68%

yield (two steps). Anal. (C₂₁H₂₆N₂O₅‚0.6H₂O) C, H, N.

2-(8-((Ca r bom eth oxym eth yl)oxy)-2-eth yl-3-(oxop en tyl-

)in d olizin -1-yl)glyoxyla m id e (27xii) a n d ca r boxylic a cid

28xii: mp 140-141 °C (hexane:EtOAc); 36% yield. Anal.

(C₂₀H₂₆N₂O₅‚0.5H₂O) C, H, N.

28xii: mp 232-233 °C (acetone:AcOEt); 37% yield; MS m/ z

360 [M]⁺.

2-(8-((Ca r bom et h oxym et h yl)oxy)-2-et h yl-3-(2-p r op yl-

p en tyl)in d olizin -1-yl)glyoxyla m id e (27xiii) a n d ca r boxy-

lic a cid 28xiii: mp 114-115 °C (hexane:EtOAc); 84% yield.

Anal. (C₂₃H₃₂N₂O₅) C, H, N.

28xiii: mp 176-177 °C (hexane:AcOEt); 81% yield; MS m/ z

402 [M]⁺. Anal. (C₂₂H₃₀N₂O₅‚1.1H₂O) C, H, N.

2-(8-((Ca r bom eth oxym eth yl)oxy)-2-eth yl-3-(n a p h th -2-

ylm eth yl)in d olizin -1-yl)glyoxyla m id e (27xiv) a n d ca r -

boxylic a cid 28xiv: mp 195-196 °C (EtOAc); quantitative

yield. Anal. (C₂₆H₂₄N₂O₅‚0.3H₂O) C, H, N.

28xxvii: mp 235-236 °C (hexane:EtOAc). Anal. (C₂₀H₂₄

N₂O₅‚0.8H₂O) C, H, N.

-

2-(8-((Car bom eth oxym eth yl)oxy)-3-(cyclopen tylm eth yl)-

2-cyclop r op ylin d olizin -1-yl)glyoxyla m id e (27xxviii) a n d

ca r boxylic a cid 28xxviii. Compound 26xxviii was prepared

as cited above and used in the next preparation without

further purification: mp 175-176 °C, 70.4% yield. Anal.

(C₂₂H₂₆N₂O₅) C, H, N.

28xxviii: mp 237-238 °C, 20% yield. Anal. (C₂₁H₂₄N₂O₅)

C, H, N.

2-(8-((Car bom eth oxym eth yl)oxy)-3-(cyclopen tylm eth yl)-

2-m eth ylin d olizin -1-yl)glyoxyla m id e (27xxix) a n d ca r -

boxylic a cid 28xxix: mp 149-150 °C, 63% yield. Anal.

(C₂₀H₂₄N₂O₅) C, H, N.

28xiv: mp 236-237 °C (AcOEt); 33% yield. Anal. (C₂₅H₂₂

N₂O₅‚0.6H₂O) C, H, N.

-

2-(8-((Ca r boxym eth yl)oxy)-3-(3,5-d i-ter t-bu tyl)ben zyl)-

2-eth ylin d olizin -1-yl)glyoxyla m id e (27xv) a n d ca r boxylic

a cid 28xv: mp 186-187 °C (EtOAc); 83% Yield (two steps).

Anal. (C₃₀H₃₈N₂O₅‚0.2H₂O) C, H, N.

28xv: mp 144-145 °C (hexane:EtOAc); 43% yield; MS m/ z

492 [M]⁺. Anal. (C₂₉H₂₆N₂O₅‚1.7H₂O) C, H, N.

2-(8-((Ca r b om et h oxym et h yl)oxy-2-et h yl-3-(2-p h en yl-

eth yl)in d olizin -1-yl)glyoxyla m id e (27xvi) a n d ca r boxylic

a cid 28xvi: mp 175-176 °C (EtOAc); 47% Yield (two steps).

Anal. (C₂₃H₂₄N₂O₅‚0.1H₂O) C, H, N.

28xxix: mp 249-251 °C (dec), 85% yield. Anal. (C₁₉H₂₂N₂O₅)

C, H, N.

28xvi: mp 233-234 °C (EtOAc); 48% yield. Anal. (C₂₂H₂₂

N₂O₅) C, H, N.

-

3-((Ca r bom eth oxym eth yl)oxy)-2-m eth ylp yr id in e (29).

This compound was prepared from 3-hydroxy-2-methylpyridine

by the procedure cited for the preparation of 14 from 13. The

residue was chromatographed (25 g) in EtOAc:hexane (2:1) to

give an oil (791 mg, 60.1%): ¹H NMR (CDCl₃) δ 2.55 (3H, s),

3.81 (3H, s), 4.67 (2H, s), 6.97 (1H, dd, J ) 8.2 Hz), 7.09 (1H,

dd, J ) 8.2, 4.8 Hz), 8.14 (1H, dd, J ) 1.4, 4.6 Hz).

8-(Car bom eth oxym eth yl)oxy)-2-m eth ylin dolizin e (30a).

((2-Methylpyridin-3-yl)oxy)acetic acid methyl ester (29) (1.75

g, 9.66 mmol) and chloroacetone (0.77 mL, 9.66 mmol) were

heated at 95 °C under N₂for 2 h. DBU (3.2 mL, 21.3 mmol)

in benzene (11 mL) was added to the salt. The mixture was

then refluxed under N₂for 1 h, poured into ice water, and then

extracted with EtOAc. The extracts were washed with water

and dried. After removal of the solvents at reduced pressure,

the residue was recrystallized from ether:hexane to give 804

mg (40% yield) of the title compound: mp 59-62 °C; ¹H NMR

(CDCl₃) δ 2.30 (3H, s), 3.80 (3H, s), 4.72 (2H, s), 5.82 (1H, d,

J ) 7.5 Hz), 6.26 (1H, t, J ) 6.9 Hz), 6.46 (1H, s), 7.08 (1H, s),

7.51 (1H, d, J ) 6.6 Hz).

2-(3-o-Ben zylben zyl)-8-((ca r bom eth oxym eth yl)oxy)-2-

eth ylin d olizin -1-yl)glyoxyla m id e (27xvii) a n d ca r boxylic

a cid 28xvii: mp 190-191 °C (EtOAc); 65% Yield (two steps).

Anal. (C₂₉H₂₈N₂O₅‚0.5H₂O) C, H, N.

28xvii: mp 220-221 °C (EtOAc); 42% yield. Anal. (C₂₈H₂₆

N₂O₅) C, H, N.

2-(8-((Car bom eth oxym eth yl)oxy)-2-eth yl-3-th ien -2-ylin -

d olizin -1-yl)glyoxyla m id e (27xviii) a n d ca r boxylic a cid

28xviii: mp 182 °C (hexane:EtOAc); 75% yield. Anal.

(C₂₀H₂₀N₂O₅S‚0.2H₂O) C, H, N, S.

28xviii: mp 251-252 °C (EtOAc); 32% yield. Anal. (C₁₉H₁₈

N₂O₅S‚0.6H₂O) C, H, N, S.

2-(8-((Ca r bom eth oxym eth yl)oxy)-2-eth yl-3-((3-th ien -2-

ylth ien -2-yl)m eth yl)in d olizin -1-yl)glyoxyla m id e (27xix)

-

a n d ca r boxylic a cid 28xix: mp 176-177 °C. Anal. (C₂₄H₂₂

-

N₂O₅S₂‚0.2H₂O) C, H, N, S.

28xix: mp 209-210 °C; 54.5% yield. Anal. (C₂₃H₂₀N₂O₅S₂)

C, H, N, S.

2-(2-E t h yl-8-((ca r b om et h oxym et h yl)oxy)-3-(m -m et h -

oxyben zyl)in d olizin -1-yl)glyoxyla m id e (27xx) a n d ca r -

boxylic a cid 28xx: mp 155-157 °C; 85% yield. Anal.

(C₂₃H₂₄N₂O₆) C, H, N.

28xx: mp 219-221 °C (dec); 80% yield. Anal. (C₂₂H₂₂

N₂O₆‚0.8H₂O) C, H, N.

2-(2-Eth yl-8-((car bom eth oxym eth yl)oxy)-3-(o-n itr oben -

zyl)in d olizin -1-yl)glyoxyla m id e (27xxi) a n d ca r boxylic

a cid 28xxi: mp 156-157 °C; 96% yield.

28xxi: mp 208-210 °C (dec); 69% yield. Anal. (C₂₁H₁₉

N₃O₇‚0.3H₂O) C, H, N.

8-((Ca r bom eth oxym eth yl)oxy)-2-eth ylin d olizin e (30b):

oil; 601 mg (82.6% from 53); ¹H NMR (CDCl₃) δ 1.29 (3H, t, J

) 7.5 Hz), 2.70 (2H, q, J ) 7.8 Hz), 3.81 (3H, s), 4.74 (2H, s),

5.86 (1H, d, J ) 6.9 Hz), 6.30 (1H, t, J ) 7.1 Hz), 6.51 (1H, s),

7.11 (1H, s), 7.56 (1H, d, J ) 4.2 Hz).

-

((2-Isop r op ylin d olizin -8-yl)oxy)a cetic a cid m eth yl es-

1

ter (30c): oil, 59% yield; H NMR (CDCl₃) δ 1.30 (6H, d, J )

6.6 Hz), 3.02 (1H, sept, J ) 6.6 Hz), 3.81 (3H, s), 4.73 (2H, s),

5.82 (1H, d, J ) 7.4 Hz), 6.27 (1H, t, J ) 7.0 Hz), 6.53 (1H, s),

7.12 (1H, s), 7.53 (1H, d, J ) 7.0 Hz).

-

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3651

28xxx: mp 229-234 °C; 79% yield; IR ν_max(Nujol) 3434,

8-((Ca r b om et h oxym et h yl)oxy)-2-cyclop r op ylin d oli-

1

zin e (30d ): oil; 76% yield; H NMR (CDCl₃) δ 0.65 (2H, m),

3334, 1731, 1650(sh), 1620, 1593 cm^-^{1 1}H NMR (CDCl₃) δ

;

0.92 (2H, m), 1.90 (1H, m), 3.81 (3H, s), 4.71 (2H, s), 5.82 (1H,

d, J ) 7.4 Hz), 6.28 (1H, d, J ) 7.4 Hz), 6.28 (1H, t, J ) 7.2

Hz), 6.34 (1H, s), 7.13 (1H, d, J ) 1.4 Hz), 7.50 (1H, d, J ) 6.8

Hz).

0.41-0.46 (2H, m), 0.91-1.01 (2H, m), 1.08-1.79 (11H, m),

1.89-2.05 (1H, m), 2.85 (2H, d, J ) 6.6 Hz), 4.73 (2H, s), 6.38

(1H, d, J ) 7.4 Hz), 6.59 (1H, br s), 6.71 (1H, t, J ) 7.2 Hz),

7.00 (1H, br s), 7.59 (1H, d, J ) 7.0 Hz).

2-(3-(Bip h en yl-2-ylm eth yl)-8-((ca r bom eth oxym eth yl)-

oxy)-2-isop r op ylin d olizin -1-yl)glyoxyla m ide (27xxxi) a n d

ca r boxylic a cid 28xxxi: mp 124-130 °C; 48.6% yield. Anal.

(C₂₉H₂₈N₂O₅‚0.2H₂O) C, H, N.

28xxxi: mp 139-141 °C. 59% yield. Anal. (C₂₈H₂₆N₂O₅‚

1.3H₂O) C, H, N.

2-(2-t er t -Bu t yl-8-((ca r b om e t h oxym e t h yl)oxy)-3-(o-

p h en ylben zyl)in d olin -1-yl)glyoxyla m id e (27xxxii) a n d

ca r boxylic a cid 28xxxii: mp 206-207 °C (EtOAc); 77.6%

yield. Anal. (C₃₀H₃₀N₂O₅‚0.7H₂O) C, H, N.

2-ter t-Bu t yl-8-((ca r b om et h oxym et h yl)oxy)in d olizin e

1

(30e): oil; 48.0% yield; H NMR (CDCl₃) δ 1.34 (9H, s), 3.82

(3H, s), 4.73 (2H, s), 5.82 (1H, d, J ) 7.5 Hz), 6.27 (1H, t, J )

6.9 Hz), 6.27 (1H, t, J ) 6.9 Hz), 6.56 (1H, s), 7.13 (1H, s),

7.53 (1H, d, J ) 7.2 Hz).

8-((Ca r b om e t h oxym e t h yl)oxy)-2-cyclop e n t ylin d oli-

1

zin e (30f): oil; 14.3% yield; H NMR (CDCl₃) δ 1.6-2.2 (8H,

m), 3.11 (1H, m), 3.83 (3H, s), 4.74 (2H, s), 5.84 (1H, d, J )

7.4 Hz), 6.29 (1H, t, J ) 7.0 Hz), 6.53 (1H, s), 7.14 (1H, s),

7.34 (1H, d, J ) 7.2 Hz).

