Synthesis and pharmacological evaluation of novel cis-3,4-Diaryl-hydroxychromanes as high affinity partial agonists for the estrogen receptor

Bioorganic & Medicinal Chemistry 10 (2002) 125–145

Synthesis and Pharmacological Evaluation of Novel

cis-3,4-Diaryl-hydroxychromanes as High Aﬃnity Partial

Agonists for the Estrogen Receptor

Paul S. Bury,* Lise B. Christiansen, Poul Jacobsen, Anker S. Jørgensen,

Anders Kanstrup, Lars Nærum, Steven Bain,^yChristian Fledelius, Birgitte Gissel,

Birgit S. Hansen, Niels Korsgaard, Susan M. Thorpe and Karsten Wassermann

˚

Novo Nordisk A/S, Novo Nordisk Park, DK-2760 Maløv, Denmark

Received 2 April 2001; accepted 9 July 2001

Abstract—The syntheses and in vitro pharmacological evaluation of a number of cis-3,4-diaryl-hydroxy-chromanes are reported,

along with the results of a thorough in vivo proﬁling of the tissue-selective estrogen partial-agonist NNC 45-0781 [3, (À)-(3S,4R)-7-

hydroxy-3-phenyl-4-(4-(2-pyrrolidinoethoxy)phenyl)chromane]. These studies showed that NNC 45-0781 is a very promising can-

didate for the prevention of post-menopausal osteoporosis, and the treatment of other health issues related to the loss of endo-

Introduction

metrial cancer, and an increased risk of developing

breast cancer. The uterine side eﬀects, however, may be

reduced by co-treatment with progesterone therapy.

The critical role performed by estrogen in the main-

tenance and development of physiological tissues other

than the female reproductive system has been increas-

ingly recognized in both males and females over recent

years. In particular, estrogen’s roles in the maintenance

of tissues such as the skeleton, the cardiovascular sys-

tem, and the central nervous system have been high-

lighted.^1À5This recognition of estrogen’s widespread

biological activity has led to the realization that a num-

ber of post-menopausal degenerative diseases, particu-

larly osteoporosis and coronary heart disease, are linked

to the decline in the production of estrogen that occurs

during the menopause.⁶Indeed, the clinical use of long-

term estrogen-based hormone replacement therapy

(ERT) in post-menopausal women has proven to be a

highly eﬀective method for reducing the risks associated

with these degenerative diseases. However, in spite of

the fact that the positive eﬀects of such long-term ERT

are increasingly accepted,⁷the beneﬁts are achieved at

the expense of a number of negative side eﬀects, includ-

ing uterine bleeding, endometrial hyperplasia, endo-

These negative side eﬀects, in turn, frequently lead to a

reduced patient compliance and reluctance to accept

ERT as a treatment form.^8,9Taking these factors into

consideration, it becomes clear that a therapeutic agent

possessing the beneﬁcial properties of estrogen, but

without estrogen’s negative side eﬀects, especially on

breast and endometrial tissue, has huge potential for the

treatment of post-menopausal degenerative disease. A

number of partial estrogens have been reported,¹⁰pos-

sessing these selective properties to various extents,

including the compounds Raloxifene (1, Fig. 1),

Tamoxifen (2, Fig. 1) and more recently, Lasofoxifene

(CP-336,156),^11À14which is currently undergoing clin-

ical trials.

Most of these selective estrogens cannot, however be

described as having ‘ideal estrogen’ proﬁles, and as such

there is still a need for the development of further tissue-

selective partial estrogens. In this article we report on

the discovery and synthesis of a new group of non-ster-

oidal partial estrogens, the cis-3,4-diaryl-hydroxy-chro-

manes, represented by the parent compound of the

series, (À)-(3S,4R)-7-hydroxy-3-phenyl-4-(4-(2-pyrroli-

dinoethoxy)phenyl)chromane (Fig. 1, NNC 45-0781, 3).

*Corresponding author. Tel.: +45-44-434882; fax: +45-44-434547;

e-mail: pjac@novonordisk.com

^yCurrent address: Skeletech Inc., 22002 26th Ave. SE, Suite 104,

Bothell, WA 98021, USA.

PII: S0968-0896(01)00257-7

126

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

Figure 1. Tissue-selective estrogenic compounds.

The syntheses and selected in vitro and in vivo proper-

ties of a number of members of this compound series

are detailed.

lization of the di-p-toluoyl d- and l-tartaric acid salts of

the intermediate methoxy-chromanes 7a and 7c. This

allowed the preparation of substantial quantities of the

optically pure enantiomers (À)-(3S,4R)-7-methoxy-3-

phenyl-4-(4-(2-pyrrolidinoethoxy)phenyl)chromane [(À)-

7a], and (À)-cis-7-methoxy-3-(4-triﬂuoromethylphenyl)-

Chemistry

4-(4-(2-pyrrolidinoethoxy)phenyl)chromane

[(À)-7c].

The general synthetic route used to prepare the series of

target chromanes detailed in this report is shown in

Scheme 1. The synthesis, which was based on a pre-

viously reported preparation of a series of analogous

chromanes,^15,16began with the condensation of 2,4⁰-

dihydroxy-4-methoxybenzophenone¹⁵with a variety of

substituted phenylacetic acids, to give the substituted

3,4-diarylchromen-2-ones 4a–j¹⁷(Scheme 1). In the spe-

ciﬁc case of 4a the O-acetyl group was removed by acid

hydrolysis to give 4-(4-hydroxyphenyl)-7-methoxy-3-

phenyl-chromen-2-one, 4a, as described by Ray and co-

workers.¹⁵Compound 4a and the chromen-2-ones, 4b–j

were then reduced with lithium aluminium hydride to

give 2,3,3-triaryl-prop-2-en-1-ol intermediates, which

were immediately ring-closed, without isolation, by heat-

ing with mineral acid, giving 3-aryl-4-(4-hydroxyphenyl)-

2H-chromenes, 5a–j. These chromenes were then cataly-

tically hydrogenated to give a series of racemic cis-3-aryl-

4-(4-hydroxyphenyl)-7-methoxychromanes, 6a–j, which

were subsequently alkylated at their free phenolic posi-

tions with selected amino-alkyl chloride electrophiles,

[e.g., 1-(2-chloroethyl)-pyrrolidine hydrochloride] to

give products 7a–p. Demethylation of 7a–p by fusion

with pyridine hydrochloride gave the desired racemic

hydroxy-chromanes, 8a–p (NB in the case of com-

pounds 7d, 7i, and 7p the pyridine hydrochloride fusion

reaction also demethylated methoxy groups on the C3-

aryl subunits, to give the dihydroxy products 8d, 8i and

8p, respectively). Small quantities, in the order of 1–

3 mg, of the separated pure enantiomers of 8a–o, namely

9a–o and 10a–o (respectively deﬁned as being the enan-

tiomers with most and least potent binding to the

estrogen receptor, 9a=3) were then isolated by pre-

parative chiral-HPLC separation as detailed in Table 1,

and used purely for in vitro analysis. In the case of the

preparation of compounds 3 (i.e., compound 9a) and 9c

an alternative chiral resolution was carried out on a

multi-gram scale, by means of the fractional crystal-

The 7-methoxy groups of (À)-7a and (À)-7c were then

demethylated by heating with pyridine hydrochloride to

give the optically pure 7-hydroxy compounds 3 (i.e., 9a)

and 9c. The absolute stereochemistry of (À)-7a, and hence

3, was determined by means of X-ray crystallographic

analysis of its (À)-di-p-toluoyl-l-tartaric acid salt.¹⁸

In addition to the preparation of the 7-hydroxy-

chromane series, the analogous 6-hydroxy-chromane,

(ꢀ)-cis-6-hydroxy-3-phenyl-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane, 16, was also prepared (Scheme 2).

The synthesis of 16, which was essentially the same as

that employed for the 7-hydroxychromanes, began with

the reaction of N,N-dimethyl 2,5-dimethoxybenzamide,

11 with 4-benzyloxyphenyllithium to give 4⁰-benzyloxy-

2,5-dimethoxybenzophenone, 12. This was then deben-

zylated by treatment with hydrobromic acid in acetic

acid, to give 2,4⁰-dihydroxy-5-methoxybenzophenone,

13. Compound 13 was then reacted with phenylacetic

acid to give the chromen-2-one, 14, which was subse-

quently reduced, ring-closed, hydrogenated, alkylated

and demethylated to give the target 6-hydro-

xychromane, 16.

In vitro pharmacological analysis

Estrogen receptor (ER) binding assay. The IC₅₀binding

aﬃnities of the chromanes to the estrogen receptor were

determined by measuring their ability to compete with

[³H]-17b-estradiol for receptor binding in ER-rich cyto-

sol derived from rabbit uterine tissue in a dextran-

coated charcoal (DCC) assay as described in previous

publications.^19,20

In vivo pharmacological analysis

Female Sprague–Dawley rats (supplied by M & B, Lille

Skensved, Denmark), 12 weeks of age, weighing

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

127

Scheme 1. (a) Ac₂O, Et₃N, aryl-acetic acid, 110 ^ꢁC. (b) i. LiAlH₄, THF; ii. HCl, 65 ^ꢁC. (c) H₂/Pd-C, ethanol. (d) Amino-alkyl chloride hydrochlo-

ride, K₂CO₃, acetone, 65 ^ꢁC. (e) Pyridine hydrochloride, 150 ^ꢁC. (f) Preparative chiral HPLC.

approximately 250 g were used in these studies. All ani-

mals were allowed free access to water and a pelleted

commercial diet (Altromin 1324) containing 0.9% cal-

cium, 0.7% phosphorous, and 0.6 IU/g Vit D₃. All ani-

mal procedures were conducted according to Novo

Nordisk A/S Animal Care approved protocols, and the

experiments were done in compliance with internal ani-

mal welfare and national guidelines.

glycol+0.9% NaCl, 1:1 v/v), while the remaining rats

(n=10 per group) received bilateral ovariectomies

(OVX) and were treated by oral gavage with either

vehicle, 17a-ethynyl estradiol (EE) (Sigma E-4876, St.

Louis, MO, USA) at doses of 1.5 nmol/g/day 3 days

weekly, or test compound dosed 5 times weekly for 5

weeks beginning 3 days post surgery. Animal body

weights were recorded once weekly. All animals in

this study were pair-fed. The amount of food con-

sumed ad libitum by the sham-operated, vehicle-

treated animals was determined once per week. The

average daily consumption of food per cage was

then calculated for each pair of animals in the

sham group and the cages in all other treatment

groups received a daily feed ration based on this

value. Food consumption of the individual cages was

monitored.

Ovariectomized rat prevention study. Vaginal cytology,

serum cholesterol, uterine tissue and appendicular ske-

leton analysis.

Sham surgeries and ovariectomies were performed while

the animals were anesthetized with a ketamine/xylazine

anesthetic mixture. Ten rats were sham-operated (sham)

and treated by daily oral gavage with vehicle (propylene

128

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

Table 1. Preparative HPLC conditions for the isolation of enantiomers 9a–o and 10a–o

No.

Column^a

Eluent^b

R_tof 9 (min)

R_tof 10 (min)

Flow (mL/min)

a

b

c

d

e

g

h

i

j

k

l

m

n

o

Chiradex A

COD P

Chiradex A

Chiradex P

COD P

Chiradex P

COD P

6:4 M/B2, pH 5.2

81:19 H/I, 0.1%D

7:3 H/I, 0.1%D

5:5 M/B1, pH 5.0

5:5 M/B2, pH 3.5

7:3 H/I, 0.1%D

19.2

36–45

24–33

62–80

20–30

30–38

43–55

46–64

80–102

17–18

15–18

24–31

72–88

64–80

12.2

29–35

17–23

31–45

10–18

21–28

19–34

22–34

28–58

20–23

16–22

33–44

50–60

0.5

6

0.8

20

6

20

6

46:54 M/B1, pH 5

4:6 M/B1, pH 3.5

4:6 M/B2, pH 4.5

54–60:46–40 H/I, 0.1%D

6:4 H/I, 0.1%D

6

20

6

7:3 H/I, 0.1%D

4:6 M/B1, pH 4.5

9:1 H/I, 0.1%D

Chiradex P

COD P

^aCOD P=250ꢂ20 mm Chiralcel OD preparative column; Chiradex A=250ꢂ4 mm Chiradex analytical column; Chiradex P=250ꢂ25 mm Chiradex

preparative column.

^bH=n-heptane, M=methanol, B1=0.1% aqueous triethylammonium acetate buﬀer, B2=0.2% aqueous triethylammonium acetate buﬀer,

D=Diisopropylethylamine, I=Isopropyl alcohol.

Scheme 2. (a) 4-BnOC₆H₄Li, THF, À78 ^ꢁC. (b) HBr, AcOH, 65 ^ꢁC. (c) C₆H₅CH₂COOH, Et₃N, Ac₂O. (d) i) LiAlH₄, THF, 0 ^ꢁC; ii) HCl, H₂O, THF,

65 ^ꢁC; iii) H₂/Pd-C, ethanol; iv) C₄H₈NCH₂CH₂Cl hydrochloride, K₂CO₃, acetone, 60 ^ꢁC. (e) Pyridine.HCl, 150 ^ꢁC.

Vaginal cytology. On the last day of treatment, vaginal

smear preparations were made using a plastic rod. The

Determination of serum cholesterol levels and uterine wet

and dry weights. Twenty-four hours after the last dose

of treatment, rats were asphyxiated by CO₂inhalation

followed by cervical dislocation. Blood samples were

collected into serum vaccutainer collection tubes, allowed

to clot on ice and centrifuged at 3000g for 10 min. Serum

aliquots were stored at À80 ^ꢁC until measurements of

total serum cholesterol were made using enzymatic cho-

lestryl ester hydrolysis and cholesterol oxidation, as fol-

samples were transferred to

immediately spray ﬁxed with ESWE cytospray

(Simonsen Weel, Copenhagen, Denmark). The

a

glass slide and

&

specimens were kept refrigerated (+4 ^ꢁC) until pro-

cessed further. The slides were stained according to

the Papanicolau technique and the relative number

of superﬁcial, intermediate and basal cells were esti-

mated. On average 106 cells were counted in each pre-

paration.

lowed by a color change reaction (CHOD-PAP,

Boehringer Mannheim, Mannheim, Germany).

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

129

Uteri were rapidly excised, trimmed free of fat, pierced,

and gently blotted to remove excess ﬂuid. They were

then cut just above the junction with the cervix and the

junction of the uterine horns with the ovaries. The

uterine wet weight was then determined immediately on

a Mettler balance. Uterine dry weights were obtained by

drying uteri at 70 ^ꢁC for 24 h before reweighing. Uteri

for histological examinations were immersion ﬁxed in

neutral buﬀered 4% formalin solution. A central cross-

section from one of the horns was embedded in paraﬃn

and sections (5 mm thick) were cut on a microtome.

Sections were stained with hematoxylin eosin according

to standard procedures, and the morphology was

described qualitatively.

vessel were added to 100 mL of extraction buﬀer (10%

glycerol, 62.5 mM Tris–HCl pH 6.8, 2.3% SDS, 1 mM

PMSF) and boiled on a water bath for 6 min. Aliquots

of 15 mL of ﬁnal lysate with 2% mercaptoethanol were

separated on a 8–16% Tris–Glycin gel (NOVEX) at 100

V for 2 h. eNOS quantities were assessed by Western

blotting [NOVEX Western Transfer Apparatus proce-

dure, 30 V, 8 Watt, subsequent application of anti-

eNOS (puriﬁed polyclonal mouse IgG1, Transduction

Laboratories, N30020) and secondary anti-mouse IgG

HRP conjugated antibody (Transduction Laboratories,

M15345)] using an ECL Western blotting detection kit

(Pharmacia, Amersham). Aortic segments from which

the endothelium was gently removed were subjected to

similar analysis. Quantitative levels of eNOS expression

were determined by use of computerized imaging ana-

lysis software.

Bone densitometry measurements. Immediately after

sacriﬁce of the test animals the tibiae were excised, ﬁxed

by immersion in 70% ethanol and their bone mineral

density (BMD) analyzed. Tomographic measurements

of total volumetric BMD (total vBMD) and trabecular

vBMD were performed by pQCT using an XCT

Research SA^TMinstrument (Stratec Medizintechnik,

Pforzheim, Germany). The estimates of total and tra-

becular vBMD were determined 5 mm below the knee

joint in right proximal tibiae. The voxel size was

0.150ꢂ0.150ꢂ0.750 mm, and threshold values of 730

and 214 mg/cm³were used for cortical and trabecular

bone, respectively. Other settings used were: contour

mode 1, peel mode 20, trabecular area 20%, and cor-

tical mode 1. Employing these settings, the coeﬃcient of

variation (CV%) as assessed by ten repeated measure-

ments (with repositioning of bone and reference line

between each measurement) was 0.84% for total vBMD

and 0.68% for trabecular vBMD.

Statistics

Statistics were calculated using GraphPad PRISM 2.0

(GraphPad Software, Inc., San Diego, CA). The

ANOVA analysis of variance test, followed by Dun-

nett’s Multiple Comparison Test, were used to compare

the diﬀerences between groups.

Results and Discussion

In vitro estrogenic activity studies. The data derived

from the ER binding assay for the cis-3,4-diaryl-7-

hydroxychromanes, which is summarized in Table 2,

clearly shows that these compounds are extremely

potent ligands for the estrogen receptor, with all but one

of the racemic compounds, 8a–p having IC₅₀values

below 35 nM. Indeed the majority of the compounds

studied had single-digit binding aﬃnities. The analo-

gous racemic 6-hydroxychromane, 16 is also a potent

ER ligand, with an IC₅₀binding aﬃnity of 6 nM. Fur-

thermore, even a brief analysis of the data for the pur-

iﬁed enantiomers, 9a–o and 10a–o clearly shows, not

unsurprisingly, that one of the cis-enantiomers is always

signiﬁcantly more potent than the other.

Osteoclast number study

As in the prevention study described above, sham and

OVX animals, 12 weeks of age, were administered vehi-

cle, control or test compound via subcutaneous or oral

route. Test compound or 17b-estradiol, as a positive

control, were administered on days 2, 4, and 7 post-

surgery. Twenty-four hours after the last dose of treat-

ment, rats were asphyxiated by CO₂inhalation followed

by cervical dislocation. Tibiae were excised, ﬁxed in

10% formalin for 24 h prior to storage in 70% ethanol,

and processed for determination of osteoclast numbers

using TRAcP (tartrate-resistant acid phosphatase)

staining of calciﬁed plastic embedded sections. Histo-

logical assessment of osteoclast numbers was performed

following TRAcP staining, with methyl green thione as

the counter-stain.

Consideration of the structural–activity relationships

displayed by the chromane series shows that the addi-

tion of a second hydroxyl functionality on the C-3 aryl

moiety is beneﬁcial for the binding aﬃnity. Chromane

8i, which carries a meta-hydroxyl functionality, possesses

sub-nanomolar aﬃnity comparable to that of 17b-estra-

diol itself (IC₅₀=0.7 nM). The trend of the binding aﬃ-

nities also shows that smaller substituents are generally

preferred over more sterically demanding groups (com-

pare 8f with 8e), and that the meta substitution pattern

on the C3-aryl moiety is generally preferable to para

substitution (compare 8j with 8e, or 8h with 8b).

Aortic expression of endothelial nitric oxide synthase

(eNOS)

One week after recovery from OVX or sham-OVX sur-

gery, rats were randomized to subcutaneous treatment

with either vehicle, test compound (10–100 nmol/g/day)

or 17b-estradiol (E) (0.3 nmol/g/day) for 7 days. Rats

were euthanized, the thoracic aortas quickly isolated

and washed in 0.9% NaCl with 1 mM PMSF prior to

storage at À80 ^ꢁC. Approximately 0.5 cm lengths of

In vivo skeletal activity. The in vitro test results sum-

marized above clearly show that the hydroxy-chro-

manes 8a–p are promising partial estrogens. A selection

of the chromanes was, therefore, further evaluated by

130

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

means of the ovariectomized rat (OVX rat) in vivo

assay; an assay designed to evaluate the skeletal estro-

genic activities of the test compounds at a standard,

orally administered dose of 10 nmol/gram body weight.

Since we suspected that the phenolic hydroxy groups

present in compounds 8a–p would probably be subject

to rapid metabolic turnover in vivo, we also included

the methoxy chromanes, (À)-7a, 7c and (À)-7c in the

test compound set, as putative pro-drugs for their

hydroxy-substituted congeners. The results of the

tomographic analysis of total and trabecular vBMD of

tibiae, as summarized in Table 3, showed notable chan-

ges following OVX operation. Vehicle treated rats

OVX’ed for 5 weeks displayed considerable decreases in

total and trabecular vBMD at the proximal tibia (ꢃ21

and 60%, respectively) relative to sham-operated con-

trols. Oral administration of the test chromanes showed

that they signiﬁcantly prevented the loss of total vBMD

and trabecular vBMD in the order of 43–105% and 39–

81%, respectively (Table 3). Likewise, 17a-ethynyl

estradiol protected tibiae against OVX-mediated loss of

both total vBMD and trabecular vBMD in the order of

89 and 61.1%, respectively (Table 3). Our supposition

that the presence of free hydroxy groups in our test

chromanes 3, and 8c may lead to rapid metabolic clear-

ance was supported by the fact that both of these com-

pounds showed somewhat weaker in vivo activity than

their methoxy analogues (À)-7a and 7c (Table 3).

Nevertheless the skeletal activity of NNC 45-0781 (3)

was comparable to that of 17a-ethynyl estradiol.

Table 2. Estrogen receptor binding aﬃnities of hydroxy-chromanes

8a–p, 9a–o and 10a–o

The pharmacological properties of compound 3, which

may be considered to be the parent compound of the

homochiral (À)-cis-3,4-diaryl-7-hydroxychromane ser-

ies, were then studied further through a series of in vivo

experiments. A full dose-response OVX rat study,

involving oral administration of compound 3 in the

range of 1–100 nmol/g body weight, showed that this

compound completely prevented the OVX-mediated

loss of total vBMD from proximal tibiae at all doses

from 10 nmol/g and above (c.f. Fig. 2).

No.