8-((Ca r bom eth oxym eth yl)oxy)-2-eth yl-3-(o-p h en ylben -

zoyl)in d olizin e (31b). This compound was prepared from

30b, according to the procedure cited for the preparation of

20 from 19: 83% yield; ¹H NMR (CDCl₃) δ 1.05 (3H, t, J ) 7.5

Hz), 2.07 (2H, q, J ) 7.5 Hz), 3.82 (3H, s), 4.74 (2H, s), 6.31

(1H, d, J ) 7.4 Hz), 6.49 (1H, d, J ) 0.6 Hz), 6.65 (1H, t, J )

7.4 Hz), 7.10-7.25 (3H, m), 7.30-7.40 (2H, m), 7.42-7.58 (5H,

m), 9.40 (1H, d, J ) 7.4 Hz).

8-((Car bom eth oxym eth yl)oxy)-3-(cycloh exylcar bon yl)-

2-cyclop r op ylin d olizin e (31c): mp 110-111.5 °C; 74% yield.

2-Alk yl-8-((ca r b om et h oxym et h yl)oxy)-3-(su b st it u t ed

m eth yl)in d olizin e (32). General procedure: A solution of

30 (1.30 mmol) and alkyl iodide (1.56 mmol) in benzene (5 mL)

was allowed to stand at room temperature for 2 d. EtOAc was

added. The mixture was washed with NaHCO₃and with

water, dried, and concentrated. The residue was chromato-

graphed in hexane:benzene (1:2).

8-((Ca r bom et h oxym et h yl)oxy)-3-(cycloh exylm et h yl)-

2-cyclop r op ylin d olizin e (32xxx): 42.8% yield; ¹H NMR

(CDCl₃) δ 0.64-0.69 (2H, m), 0.88-0.94 (2H, m), 1.04-1.17

(5H, m), 1.62-1.74 (6H, m), 1.80-1.89 (1H, m), 2.80 (2H, d, J

) 6.6 Hz), 3.81 (3H, s), 4.72 (2H, s), 5.81 (1H, d, J ) 6.9 Hz),

6.22 (1H, s), 6.33 (1H, t, J ) 7.1 Hz), 7.40 (1H, d, J ) 7.2 Hz).

8-((C a r b o m e t h o x y m e t h y l)o x y )-2-i s o p r o p y l-3-(o-

p h en ylben zyl)in d olizin e (32xxxi): mp 115-117 °C; 37%

yield. Anal. (C₂₇H₂₇NO₃‚0.3C₆H₆) C, H, N.

28xxxii: mp 221-222 °C (EtOAc); quantitative yield. Anal.

(C₂₉H₂₈N₂O₅‚0.6C₆H₆) C, H, N.

2-(8-((Ca r b om et h oxym et h yl)oxy)-2-cyclop en t yl-3-(o-

p h en ylben zyl)in d olin -1-yl)glyoxyla m id e (27xxxiii) a n d

ca r boxylic a cid 28xxxiii: mp 119-121 °C (benzene); 77.6%

yield. Anal. (C₃₀H₂₈N₂O₅‚0.7H₂O) C, H, N.

28xxxiii: mp 147-148 °C (EtOAc); 73.4% yield.

2-(8-((Ca r bom eth oxym eth yl)oxy)-2-eth yl-3-(m -p h en yl-

ben zyl)in d olin -1-yl)glyoxyla m id e (27xxxiv) a n d ca r box-

ylic a cid 28xxxiv: mp 204-205 °C (EtOAc); 11.5% yield. Anal.

(C₂₈H₂₆N₂O₅‚0.2H₂O) C, H, N.

28xxxiv: mp 241-244 °C (EtOAc); 73.5% yield.

2-(8-((Ca r bom eth oxym eth yl)oxy)-2-eth yl-3-(3-p h en yl-

2-p r op en yl)in d olin -1-yl)glyoxyla m id e (27xxxv) a n d ca r -

boxylic a cid 28xxxv: mp 260-262 °C (EtOAc); 73.7% yield;

IR ν_max(Nujol) 3350, 3199, 1754, 1664, 1611, 1493 cm^-1. Anal.

(C₂₄H₂₄N₂O₅‚0.2H₂O) C, H, N.

28xxxv: mp 222-224 °C (EtOAc); 71.3% yield. Anal.

(C₂₃H₂₂N₂O₅) C, H, N.

2-(8-((Ca r bom eth oxym eth yl)oxy)-2-eth yl-3-(3-p h en yl-

2-p r op a n yl)in d olin -1-yl)glyoxyla m id e (27xxxvi) a n d Ca r -

boxylic Acid 28xxxvi. A mixture of the olefin 27xxxv (180

mg, 0.428 mmol) and 10% Pd-C (13 mg) in EtOAc (15 mL)

was stirred in hydrogen for 4 h. The catalyst was filtered and

washed with EtOAc. The filtrate was concentrated under

reduced pressure. The residue was recrystallized from EtOAc

to yield 103 mg (56.9%); mp 167 °C. Anal. (C₂₄H₂₆N₂O₅‚0.1H₂O)

C, H, N.

28xxxvi: mp 215-217 °C; 93.1% yield. Anal. (C₂₃H₂₄N₂O₅‚

0.4H₂O) C, H, N.

2-(8-((Ca r b om et h oxym et h yl)oxy)-2-cyclop r op yl-3-(1-

n aph th ylm eth yl)in dolin -1-yl)glyoxylam ide (27xxxvii) an d

ca r boxylic a cid 28xxxvii: amorphous solid; 44.3% yield.

Anal. (C₂₇H₂₄N₂O₅‚0.8C₆H₆) C, H, N.

1,3-Bis(o-ph en ylben zyl)-8-((car bom eth oxym eth yl)oxy)-

2-isop r op ylin d olizin e: mp 215-219 °C (AcOEt:hexane); 9.2%

yield. Anal. (C₄₀H₃₇NO₃‚0.6H₂O) C, H, N.

2-t er t -B u t y l-8-((c a r b o m e t h o x y m e t h y l)o x y )-3-(o-

p h en ylben zyl)in d olizin e (32xxxii): mp 155-157 °C (hex-

ane); 22.5% yield. Anal. (C₂₈H₂₉NO₃‚0.4C₆H₆) C, H, N.

1 ,3 -B i s (o -p h e n y l b e n z y l )-2 -t e r t -b u t y l -8 -((c a r b o -

m eth oxym eth yl)oxy)in d olizin e: mp 230-234 °C; 1.8%

1

yield; IR ν

(Nujol) 1767, 1732, 1472, 1450, 1438 cm^-1; H

max

28xxxvii: mp 205-207 °C (EtOAc); 70.7% yield. Anal.

(C₂₆H₂₂N₂O₅‚0.4H₂O) C, H, N.

NMR (CDCl₃) δ 1.19 (9H, s), 3.64 (3H, s), 4.29 (2H, s), 4.44

(2H, s), 4.61 (2H, br s), 5.73 (1H, d, J ) 7.2 Hz), 6.16 (1H, t, J

) 7.2 Hz), 6.54 (1H, d, J ) 7.8 Hz), 6.81 (1H, t, J ) 7.5 Hz),

6.99 (1H, d, J ) 7.5 Hz), 7.1-7.55 (8H, m).

8-(Ben zyloxy)-1-car beth oxy-2-m eth oxyin dolizin e (17c).

A mixture of 16b (1 g, 3.69 mmol) and methyl bromoacetate

(10 mL) was stirred at 50°C for 18 h in N₂. Ether was added

to the reaction mixture. The insoluble oil was washed with

ether, dried, and concentrated. A mixture of the pyridinium

salt and K₂CO₃(4.2g, 36.85 mmol) was stirred in 2-butanone

(17 mL) at room temperature for 4 h. Dimethyl sulfate (2.5

mL, 26.38 mmol) in 2-butanone (3 mL) was added, then the

mixture was heated to 60 °C. Water was added. The mixture

was extracted with EtOAc. The extracts were dried. After

removal of the solvent, the residue was chromatographed in

hexane:EtOAc 5:1 to give 17c: 382 mg (32% yield); IR ν_max

(neat) 2970, 1693, 1555, 1527, 1452, 1370, 1304 cm^-1; ¹H NMR

(CDCl₃) δ 1.11 (3H, t, J ) 7.0 Hz), 3.86 (3H, s), 4.12 (2H, q, J

) 7.0 Hz), 5.15 (2H, s), 6.30 (1H, d, J ) 7.8 Hz), 6.46 (1H, dd,

J ) 6.6, J ) 7.8 Hz), 7.26-7.54 (5H, m).

2-(8-(Be n zyloxy)-2-m e t h oxy-3-(o-p h e n ylb e n zyl)in -

d olizin -1-yl)glyoxyla m id e (25xxxviii): mp 183-184 °C

(hexane:EtOAc). Anal. (C₃₁H₂₆N₂O₄0.2H₂O) C, H, N.

2-(8-((C a r b o m e t h o x y m e t h y l)o x y )-2-m e t h o x y -3-(o-

ph en ylben zyl)in dolizin -1-yl)glyoxylam ide (27xxxviii) an d

ca r boxylic a cid 28xxxviii: mp 188-189 °C (hexane:EtOAc).

56% yield (two steps). Anal. (C₂₇H₂₄N₂O₆‚0.2H₂O) C, H, N.

8-((C a r b o m e t h o x ym e t h y l)o x y )-2-c y c lop e n t yl-3-(o-

p h en ylben zyl)in d olizin e (32xxxiii): mp 145-148 °C (hex-

ane); 26.2% yield. Anal. (C₃₁H₃₀N₂O₅‚0.3H₂O) C, H, N.

1,3-Bis-(o-ph en ylben zyl)-8-((car bom eth oxym eth yl)oxy)-

2-cyclop r op ylin d olizin e: mp 194-195 °C; 5.2% yield. Anal.

(C₄₂H₃₉NO₃‚0.3H₂O) C, H, N.

8-((Car bom eth oxym eth yl)oxy)-2-eth yl-3-(m-ph en ylben -

zyl)in d olizin e (32xxxiv), 8-((Ca r bom eth oxym eth yl)oxy)-

2-eth yl-3-(3-p h en yl-2-p r op en yl)in d olizin e (32xxxv) a n d

8-((Ca r bom eth oxym eth yl)oxy)-2-cyclop r op yl-3-(1-n a p h -

th ylm eth yl)in d olizin e (56j). These products could not be

isolated from 1,3-disubstituted indolizine and used in the next

preparation without further purification.

2-(2-Alk yl-8-((ca r b om e t h oxym e t h yl)oxy)-3-(su b st i-

tu ted m eth yl)in d olizin -1-yl)glyoxyla m id e (27). General

procedure: These compounds were prepared from 32, accord-

ing to the procedure described for the synthesis of 5a .

2-(8-((Car bom eth oxym eth yl)oxy)-3-(cycloh exylm eth yl)-

2-cyclop r op ylin d olizin -1-yl)glyoxyla m id e (27xxx) a n d

ca r boxylic a cid 28xxx: mp 153-157 °C; 53.7% yield. Anal.

(C₂₃H₂₈N₂O₅‚0.4AcOEt) C, H, N.

3652 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

28xxxviii: mp 197-198 °C (EtOAc); 32% yield. Anal.

(C₂₆H₂₂N₂O₆) C, H, N.

dried, and concentrated to give a mixture of 24g and the

dicarboxylic acid.

The solid in toluene (5 mL) was heated under reflux for 1 h

and concentrated. The residue was chromatographed (25 g)

in hexane:EtOAc (5:1) and crystallized from hexane: 191 mg

(87.0%); mp 94 °C. Anal. (C₁₆H₁₅NOS‚0.05C₆H₆) C, H, N, S.

2-(8-(Ben zyloxy)-2-(m eth ylth io)-3-(o-p h en ylben zyl)in -

dolizin -1-yl)glyoxylam ide (25xxxix): mp 199-201 °C; 28.5%

Yield from 24g. Anal. (C₃₁H₂₆N₂O₃S) C, H, N, S.

2-(8-H yd r oxy-2-(m e t h ylt h io)-3-(o-p h e n ylb e n zyl)in -

d olizin -1-yl)glyoxyla m id e (26xxxix). A 1 N solution of

BBr₃in CH₂Cl₂(0.7 mL, 0.7 mmol) was added to a solution of

the benzyl ether 25xxxix (85 mg, 0.168 mmol) in CH₂Cl₂(1

mL) with cooling in ice. The mixture was stirred at 0 °C for

1 h. Ice water was added. The mixture was extracted with

CH₂Cl₂:MeOH. The extracts were washed with water, dried,

and concentrated. The residue was recrystallized from EtOAc

(mp 138-142 °C).

Dieth yl 2-(3-Ben zyloxyp yr id in io)-3-th ion io-4-th ia h ep t-

2-en ed ioa te (33). A solution of benzyloxypyridine (21.73 g,

0.117 mol) and ethyl bromoacetate (19.6 g, 0.117 mol) in

benzene (85 mL) was stirred at 65 °C for 2 h and concentrated.