G

Side chain

ER Binding (IC₅₀, nM)

n

m

Racemate Enantiomer Enantiomer

8

9

10

a

b

c

d

e

H

para-F

1

2

1

2

1

2

18

2

1.8

21

400

1500

410

5

31

2

12

55

13

1

para-CF₃

para-OH

para-Me

para-Phenyl

meta-CF₃

meta-F

meta-OH

meta-Me

H

1

140

In an eﬀort to estimate the direct anti-resorptive activity

of compound 3 in the OVX rat, its action on the num-

ber of osteoclasts found on trabecular surfaces in tibiae

was assessed following both subcutaneous and oral

administration at equimolar doses. Study of osteoclasts

in rat tibiae, 1-week post OVX, showed a signiﬁcant

increase in osteoclast activity, as evaluated by means of

a change in TRAcP (tartrate-resistant acid phosphatase)

positive stained multinuclear cells (Fig. 3A). Adminis-

tration of compound 3 in three separate doses of

2 nmol/g body weight over the course of 1-week post

N/A

5

1100

N/A

550

f

g

h

i

j

k

l

m

n

o

p

2

1700

160

320

85

100

360

1300

800

0.01

0.3

0.04

1.6

2

17

2

0.2

3

2

23

3

6

2

H

para-CF₃

para-Me

para-F

0.1

N/A

meta-OH

N/A

Table 3. Total and trabecular vBMD determined by pQCT in ovariectomized rats following treatment with novel cis-3,4-diaryl-7-hydroxy-

chromanes (3, 8c, & 8e, 10 nmol/g), cis-3,4-diaryl-7-methoxychromanes [(À)-7a, 7c, (À)-7c, & 7i, 10 nmol/g] or 17a-ethynyl estradiol (EE, 1.5 nmol/

g)^c

Total vBMD mg/cm³

Trabec vBMD mg/cm³

Total vBMD % protection

Trabec vBMD % protection

Sham (n=34)

OVX (n=32)

702.7ꢀ44.7^NA,d

334.2ꢀ69.4^NA,d

100.0ꢀ25.8^NA,d

100.0ꢀ31.4^NA,d

556.5ꢀ33.6^b,NA

133.7ꢀ42.0^b,NA

0.0ꢀ21.3^b,NA

0.0ꢀ18.3^b,NA

3=9a (n=10)

(À)-7a (n=6)

7c (n=6)

683.1ꢀ36.4^a,d

645.5ꢀ28.7^NS,d

677.6ꢀ9.7^NS,d

670.9ꢀ28.9^NS,d

638.2ꢀ29.6^NS,d

629.8ꢀ35.8^b,d

657.4ꢀ55.9^b,d

685.2ꢀ54.7^NS,d

288.8ꢀ72.8^a,d

252.6ꢀ43.4^NS,d

238.7ꢀ20.0^NS,d

282.3ꢀ66.1^NS,d

231.4ꢀ58.6^NS,d

240.4ꢀ48.4^b,d

226.6ꢀ77.5^b,d

255.8ꢀ64.6^NS,d

76.5ꢀ22.7^a,d

78.3ꢀ32.3^NS,d

105.0ꢀ8.1^NS,d

96.2ꢀ20.1^NS,d

72.2ꢀ24.7^NS,d

43.3ꢀ22.3^b,d

55.5ꢀ37.1^b,d

89.0ꢀ33.1^NS,d

62.7 ꢀ35.6^a,d

81.2ꢀ24.0^NS,d

73.5ꢀ11.1^NS,d

79.45ꢀ35.6^NS,d

69.5ꢀ32.4^NS,d

39.1ꢀ23 7^b,d

47.5ꢀ35.0^b,d

61.1ꢀ30.9^NS,d

(À)-7c (n=8)

7i (n=6)

8c (n=10)

8e (n=10)

EE (n=33)

Data are given as the meanꢀSD. Group sizes are given in brackets. The notations NS, a, b, c or d, left and right of the comma respectively indicate

whether a value is diﬀerent from that of the sham or the OVX group.

^ap<0.05 versus sham.

^bp<0.01 versus sham.

^cp<0.05 versus OVX.

^dp<0.01 versus OVX. NA=non-applicable; NS=non-signiﬁcant.

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

131

surgery, completely prevented this change in OVX-

mediated osteoclast numbers. Comparison of the eﬀects

seen following oral or subcutaneous dosing allowed an

estimation of compound 3s ‘apparent oral bioavail-

ability’²¹at the target tissue, which was calculated as

being approximately 63%. It is also notable that sub-

cutaneous administration of compound 3, and intra-

peritoneal administration of 17b-estradiol produced

anti-resorptive activities of the same order of magnitude

(Fig. 3B).

Eﬀects on serum cholesterol levels and epithelial NOS

expression. The eﬀect of compound 3 on serum choles-

terol levels was also assessed as part of the OVX-rat

study. As can be seen from Figure 4, total serum cho-

lesterol was signiﬁcantly increased in the vehicle-treated

group as compared to the sham animals. All of the ani-

mals receiving compound 3 at doses of 10 nmol/g or

higher, had signiﬁcantly lower levels of total serum

cholesterol as compared to the vehicle treated group.

Likewise, the well-known cholesterol lowering eﬀect of

estrogen treatment was clearly observed in those OVX

animals dosed with 17a-ethynyl estradiol.

The atheroprotective eﬀect of estrogen is speculated to

be mediated, in part, through the nitric oxide (NO)

pathway. By use of immunoblotting of proteins from

vessels of treated rats, the regulative activity of com-

pound 3 on thoracic aortic eNOS expression in ovar-

iectomized rats was evaluated. After one week of vehicle

treatment post OVX the expression levels of eNOS were

reduced to approximately 40% of those in sham-oper-

ated animals. Daily administration of 17b-estradiol

(0.3 nmol/g) signiﬁcantly preserved the expression of

eNOS in OVX rats to the level of sham animals (Fig. 5).

No estrogen-mediated response on eNOS expression

was observed in endothelial-denuded aortic segments

(Fig. 5). These data directly show that OVX associated

down-regulation of endothelial-dependent aortic eNOS

expression may be restored by estrogen replacement in

vivo. Also, analysis of aortic eNOS expression from

OVX rats treated with compound 3, revealed estrogenic

activity in a dose-dependent manner following 1 week of

post OVX treatment (Fig. 5), although this eﬀect did

not reach statistical signiﬁcance over the 1 week treat-

ment period. The eﬀect of compound 3 on eNOS

Figure 2. Skeletal activity of compound 3 (NNC 45-0781) (*) and

17a-ethynyl estradiol (~) on total bone mineral density (BMD) in the

proximal tibia of the ovariectomized rat. Data are expressed as per-

centage protection relative to BMD in vehicle treated OVX rats and

represent mean and SEM for 10 animals per group. (**p<0.01 vs

OVX, vehicle).

Figure 3. Oral administration of compound 3 (NNC 45-0781) reduces

the osteoclast number on trabecular surfaces in tibiae of the ovar-

iectomized rat. (A) Section of tibia showing TRAcP positive stained

osteoclasts at the trabecular surface (arrow). (B) Data represent mean

and SEM for 5 animals per group. (**p<0.01 vs OVX, vehicle).

Figure 4. Activity of orally administered compound 3 (NNC 45-0781)

or 17a-ethynyl estradiol on total serum cholesterol in the ovar-

iectomized rat. Data represent mean and SEM for 10 animals per

group. (**p<0.01 vs OVX, vehicle).

132

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

expression did reach statistical signiﬁcance, however,

following extended treatment periods of up to 5 weeks

post OVX.²²

estradiol treatment (Fig. 6). In contrast, 5 weeks of

treatment with compound 3 at 10 and 50 nmol/g did not

change the relative amount of dry matter in uterine tis-

sue when compared to the vehicle treated animals (Fig.

6).

Vaginal cytology. Estrogen initiates a maturation of the

vaginal mucosa both by increasing the thickness and the

number of corniﬁed superﬁcial cells. The relative

appearance of vaginal squamous epithelium cells in a

vaginal smear preparation reﬂects the degree of estrogen

stimulation in an animal. Analysis of vaginal smear

preparations from OVX’ed rats following treatment

with compound 3 revealed stimulatory eﬀects on the

maturation of the vaginal mucosa, which resembled the

beneﬁcial eﬀects of estradiol treatment (Table 4). Fur-

thermore, in smaller doses, compound 3, like estradiol,

was able to inhibit the inﬂammatory response, which is

characteristic for the atrophic mucosa (Table 4).

Morphological analyses of the uteri derived from the

OXV-rat study showed that animals treated with com-

pound 3 had non-proliferative epithelia (Fig. 7). The

main eﬀect of compound 3 on the uteri was observed to

be an increase in the height of the cells in the uterine

surface epithelium upon treatment with doses beyond

50 nmol/g. The nuclei of the cells, however, remained in

the non-proliferative, non cancerous, basal state (i.e.,

the nuclei were situated at the base of the epithelial

cells). Importantly, at the lower dose of 10 nmol/g, the

dose at which the maximal skeletal anti-resorptive eﬀect

was observed, (Fig. 2) no signiﬁcant eﬀect of compound

3 treatment was visible. This was in contrast to the eﬀect

seen with the 17b-estradiol treated animals, or with the

sham operated group, which still possessed their endo-

genous estradiol production (Fig. 7a, b and h). In these

estradiol-exposed animals, the nuclei of the surface epi-

thelium of the uterine cavity were stimulated. They were

Uterotrophic activity. Analysis of the uterine wet and

dry weights from the OVX-rat study showed that, when

compared with sham animals, the OVX-vehicle group

experienced a reduction in the uterine wet weight and

consequently a signiﬁcant increase in relative dry mat-

ter. These relative changes were virtually reversed by

Figure 5. Changes of aortic eNOS protein expression upon administration of compound 3 (NNC 45-0781) or 17b-estradiol in the ovariectomized

rat. (A) Western blot showing 140 kDa eNOS protein. Lane 1: human endothelial lysate; Lane 2: OVX, vehicle; Lane 3: OVX, 17b-estradiol

(0.3 nmol/g/day for 7 days); Lane 4: as lane 2 with protein extract from endothelial-denuded aorta; Lane 5: as lane 3 with protein extract from

endothelial-denuded aorta. (B) Quantitative eNOS protein levels from Western blot (A). (C) Animals received bilateral ovariectomies 1 week prior

to daily subcutaneous administration of compound 3 or 17b-estradiol. Data represent mean and SEM from 3–9 animals per group. (**p<0.01 vs

OVX, vehicle).

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

133

Table 4. Percentage distribution of basal, intermediate, or superﬁcial squamous epithelial cell types in vaginal smears, plus the number of inﬂam-

matory cells present after treatment with 3 or EE. Data represent mean and SEM from 10 animals per group

Treatment

Basal

Intermediate

Superﬁcial

Leucocytes

Sham, vehicle

OVX, vehicle

4.4ꢀ2.1*

17.9ꢀ4.1

24.8ꢀ4.2

14.1ꢀ1.8

7.6ꢀ2.1

80.4ꢀ2.5

61.7ꢀ5.5

62.5ꢀ4.9

51.2ꢀ3.5

46.8ꢀ3.1

43.5ꢀ6.3

50.4ꢀ4.9

15.2ꢀ2.4

variable

many

few

20.4ꢀ4.4

OVX, 3 (1 nmol/g)

OVX, 3 (10 nmol/g)

OVX, 3 (50 nmol/g)

OVX, 3 (100 nmol/g)

OVX, EE (2.5 nmol/g)

12.7ꢀ3.2

34.7ꢀ5.0

45.6ꢀ4.8**

49.2ꢀ6.2**

41.5ꢀ5.3**

7.3ꢀ1.4

few

8.1ꢀ1.3

*p<0.001 (versus OVX, vehicle).

**p<0.005 (versus OVX, vehicle).

sue-selective partial estrogens. Treatment of ovar-

iectomized rats with compound 3 completely prevented

the loss of bone mineral density resulting from the

removal of endogenous estrogen production, and simi-

larly brought about the same lowering of serum choles-

terol levels as seen with 17a-ethynyl estradiol treatment.

Positive, dose-dependent, eﬀects on vaginal cytology,

and on the levels of aortic eNOS expression, along with

a dose-dependent reduction in trabecular osteoclast

numbers, were also seen in those animals treated with

compound 3. Whilst compound 3 was able to bring

about these beneﬁcial estrogenic eﬀects, the corre-

sponding negative uterotrophic changes normally

observed with estradiol treatment were not seen in those

animals dosed with compound 3. In particular, the

dangerous proliferative eﬀects on endometrial tissue

were not observed. In conclusion, therefore, the phar-

macological proﬁle of the cis-3,4-diaryl-7-hydro-

xychromane, NNC 45-0781 shows that it is a very

promising tissue-selective estrogen agonist.

Figure 6. Changes in relative dry matter of uterine tissue after oral

administration of compound 3 (NNC 45-0781) or 17a-ethynyl estra-

diol in the ovariectomized rat. Data represent mean and SEM for 10

animals per group. a: p<0.01 versus OVX-vehicle; b: p<0.01 versus

sham, OVX-vehicle treated, and EE-treated groups.

enlarged, with a dense chromatin, and they were situ-

ated at all levels of the epithelial cells, giving the epi-

thelium a stratiﬁed appearance, so-called pseudo-

stratiﬁcation. Furthermore, even at very low doses of

estradiol treatment, prominent nucleoli were present in

the stimulated nuclei. This characteristic could not be

observed after treatment with compound 3. Even at the

higher dose levels, the glands and stroma were mor-

phologically unaﬀected after treatment with compound

3 when compared with the OVX and vehicle treated

groups. Consequently, since the eﬀects of compound 3

treatment on the nuclei were observed only at doses

higher than that required for the maximal skeletal anti-

resorptive eﬀect, it is clear that compound 3 had a

therapeutic window in which maximal bone preserving

activity was achieved without stimulating endometrial

tissue.

Experimental

All reactions were carried out using conventional tech-

niques. Those processes involving the use of moisture-

sensitive reagents were performed using oven-dried

glassware, under an atmosphere of dry nitrogen. Sol-

vents were used as supplied from commercial sources

except for THF, which was freshly distilled from a

sodium and benzophenone mixture immediately before

use. Reaction progress was monitored by means of TLC

on Macherey–Nagel Alugram¹SIL G/UV plates. Col-

umn chromatography was performed using Macherey–

Nagel 230–400 mesh silica gel 60. Melting points were

recorded using a Buchi B-545 open capillary melting

1

point apparatus and are uncorrected. H NMR spectra

were recorded using Bruker DRX400, DRX300 or

DPX200 spectrometers in suitable deuterated solvents,

as indicated. Chemical shifts values (d) are reported in

parts per million relative to tetramethylsilane as an

internal standard. Elemental analyses were performed

by Novo Nordisk microanalysis laboratories. Mass

spectra (MS) were recorded as electron impact (EI)

spectra at 70 eV on a Finnigan MAT-TSQ70 mass

spectrometer. High-resolution mass spectra (HR-MS)

were determined at the Department of Chemistry, Uni-

versity of Southern Denmark, on an IonSpec HiRes

MALDI (Matrix Assisted Laser Desorption Ionisation)

Conclusion

In summary, the various pharmacological assays

detailed above clearly show that the cis-3,4-diaryl-

hydroxychromanes, as represented by compound 3

(NNC 45-0781) are an extremely promising class of tis-

134

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

resulting mixture of aqueous solution plus sticky solid

was diluted with ethyl acetate (300 mL) to dissolve the

solid, and the organic layer separated. The aqueous

phase was further extracted with ethyl acetate

(2ꢂ100 mL) and the combined organic layers washed

with water, saturated sodium chloride solution, dried

over sodium sulfate and evaporated to give a yellow/

orange solid, which was recrystallized from 2:1 ethanol/

water (600 mL) to give 4b as oﬀ-white needles, which

were vacuum dried: 7.98 g (65% yield), mp 173–176 ^ꢁC.

¹H NMR (CDCl₃, 300 MHz) d: 2.32 (s, 3H); 3.89 (s,

3H); 6.78 (dd, 1H); 6.82–6.95 (m, 3H); 7.03–7.14 (m,

6H); 7.15 (d, 1H). MS (EI): 404 (M⁺), 362, 334, 319, 43.

Elemental analysis; calcd for C₂₄H₁₇FO₅: C, 71.28; H,

4.24%; found C, 71.26; H, 4.25%.

4-(4-Acetoxyphenyl)-7-methoxy-3-(4-(triﬂuoromethyl)-

phenyl)chromen-2-one (4c). The title compound was

prepared as described for 4b, from 4-triﬂuoro-

methylphenylacetic acid (4.63 g, 30.0 mmol) and 2,4⁰-

dihydroxy-4-methoxybenzophenone (7.33 g, 30.0 mmol);

crude product recrystallized fr_ꢁom aqueous ethanol:

1

9.56 g (70% yield), mp 198–201 C. H NMR (CDCl₃,

300 MHz) d: 2.31 (s, 3H), 3.90 (s, 3H), 6.79 (dd, 1H),

6.93 (d, 1H), 7.05–7.15 (m, 4H), 7.17 (d, 1H), 7.21–7.27

(m, 2H), 7.42–7.49 (m, 2H). MS (EI): 454 (M⁺), 412,

384, 369, 43. Elemental analysis; calcd for C₂₅H₁₇F₃O₅;

C, 66.08; H, 3.77%; found C, 66.04; H, 3.77%.

4-(4-Acetoxyphenyl)-7-methoxy-3-(4-methoxyphenyl)-

chromen-2-one (4d). The title compound was prepared

as described for 4b, from 4-methoxyphenylacetic acid

(4.99 g, 30.0 mmol) and 2,4⁰-dihydroxy-4-methoxy-

benzophenone (7.33 g, 30.0 mmol); crude product tritu-

rated with hot ethanol: 5.09 g (40% yield), mp 208–

ꢁ

1

212 C. H NMR (CDCl₃, 200 MHz) d: 2.32 (s, 3H),

3.75 (s, 3H), 3.88 (s, 3H), 6.68–6.80 (m, 3H), 6.91 (d,

1H), 6.99–7.18 (m, 7H). MS (EI): 416 (M⁺), 374, 346,

331, 43.

4-(4-Acetoxyphenyl)-7-methoxy-3-(4-methylphenyl)chro-

men-2-one (4e). The title compound was prepared as

described for 4b, from 4-methylphenylacetic acid

(4.51 g, 30.0 mmol) and 2,4⁰-dihydroxy-4-methoxy-

benzophenone (7.33 g, 30.0 mmol); crude product

recrystallized from aqueous ethanol: 5.72 g (47% yield),

Figure 7. Photomicrographs of uterine surface epithelium in rats upon

oral administration of compound 3 (NNC 45-0781). a intact untreated

baseline at 5 weeks; b Sham, vehicle; c OVX-vehicle; d OVX, 3

(1 nmol/g); e OVX, 3 (10 nmol/g); f OVX, 3 (50 nmol/g); g OVX, 3

(100 nmol/g); h OVX, 17b-estradiol (0.5 nmol/g). Compound 3 and

17b-estradiol were administered 5 and 2 times weekly for 5 weeks,

respectively.

mp 192–196 ^ꢁC. H NMR (CDCl₃, 300 MHz) d: 2.25 (s,

1

3H), 2.30 (s, 3H), 3.90 (s, 3H), 6.76 (dd, 1H), 6.91 (d,

1H), 6.96–7.03 (m, 4H), 7.03–7.17 (m, 5H). MS (EI):

400 (M⁺), 358, 330, 315, 43. Elemental analysis; calcd

for C₂₅H₂₀O₅; C, 74.99; H, 5.03%; found C, 75.13; H,

5.11%.

Fourier Transform mass spectrometer. The inter-

mediates, 2,4⁰-dihydroxy-4-methoxybenzophenone, and

4-(4-hydroxyphenyl)-7-methoxy-3-phenylchromen-2-one,

4a were prepared according to literature procedures.¹⁵

4-(4-Acetoxyphenyl)-3-(4-biphenyl)-7-methoxychromen-

2-one (4f). The title compound was prepared as descri-

bed for 4b, from 4-biphenylacetic acid (6.37 g,

30.0 mmol) and 2,4⁰-dihydroxy-4-methoxybenzophen-

one (7.33 g, 30.0 mmol); crude product triturate_ꢁd with

4-(4-Acetoxyphenyl)-3-(4-ﬂuorophenyl)-7-methoxychro-

mixture of 2,4⁰-dihydroxy-4-

men-2-one (4b).

A

1

methoxybenzophenone (7.33 g, 30.0 mmol), acetic

anhydride (15 mL), triethylamine (5.5 mL, 39.5 mmol),

and 4-ﬂuorophenylacetic acid (4.63 g, 30.0 mmol) was

stirred at 135 ^ꢁC for 18 h, the resulting orange solution

poured into water (120 mL) and stirred for 3 h. The

boiling acetone: 7.12 g (51% yield), mp 229–234 C. H

NMR (CDCl₃, 300 MHz) d: 2.29 (s, 3H), 3.90 (s, 3H),

6.78 (dd, 1H), 6.83 (d, 1H), 7.04–7.11 (m, 2H), 7.12–7.22

(m, 5H), 7.35–7.47 (m, 5H), 7.51–7.56 (m, 2H). MS (EI):

462 (M⁺), 420, 392, 377, 43. Elemental analysis; calcd

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

135

for C₃₀H₂₂O₅; C, 77.91; H, 4.79%; found C, 77.56; H,

4.80%.

perature, the aqueous layer separated and extracted

twice with toluene (500 mL and 200 mL). The combined

organic phases were evaporated, the solid residue dis-

solved in ethanol (500 mL) and the solvents evaporated

again to give an orange solid, which was dissolved in

hot ethanol (800 mL), diluted with water (400 mL) and

cooled to room temperature. This resulted in the crys-

tallization of the product, 5a as colorless needles, which

were collected and vacuum dried; 234 g (81% yield), mp

156–157 ^ꢁC (aqueous ethanol). ¹H NMR (CDCl₃,

300 MHz) d: 3.80 (s, 3H), 4.82 (bs, 1H), 5.08 (s, 2H),

6.40 (dd, 1H), 6.51 (d, 1H), 6.73 (d, 2H), 6.78 (d, 1H),

6.94–7.02 (m, 4H), 7.05–7.18 (m, 3H). HR-MS; calcd

for C₂₂H₁₉O₃(M+H⁺) 331.1334, found 331.1349.