The residue was washed with EtOAc.

A solution of aqueous NaOH (11.80 g, 0.295 mol, 35 mL)

was added dropwise to a solution of the residue, CS₂(10.8 g,

0.142 mol), water (24 mL), and EtOH (120 mL). The mixture

was stirred for 30 min. Ethyl acrylate (11.8 g, 0.118 mol) was

added dropwise. The mixture was stirred for 1 h. Ice water

was added. The solid was collected by filtration, washed with

water, dried (10.9 g, 20.8%), and recrystallized from CHCl₃:

1

ether: mp 162-164 °C; IR ν_max(Nujol) 1719, 1644 cm^-1; H

NMR (CDCl₃) δ 1.16 (3H, t, J ) 6.9 Hz), 1.26 (3H, t, J ) 7.2

Hz), 2.80 (2H, t, J ) 7.5 Hz), 3.58 (2H, t, J ) 7.5 Hz), 4.13

(2H, q, J ) 6.9 Hz), 4.15 (2H, q, J ) 7.2 Hz), 5.21 (2H, s), 7.42

(5H, s), 7.73 (1H, dd, J ) 9.0, 6.0 Hz), 7.87 (1H, ddd, J ) 8.7,

2.4, 1.2 Hz), 8.12 (1H, dt, J ) 6.0, 1.2 Hz), 8.22 (1H, dd, J )

2.1, 0.9 Hz). Anal. (C₂₂H₂₅NO₅S₂‚0.05CHCl₃‚0.3H₂O) C, H,

N, S, Cl.

2-(8- an d 6-((Car bom eth oxym eth yl)oxy)-2-(m eth ylth io)-

3-(o-p h en ylben zyl)in d olizin -1-yl)glyoxyla m id e (27xxxix)

a n d ca r boxylic a cid 28xxxix: mp 88-91 °C; 41.3% yield.

28xxxix: mp 200-205 °C; 65.4% yield. Anal. (C₂₆H₂₂N₂O₅S)

C, H, N, S.

8- a n d 6-(Ben zyloxy)-1,3-d ica r b et h oxy-2-(2-(ca r bet h -

oxyeth yl)th io)in d olizin e (34a + 34b). A solution of ethyl

bromoacetate (2.70 g, 16.2 mmol) and the salt 33 (6.03 g, 13.5

mmol) in CHCl₃(40 mL) was allowed to stand for 3 d and

cooled in ice. A solution of DBU (2.47 g, 16.2 mmol) and

chloranil (3.32 g, 13.5 mmol) was added. The mixture was

stirred at 0 °C for 6 h and chromatographed (120 g) in CHCl₃

to give a ca. 10:1 mixture of 34a and 34b, (6.0 g, 89.1%) as an

oil.

2-Eth yl-7-m eth oxyin d olizin e (37a ) a n d 2-Cyclop r op yl-

7-m eth oxyin d olizin e (37b). 4-Methoxypicoline was treated

as in the procedure for the preparation of 24 from 23.

1

37a : 29.4% yield; IR ν_max(KBr) 2962, 1648 cm^-1; H NMR

(CDCl₃) δ 1.27 (3H, t, J ) 7.2 Hz), 2.67 (2H, q, J ) 7.4 Hz),

3.77 (3H, s), 6.06 (1H, s), 6.14 (1H, dd, J ) 7.6, 2.6 Hz), 6.52

(1H, d, J ) 2.4 Hz), 6.94 (1H, s), 7.66 (1H, d, J ) 7.6 Hz). MS

m/ z 175.0982 [M]⁺

.

37b: mp 101-102 °C (hexane); 27.3% yield. Anal. (C₁₂H₁₃

-

8-(Be n zyloxy)-1,3-d ica r b e t h oxy-2-m e r ca p t oin d oli-

zin e (35a ). KOtBu (2.73 g, 24.3 mmol) was added in small

portions to a solution of the ester 34a +b (9.88 g, 19.8 mmol)

in DMF (25 mL) with cooling in ice. The mixture was stirred

at 50 °C for 5 h. Ice water and then dilute HCl were added.

The mixture was extracted with EtOAc. The extracts were

washed with water, dried, and concentrated. The residue was

chromatographed (200 g) in hexane:EtOAc (2:1). Both frac-

tions of larger and smaller R_fvalues were crystallized from

benzene:hexane.

NO) C, H, N.

2-Alk yl-7-m eth oxy-3-(su bstitu ted ca r bon yl)in d olizin e

(38). Indolizine compound 37 was converted to 38 by the same

procedure cited for the preparation of 11 from 10.

3-Ben zoyl-2-eth yl-7-m eth oxyin d olizin e (38a ): mp 105-

106 °C (hexane); 70.5% yield; IR ν_max(KBr) 3057, 2966, 2926,

1

2868, 1645 cm^-1; H NMR (CDCl₃) δ 1.02 (3H, t, J ) 7.5 Hz),

2.17 (2H, q, J ) 7.5 Hz), 3.88 (3H, s), 6.23 (1H, s), 6.54 (1H,

dd, J ) 2.7, 7.8 Hz), 6.72 (1H, d, J ) 2.1 Hz), 7.40-7.49 (3H,

m), 7.56-7.60 (2H, m), 9.67 (1H, d, J ) 7.5 Hz). Anal. (C₁₈H₁₇

-

35a , the fraction having the larger R_fvalue: mp 125-127

1

°C; 1.12 g (16.7%); IR ν_max(Nujol) 1661, 1508 cm^-1; H NMR

NO₂‚0.5H₂O) C, H, N.

2-Cyclop r op yl-7-m et h oxy-3-(o-p h en ylb en zoyl)in d oli-

(CDCl₃) δ 1.46 (3H, t, J ) 6.9 Hz), 1.48 (3H, t, J ) 7.5 Hz),

4.42 (2H, q, J ) 6.9 Hz), 4.46 (2H, q, J ) 7.2 Hz), 5.09 (2H, s),

7.04 (1H, s), 7.15 (1H, dd, J ) 9.9, 2.4 Hz), 7.3-7.55 (5H, m),

1

zin e (38b): a yellow oil; quantitative yield; H NMR (CDCl₃)

δ 0.48 -0.69 (2H, m), 1.11 (1H, m), 3.82 (3H, s), 5.71 (1H, s),

6.45 (1H, dd, J ) 2.8, 7.6 Hz), 6.57 (1H, d, J ) 2.6 Hz), 7.15-

7.54 (9H, m), 9.76 (1H, d, J ) 7.6 Hz).

8.09 (1H, dd, J ) 9.6, 0.6 Hz), 9.41 (1H, s). Anal. (C₂₁H₂₁

NO₅S) C, H, N, S.

-

2-Eth yl-7-m eth oxy-3-(o-ph en ylben zoyl)in dolizin e (38c):

mp 140-141 °C (ether); 90.2% yield. Anal. (C₂₄H₂₃NO) C, H,

N.

3-(Cycloh exylca r b on yl)-2-et h yl-7-m et h oxyin d olizin e

(38d ): mp 112-113 °C (hexane); 41.1% yield; IR ν_max(KBr)

2923, 2848, 1644 cm^-1. Anal. (C₁₈H₂₃NO₂‚0.1H₂O) C, H, N.

3-Ben zyl-2-eth yl-7-m eth oxyin d olizin e (39a ): amorphous

The fraction having the smaller R_fvalue: mp 81-82 °C;

4.59 g (58.1%); IR ν_max(Nujol) 1686, 1655, 1543, 1493 cm^-1

;

¹H NMR (CDCl₃) δ 1.10 (3H, t, J ) 6.9 Hz), 1.47 (3H, t, J )

7.2 Hz), 4.45 (2H, q, J ) 7.5 Hz), 5.16 (2H, s), 5.56 (1H, s),

6.58 (1H, d, J ) 7.5 Hz), 6.73 (1H, t J ) 6.9 Hz), 7.3-7.5 (5H,

m), 9.15 (1H, dd, J ) 7.2, 0.9 Hz). Anal. (C₂₁H₂₁NO₅S‚0.4H₂O)

C, H, N, S.

solid; 22.0% yield; IR ν_max(KBr) 3002, 2956, 2926, 1646 cm^-1

;

8-(B e n zy lo x y )-1,3-d ic a r b e t h o x y -2-(m e t h y lt h io )in -

d olizin e (35b). NaH (60%, 76 mg) was added to a solution

of the thiol 35a (690 mg, 1.73 mmol) in DMF (4 mL) with

cooling in ice under N₂. A solution of iodomethane (295 mg,

2.08 mmol) in DMF (1 mL) was added dropwise to the mixture

with cooling in ice. The mixture was stirred at room temper-

ature for 2 h, acidified with dilute HCl, and extracted with

EtOAc. The extracts were washed with water, dried, and

concentrated. The residue was chromatographed in hexane:

EtOAc (5:1 to 3:2) to give 732 mg of an oil (quantitative

yield): ¹H NMR (CDCl₃) δ 1.13 (3H, t, J ) 6.9 Hz), 1.45 (3H,

t, J ) 7.2 Hz), 2.47 (3H, s), 4.00 (2H, q, J ) 7.2 Hz), 4.45 (2H,

q, J ) 7.5 Hz), 5.13 (2H, s), 6.46 (1H, d, J ) 7.5 Hz), 6.70 (1H,

t J ) 7.2 Hz), 7.3-7.5 (5H, m), 9.06 (1H, dd, J ) 6.9, 0.6 Hz).

8- a n d 6-(Ben zyloxy)-2-(m eth ylth io)in d olizin e (24g).

Aqueous KOH (10%, 5 mL) was added to a solution of the

diester 35b (337 mg, 0.815 mmol) in DMSO (5 mL). The

mixture was heated under reflux for 8 h. After cooling, the

mixture was acidified with dilute HCl with cooling in ice and

extracted with EtOAc. The extracts were washed with water,

¹H NMR (CDCl₃) δ 1.27 (3H, dt, J ) 7.5, 1.2 Hz), 2.69 (2H, q,

J ) 7.5 Hz), 3.76 (3H, s), 4.20 (2H, s), 6.09 (1H, dd, J ) 2.4,

7.5 Hz), 6.18 (1H, s), 6.59 (1H, d, J ) 2.1 Hz), 7.04 (2H, d, J

) 7.2 Hz), 7.14-7.27 (3H, m), 7.25 (1H, d, J ) 7.2 Hz).

2-Cyclop r op yl-7-m et h oxy-3-(o-p h en ylb en zyl)in d oli-

zin e (39b): mp 109-110 °C (hexane); 44.3% yield. Anal.

(C₂₅H₂₃NO) C, H, N.

2-Eth yl-7-m eth oxy-3-(o-p h en ylben zyl)in d olizin e (39c):

mp 100-101 °C (hexane); 39.2% yield. Anal. (C₂₄H₂₃NO) C,

H, N.

3-(Cycloh e xylm e t h yl)-2-e t h yl-7-m e t h oxyin d olizin e

(39d ): amorphous yellow solid; 48.2% yield.

2-(3-Ben zyl-2-eth yl-7-m eth oxyin d olizin -1-yl)glyoxyla -

m id e (40a ): amorphous solid; 78.9% yield; IR ν_max(KBr) 3500,

1

3386, 3004, 2962, 1689, 1644, 1601 cm^-1; H NMR (CDCl₃) δ

1.23 (3H, dt, J ) 7.5, 1.2 Hz), 2.98 (2H, q, J ) 7.8 Hz), 3.87

(3H, s), 4.21 (2H, s), 5.57 (1H, br s), 6.42 (1H, dd, J ) 2.7, 7.5

Hz), 6.79 (1H, br s), 7.08 (1H, d, J ) 6.9 Hz), 7.21 (3H, m),

7.51 (1H, d, J ) 7.5 Hz), 7.82 (1H, d, J ) 2.7 Hz).

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3653

2-(2-Cyclop r op yl-7-m e t h oxy-3-(o-p h e n ylb e n zyl)in -

d olizin -1-yl)glyoxyla m id e (40b): mp 194-195 °C (benzene:

hexane); 50.1% yield. Anal. (C₂₇H₂₄N₂O₃) C, H, N.

2-(2-E t h yl-7-m et h oxy-3-(o-p h en ylb en zyl)in d olizin -1-

yl)glyoxylyla m id e (40c): mp 101-106 °C (benzene:hexane);

75.9% yield. Anal. (C₂₆H₂₄N₂O₃‚0.3C₆H₆) C, H, N.

2-(3-(Cycloh exylm eth yl)-2-eth yl-7-m eth oxyin d olizin -1-

yl)glyoxyla m id e (40d ): mp 178-180 °C (THF:hexane); 50.4%

yield. Anal. (C₂₀H₂₅N₂O₃‚0.2THF) C, H, N.

2-(3-Ben zyl-2-et h yl-7-h yd r oxyin d olizin -1-yl)glyoxyl-

a m id e (41a ): amorphous solid; 49% yield; ¹H NMR (CDCl₃) δ

1.11 (3H, t, J ) 7.2 Hz), 2.86 (2H, t, J ) 7.2 Hz), 4.24 (2H, s),

6.52 (1H, dd, J ) 2.1, 7.5 Hz), 7.08-7.30 (6H, m), 7.43 (1H, d,

J ) 2.4 Hz), 7.51 (1H, s), 7.92 (1H, d, J ) 6.9 Hz), 7.98 (1H,

s).

collected with filtration to give 43g: 96.2 mg (60.9%); mp 99-

108 °C (dec). Anal. (C₂₈H₂₆N₂O₅‚1.2H₂O) C, H, N.

2-(7-((3-Ca r b et h oxyp r op yl)oxy)-2-et h yl-3-(o-p h en yl-

ben zyl)in d olizin -1-yl)a ceta m id e (44a ) a n d Ca r boxylic

Acid 44b. BH₃-t-BuNH₂complex (125 mg, 1.44 mmol) was

added to a mixture of AlCl₃(13 mg, 0.097 mmol) in toluene

(10 mL) with cooling in ice. The mixture was stirred at 0 °C

for 10 min. A solution of the glyoxylamide 42c (246 mg, 0.48

mmol) in toluene (5 mL) was added to the solution. The

solution was heated at 60 °C for 2 h. After cooling, the solution

was poured to ice-cold dilute HCl. The mixture was extracted

with CH₂Cl₂. The extracts were washed with water, dried,

and concentrated. The residue was chromatographed in

EtOAc:hexane (4:1) and recrystallized from hexane: 190 mg

(79.4%); mp 128-130 °C. Anal. (C₃₁H₃₄N₂O₄‚0.6H₂O) C, H,

N.

2-(2-Cyclop r op yl-7-h yd r oxy-3-(o-p h e n ylb e n zyl)in -

d olizin -1-yl)glyoxyla m id e (41b): amorphous solid; 12.6%

yield.

44b: mp 105-120 °C (dec); 62.0% yield. Anal. (C₃₁H₃₄N₂O₄‚

0.6H₂O) C, H, N.

2-(2-E t h yl-7-h yd r oxy-3-(o-p h en ylb en zyl)in d olizin -1-

yl)glyoxylyla m id e (41c): mp 125-129 °C (benzene:hexane);

36.9% yield. Anal. (C₂₅H₂₂N₂O₃‚0.2C₆H₆‚0.5H₂O) C, H, N.

2-(3-(Cycloh exylm eth yl)-2-eth yl-7-h yd r oxyin d olizin -1-

yl)glyoxyla m id e (41d ): amorphous solid; 28.0% yield.

2-(3-Ben zyl-7-((3-ca r beth oxyp r op yl)oxy)-2-eth ylin d o-

lizin -1-yl)glyoxyla m id e (42a ) a n d ca r boxylic a cid 43a : mp

146-149 °C; 54.% yield; IR ν_max(KBr) 3430, 3170, 2958, 2928,

1731, 1674, 1645 cm^-1; ¹H NMR (CDCl₃) δ 1.22 (3H, t, J ) 7.5

Hz), 1.25 (3H, t, J ) 7.2 Hz), 2.13 (2H, m), 2.49 (2H, q, J )

7.2 Hz), 2.97 (2H, q, J ) 7.5 Hz), 4.08 (2H, t, J ) 6.3 Hz), 4.14

(2H, q, J ) 7.2 Hz), 4.21 (2H, s), 5.56 (1H, br s), 6.40 (1H, dd,

J ) 2.7, 7.2 Hz), 6.78 (1H, br s), 7.08 (2H, d, J ) 7.8 Hz), 7.21-

7.29 (3H, m), 7.50 (1H, d, J ) 7.2 Hz), 7.78 (1H, d, J ) 2.7

Hz). Anal. (C₂₅H₂₈N₂O₃‚0.2H₂O) C, H, N.

3-((Ben zyloxycar bon yl)am in o)-2-m eth ylpyr idin e (45b).

A mixture of 3-aminopicoline 45a (0.60 g, 5.5 mmol), N-

(benzyloxycarbonyl)succinimide (2.1 g, 8.3 mmol), and DMF

(2 mL) was left for 2 d. The reaction mixture was poured into

water, extracted with EtOAc, washed with water, and dried.

The solvent was removed. The residue was chromatographed

by eluting with EtOAc:hexane to give 45b (0.92 g, 68%), mp

76-78 °C; IR ν_max(Nujol) 1725, 1551, 1227, 1061 cm^{-1 1}H

;

NMR (CDCl₃) δ 2.49 (3H, s), 5.22 (3H, s), 7.16 (1H, m), J )

8.7 Hz), 7.36-7.45 (5H, m), 8.15-8.27 (2H, m). Anal.

(C₁₄H₁₄N₂O₂) C, H, N.

3-(N -(B e n zy lo x y c a r b o n y l)-N -((m e t h o x y c a r b o n y l)-

m eth yl)a m in o)-2-m eth ylp yr id in e (46). To a suspension of

NaH (60% dispersion in oil, 0.17 g, 4.2 mmol) in DMF (3 mL)

was added 45b (0.92 g, 3.8 mmol) in DMF (5 mL) at 0 °C with

stirring under N₂. Stirring was continued for 1 h, at which

time methyl bromoacetate (0.40 mL, 4.2 mmol) was added. The

reaction mixture was stirred at room temperature for an

additional 2.5 h. The reaction mixture was poured into water,

extracted with EtOAc, washed with water, and dried. The

solvent was removed. The product was purified by column

chromatography in EtOAc:hexane (1:1) to yield 46 (1.07 g, 90%)

as a yellow oil: ¹H NMR (CDCl₃) δ 2.43 (3/4H, s), 2.51 (1/4H,

m), 3.68 (1/4H, m), 3.76 (3/4H, s), 3.85 (1H, d, J ) 18 Hz),

4.69 (1H, d, J ) 18 Hz), 5.06-5.21 (3/2H, m), 5.22 (1/2H, s),

7.13-7.37 (6H, m), 7.73 (1H, m), 8.45 (1H, m).

43a : mp 178-183 °C (dec); 77.0% yield; IR ν_max(KBr) 3700-

1

2400, 3085, 2925, 1710, 1644 cm^-1; H NMR (CDCl₃) δ 1.22

(3H, t, J ) 7.5 Hz), 2.14 (2H, t, J ) 6.9 Hz), 2.97 (2H, q, J )

7.5 Hz), 4.11 (2H, t, J ) 6.3 Hz), 4.20 (2H, s), 6.38 (1H, br s),

6.41 (1H, dd, J ) 7.2, 2.4 Hz), 6.96 (2H, br s), 7.08 (2H, d, J )

6.9 Hz), 7.23-7.26 (3H, m), 7.51 (1H, d, J ) 7.5 Hz), 7.75 (1H,

d, J ) 2.7 Hz). Anal. (C₂₃H₂₄N₂O₃‚0.3H₂O) C, H, N.

2-(7-((3-Ca r b e t h oxyp r op yl)oxy)-2-cyclop r op yl-3-(o-

p h en ylben zyl)in d olizin -1-yl)glyoxyla m id e (42b) a n d ca r -

boxylic a cid 43b: amorphous solid; 84.2% yield.

43b: mp 112-121 °C, (dec); 69.6% yield. Anal. (C₃₀H₂₈N₂O₅‚

1.2H₂O) C, H, N.

3-Ben zyl-8-(N-(b en zyloxyca r b on yl)-N-((m et h oxyca r -

bon yl)m eth yl)am in o)-2-m eth ylin dolizin e (32xl): 42% yield;

¹H NMR (CDCl₃) δ 2.34 (3H, s), 3.67-3.77 (3H, m), 4.21-4.46

(4H, m), 5.15 (2/3H, s), 5.25 (1/3H, s), 6.28-6.37 (2H, m), 6.77

(1H, m), 7.04-7.50 (11H, m).

2-(7-((3-Ca r b et h oxyp r op yl)oxy)-2-et h yl-3-(o-p h en yl-

ben zyl)in d olizin -1-yl)glyoxylyla m id e (42c) a n d ca r boxy-

lic a cid 43c: mp 131-133 °C (benzene:hexane); 70.9% yield.

Anal. (C₃₁H₃₂N₂O₅‚0.2H₂O) C, H, N.

(43c): mp 112-116 °C (dec); 67.0% yield. Anal. (C₂₉H₂₈N₂O₅‚

0.9H₂O) C, H, N.

2-(7-((3-Ca r beth oxyp r op yl)oxy)-3-(cycloh exylm eth yl)-

2-eth yl-h yd r oxyin d olizin -1-yl)glyoxyla m id e (42d ) a n d

ca r boxylic a cid 43d : mp 150-151 °C (THF:hexane); 87.0%

yield. Anal. (C₂₅H₃₄N₂O₅) C, H, N.

43d : mp 201-202.5 °C; 92.4% yield. Anal. (C₂₃H₃₀N₂O₅‚

0.3H₂O) C, H, N.

8-(N -(B e n zy lo x y c a r b o n y l)-N -((m e t h o x y c a r b o n y l)-

m e t h yl)a m in o)-3-(cycloh e xylm e t h yl)-2-m e t h ylin d oli-

1

zin e (32xli): 31% yield; H NMR (CDCl₃) δ 0.82-1.80 (11H,

m), 2.25 (3H, s), 2.70 (2H, d, J ) 7 Hz), 3.66 (3/4H, s), 3.74

(9/4H, s), 4.10-4.55 (2H, m), 5.15 (3/2H, s), 5.23 (1/2H, s), 6.19

(3/4H, s), 6.23 (1/4H, s), 6.43 (1H, m), 6.73 (3/4H, d, J ) 7 Hz),

6.79 (1/4H, d, J ) 7 Hz), 7.12-7.42 (5H, m), 7.64 (1H, d, J )

7 Hz).

2-(7-((Ca r beth oxym eth yl)oxy)-2-eth yl-3-(o-p h en ylben -

zyl)in dolizin -1-yl)glyoxylam ide (42e) an d car boxylic acid

43e: mp 119-121 °C (THF:hexane); 86.6% yield. Anal.

(C₂₉H₂₈N₂O₅‚0.3H₂O) C, H, N.

43e: mp 226 °C (dec); 81.0% yield. Anal. (C₂₇H₂₄N₂O₅‚

0.3EtOAc‚0.7H₂O) C, H, N.

2-(3-Ben zyl-8-(N-(ben zyloxyca r bon yl)-N-((m eth oxyca r -

b on yl)m et h yl)a m in o)-2-m et h ylin d olizin -1-yl)glyoxyla -

m id e (27xl): 66% yield; ¹H NMR (CDCl₃) δ 2.44 (1H, s), 2.45

(2H, s), 3.67 (1H, s), 3.73 (2H, s), 3.80 (1H, d, J ) 18 Hz), 4.24

(2H, s), 4.71 (1H, d, J ) 18 Hz), 5.00-5.31 (2H, m), 6.64 (1H,

m), 7.04-7.42 (11H, m), 7.62 (1H, m).

2-(7-((5-Ca r b et h oxyp en t yl)oxy)-2-et h yl-3-(o-p h en yl-

ben zyl)in d olizin -1-yl)glyoxyla m id e (42f) a n d ca r boxylic

a cid 43f: mp 122-123 °C (MeOH:Et₂O:hexane); 81.0% yield.

Anal. (C₃₂H₃₄N₂O₅‚0.3H₂O) C, H, N.

2-(8-(N-(b en zyloxyca r b on yl)-N-((m et h oxyca r b on yl)-

m eth yl)a m in o)-3-(cycloh exylm eth yl)-2-m eth ylin d olizin -

1-yl)glyoxyla m id e (27xli): 72% yield; ¹H NMR (CDCl₃) δ

1.00-1.26 (4H, m), 1.50-1.78 (7H, m), 2.32 (1H, s), 2.33 (2H,

s), 2.70 (2H, d, J ) 7 Hz), 3.67 (1H, s), 3.73 (2H, s), 3.78 (2/

3H, d, J ) 18 Hz), 3.79 (1/3H, d, J ) 18 Hz), 4.60 (1/3H, d, J

) 18 Hz), 4.69 (2/3H, d, J ) 18 Hz), 5.03 (2/3H, d, J ) 13 Hz),

5.19 (1/3H, d, J ) 13 Hz), 5.23 (2/3H, d, J ) 13 Hz), 5.25 (1/

3H, d, J ) 13 Hz), 6.73 (2/3H, t, J ) 7 Hz), 6.79 (1/3H, t, J )

7 Hz), 7.14-7.43 (6H, m), 7.79 (1H, m).

43f: mp 84-94 °C (dec); 72.0% yield. Anal. (C₃₀H₃₀N₂O₅‚

0.9H₂O) C, H, N.