4-(4-Acetoxyphenyl)-7-methoxy-3-(3-(triﬂuoromethyl)-

phenyl)chromen-2-one (4g). The title compound was

prepared as described for 4b, from 3-(triﬂuoro-

methyl)phenylacetic acid (6.13 g, 30.0 mmol) and 2,4⁰-

dihydroxy-4-methoxybenzophenone (7.33 g, 30.0 mmol);

crude product recrystallized from hot ethanol: 9.52 g

(69% yield), mp 150.5–151.5 ^ꢁC. ¹H NMR (CDCl₃,

300 MHz) d: 2.30 (s, 3H), 3.90 (s, 3H), 6.80 (dd, 1H),

6.94 (d, 1H), 7.05–7.24 (m, 5H), 7.30–7.50 (m, 4H). MS

(EI): 454 (M⁺), 412, 384, 369, 43. Elemental analysis;

calcd for C₂₅H₁₇F₃O₅; C, 66.08; H, 3.77%; found C,

66.13; H, 3.79%.

3-(4-Fluorophenyl)-4-(4-hydroxyphenyl)-7-methoxy-2H-

chromene (5b). Lithium aluminium hydride (0.76 g,

20.03 mmol) was added in small portions to a stirred

tetrahydrofuran (150 mL) solution of 4-(4-acetoxy-

phenyl)-3-(4-ﬂuorophenyl)-7-methoxychromen-2-one (4b,

4.04 g, 9.99 mmol). After complete addition, the mixture

was stirred at room temperature for 30 min, and then

treated dropwise with 6 M hydrochloric acid (30 mL).

The resulting mixture was heated to 60–65 ^ꢁC for 3 h,

cooled and diluted with water (100 mL) and ethyl ace-

tate (50 mL). The aqueous layer was separated and fur-

ther extracted with ethyl acetate (3ꢂ100 mL). The

combined organic phase was washed with saturated

aqueous sodium chloride, dried over sodium sulfate and

evaporated to give an orange solid. This was recrys-

tallized from ethanol/water (75 mL, 4:1) to give the ﬁrst

crop of product 5b, as colorless needles. The mother

liquors were evaporated to give an orange gum, which

was subjected to a second aqueous ethanol recrystalli-

zation to give a second crop of 5b; the solids were com-

bined and vacuum dried; 2.47 g (70% yield), mp 155–

4-(4-Acetoxyphenyl)-3-(3-ﬂuorophenyl)-7-methoxychro-

men-2-one (4h). The title compound was prepared as

described for 4b, from 3-ﬂuorophenylacetic acid (4.63 g,

30.0 mmol)

and

2,4⁰-dihydroxy-4-methoxybenzo-

phenone (7.33 g, 30.0 mmol). First crop of product

recrystallized from aqueous ethanol, mother liquors

evaporated and resulting solid recrystallized from aqu-

eous acetone to give a second crop of solid, which was

mixed with the ﬁrst: combined product 8.39 g (69%

yield), mp 179–180.5 ^ꢁC. ¹H NMR (CDCl₃, 300 MHz) d:

2.30 (s, 3H), 3.89 (s, 3H), 6.78 (dd, 1H), 6.82–6.94 (m,

4H), 7.04–7.20 (m, 6H). MS (EI): 404 (M⁺), 362, 334,

319, 123, 43. Elemental analysis; calcd for C₂₄H₁₇FO₅;

C, 71.28; H, 4.24%; found C, 71.31; H, 4.24%.

4-(4-Acetoxyphenyl)-7-methoxy-3-(3-methoxyphenyl)-

chromen-2-one (4i). The title compound was prepared

as described for 4b, from 3-methoxyphenylacetic acid

(4.99 g, 30.0 mmol) and 2,4⁰-dihydroxy-4-methoxy-

benzophenone (7.33 g, 30.0 mmol); crude product

recrystallized from ethanol: 7.93 g (63% yield), mp

156.5 ^ꢁC. H NMR (CDCl₃, 300 MHz) d: 3.79 (s, 3H),

1

155.5–157 ^ꢁC. H NMR (CDCl₃, 300 MHz) d: 2.30 (s,

4.80 (bs, 1H), 5.20 (s, 2H), 6.40 (dd, 1H), 6.51 (d, 1H),

6.70–7.00 (m, 9H). MS (EI): 348 (M⁺), 255, 253.

1

3H), 3.65 (s, 3H), 3.90 (s, 3H), 6.62 (m, 1H), 6.69–6.80

(m, 3H), 6.90 (d, 1H), 7.03–7.20 (m, 6H). MS (EI): 416

(M⁺), 374, 346, 331, 43.

4-(4-Hydroxyphenyl)-7-methoxy-3-(4-(triﬂuoromethyl)-

phenyl)-2H-chromene (5c). The title compound was pre-

pared as described for 5b from 4-(4-acetoxyphenyl)-7-

methoxy-3-(4-(triﬂuoromethyl)phenyl)chromen-2-one

(4c, 4.54 g, 9.99 mmol); crude product recrystallized in

two crops from aqueous ethanol: 3.59 g (91% combined

4-(4-Acetoxyphenyl)-7-methoxy-3-(3-methylphenyl)chro-

men-2-one (4j). The title compound was prepared as

described for 4b, from 3-methylphenylacetic acid

(4.51 g, 30.0 mmol) and 2,4⁰-dihydroxy-4-methoxy-

benzophenone (7.33 g, 30.0 mmol); crude product

recrystallized from ethanol: 7.46 g (62% yield), mp

yield), mp 169–171 ^ꢁC. H NMR (CDCl₃, 300 MHz) d:

1

3.80 (s, 3H), 4.85 (bs, 1H), 5.05 (s, 2H), 6.42 (dd, 1H),

6.52 (d, 1H), 6.72–6.82 (m, 3H), 6.96 (dm, 2H), 7.07

(dm, 2H), 7.40 (dm, 2H). MS (EI): 398 (M⁺), 305, 253.

Elemental analysis; calcd for C₂₃H₁₇F₃O₃; C, 69.34; H,

4.30%; found C, 69.00; H, 4.27%.

ꢁ

1

137.5–139.5 C. H NMR (CDCl₃, 300 MHz) d: 2.22 (s,

3H), 2.30 (s, 3H), 3.89 (s, 3H), 6.77 (dd, 1H), 6.84–7.00

(m, 4H), 7.00–7.20 (m, 6H). MS (EI): 400 (M⁺), 358,

330, 315, 43. Elemental analysis; calcd for C₂₅H₂₀O₅; C,

74.99; H, 5.03%; found C, 74.51; H, 5.01%.

4-(4-Hydroxyphenyl)-7-methoxy-3-(4-methoxyphenyl)-

2H-chromene (5d). The title compound was prepared as

described for 5b from 4-(4-acetoxyphenyl)-7-methoxy-3-

(4-methoxyphenyl)chromen-2-one (4d, 4.16 g, 9.99 mmol);

crude product recrystallized in two crops from aqueous

ethanol: 2.72 g (75% combined yield), mp 176–178 ^ꢁC.

¹H NMR (CDCl₃, 200 MHz) d: 3.75 (s, 3H), 3.80 (s,

3H), 4.78 (bs, 1H), 5.04 (s, 2H), 6.39 (dd, 1H), 6.50 (d,

1H), 6.63–6.80 (m, 5H), 6.85–7.03 (m, 4H). MS (EI):

360 (M⁺), 267, 253. Elemental analysis; calcd for

4-(4-Hydroxyphenyl)-7-methoxy-3-phenyl-2H-chromene

(5a). A solution of 4-(4-hydroxyphenyl)-7-methoxy-3-

phenylchromen-2-one (4a⁰, 300 g, 0.87 mol) in dry tetra-

hydrofuran (2 L) was added over a 30 min period to a

stirred suspension of lithium aluminium hydride (66.3 g,

1.75 mol) in dry tetrahydrofuran (1 L), and the resulting

mixture stirred for 30 min. Hydrochloric acid (6M, 2 L)

was added carefully, and the mixture stirred at 60 ^ꢁC for

1 h. The resulting solution was cooled to room tem-

136

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

C₂₃H₂₀O₄; C, 76.65; H, 5.59%; found C, 76.59; H,

5.67%.

4-(4-Hydroxyphenyl)-7-methoxy-3-(3-methylphenyl)-2H-

chromene (5j). The title compound was prepared as

described for 5b from 4-(4-acetoxyphenyl)-7-methoxy-3-

(3-methylphenyl)chromen-2-one (4j, 4.00 g, 9.99 mmol);

crude product recrystallized in two crops from aqueous

ethanol: 1.88 g (54% combined yield), mp 135–137 ^ꢁC.

¹H NMR (CDCl₃, 300 MHz) d: 2.20 (s, 3H), 3.80 (s,

3H), 4.75 (bs, 1H), 5.05 (s, 2H), 6.39 (dd, 1H), 6.51 (d,

1H), 6.68–6.83 (m, 5H), 6.87–7.06 (m, 4H). MS (EI):

344 (M⁺), 253, 251.

4-(4-Hydroxyphenyl)-7-methoxy-3-(4-methylphenyl)-2H-

chromene (5e). The title compound was prepared as

described for 5b from 4-(4-acetoxyphenyl)-7-methoxy-3-

(4-methylphenyl)chromen-2-one (4e, 4.00 g, 9.99 mmol);

crude product recrystallized in two crops from aqueous

ethanol: 2.50 g (73% combined yield), mp 184–186 ^ꢁC.

¹H NMR (CDCl₃, 300 MHz) d: 2.25 (s, 3H), 3.80 (s,

3H), 4.68 (bs, 1H), 5.06 (s, 2H), 6.39 (dd, 1H), 6.50 (d,

1H), 6.70–6.79 (m, 3H), 6.86 (dm, 2H), 6.92–7.02 (m,

4H). MS (EI): 344 (M⁺), 329, 253, 251. Elemental ana-

lysis; calcd for C₂₃H₂₀O₃; C, 80.21; H, 5.85%; found C,

80.20; H, 5.92%.

(ꢀ)-cis-4-(4-Hydroxyphenyl)-7-methoxy-3-phenylchro-

mane (6a). Palladium (10 wt% on activated carbon,

50% water, 10 g, 5 mmol) was added at 60 ^ꢁC to a stir-

red solution of 4-(4-hydroxyphenyl)-7-methoxy-3-

phenyl-2H-chromene (5a, 86.44 g, 0.26 mol) in hot eth-

anol (2 L) and the resulting mixture hydrogenated on a

Parr apparatus at elevated pressure for 18 h. The

resulting hot suspension was ﬁltered through Celite¹to

remove the catalyst, and the ﬁlter cake washed with hot

ethanol. The ﬁltrate was concentrated in vacuo to

approximately 1 L, and cooled in an ice bath. The

resulting ﬁrst crop of solid product was collected by ﬁl-

tration, the mother liquors evaporated to dryness, and

the residue washed with ethanol to give a second crop of

solid. The crops were combined to give the colorless

solid product, 6a; 76.10 g (81% yield), mp 188–190 ^ꢁC.