2-(7-((2-Ca r boxyeth yl)oxy)-2-eth yl-3-(o-p h en ylben zyl)-

in d olizin -1-yl)glyoxyla m id e (43g). Propiolactone (25 mg,

0.336 mmol) was added dropwise to a solution of 41c (133.7

mg, 0.336 mmol) and KOt-Bu (37.6 mg, 0.336 mmol) in THF

(4 mL) under N₂. The mixture was stirred for 21 h. Water

was added. The mixture was washed with EtOAc. The

aqueous phase was acidified with HCl. The precipitate was

2-(3-Be n zyl-8-((m e t h oxyca r b on yl)m e t h yl)a m in o)-2-

m eth ylin d olizin -1-yl)glyoxyla m id e (47xl) a n d Ca r boxylic

Acid 28xl. A mixture of the indolizine 27xl (88 mg, 0.17

3654 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

mmol) and 10% Pd-C (0.02 g) in EtOAc (5 mL) was stirred in

H₂atmosphere for 3 h. The catalyst was filtered and the

filtrate was concentrated. Crystallization of the residue from

THF:ether afforded 47xl (51 mg, 78%): mp 186-188 °C. Anal.

(C₂₁H₂₁N₃O₄) C, H, N.

28xl: mp 293 °C (dec) (MeOH:ether); 61% yield.

2-(8-((m et h oxyca r b on yl)m et h yl)a m in o)-3-(cycloh ex-

ylm eth yl)-2-m eth ylin dolizin -1-yl)glyoxylam ide (47xli) an d

ca r boxylic a cid 28xli: mp 173-177 °C (MeOH:ether:hexane);

90% yield. Anal. (C₂₁H₂₇N₃O₄‚0.2H₂O) C, H, N.

28xl: mp >300 °C (MeOH:ether); 47% yield.

2-(3-Ben zyl-8-((ca r boxym et h yl)oxy)-2-et h ylin d olizin -

1-yl)-N-m eth ylglyoxyla m id e (51a ): mp 212-213 °C (AcO-

Et); 47% yield; IR ν_max(KBr) 3361, 2965, 2931, 1766, 1609,

1

1308, 1093 cm^-1; H NMR (CDCl₃) δ 1.22 (3H, t, J ) 7.6 Hz),

2.87 (2H, q, J ) 7.6 Hz), 3.05 (3H, d, J ) 5.4 Hz), 4.26 (2H, s),

4.73 (2H, s), 6.39 (1H, d, J ) 7.6 Hz), 6.59 (1H, dd, J ) 6.4,

7.6 Hz), 7.66-7.11 (2H, m), 7.22-7.29 (3H, m), 7.42 (1H, d, J

) 6.4 Hz). Anal. (C₂2H₂2N₂O₅) C, H, N.

(3-Ben zyl-8-((ca r b oxym et h yl)oxy)-2-et h ylin d olizin -1-

yl)N,N-d im eth ylglyoxyla m id e (51b): mp 166-167 °C (AcO-

Et); 49% yield; IR ν_max(KBr) 3435, 2937, 1764, 1608, 1195

cm^-1; ¹H NMR (CDCl₃) δ 1.24 (3H, t, J ) 7.6 Hz), 2.99 (2H, q,

J ) 7.6 Hz), 3.15 (3H, s), 4.26 (2H, s), 4.21 (3H, s), 4.27 (2H,

s), 4.74 (2H, s), 6.50 (1H, d, J ) 8.0 Hz), 6.63 (1H, dd, J ) 6.4,

8.0 Hz), 7.05-7.10 (2H, m), 7.22-7.29 (3H, m), 7.44 (1H, d, J

) 6.4 Hz). Anal. (C₂3H₂4N₂O₅‚0.9H₂O) C, H, N.

2-(3-Be n zyl-8-((m e t h oxyca r b on yl)m e t h yl)a m in o)-2-

m et h ylin d olizin -1-yl)a cet a m id e (48a ) a n d ca r b oxylic

a cid 48b: mp 147-150 °C (dec) (EtOH:ether:hexane); 55%

yield.

48b: 60% yield.

3-(4-Meth oxyph en yl)-2-m eth ylacr ylic Acid (53a): A mix-

ture of p-anisaldehyde (26.6 g, 0.195 mol), propionic anhydride

(43.0 mL, 0.347 mol) and sodium propionate (18.8 g, 0.195 mol)

was heated at 150 °C overnight. After cooling, the reaction

mixture was basified with 4N NaOH and washed with ether.

The aqueous phase was acidified with conc. HCl and the

precipitate was filtered to yield 53a , 28.5 g (76%), mp 152-

155 °C. ¹H NMR (CDCl₃) δ 2.16 (3H, d, J ) 1.2 Hz), 3.85 (3H,

s), 6.95 (2H, d, J ) 8.7 Hz), 7.44 (2H, d, J ) 8.7 Hz), 7.78 (1H,

br s); IR ν_max(KBr) 1662, 1605, 1570, 1510 cm^-1; EIMS m/ z

192 (M⁺, base peak). Anal. (C₁₁H₁₂O₃) C, H.

2-(3-(B ip h e n y l-2-y lm e t h y l)-2-e t h y l-8-(s u b s t it u t e d

m eth yloxy)in d olizin -1-yl)glyoxyla m id e (49a -e). General

procedure: 2-(3-(Biphenyl-2-ylmethyl)-2-ethyl-8-((hydroxy-

methyl)oxy)indolizin-1-yl)glyoxylamide (26ii) was treated with

the same procedure as for the preparation of 27 from 26.

2-(3-(Bip h en yl-2-yl-m et h yl)-2-et h yl-8-(((2-t r it ylt et r a -

zolyl)m eth yl)oxy)in d olizin -1-yl)glyoxyla m id e (49a ): mp

119-121 °C; 66% yield; IR ν_max(Nujol) 3439, 3363, 3166, 1734,

1

1685, 1607, 1495, 1249 cm^-1; H NMR (CDCl₃) δ 1.17 (3H, t,

J ) 7.5 Hz), 2.78 (2H, q, J ) 7.5 Hz), 4.10 (2H, s), 4.85 (1H, br

s), 5.42 (2H, s), 6.05 (1H, br s), 6.45 (1H, t, J ) 7.2 Hz), 6.58

(1H, d, J ) 7.2 Hz), 6.77 (1H, d, J ) 7.5 Hz), 7.03 (1H, d, J )

6.9 Hz), 7.08-7.18 (7H, m), 7.22-7.54 (16H, m).

3-(3-Meth oxyp h en yl)-2-m eth yla cr ylic a cid (53b): mp

78-79 °C; 93% yield. Anal. (C₁₁H₁₂O₃) C, H.

2-Eth yl-3-(3-m eth oxyp h en yl)a cr ylic a cid (53c): mp 89-

90 °C; 24% yield. Anal. (C₁₂H₁₄O₃) C, H.

2-(3-(B ip h e n y l-2-y lm e t h y l)-2-e t h y l-8-((t e t r a zo ly l-

m eth yl)oxy)in d olizin -1-yl)glyoxyla m id e (49b). mp 206-

209 °C (dec); 60% yield. Anal. (C₂₇H₂₄N₆O₃‚0.1H₂O) C, H, N.

2-(3-(Bip h en yl-2-ylm et h yl)-2-m et h yl-8-(p yr id in -2-yl-

m eth oxy)in d olizin -1-yl)glyoxyla m id e (49c): mp 196-197

3-(4-Meth oxyp h en yl)-2-m eth ylp r op ion ic Acid (54a ). A

mixture of the acrylic acid 53a (28.3 g, 0.147 mol) and 10%

palladium-coal (2.49 g) in methanol (350 mL) was hydroge-

nated under 3 atm overnight. The catalyst was filtered off

and the solvent was evaporated to give 54a (21.2 g, 74%): mp

1

°C (hexane:AcOEt); 4.2% yield; H NMR (CDCl₃) δ 2.38 (3H,

s), 4.11 (2H, s), 4.81 (1H, br s), 5.11 (2H, s), 6.13 (1H, br s),

6.35 (1H, d, J ) 7.5 Hz), 6.44 (1H, t, J ) 7.2 Hz), 6.81 (1H, d,

J ) 7.2 Hz), 7.02 (1H, d, J ) 6.0 Hz), 7.14-7.20 (1H, m), 7.25-

7.33 (1H, m), 7.35-7.55 (9H, m).

1

43-44 °C; H NMR (CDCl₃) δ 1.17 (3H, d J ) 6.8 Hz), 2.54-

2.83 (2H, m), 3.01 (1H, dd, J ) 5.4, 12.4 Hz), 3.79 (3H, s), 6.83

(2H, d, J ) 8.7 Hz), 7.10 (2H, d, J ) 8.7 Hz); IR ν_max(film)

3424, 1709, 1612, 1584 cm^-1; EIMS m/ z 121 (base peak), 194

(M⁺). Anal. (C₁₁H₁₄O₃) C, H.

2-(3-(Bip h en yl-2-ylm et h yl)-2-m et h yl-8-(p yr id in -4-yl-

m eth oxy)in d olizin -1-yl)glyoxyla m id e (49d ): mp 195-197

°C (hexane:AcOEt); 3.4% yield.

3-(3-Meth oxyph en yl)-2-m eth ylpr opion ic acid (54b): 75%

yield. Anal. (C₁₁H₁₄O₃‚0.1H₂O) C, H.

2-(3-Met h oxyben zyl)bu t yr ic a cid (54c): quantitative

yield. Anal. (C₁₂H₁₆O₃) C, H.

2-(3-(Bip h en yl-2-ylm et h yl)-2-m et h yl-8-(q u in olin -2-yl-

m eth oxy)in d olizin -1-yl)glyoxyla m id e (49e): mp 165-167

1

°C (hexane:AcOEt); 3.4% yield; H NMR (CDCl₃) δ 2.41 (3H,

s), 4.11 (2H, s), 5.31 (1H, br s), 5.47 (2H, s), 6.26-6.38 (2H,

m), 6.51 (1H, br s), 6.83 (1H, d, J ) 7.8 Hz), 6.98-7.01 (1H,

m), 7.14-7.24 (1H, m), 7.25-7.31 (3H, m), 7.40-7.60 (5H, m),

7.69-7.82 (3H, m), 8.04-8.17 (2H, m).

2-(8-((3-Ca r bom eth oxyp r op yl)oxy)-2-eth yl-3-(o-p h en yl-

ben zyl)in d olizin -1-yl)glyoxyla m id e (49f) a n d ca r boxylic

a cid 49g: mp 126-127 °C; 42% yield. Anal. (C₃₁H₃₂N₂O₅‚

0.5H₂O) C, H, N.

2-(2-Br om o-5-m eth oxyben zyl)bu tyr ic Acid (55). To a

solution of the butyric acid 54a (33.9 g, 0.163 mmol) in acetic

acid (50 mL) was added a solution of bromine (10.5 mL, 0.204

mmol) in acetic acid (20 mL) at 0 °C. The resulting solution

was stirred at room temperature for 2.5 h and then the mixture

was partitioned between water and AcOEt. The aqueous layer

was extracted with AcOEt, and the combined organic layers

were washed with saturated Na₂S₂O₃and water, dried, and

evaporated. The residue 55 (51.8 g) was used to the next

preparation without further purification: mp 39-42 °C; ¹H

NMR (CDCl₃) δ 1.00 (3H, t, J ) 7.4 Hz), 1.55-1.83 (2H, m),

2.68-3.08 (3H, m), 3.75 (3H, s), 6.65 (1H, dd, J ) 8.8, 3.0 Hz),

6.78 (1H, d, J ) 3.0 Hz), 7.41 (1H, d, J ) 8.8 Hz). IR ν_max

49g: mp 185-187 °C; 71% yield. Anal. (C₂₉H₂₈N₂O₅‚0.3H₂O)

C, H, N.

2-(8-((2-Ca r boxyeth yl)oxy)-2-eth yl-3-(o-p h en ylben zyl)-

in d olizin -1-yl)glyoxyla m id e (49h ): mp 185-187 °C; 11%

yield;

2-(8-((Cya n om eth yl)oxy)-2-eth yl-3-(1-n a p h th ylm eth yl)-

in d olizin -1-yl)glyoxyla m id e (50a ): mp 212-215 °C (ether);

45% yield. Anal. (C₂₁H₁₈N₃O₃Cl) C, H, N.

2-(8-((Cya n om eth yl)oxy)-2-eth yl-3-(1-n a p h th ylm eth yl)-

in d olizin -1-yl)glyoxyla m id e (50b). A mixture of the nitrile

derivative 50a (100 mg, 0.253 mmol) and trimethyltin azide

(68 mg, 0.329 mmol) in toluene (2.5 mL) was heated under

reflux for 23 h. The precipitate was collected by filtration and

suspended in toluene (2 mL). HCl gas was introduced. The

mixture was stirred at room temperature for 20 min and then

concentrated. EtOAc was added. The mixture was extracted

with 1 N KOH. The aqueous phase was washed with CH₂Cl₂,

acidified with dilute HCl, and extracted with EtOAc. The

extracts were washed with water and dried. After removal of

the solvent, the residue was dissolved in ether. The insoluble

materials were removed by filtration and hexane was added

to the filtrate to give 50b (25 mg, 23% yield): mp 140-143 °C

(dec) (ether:hexane).

(KBr) 3010, 1689, 1593, 1577 cm^-1

.

4-Br om o-2-eth yl-7-m eth oxy-1-in d a n on e (56). A mixture

of the butyric acid 55 (51.6 g) and polyphosphoric acid (511 g)

was heated at 100 °C for 2.5 h. The mixture was poured into

water and extracted with AcOEt. The combined extracts were

washed with water, 5% NaHCO₃, and brine and dried. After

removal of the solvent, the residue was chromatographed by

eluting with hexane:AcOEt (4:1 to 1:2) to give 56 (30.0 g): ¹H

NMR (CDCl₃) δ 1.02 (3H, s, J ) 7.4 Hz), 1.40-1.66 (1H, m),

1.85-2.10 (1H, m), 2.52-2.76 (2H, m), 3.19 (1H, dd, J ) 18.2,

8.0 Hz), 3.94 (3H, s), 6.72 (1H, d, J ) 8.8 Hz), 7.64 (1H, d, J

) 8.8 Hz); IR ν_max(film) 1712, 1585 cm^-1; EIMS m/ z 240 (base

peak), 268 (M⁺); HR-EIMS calcd for C₁₂H₁₃BrO₂268.0098,

found 268.0079.

6-Meth oxy-2-m eth yl-1-in d a n on e (57a ). To the propionic

acid 54a (21.0 g, 0.108 mol) was added polyphosphoric acid

(200 g) at 50 °C. The reaction was maintained at 90 °C for 2

h. The mixture was poured into water, stirred at room

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3655

temperature overnight, and extracted with ether. The com-

bined extracts were washed with aqueous NaHCO₃and brine

and dried. After removal of the solvent, the residue was

chromatographed by eluting with CH₂Cl₂:MeOH (10:0 to 9:1)

and hexane:AcOEt (9:1 to 4:1) to give 57a (7.45 g, 39%): ¹H

NMR (CDCl₃) δ 1.31 (3H, d J ) 7.2 Hz), 2.58-2.84 (2H, m),

3.33 (1H, dd, J ) 16.1, 7.1 Hz), 3.84 (3H, s), 7.15-7.23 (2H,

m), 7.30-7.40 (1H, m).

7-Meth oxy-2-m eth yl-1-in d a n on e (57b): 17% yield. Anal.

(C₁₁H₁₂O₂‚0.1H₂O) C, H.

2-Eth yl-7-m eth oxy-1-in d a n on e (57c): three steps yield

51%; mp 67-69 °C. Anal. (C₁₂H₁₄O₂) C, H.

Eth yl (6-Meth oxy-2-m eth yl-3H-in den -1-yl)acetate (58a).

To a solution of triethyl phosphonoacetate (17.2 g, 76.7 mmol)

in toluene (100 mL) was added 60% NaH (3.06 g, 76.5 mmol)

at 0 °C. After the reaction mixture was stirred for 1 h at this

temperature, a solution of the indanone 57a (1.35 g, 7.63

mmol) in toluene (25 mL) was slowly added. The mixture was

refluxed for 4 h and then was poured into 1 N HCl and

extracted with AcOEt. The extract was washed with water,

dried, and concentrated to produce a crude residue, which was

chromatographed by eluting with hexane:AcOEt (19:1) to give

the mixture of the compound 58a and its positional isomer

(1.65 g, 88%). The mixture was used to the next preparation

without further purification: ¹H NMR (CDCl₃) δ 1.24 (3H, t,

J ) 7.2 Hz), 2.12 (3H, s), 3.27 (2H, s), 3.49 (2H, s), 3.83 (3H,

s), 4.14 (2H, q, J ) 7.2 Hz), 6.68 (1H, dd, J ) 2.5, 8.1 Hz),

6.86 (1H, d, J ) 2.5 Hz), 7.24 (1H, d, J ) 8.1 Hz).

[(3Z)-Ben zylid en e-6-m eth oxy-2-m eth yl-3H-in d en -1-yl]-

a cetic a cid (61a ). To a solution of the crude indene 58a (1.64

g, 6.66 mmol) in MeOH (20 mL) were added benzaldehyde

(1.35 mL, 13.3 mmol) and 1 N NaOMe (20.0 mL, 20 mmol) at

room temperature. The resulting solution was refluxed for 160

min, evaporated, poured into 1 N HCl, and extracted with

AcOEt. The organic layer was washed with water, dried, and

concentrated. The residue was chromatographed by eluting

with hexane:AcOEt (9:1) and then CHCl₃:MeOH (9:1) and

recrystallized (hexane:AcOEt) to afford 61a : 0.841 g (41%

1

yield); mp 146-160 °C; H NMR (CDCl₃) δ 2.19 (3H, s), 3.59

(2H, s), 3.78 (3H, s), 6.40 (1H, dd, J ) 8.2, 2.4 Hz), 6.75 (1H,

d, J ) 2.4 Hz), 7.12 (1H, s), 7.24 (1H, d, J ) 8.2 Hz), 7.30-

7.56 (5H, m); IR ν_max(KBr) 3428, , 2834, 1701, 1611, 1582 cm^-1

;

EIMS m/ z 306 (M⁺, base peak). Anal. (C₂₀H₁₈O₃‚0.2H₂O) C,

H.

[3(Z)-Ben zilid en e-7-m eth oxy-2-m eth yl-3H-in d en -1-yl]-

a cet ic a cid (61b ): mp 165-175 °C; 59% yield. Anal.

(C₂₀H₁₈O₃‚0.6H₂O) C, H.

[3(Z)-Ben zylid en e-2-et h yl-7-m et h oxy-3H -in d en -1-yl]-

a cetic a cid (61c): 166-188 °C (dec); 47% yield. Anal. (C₂₁

H₂₀O₃‚0.4H₂O): C, H.

-

(Z)-2-[3-(Bip h en yl-2-ylm eth ylen e)-2-eth yl-7-m eth oxy-

3H-in d en -1-yl]a cetic a cid (61d ): mp 230-232 °C; 39% yield;

EIMS m/ z 165 (base peak), 396 (M⁺); HR-EIMS calcd for

C₂₇H₂₄O₃396.1774, found 396.1772.

(E/Z)-[3-(2-Ben zylben zylid en e)-2-eth yl-7-m eth oxy-3H-

in d en -1-yl]a cetic a cid (61e): mp 119.5-136 °C; 62% yield.

Anal. (C₂₈H₂₆O₃‚0.3H₂O) C, H.

(Z)-[3-(3-Ch lor oben zylid en e)-2-eth yl-7-m eth oxy-3H-in -

d en -1-yl]a cetic a cid (61f): mp 173-178 °C; 79% yield. Anal.

(C₂₁H₁₉O₃Cl 0.3H₂O) C, H, Cl.

(Z)-[3-(2,3-Dich lor ob en zylid en e)-2-et h yl-7-m et h oxy-

3H-in d en -1-yl]a cetic a cid (61g): mp 214.5-222 °C; 63%

yield; EIMS m/ z 388 (M⁺, base peak); HR-EIMS calcd for

C₂₁H₁₈O₃Cl₂388.0632, found 388.0619.

(Z)-(2-Eth yl-7-m eth oxy-3-(n a p h th a len -1-ylm eth ylen e)-

3H-in d en -1-yl)a cetic a cid (61i): mp 188-191 °C; 46% yield.

Anal. (C₂₅H₂₂O₃) C, H.

(Z)-(2-Eth yl-7-m eth oxy-3-(n a p h th a len -2-ylm eth ylen e)-

3H-in d en -1-yl)a cetic a cid (61j): mp 188-192.5 °C; 56%

yield. Anal. (C₂₅H₂₂O₃) C, H.

E t h yl (7-m et h oxy-2-m et h ylin d en -1-ylid en e)a cet a t e

(59b): 49% yield; ¹H NMR (CDCl₃) δ 1.24 (3H, d, J ) 6.6 Hz),

1.27 (3H, t, J ) 7.0 Hz), 2.50-2.71 (1H, m), 2.93-3.19 (2H,

m), 3.81 (3H, s), 4.21 (2H, q, J ) 7.0 Hz), 5.81 (1H, d, J ) 2.0

Hz), 6.70 (1H, d, J ) 8.4 Hz), 6.86 (1H, d, J ) 7.6 Hz), 7.25

(1H, t, J ) 7.8 Hz).

Eth yl (2-eth yl-7-m eth oxyin dan -1-yliden e)acetate (59c):

36% yield. Anal. (C₁₆H₂₀O₃‚0.1H₂O) C, H.

Eth yl (2-Br om o-7-m eth oxy-2-m eth ylin d a n -1-ylid en e)-

a ceta te (60b). To a solution of the ester compound 59a (1.39

g, 5.65 mmol) in CCl₄(15 mL) were added NBS (1.11 g, 6.22

mmol) and benzoyl peroxide (68.5 mg, 0.283 mmol). The

mixture was stirred at 50 °C for 6 h, filtered, washed with

saturated Na₂S₂O₃, and dried. After removal of the solvent,

the residue was chromatographed by eluting with hexane:

2-[3(Z)-Ben zylid en e-6-m et h oxy-2-m et h yl-3H-in d en -1-

yl]a ceta m id e (62a ). To a solution of the acetic acid derivatve

61a (200 mg, 0.645 mmol) in CH₃CN (10.0 mL) were added

Et₃N (0.140 mL, 1.00 mmol) and benzotriazol-1-yloxytris-

(dimethylamino)phosphonium hexafluorophosphate (434 mg,

0.981 mmol) at 0 °C. The resulting solution was stirred at

room temperature for 45 min, and then 28% NH₄OH (0.440

mL) was added. After 30 min, the mixture was poured into 2

N HCl and extracted with AcOEt. The organic layer was

washed with water and dried. After removal of the solvent,

the residue was chromatographed twice by eluting with CH₂-

Cl₂:MeOH (99:1 to 98.5:1.5) and hexane:AcOEt (1:1 to 1:9) to

1

AcOEt (19:1) to afford 60b (0.424 g, 23%): mp 85-91 °C; H

NMR (CDCl₃) δ 1.23 (3H, t, J ) 7.2 Hz), 2.12 (3H, s), 3.42

(2H, s), 3.84 (3H, s), 4.22 (2H, qd, J ) 7.2, 1.0 Hz), 6.02 (1H,

s), 6.79 (1H, d, J ) 8.0 Hz), 7.01 (1H, dd, J ) 7.2, 0.8 Hz),

7.13 (1H, t, J ) 7.7 Hz); IR ν_max(KBr) 1750, 1580 cm^-1; EIMS

m/ z 199 (base peak), 324 (M⁺); HR-EIMS calcd for C₁₅H₁₇BrO₃

324.0361, found 324.0377.

E t h yl (2-Br om o-2-et h yl-7-m et h oxyin d a n -1-ylid en e)-

a ceta te (60c). This compound was used in the next step

without purification.

1

Eth yl (7-Meth oxy-2-m eth yl-3H-in den -1-yl)acetate (58b).

The mixture of the ester compound 60b (388 mg, 1.19 mmol)

and PtO₂(38.4 mg) in AcOH (4.0 mL) was hydrogenated under

ordinary atmosphere overnight. The catalyst was filtered off

and the solvent was evaporated. The residue was chromato-

graphed by eluting with hexane:AcOEt (97:3 to 9:1) and

crystallized from hexane:AcOEt to give 58b (170 mg, 59%):

mp 76-79 °C; ¹H NMR (CDCl₃) δ 1.25 (3H, s, J ) 7.0 Hz),

2.04 (3H, s), 3.32 (2H, s), 3.67 (2H, s), 3.78 (3H, s), 4.16 (2H,

q, J ) 7.0 Hz), 6.73 (1H, d, J ) 7.8 Hz), 6.98 (1H, d, J ) 6.6

give 62a : 183 mg (92%); mp 174-178 °C; H NMR (CDCl₃) δ

2.22 (3H, s), 3.55 (2H, s), 3.79 (3H, s), 5.44 (1H, br s), 5.64

(1H, br s), 6.44 (1H, dd, J ) 8.4, 2.4 Hz), 6.73 (1H, d, J ) 2.4

Hz), 7.16 (1H, s), 7.29 (1H, d, J ) 8.4 Hz), 7.32-7.60 (5H, m);

IR ν_max(KBr) 3389, 3196, 1653, 1614 cm^-1; EIMS m/ z 305 (M⁺,

base peak). Anal. (C₂₀H₁₉NO₂‚0.3H₂O) C, H, N.

2-[3(Z)-Ben zilid en e-7-m et h oxy-2-m et h yl-3H -in d en -1-

yl]a ceta m id e (62b): mp 175-177 °C; 96% yield; EIMS m/ z

305 (base peak, M⁺); HR-EIMS calcd for C₂₀H₁₉NO₂305.1414,

found 305.1416.