¹H NMR (DMSO-d₆, 300 MHz) d: 3.55 (ddd, 1H), 3.73

(s, 3H), 4.18–4.25 (m, 2H), 4.35 (dd, 1H), 6.30–6.68 (m,

2H), 6.40–6.50 (m, 4H), 6.72–6.82 (m, 3H), 7.11–7.19

(m, 3H), 9.10 (s, 1H). HR-MS; calculated for C₂₂H₂₁O₃

(M+H⁺) 333.1490, found 333.1482.

3-(4-Biphenyl)-4-(4-hydroxyphenyl)-7-methoxy-2H-chro-

mene (5f). The title compound was prepared as descri-

bed for 5b from 4-(4-acetoxyphenyl)-3-(4-biphenyl)-7-

methoxychromen-2-one (4f, 4.62 g, 9.99 mmol); crude

product recrystallized in two crops from aqueous etha-

nol: 3.29 g (81% combined yield), mp 198.5–200.5 ^ꢁC.

¹H NMR (CDCl₃+drop DMSO-d₆, 300 MHz) d: 3.80

(s, 3H), 5.10 (s, 2H), 6.40 (dd, 1H), 6.51 (d, 1H), 6.74–

6.82 (m, 2H), 6.83 (d, 1H), 6.92–7.00 (m, 2H), 7.01–7.09

(m, 2H), 7.27–7.34 (m, 1H), 7.34–7.43 (m, 4H), 7.50–7.56

(m, 2H), 8.50 (s, 1H). MS (EI): 406 (M⁺), 313, 152, 77.

4-(4-Hydroxyphenyl)-7-methoxy-3-(3-(triﬂuoromethyl)-

phenyl)-2H-chromene (5g). The title compound was pre-

pared as described for 5b from 4-(4-acetoxyphenyl)-7-

methoxy-3-(3-(triﬂuoromethyl)phenyl)chromen-2-one

(4g, 4.54 g, 9.99 mmol); crude product recrystallized

from CH₂Cl₂and light petroleum (2:5, respectively):

(ꢀ)-cis-3-(4-Fluorophenyl)-4-(4-hydroxyphenyl)-7-meth-

oxychromane (6b). Palladium (10 wt% on activated car-

bon, 0.20 g, 0.19 mmol, 3 mol%) was added to a

solution of 3-(4-ﬂuorophenyl)-4-(4-hydroxyphenyl)-7-

methoxy-2H-chromene (5b, 1.74 g, 4.99 mmol) in abso-

lute ethanol (150 mL) and the mixture stirred under a

hydrogen atmosphere at ambient pressure for 22 h. The

catalyst was removed by ﬁltration through Celite¹, the

ﬁlter cake washed with extra ethanol, and the ﬁltrate

evaporated to dryness. The resulting oﬀ-white solid was

recrystallized from aqueous ethanol; giving the product

6b as colorless needles, which contained 0.75 mol equiv

of ethanol of crystallization; 1.46 g (75% yield), mp

163–165 ^ꢁC. ¹H NMR (CDCl₃, 300 MHz) d: 1.25 (t,

2.4H, 0.75 EtOH), 3.55 (ddd, 1H), 3.73 (q, 1.6H, 0.75

EtOH), 3.81 (s, 3H), 4.16–4.25 (m, 2H), 4.38 (dd, 1H),

4.90 (bs, 1H), 6.44–6.58 (m, 6H), 6.59–6.68 (m, 2H),

6.80–6.90 (m, 3H). MS (EI): 350 (M⁺), 227, 211. Ele-

3.14 g (79% yield), mp 172–175 ^ꢁC. H NMR (CDCl₃,

1

200 MHz) d: 3.80 (s, 3H), 4.85 (bs, 1H), 5.06 (s, 2H),

6.42 (dd, 1H), 6.52 (d, 1H), 6.70–6.79 (m, 2H), 6.80 (d,

1H), 6.90–7.00 (m, 2H), 7.09–7.40 (m, 4H). MS (EI):

398 (M⁺), 305, 253.

3-(3-Fluorophenyl)-4-(4-hydroxyphenyl)-7-methoxy-2H-

chromene (5h). The title compound was prepared as

described for 5b from 4-(4-acetoxyphenyl)-3-(3-ﬂuoro-

phenyl)-7-methoxychromen-2-one (4h, 4.04 g, 9.99 mmol);

crude product recrystallized in two crops from aqueous

ethanol: 2.49 g (71% combined yield), mp 139.5–

140.5 ^ꢁC. H NMR (CDCl₃, 300 MHz) d: 3.80 (s, 3H),

1

5.05 (s, 2H), 6.41 (dd, 1H), 6.51 (d, 1H), 6.66 (dm, 1H),

6.71–6.84 (m, 5H), 6.93–7.00 (m, 2H), 7.06–7.15 (m,

1H), phenolic OH not observed. MS (EI): 348 (M⁺),

255, 253.

ꢄ

mental analysis; calcd for C₂₂H₁₉FO₃0.75C₂H₅OH; C,

73.33; H, 6.13%; found C, 73.32; H, 6.11%.

4-(4-Hydroxyphenyl)-7-methoxy-3-(3-methoxyphenyl)-

2H-chromene (5i). The title compound was prepared as

described for 5b from 4-(4-acetoxyphenyl)-7-methoxy-3-

(3-methoxyphenyl)chromen-2-one (4i, 4.16 g, 9.99 mmol);

crude product recrystallized in two crops from aqueous

ethanol: 2.82 g (78% combined yield), mp 169.5–171 ^ꢁC.

¹H NMR (CDCl₃, 300 MHz) d: 3.59 (s, 3H), 3.80 (s,

3H), 4.78 (bs, 1H), 5.06 (s, 2H), 6.40 (dd, 1H), 6.49 (m,

1H), 6.51 (d, 1H), 6.59 (dm, 1H), 6.66 (dm, 1H), 6.70–

6.80 (m, 3H), 6.99 (dm, 2H), 7.08 (dd, 1H). MS (EI):

360 (M⁺), 267, 253.

(ꢀ)-cis-4-(4-Hydroxyphenyl)-7-methoxy-3-(4-(triﬂuoro-

methyl)phenyl)chromane (6c). The title compound was

prepared as described for 6b from 4-(4-hydroxyphenyl)-

7-methoxy-3-(4-(triﬂuoromethyl)phenyl)-2H-chromene

(5c, 2.99 g, 7.51 mmol) and palladium (10 wt% on acti-

vated carbon, 0.40 g, 0.38 mmol, 5 mol%) in absolute

ethanol (100 mL); crude product recrystallized in two

crops from aqueous ethanol to give 6c as colorless nee-

dles: 2.52 g (73% combined yield), mp 211–213 ^ꢁC. H

1

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

137

NMR (CDCl₃, 300 MHz) d: 3.63 (ddd, 1H), 3.81 (s,

3H), 4.20–4.28 (m, 2H), 4.44 (dd, 1H), 4.60 (bs, 1H),

6.43–6.58 (m, 6H), 6.79 (dm, 2H), 6.84 (d, 1H), 7.41

(dm, 2H). MS (EI): 400 (M⁺), 227, 211. Elemental

analysis; calcd for C₂₃H₁₉F₃O₃; C, 68.99; H, 4.78%;

found C, 69.00; H, 4.78%.

dles, which contained approximately 0.5 mol equiv of

ethanol of crystallization: 1.76 g (82% combined yield),

mp 97.5–99 ^ꢁC. ¹H NMR (CDCl₃, 300 MHz) d: 3.63

(ddd, 1H), 3.81 (s, 3H), 4.18–4.27 (m, 2H), 4.43 (dd,

1H), 4.95 (bs, 1H), 6.41–6.59 (m, 6H), 6.81–6.90 (m,

3H), 7.27 (dd, 1H), 7.44 (d, 1H). MS (EI): 400 (M⁺),

227, 211.

(ꢀ)-cis-4-(4-Hydroxyphenyl)-7-methoxy-3-(4-methoxy-

phenyl)chromane (6d). The title compound was pre-

pared as described for 6b from 4-(4-hydroxyphenyl)-7-

methoxy-3-(4-methoxyphenyl)-2H-chromene (5d, 1.80 g,

4.99 mmol) and palladium (10 wt% on activated carbon,

0.10 g, 0.09 mmol, 2 mol%) in absolute ethanol

(150 mL); crude product recrystallized in two crops

from aqueous ethanol to give 6d as colorless needles:

1.63 g (90% combined yield), mp 157.5–158.5 ^ꢁC. ¹H

NMR (CDCl₃+drop DMSO-d₆, 300 MHz) d: 3.48

(ddd, 1H), 3.75 (s, 3H), 3.78 (s, 3H), 4.11–4.22 (m, 1H),

4.13 (d, 1H), 4.36 (dd, 1H), 6.38–6.50 (m, 4H), 6.51–6.61

(m, 4H), 6.64–6.71 (m, 2H), 6.83 (d, 1H), 8.57 (bs, 1H).

MS (EI): 362 (M⁺), 227, 211, 134, 119, 91. Elemental

analysis; calcd for C₂₃H₂₂O₄; C, 76.22; H, 6.12%; found

C, 76.13; H, 6.25%.

(ꢀ)-cis-3-(3-Fluorophenyl)-4-(4-hydroxyphenyl)-7-meth-

oxychromane (6h). The title compound was prepared as

described for 6b from 3-(3-ﬂuorophenyl)-4-(4-hydroxy-

phenyl)-7-methoxy-2H-chromene (5h, 1.22 g, 3.50 mmol)

and palladium (10 wt% on activated carbon, 0.20 g,

0.19 mmol, 5 mol%) in absolute ethanol (100 mL); crude

product recrystallized in two crops from aqueous etha-

nol to give 6h as colorless needles: 1.00 g (81% com-

bined yield), mp 183–183.5 ^ꢁC. ¹H NMR (CDCl₃,

300 MHz) d: 3.57 (ddd, 1H), 3.81 (s, 3H), 4.20–4.27 (m,

2H), 4.38 (dd, 1H), 4.55 (s, 1H), 6.38 (dd, 1H), 6.44–

6.60 (m, 7H), 6.82–6.92 (m, 2H), 7.08–7.18 (m, 1H). MS

(EI): 350 (M⁺), 227, 211. Elemental analysis; calcd for

C₂₂H₁₉FO₃; C, 75.41; H, 5.47%; found C, 75.46; H,

5.53%.

(ꢀ)-cis-4-(4-Hydroxyphenyl)-7-methoxy-3-(4-methylphe-

nyl)chromane (6e). The title compound was prepared as

described for 6b from 4-(4-hydroxyphenyl)-7-methoxy-3-

(4-methylphenyl)-2H-chromene (5e, 1.72 g, 4.99 mmol)

and palladium (10 wt% on activated carbon, 0.30 g,

0.28 mmol, 6 mol%) in absolute ethanol (200 mL); crude

product recrystallized in two crops from aqueous etha-

nol to give 6e as colorless needles, which contained 0.25

mol equiv of ethanol of crystallization: 1.68 g (93%

combined yield), mp 165.5–166.5 ^ꢁC. ¹H NMR

(CDCl₃+drop DMSO-d₆, 300 MHz) d: 2.29 (s, 3H),

3.53 (ddd, 1H), 3.80 (s, 3H), 4.15–4.25 (m, 2H), 4.39

(dd, 1H), 4.74 (bs, 1H), 6.42–6.60 (m, 8H), 6.84 (d, 1H),

6.96 (dm, 2H). MS (EI): 346 (M⁺), 227, 211.

(ꢀ)-cis-4-(4-Hydroxyphenyl)-7-methoxy-3-(3-methoxy-

phenyl)chromane (6i). The title compound was prepared

as described for 6b from 4-(4-hydroxyphenyl)-7-meth-

oxy-3-(3-methoxyphenyl)-2H-chromene (5i, 2.52 g,

6.99 mmol) and palladium (10 wt% on activated carbon,

0.10 g, 0.09 mmol, 1 mol%) in absolute ethanol

(300 mL); crude product recrystallized in two crops

from aqueous ethanol to give 6i as colorless needles:

2.34 g (93% combined yield), mp 195.5–196.5 ^ꢁC. ¹H

NMR (CDCl₃, 300 MHz) d: 3.55 (ddd, 1H), 3.65 (s,

3H), 3.80 (s, 3H), 4.19–4.27 (m, 2H), 4.39 (dd, 1H), 4.58

(bs, 1H), 6.18 (m, 1H), 6.31 (dm, 1H), 6.43–6.58 (m,

6H), 6.72 (dm, 1H), 6.84 (d, 1H), 7.08 (dd, 1H). MS

(EI): 362 (M⁺), 227, 211. Elemental analysis; calcd for

C₂₃H₂₂O₄; C, 76.2; H, 6.1%; found C, 75.9; H, 6.1%.

(ꢀ)-cis-3-(4-Biphenyl)-4-(4-hydroxyphenyl)-7-methoxy-

chromane (6f). The title compound was prepared as

described for 6b from 3-(4-biphenyl)-4-(4-hydroxy-

phenyl)-7-methoxy-2H-chromene (5f, 2.03 g, 4.99 mmol)

and palladium (10 wt% on activated carbon, 0.30 g,

0.28 mmol, 6 mol%) in absolute ethanol (300 mL); crude

product recrystallized from aqueous ethanol to give 6f

as colorless needles: 1.67 g (81% yield), mp 225–

(ꢀ)-cis-4-(4-Hydroxyphenyl)-7-methoxy-3-(3-methylphe-

nyl)chromane (6j). The title compound was prepared as

described for 6b from 4-(4-hydroxyphenyl)-7-methoxy-

3-(3-methylphenyl)-2H-chromene (5j, 1.03 g, 2.99 mmol)

and palladium (10 wt% on activated carbon, 0.16 g,

0.15 mmol, 5 mol%) in absolute ethanol (150 mL);

crude product recrystallized in two crops from aqueous

ethanol to give 6j as colorless needles: 0.93 g (90%

combined yield), mp 158–159 ^ꢁC. ¹H NMR (CDCl₃,

300 MHz) d: 2.23 (s, 3H), 3.53 (ddd, 1H), 3.80 (s, 3H),

4.16–4.25 (m, 2H), 4.39 (dd, 1H), 4.63 (bs, 1H), 6.40–

6.58 (m, 8H), 6.85 (d, 1H), 6.95–7.08 (m, 2H). MS (EI):

346 (M⁺), 227, 211. Elemental analysis; calcd for

C₂₃H₂₂O₄; C, 79.74; H, 6.40%; found C, 79.77; H,

6.54%.

226.5 ^ꢁC. H NMR (DMSO-d₆, 300 MHz) d: 3.58 (ddd,

1

1H), 3.74 (s, 3H), 4.21–4.30 (m, 2H), 4.39 (dd, 1H),

6.37–6.52 (m, 6H), 6.82 (d, 1H), 6.81–6.90 (m, 2H),

7.30–7.38 (m, 1H), 7.39–7.52 (m, 4H), 7.59–7.66 (m,

2H), 9.15 (s, 1H). MS (EI): 408 (M⁺), 227, 211, 180.

Elemental analysis; calcd for C₂₈H₂₄O₃; C, 82.33; H,

5.92%; found C, 82.57; H, 6.03%.

(ꢀ)-cis-4-(4-Hydroxyphenyl)-7-methoxy-3-(3-(triﬂuoro-

methyl)phenyl)chromane (6g). The title compound was

prepared as described for 6b from 4-(4-hydroxyphenyl)-

7-methoxy-3-(3-(triﬂuoromethyl)phenyl)-2H-chromene

(5g, 2.0 g, 5.02 mmol) and palladium (10 wt% on acti-

vated carbon, 0.30 g, 0.28 mmol, 6 mol%) in absolute

ethanol (100 mL); crude product recrystallized in two

crops from aqueous ethanol to give 6g as colorless nee-

(ꢀ)-cis-7-Methoxy-3-phenyl-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane ((ꢀ)-7a). A solution of (ꢀ)-cis-4-(4-

hydroxyphenyl)-7-methoxy-3-phenylchromane

(6a,

74.3 g, 0.173 mol) and sodium hydroxide (24.3 g,

0.608 mol) in toluene (700 mL) and water (12 mL) was

heated to 75 ^ꢁC and 1-(2-chloroethyl)pyrrolidine hydro-

chloride (46.2 g, 0.272 mol) added in six portions at

138

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

30 min intervals. The resulting mixture was stirred at

75 ^ꢁC for 4 h, diluted with water (1 L), and the aqueous

phase separated and extracted with toluene (300 mL).

The combined organic layers were dried (Na₂SO₄) and

evaporated to give a solid, which was recrystallized

from hot methanol (1 L), to give the product 7a as col-

orless needles, which were collected and vacuum dried;

chloride (0.28 g, 1.67 mmol) and sodium iodide (0.01 g,

0.07 mmol) in dry acetone (35 mL). The crude product

was recrystallized from aqueous ethanol to give 7d as

colorless needles; 0.47 g (69% yield), mp 133–134 ^ꢁC. ¹H

NMR (CDCl₃, 300 MHz) d: 1.75–1.85 (m, 4H), 2.55–

2.65 (m, 4H), 2.85 (t, 2H), 3.52 (ddd, 1H), 3.76 (s, 3H),

3.81 (s, 3H), 4.02 (t, 2H), 4.15–4.23 (m, 2H), 4.37 (dd,

1H), 6.45 (dd, 1H), 6.48–6.54 (m, 3H), 6.54–6.60 (m,

2H), 6.60–6.66 (m, 2H), 6.66–6.73 (m, 2H), 6.84 (d, 1H).

MS (EI): 459 (M⁺), 84. HR-MS; calcd for C₂₉H₃₄NO₄

(M+H⁺) 460.2488, found 460.2491. Elemental analy-

sis; calcd for C₂₉H₃₃NO₄; C, 75.79; H, 7.24; N, 3.05%;

found C, 75.90; H, 7.47; N, 3.12%.

79.6 g (83% yield), mp 113–114 ^ꢁC. H NMR (DMSO-

1

d₆, 400 MHz) d: 1.6–1.7 (m, 4H), 2.40–2.50 (m, 4H),

2.70 (t, 2H), 3.55 (ddd, 1H), 3.73 (s, 3H), 3.92 (t, 2H),

4.20–4.30 (m, 2H), 4.37 (dd, 1H), 6.41–6.50 (m, 4H),

6.60 (d, 2H), 6.74–6.80 (m, 3H), 7.11–7.19 (m, 3H). HR-

MS; calcd for C₂₈H₃₂NO₃(M+H⁺) 430.2382, found

430.2372.

(ꢀ)-cis-7-Methoxy-3-(4-methylphenyl)-4-(4-(2-pyrrolidi-

noethoxy)phenyl)chromane (7e). The title compound

was prepared as described for 7b from (ꢀ)-cis-4-(4-

hydroxyphenyl) - 7 - methoxy - 3 - (4 - methylphenyl)chro-

mane, (6e, 0.69 g, 2.0 mmol), potassium carbonate

(2.76 g, 20 mmol), 1-(2-chloroethyl)pyrrolidine hydro-

chloride (0.38 g, 2.23 mmol) and sodium iodide (0.01 g,

0.07 mmol) in dry acetone (100 mL). The crude product

was recrystallized from ethanol to give 7e as colorless

needles, which contained 0.25 mol equiv of ethanol of

(ꢀ)-cis-3-(4-Fluorophenyl)-7-methoxy-4-(4-(2-pyrrolidi-

noethoxy)phenyl)chromane (7b). Potassium carbonate

(13.90 g, 100.6 mmol),

1-(2-chloroethyl)pyrrolidine

hydrochloride (1.87 g, 10.99 mmol) and sodium iodide

(0.07 g, 0.5 mmol) were added to a stirred solution of

(ꢀ)-cis-3-(4-ﬂuorophenyl)-4-(4-hydroxyphenyl)-7-meth-

oxychromane, (6b, 3.50 g, 9.99 mmol) in dry acetone

(200 mL) and the mixture stirred at 60 ^ꢁC, under reﬂux,

for 24 h. The mixture was cooled to room temperature,

the inorganic solids removed by ﬁltration, and the ﬁlter

cake washed with extra acetone. The ﬁltrate was eva-

porated to give an oﬀ-white solid, which was recrys-

tallized from ethanol to give the product, 7b as colorless

needles; 3.63 g (81% yield), mp 93–95 ^ꢁC. ¹H NMR

(CDCl₃, 300 MHz) d: 1.75–1.85 (m, 4H), 2.55–2.65 (m,

4H), 2.85 (t, 2H), 3.55 (ddd, 1H), 3.81 (s, 3H), 4.08 (t,

2H), 4.16–4.23 (m, 2H), 4.37 (dd, 1H), 6.43–6.53 (m,

4H), 6.57–6.66 (m, 4H), 6.80–6.88 (m. 3H). MS (EI):

447 (M⁺), 84. HR-MS; calcd for C₂₈H₃₁FNO₃

(M+H⁺) 448.2288, found 448.2279.

crystallization; 0.78 g (87% yield), mp 115–116.5 ^ꢁC. H

1

NMR (CDCl₃, 300 MHz) d: 1.70–1.90 (m, 4H), 2.29 (s,

3H), 2.50–2.67 (m, 4H), 2.80–2.90 (m, 2H), 3.53 (ddd,

1H), 3.80 (s, 3H), 3.94–4.05 (m, 2H), 4.15–4.25 (m, 2H),

4.40 (dd, 1H), 6.40–6.66 (m, 8H), 6.84 (d, 1H), 6.94 (dm,

2H). MS (EI): 443 (M⁺), 84. HR-MS; calcd for

C₂₉H₃₄NO₃(M+H⁺) 444.2538, found 444.2541. Ele-

ꢄ

mental analysis; calcd for C₂₉H₃₃NO₃0.25C₂H₅OH; C,

77.86; H, 7.64; N, 3.08%; found C, 78.00; H, 7.72; N,

3.08%.