Hz), 7.06 (1H, t, J ) 7.7 Hz); IR ν_max(KBr) 1735, 1578 cm^-1

;

2-[3(Z)-Ben zylid en e-2-eth yl-7-m eth oxy-3H-in d en -1-yl]-

a ceta m id e (62c): mp 153-156 °C; 99% yield; EIMS m/ z 260

(base peak), 319 (M⁺).

EIMS m/ z 172 (base peak), 246 (M⁺). Anal. (C₁₅H₁₈O₃‚0.1H₂O)

C, H.

Eth yl (2-Eth yl-7-m eth oxy-3H-in d en -1-yl)a ceta te (58c).

Method A yielded 32% in two steps.

(Z)-2-[3-(Bip h en yl-2-ylm eth ylen e)-2-eth yl-7-m eth oxy-

3H-in d en -1-yl]a ceta m id e (62d ): mp 190-200 °C; 91% yield;

EIMS m/ z 165 (base peak), 395 (M⁺); HR-EIMS calcd for

C₂₇H₂₅NO₂395.1883, found 395.1885.

(E/Z)-2-[3-(2-Ben zylb en zylid en e)-2-et h yl-7-m et h oxy-

3H-in d en -1-yl]a ceta m id e (62e): mp 133-147 °C; 74% yield;

EIMS m/ z 409 (M⁺, base peak).

Method B: To a solution of the ester compound 59c (4.15 g,

0.0160 mol) in CHCl₃(40 mL) was added three drops of

concentrated H₂SO₄. The resulting solution was refluxed for

40 min and dried over K₂CO₃. After removal of the solvent,

the residue was chromatographed by eluting with hexane:

AcOEt (98:2 to 95:5) to give 58c (3.55 g, 85%). Anal.

(C₁₆H₂₀O₃‚0.5H₂O) C, H.

(Z)-2-[3-(3-Ch lor oben zylid en e)-2-eth yl-7-m eth oxy-3H-

in d en -1-yl]a ceta m id e (62f): mp 204-208 °C; 85% yield;

3656 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19

Hagishita et al.

EIMS m/ z 294 (base peak), 353 (M⁺); HR-EIMS calcd for

C₂₁H₂₀NO₂Cl 353.1181, found 353.1160.

(Z)-2-[3-(2,3-Dich lor oben zylid en e)-2-eth yl-7-m eth oxy-

3H-in d en -1-yl]a ceta m id e (62g): mp 170-176.5 °C; 81%

yield; HR-EIMS calcd for C₂₁H₁₉NO₂Cl₂387.0791, found

387.0798.

(Z)-2-[2-E t h yl-7-m et h oxy-3-(3-(t r iflu or om et h yl)b en -

zylid en e)-3H-in d en -1-yl]a ceta m id e (62h ): mp 205.5-208

°C; 32% yield (two steps). Anal. (C₂₂H₂₀NO₂F₃) C, H, N, F.

(Z)-2-(2-Eth yl-7-m eth oxy-3-(n aph th alen -1-ylm eth ylen e)-

3H-in d en -1-yl)a ceta m id e (62i): mp 172-175.5 °C; 91%

yield. Anal. (C₂₅H₂₃NO₂‚0.1H₂O) C, H, N.

(Z)-2-(2-Eth yl-7-m eth oxy-3-(n aph th alen -2-ylm eth ylen e)-

3H-in d en -1-yl)a ceta m id e (62j): mp 221-223 °C; 80% yield.

Anal. (C₂₅H₂₃NO₂‚0.3H₂O) C, H, N.

(Z)-Eth yl [[3-(bip h en yl-2-ylm eth ylen e)-1-(ca r ba m oyl-

m eth yl)-2-eth yl-3H-in d en -7-yl]oxy]a ceta te (64d ): mp 161-

163 °C; 76% yield. Anal. (C₃₀H₂₉NO₄‚1.5H₂O) C, H, N.

E t h yl

(Z)-[[1-(2-b en zylb en zylid en e)-3-(ca r b a m oyl-

m eth yl)-2-eth yl-1H-in den -4-yl]oxy]acetate (64e): mp 157.5-

158.5 °C; 83% yield. Anal. (C₃₁H₃₁NO₄‚0.4H₂O) C, H, N.

E t h yl (Z)-[[3-(ca r b a m oylm et h yl)-1-(3-ch lor ob en zyli-

d en e)-2-eth yl-1H-in d en -4-yl]oxy]a ceta te (64f): mp 182.5-

184 °C; 57% yield. Anal. (C₂₄H₂₄NO₄Cl) C, H, N, Cl.

E t h yl (Z)-[[3-(ca r b a m oylm et h yl)-1-(2,3-d ich lor ob en -

zylid en e)-2-et h yl-1H -in d en -4-yl]oxy]a cet a t e (64g): mp

185.5-187.5 °C; 83% yield. Anal. (C₂₄H₂₃NO₄Cl₂) C, H, N,

Cl.

Eth yl (Z)-[[3-(ca r ba m oylm eth yl)-2-eth yl-1-(3-(tr iflu o-

r om eth yl)ben zylid en e)-1H-in d en -4-yl]oxy]a ceta te (64h ):

mp 175.5-182.5 °C; 76% yield; EIMS m/ z 400 (base peak),

459 (M⁺); HR-EIMS calcd for C₂₅H₂₄NO₄F₃459.1656, found

459.1669.

2-[3(Z)-Ben zylid en e-6-h yd r oxy-2-m et h yl-3H -in d en -1-

yl]a ceta m id e (63a ): 49% yield; mp 178-180 °C; ¹H NMR

(CDCl₃) δ 2.20 (3H, s), 3.56 (2H, s), 5.55 (1H, br s), 5.77 (1H,

br s), 6.41 (1H, d, J ) 8.4, 2.4 Hz), 6.69 (1H, d, J ) 2.4 Hz),

7.14 (1H, s), 7.25 (1H, d, J ) 8.4 Hz), 7.30-7.56 (6H, m); IR

Eth yl (Z)-((3-(ca r ba m oylm eth yl)-2-eth yl-1-(n a p h th a -

len -1-ylm eth ylen e)-1H-in d en -4-yl)oxy)a ceta te (64i): mp

153.5-160 °C; 64% yield. Anal. (C₂₈H₂₇NO₄‚0.4H₂O) C, H,

N.

ν

_max(KBr) 3212, 1657, 1602 cm^-1; EIMS m/ z 232 (base peak),

291 (M⁺). Anal. (C₁₉H₁₇NO₂‚0.4H₂O) C, H, N.

Eth yl (Z)-((3-(ca r ba m oylm eth yl)-2-eth yl-1-(n a p h th a -

len -2-ylm eth ylen e)-1H-in d en -4-yl)oxy)a ceta te (64j): mp

201-204 °C; 77% yield. Anal. (C₂₈H₂₇NO₄‚0.8H₂O) C, H, N.

4-[[1(Z)-Ben zylid en e-3-(ca r b a m oylm et h yl)-2-m et h yl-

1H-in d en -5-yl]oxy]bu ta n oic Acid (65a ). NaOH (1 N, 0.200

mL, 0.200 mmol) was added to a solution of 64a (39.4 mg,

0.0972 mmol) in DMSO (1.0 mL) at room temperature. The

solution was stirred at room temperature for 75 min and

partitioned between 1 N HCl and AcOEt. The organic layer

was separated, washed with water, dried, and evaporated.

Recrystallization from AcOEt afforded 65a (19.5 mg, 53%): mp

2-[3(Z)-Ben ziliden e-7-h ydr oxy-2-m eth yl-3H-in den -1-yl]-

a ceta m id e (63b): mp 200-203 °C; quantitative yield; EIMS

m/ z 274 (base peak), 291 (M⁺); HR-EIMS calcd for C₁₉H₁₇NO₂

291.1258, found 291.1253.

(Z)-2-(3-Ben zylid en e-2-eth yl-7-h yd r oxy-3H-in d en -1-yl)-

a ceta m id e (63c): mp 176-180 °C (dec); 87% yield. Anal.

(C₂₀H₁₉NO₂‚0.8H₂O) C, H, N.

(Z)-2-[3-(Bip h en yl-2-ylm et h ylen e)-2-et h yl-7-h yd r oxy-

3H-in d en -1-yl]a ceta m id e (63d ): mp 168-172 °C; 49% yield.

Anal. (C₂₆H₂₃NO₂‚0.2H₂O) C, H, N.

(Z)-2-[3-(2-Ben zylben zylid en e)-2-eth yl-7-h yd r oxy-3H-

in d en -1-yl]a ceta m id e (63e): mp 137.5-153.5 °C; 72% yield.

Anal. (C₂₇H₂₅NO₂‚0.2H₂O) C, H, N.

(Z)-2-[3-(3-Ch lor oben zylid en e)-2-eth yl-7-h yd r oxy-3H-

in d en -1-yl]a ceta m id e (63f): mp 185-185.5 °C; 79% yield.

Anal. (C₂₀H₁₈NO₂Cl‚0.2H₂O) C, H, N, Cl.

(Z)-2-[3-(2,3-Dich lor oben zylid en e)-2-eth yl-7-h yd r oxy-

3H-in d en -1-yl]a ceta m id e (63g): mp 193-194.5 °C; 90%

yield. Anal. (C₂₀H₁₇NO₂Cl₂) C, H, N, Cl.

(Z)-2-[2-E t h yl-7-h yd r oxy-3-(3-(t r iflu or om e t h yl)b e n -

zylid en e)-3H-in d en -1-yl]a ceta m id e (63h ): mp 184.5-186

°C; 96% yield. Anal. (C₂₁H₁₈NO₂F₃) C, H, N, F.

(Z)-2-(2-Eth yl-7-h ydr oxy-3-(n aph th alen -1-ylm eth ylen e)-

3H-in d en -1-yl)a ceta m id e (63i): mp 189-189.5 °C; 92% yield.

Anal. (C₂₄H₂₁NO₂‚0.3H₂O) C, H, N.

1

187-188 °C; H NMR (d₆-DMSO) δ 1.82-2.02 (2H, m), 2.14

(3H, s), 2.36 (2H, t, J ) 7.0 Hz), 3.94 (1H, t, J ) 6.3 Hz), 6.42

(1H, dd, J ) 8.4, 2.0 Hz), 6.85 (1H, d, J ) 2.0 Hz), 6.96 (1H,

br s), 7.13 (1H, d, J ) 8.4 Hz), 7.16 (1H, s), 7.32-7.57 (6H,

m); IR ν_max(KBr) 3462, 3342, 1715, 1697, 1647, 1613, 1582

cm^-1; EIMS m/ z 232 (base peak), 377 (M⁺). Anal. (C₂₃H₂₃

NO₄‚0.5H₂O) C, H, N.

-

[[1(Z)-Ben zylid en e-3-(ca r ba m oylm eth yl)-2-m eth yl-1H-

in d en -4-yl]oxy]a cetic a cid (65b): mp 224-226 °C; 55%

yield; EIMS m/ z 349 (base peak, M⁺); HR-EIMS calcd for

C₂₁H₁₉NO₄349.1312, found 349.1311.

(Z)-((3-Ben zylid en e-1-(ca r b a m oylm et h yl)-2-et h yl-3H-

in d en -7-yl)oxy)a cetic a cid (65c): mp 119-205 °C; 91%

yield; EIMS m/ z 304 (base peak), 363 (M⁺); HR-EIMS calcd

C₂₂H₂₁NO₄363.1469, found 363.1485.

(Z)-2-(2-Eth yl-7-h ydr oxy-3-(n aph th alen -2-ylm eth ylen e)-

3H-in d en -1-yl)-a ceta m id e (63j): mp 200-201.5 °C; 65%

yield. Anal. (C₂₄H₂₁NO₂‚0.2H₂O) C, H, N.

(Z)-[[1-(Biph en yl-2-ylm eth ylen e)-3-(car bam oylm eth yl)-

2-eth yl-1H-in d en -4-yl]oxy]a cetic a cid (65d ): mp 205-209

°C; 93% yield; Anal (C₂₈H₂₅NO₄‚0.3H₂O) C, H, N.

E t h yl 4-[[1(Z)-Ben zylid en e-3-(ca r b a m oylm et h yl)-2-

m eth yl-1H-in d en -5-yl]oxy]bu ta n a te (64a ). To compound

63a (43.7 mg, 0.150 mmol) in DMF (1.0 mL) was added 60%

NaH (21.3 mg, 0.533 mmol). After addition, the mixture was

stirred at room temperature for 60 min, and then ethyl

4-bromobutyrate (75 µL, 0.524 mmol) was added. The mixture

was stirred at 0 °C for 45 min and then at room temperature

for 75 min and partitioned between 1 N HCl and AcOEt. The

organic layer was separated, washed with water, dried,

filtered, and concentrated. The residue was purified by

preparative TLC (200 × 200 × 0.25 mm, elution with AcOEt)

to give 64a (38.0 mg, 63%): mp 124-128 °C; ¹H NMR (CDCl₃)

δ 1.25 (3H, t, J ) 7.0 Hz), 1.99-2.17 (2H, m), 2.21 (3H, s),

2.50 (2H, t, J ) 7.2 Hz), 3.54 (2H, s), 3.98 (2H, t, J ) 6.3 Hz),

4.14 (2H, q, J ) 7.0 Hz), 5.50 (1H, br s), 5.67 (1H, br s), 6.42

(1H, dd, J ) 8.2, 2.4 Hz), 6.73 (1H, d, J ) 2.4 Hz), 7.16 (1H,

s), 7.27 (1H, d, J ) 8.2 Hz), 7.32-7.58 (5H, m); IR ν_max(KBr)

2972, 2919, 1739, 1687, 1655, 1614 cm^-1; EIMS m/ z 115 (base

peak), 405 (M⁺). Anal. (C₂₅H₂₇NO₄‚0.9H₂O) C, H, N.

Eth yl [[1(Z)-ben zylid en e-3-(ca r ba m oylm eth yl)-2-m eth -

yl-1H-in d en -4-yl]oxy]a ceta te (64b): 77% yield; mp 162-165

°C. Anal. (C₂₃H₂₃NO₄‚0.8H₂O) C, H, N.

(Z)-[[1-(2-Ben zylben zylid en e)-3-(ca r ba m oylm eth yl)-2-

eth yl-1H-in d en -4-yl]oxy]a cetic a cid (65e): mp 194-200 °C;

quantitative yield; EIMS m/ z 179 (base peak), 453 (M⁺); HR-

EIMS calcd for C₂₉H₂₇NO₄453.1938, found 453.1944.

(Z)-[[3-(Ca r ba m oylm eth yl)-1-(3-ch lor oben zylid en e)-2-

eth yl-1H-in d en -4-yl]oxy]a cetic a cid (65f): mp 213.5-214

°C; 82% yield. Anal. (C₂₂H₂₀NO₄Cl‚0.3H₂O) C, H, N, Cl.

(Z)-[[3-(Car bam oylm eth yl)-1-(2,3-dich lor oben zyliden e)-

2-eth yl-1H-in d en -4-yl]oxy]a cetic a cid (65g): mp 226-228.5

°C; 89% yield; EIMS m/ z 378 (base peak), 431 (M⁺); HR-EIMS

calcd for C₂₂H₁₉NO₄Cl₂431.0689, found 431.0685.

(Z)-[[3-(Ca r ba m oylm eth yl)-2-eth yl-1-(3-(tr iflu or om eth -

yl)ben zylid en e)-1H-in d en -4-yl]oxy]a cetic a cid (65h ): mp

207-211.5 °C; 70% yield. Anal. (C₂₃H₂₀NO₄F₃) C, H, N, F.

(Z)-((3-(Ca r ba m oylm eth yl)-2-eth yl-1-n a p h th a len -1-yl-

m eth ylen e-1H-in d en -4-yl)oxy)a cetic a cid (65i): mp 210.5-

213 °C; 90% yield; EIMS m/ z 354 (base peak), 413 (M⁺); HR-

EIMS calcd for C₂₆H₂₃NO₄413.1624, found 413.1621.

(Z)-((3-(Ca r ba m oylm eth yl)-2-eth yl-1-n a p h th a len -2-yl-

m eth ylen e-1H-in d en -4-yl)oxy)a cetic a cid (65j): mp 210.5-

215.5 °C; 70% yield; EIMS m/ z 354 (base peak), 413 (M⁺); HR-

EIMS calcd for C₂₆H₂₃NO₄413.1626, found 413.1629.

(Z)-Met h yl ((3-Ben zyl-1-(ca r b a m oylm et h yl)-2-et h yl-

3H-in d en -7-yl)oxy)a ceta te (66a ) a n d (Z)-Meth yl ((3-Ben -

zyl-1-(ca r b a m oylm e t h yl)-2-e t h yl-1H -in d e n -7-yl)oxy)-

(Z)-Eth yl ((3-ben zyliden e-1-(car bam oylm eth yl)-2-eth yl-

3H-in d en -7-yl)oxy)a ceta te (64c): mp 139-142 °C; 61% yield.

Anal. (C₂₄H₂₅NO₄‚0.1H₂O) C, H, N.

Potent Inhibitors of Secretory Phospholipase A2

J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 19 3657

a ceta te (67a ). A mixture of the methyl ester of 65a (113 mg,

0.300 mmol) and 5% Pd-C (11.9 mg) in MeOH (5.0 mL) was

hydrogenated under normal atmosphere for 18 min. The

catalyst was filtered off and the solvent was evaporated. The

residue was purified by preparative TLC (200 × 200 × 0.25

mm, eluting with AcOEt) to give the crude product which was

recrystallized from CHCl3:hexane to afford the pure product

66a (48.8 mg, 43%): mp 118-121 °C; ¹H NMR (300 MHz,

CDCl₃) δ 1.17 (3H, t, J ) 7.5 Hz), 2.40 (1H, qd, J ) 7.5, 15.0

Hz), 2.71 (1H, qd, J ) 7.5, 15.0 Hz), 2.78 (1H, dd, J ) 7.8,

13.8 Hz), 3.37 (1H, dd, J ) 4.2, 13.8 Hz), 3.56 (1H, d, J ) 15.3

Hz), 3.73 (1H, d, J ) 14.7 Hz), 3.72-3.83 (1H, m), 3.79 (3H,

s), 4.65 (2H, s), 4.97 (1H, br s), 5.75 (1H, br s), 6.62 (1H, d, J

) 8.4 Hz), 6.76 (1H, d, J ) 7.2 Hz), 6.91-7.00 (2H, m), 7.01

(1H, t, J ) 7.8 Hz), 7.07-7.28 (3H, m); IR ν_max(KBr) 3136,

3023, 1743, 1686 cm^-1; EIMS m/ z 334 (base peak), 379 (M⁺).

Anal. (C₂₃H₂₅NO₄) C, H, N.

zomethane solution was added. The mixture was incubated

for 15 min at room temperature. An aliquot (10-15 µL) of

the mixture was injected onto a Supersphere RP-8 column and

eluted with 93% CH₃CN. The amount of released oleic acid

was calculated by the ratio to margaric acid. Each sample

was titrated in duplicate, and the values were averaged for

plotting and calculation of IC₅₀values. Inhibition generated

by enzyme reactions containing inhibitors relative to the

uninhibited control reactions were calculated. IC₅₀values

were determined by plotting log concentration versus inhibi-

tion values in the range from 10 to 90% inhibition.

Ack n ow led gm en t. We would like to acknowledge

our colleagues at Lilly Research Laboratories, India-

napolis, IN, who have collaborated with us during the

course of this project. We thank Drs. H. Arita and Y.

Hori for their support asd suggestions throughout the

course of this work.

67a : mp 183-186 °C; ¹H NMR (300 MHz, CDCl₃) δ 1.15

(3H, t, J ) 7.5 Hz), 2.62 (1H, qd, J ) 7.5, 15.0 Hz), 2.73 (1H,

qd, J ) 7.5, 15.0 Hz), 2.89 (1H, dd, J ) 4.5, 13.8 Hz), 3.25

(1H, dd, J ) 5.3, 13.8 Hz), 3.80 (1H, s), 3.89-3.95 (3H, m),

4.72 (1H, ABq, A part J ) 16.7 Hz), 4.81 (1H, ABq, B part J

) 16.7 Hz), 4.90 (1H, br s), 5.97 (1H, br s), 6.48 (1H, d, J )

8.1 Hz), 6.75 (1H, d, J ) 7.2 Hz), 7.11 (1H, t, J ) 7.8 Hz),

Refer en ces

(1) (a) Mayer, R. J .; Marshall, L. A. New Insights on Mammalian

Phopspholipase A2(s); Comparison of Arachidonoyl-Selective and

-Non Selective Enzymes. FASEB J . 1993, 7, 339-348. (b)

Bomalaski, J . S.; Clark, M. A. Phospholipase A2 and Arthritis.

Arthritis Rheumatism 1993, 36, 190-198.

7.10-7.28 (5H, m); IR ν_max(KBr) 3387, 3195, 1750, 1646 cm^-1

;

EIMS m/ z 334 (base peak), 379 (M⁺).

(Z)-(3-Ben zyl-1-(ca r ba m oylm eth yl)-2-eth yl-3H-in d en -

7-yloxy)a cetic a cid (66b): 50% Yield, mp 193-197 °C

(CHCl₃:hexane). Anal. (C₂₂H₂₃NO₄‚0.4H₂O) C, H, N.

(Z)-((3-Ben zyl-1-(ca r ba m oylm eth yl)-2-eth yl-1H-in d en -

7-yl)oxy)a cetic a cid (67b): 90% yield; EIMS m/ z 231 (base

peak), 365 (M⁺); HR-EIMS calcd for C₂₂H₂₃NO₄365.1626,

found 365.1630.

En zym e Assa y. Phospholipase A2 activity was measured

by established procedures using racemic diheptanoylthiophos-

phatidylcholine/Triton mixed micelle (chromogenic assay)¹⁸or

1-palmitoyl-2-oleoyl-sn-phosphatidylcholine/deoxycholic acid

mixed micelle (PC/DOC assay)^19,20as substrate.

(2) (a) Vadas, P.; Pruzanski, W.; Stefanski, E.; Ruse, J .; Farewell,

V.; McLaughlin, J .; Bombardier, C. Concordance of Endogeneous

Cortisol and Phospholipase A2 Levels in Gram-Negative Septic

Shock: A Prospective Study. J . Lab. Clin. Med. 1988, 111, 584.

(b) Aufenanger, J .; Zimmer, W.; Kattermann, R. Characteristics

and Clinical Application of a Radiometric Escherichia Coli-Based

Phospholipase A2 Assay Modified for Serum Analysis. Clin.

Chem. 1993, 39, 605-613.

(3) Nevalainen, T. J . The role of phospholipase A in acute pancre-

atitis. Scand. J . Gastroenterol 1980, 15, 641-650.

(4) (a) Vadas, P.; Pruzanski, W. Role of Secretory Phospholipase A2

in the Pathobiology of Disease. Lab. Invest. 1986, 55, 391-404.

(b) Pruzanski, W.; Vadas, P. Secretory Synovial Fluid Phos-

phlipase A2 and its Role in the Pathogenesis of Inflammation

in Athritis. J . Rheumatol. 1988, 15, 1601-1603. (c) Pruzanski,

W., Vadas, P. Phospholipase A2: A Mediator Between Proximal

and Distal Effectors of Inflammation. Immunol. Today 1991, 12,

143-146.

Ch r om ogen ic Assa y. A 200 µL portion of the reaction

mixture containing 1 mM diheptanoylthiophosphatidylcholine,

0.3 mM Triton, 0.12 mM DTNB, 10 mM CaCl₂, 0.1 M KCl,

and 0.1% BSA in 25 mM Tris-HCl buffer (pH 7.5) was added

to the wells of a microplate. Test compounds (10 µL) were

added to each well as DMSO solutions. To the control wells

was added 10 µL of DMSO. Reactions were initiated by

addition of 50 ng of the enzyme in 10 µL of AcONa buffer (pH

4.5) containing 0.2 M NaCl and incubated at 40 °C for 30 min.

The reaction was monitored by the absorbance of wells at 405

nm with an automatic plate reader. The IC₅₀values were

determined by diluting test compounds serially 5-fold. Inhibi-

tion measured at 405 nm, generated by enzyme reactions

containing inhibitors relative to the uninhibited control reac-

tions, was determined. Each sample was titrated in triplicate,

and result values were averaged for plotting and calculation

of IC₅₀values. IC₅₀values were determined by plotting log

concentration versus inhibition values in the range from 10

to 90% inhibition.

P C/DOC Assa y. A 160 µL portion of the reaction mixture

containing 1 mM 1-palmitoyl-2-oleoylphosphatidylcholine, 3

mM sodium deoxycholic acid, 10 mM CaCl₂, 150 mM NaCl,

and 0.1% BSA in 100 mM Tris-HCl buffer (pH 8.0) was added

to the test tube. Test compounds (20 µL) were added to each

tube as DMSO solution and preincubated at 40 °C for 10 min.

Reactions were initiated by addition of 20 ng of the enzyme in

20 µL of AcONa buffer (pH 4.5) containing 0.2 M NaCl and

incubated at 40 °C for 30 min. Reactions were stopped by

addition of 800 µL of Dole reagent.²²Margaric acid (6 nM) in

heptane (12 µL) was added as an internal standard. Then 320

µL of distilled water and 480 µL of heptane were added, and

the solution was shaken for 10 s. After centrifugation at 20

°C for 30 s at 10 000 rpm, 400 µL of the upper phase was

pipetted into another tube containing 15-20 mg of silicic acid

powder, and then the solution was shaken for 30 s. After

centrifugation for 30 s at 10 000 rpm, 150 µL of heptane was

transfered into another tube, and the heptane was removed

using a water aspirator. Then 100 µL of 0.05% 9-anthryldia-

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J M960395Q

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Potent inhibitors of secretory phospholipase A2: Synthesis and inhibitory activities of indolizine and indene derivatives

DOI: 10.1021/jm960395q

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