(ꢀ)-cis-7-Methoxy-3-(4-biphenyl)-4-(4-(2-pyrrolidinoe-

thoxy)phenyl)chromane (7f). The title compound was

prepared as described for 7b from (ꢀ)-cis-3-(4-biphe-

nyl)-4-(4-hydroxyphenyl)-7-methoxychromane, (6f, 0.61g,

1.50 mmol), potassium carbonate (2.10 g, 15 mmol), 1-(2-

chloroethyl)pyrrolidine hydrochloride (0.31 g, 1.82 mmol)

and sodium iodide (0.01 g, 0.07 mmol) in dry acetone

(100 mL). The crude product was recrystallized from

aqueous acetone to give 7f as colorless needles; 0.28 g

(36% yield), mp 190.5–192 ^ꢁC. ¹H NMR (CDCl₃+drop

DMSO-d₆, 300 MHz) d: 1.60–1.70 (m, 4H), 2.42–2.50

(m, 4H), 2.70 (t, 2H), 3.60 (ddd, 1H), 3.75 (s, 3H), 3.93

(t, 2H), 4.27 (dd, 1H), 4.32 (d, 1H), 4.40 (dd, 1H), 6.45

(dd, 1H), 6.50 (d, 1H), 6.47–6.56 (m, 2H), 6.60–6.67 (m,

2H), 6.81 (d, 1H), 6.81–6.88 (m, 2H), 7.29–7.37 (m, 1H),

7.38–7.50 (m, 4H), 7.58–7.65 (m, 2H). MS (EI): 505

(M⁺), 84. HR-MS; calcd for C₃₄H₃₆NO₃(M+H⁺)

506.2695, found 506.2689. Elemental analysis; calcd for

C₃₄H₃₅NO₃; C, 80.76; H, 6.98; N, 2.77%; found C,

81.13; H, 7.05; N, 2.58%.

(ꢀ)-cis-7-Methoxy-4-(4-(2-pyrrolidinoethoxy)phenyl)-3-

(4-(triﬂuoromethyl)phenyl)chromane (7c). The title com-

pound was prepared as described for 7b from (ꢀ)-cis-4-

(4-hydroxyphenyl)-7-methoxy-3-(4-(triﬂuoromethyl)ph-

enyl)chromane, (6c, 0.80 g, 2.0 mmol), potassium car-

bonate (2.76 g, 20 mmol), 1-(2-chloroethyl)pyrrolidine

hydrochloride (0.38 g, 2.23 mmol) and sodium iodide

(0.01 g, 0.07 mmol) in dry acetone (100 mL). The crude

product was recrystallized from ethanol to give 7c as

colorless needles, which contained 0.25 mol equiv of

ethanol of crystallization; 0.93 g (88% yield), mp 119–

121 ^ꢁC. H NMR (CDCl₃, 300 MHz) d: 1.75–1.85 (m,

1

4H), 2.55–2.65 (m, 4H), 2.85 (t, 2H), 3.62 (ddd, 1H),

3.81 (s, 3H), 4.01 (t, 2H), 4.19–4.28 (m, 2H), 4.44 (dd,

1H), 6.44–6.54 (m, 4H), 6.64 (dm, 2H), 6.78 (dm, 2H),

6.84 (d, 1H), 7.40 (dm, 2H). MS (EI): 497 (M⁺), 84.

HR-MS; calcd for C₂₉H₃₁F₃NO₃(M+H⁺) 498.2256,

found 498.2243. Elemental analysis; calcd for

ꢄ

C₂₉H₃₀F₃NO₃0.25C₂H₅OH; C, 69.60; H, 6.24; N,

2.75%; found C, 69.94; H, 6.23; N, 2.67%.

(ꢀ)-cis-7-Methoxy-4-(4-(2-pyrrolidinoethoxy)phenyl)-3-

(3-(triﬂuoromethyl)phenyl)chromane (7g). The title com-

pound was prepared as described for 7b from (ꢀ)-cis-4-

(4-hydroxyphenyl)-7-methoxy-3-(3-(triﬂuoromethyl)ph-

enyl)chromane, (6g, 0.40 g, 1.0 mmol), potassium car-

bonate (1.38 g, 10 mmol), 1-(2-chloroethyl)pyrrolidine

hydrochloride (0.19 g, 1.12 mmol) and sodium iodide

(ꢀ)-cis-7-Methoxy-3-(4-methoxyphenyl)-4-(4-(2-pyrroli-

dinoethoxy)phenyl)chromane (7d). The title compound

was prepared as described for 7b from (ꢀ)-cis-4-(4-

hydroxyphenyl)-7-methoxy-3-(4-methoxyphenyl)chrom-

ane, (6d, 0.54 g, 1.49 mmol), potassium carbonate

(2.10 g, 15.2 mmol), 1-(2-chloroethyl)pyrrolidine hydro-

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

139

(0.01 g, 0.07 mmol) in dry acetone (50 mL). The crude

product was recrystallized from aqueous ethanol to give

7g as colorless needles; 0.33 g (65% yield), mp 98.5–

evaporated, giving a sticky yellow gum which was trea-

ted with ethanol (1 mL) and ether (30 mL) and stirred,

resulting in the precipitation of the hydrochloride salt of

7j an oﬀ-white solid; 0.51 g (53% yield), mp 167–170 ^ꢁC.

¹H NMR (DMSO-d₆, 300 MHz) d: 1.80–2.05 (bm, 4H),

2.18 (s, 3H), 2.95–3.15 (bm, 2H), 3.45–3.60 (bm, 5H),

3.74 (s, 3H), 4.15–4.40 (m, 5H), 6.40–6.55 (m, 5H), 6.62

(m, 1H), 6.68–6.84 (m, 3H), 6.95–7.08 (m, 2H), 10.74

(bs, 1H). MS (EI): 443 (M⁺of free base), 84. HR-MS;

calcd for C₂₉H₃₄NO₃(M+H⁺) 444.2538, found

444.2532.

99.5 ^ꢁC. H NMR (CDCl₃, 300 MHz) d: 1.70–1.90 (m,

1

4H), 2.55–2.65 (m, 4H), 2.85 (t, 2H), 3.63 (ddd, 1H),

3.81 (s, 3H), 3.94–4.06 (m, 2H), 4.17–4.27 (m, 2H), 4.44

(dd, 1H), 6.42–6.57 (m, 4H), 6.64 (dm, 2H), 6.80–6.90

(m, 3H), 7.26 (dd, 1H), 7.43 (d, 1H). MS (EI): 497

(M⁺), 84. HR-MS; calcd for C₂₉H₃₁F₃NO₃(M+H⁺)

498.2256, found 498.2243. Elemental analysis; calcd for

C₂₉H₃₀F₃NO₃; C, 70.01; H, 6.08; N, 2.82%; found C,

69.90; H, 6.12; N, 2.77%.

(ꢀ)-cis-7-Methoxy-3-phenyl-4-(4-(2-piperidinoethoxy)-

phenyl)chromane (7k). The title compound was prepared

as described for 7b from (ꢀ)-cis-4-(4-hydroxyphenyl)-7-

methoxy-3-phenyl-chromane, (6a, 0.332 g, 1.0 mmol),

potassium carbonate (1.40 g, 10.1 mmol), 1-(2-chlor-

oethyl)piperidine hydrochloride (0.19 g, 1.03 mmol) and

sodium iodide (0.01 g, 0.07 mmol) in dry acetone

(25 mL). The crude product was puriﬁed by recrystalli-

zation from aqueous acetone to give the colorless solid,

7k; 0.388 g (87% yield), mp 113–117 ^ꢁC. ¹H NMR

(CDCl₃, 300 MHz) d: 1.38–1.48 (m, 2H), 1.52–1.63 (m,

4H), 2.42–2.52 (m, 4H), 2.71 (t, 2H), 3.58 (ddd, 1H),

3.80 (s, 3H), 4.00 (t, 2H), 4.22 (d, 1H), 4.24 (dd, 1H),

4.43 (dd, 1H), 6.43–6.54 (m, 4H), 6.60 (m, 2H), 6.64–

6.71 (m, 2H), 6.84 (d, 1H), 7.10–7.19 (m, 3H). MS (EI):

443 (M⁺), 84. HR-MS; calcd for C₂₉H₃₄NO₃(M+H⁺)

444.2538, found 444.2534. Elemental analysis; calcd for

C₂₉H₃₃NO₃; C, 78.52; H, 7.50; N, 3.16%; found C,

78.26; H, 7.85; N, 2.92%.

(ꢀ)-cis-3-(3-Fluorophenyl)-7-methoxy-4-(4-(2-pyrrolidi-

noethoxy)phenyl)chromane (7h). The title compound was

prepared as described for 7b from (ꢀ)-cis-3-(3-ﬂuor-

ophenyl)-4-(4-hydroxyphenyl)-7-methoxychromane, (6h,

0.35 g, 1.0 mmol), potassium carbonate (1.38 g,

10 mmol), 1-(2-chloroethyl)pyrrolidine hydrochloride

(0.19 g, 1.12 mmol) and sodium iodide (0.01 g,

0.07 mmol) in dry acetone (50 mL). The crude product

was puriﬁed by column chromatography on silica gel

(5% methanol in CH₂Cl₂eluent) to give 7h as a color-

less glass; 0.35 g (79% yield). ¹H NMR (CDCl₃,

300 MHz) d: 1.70–1.90 (m, 4H), 2.55–2.65 (m, 4H), 2.85

(t, 2H), 3.56 (ddd, 1H), 3.80 (s, 3H), 4.02 (t, 2H), 4.19–

4.27 (m, 2H), 4.38 (dd, 1H), 6.38 (dm, 1H), 6.42–6.55

(m, 5H), 6.59–6.68 (m, 2H), 6.81–6.90 (m, 2H), 7.06–

7.16 (m, 1H). MS (EI): 447 (M⁺), 84. HR-MS; calcd for

C₂₈H₃₁FNO₃(M+H⁺) 448.2288, found 448.2262.

(ꢀ)-cis-7-Methoxy-3-(3-methoxyphenyl)-4-(4-(2-pyrroli-

dinoethoxy)phenyl)chromane (7i). The title compound

was prepared as described for 7b from (ꢀ)-cis-4-(4-hydro-

xyphenyl)-7-methoxy-3-(3-methoxyphenyl)chromane (6i,

0.73g, 2.01 mmol), potassium carbonate (2.76 g, 20mmol),

(ꢀ)-cis-7-Methoxy-3-phenyl-4-(4-(3-piperidinopropoxy)-

phenyl)chromane (7l). The title compound was prepared

as described for 7b from (ꢀ)-cis-4-(4-hydroxyphenyl)-7-

methoxy-3-phenyl-chromane, (6a, 0.332 g, 1.0 mmol),

potassium carbonate (1.40 g, 10.1 mmol), 1-(3-chloro-

propyl)piperidine hydrochloride (0.20 g, 1.01 mmol) and

sodium iodide (0.01 g, 0.07 mmol) in dry acetone

(25 mL). The crude product was puriﬁed by recrystalli-

zation from aqueous acetone to give the colorless solid,

7k; 0.367 g (80% yield), mp 116.5–118 ^ꢁC. ¹H NMR

(CDCl₃, 300 MHz) d: 1.38–1.48 (m, 2H), 1.52–1.63 (m,

4H), 1.91 (pentet, 2H), 2.31–2.46 (m, 6H), 3.58 (ddd,

1H), 3.80 (s, 3H), 3.90 (t, 2H), 4.22 (d, 1H), 4.25 (dd,

1H), 4.43 (dd, 1H), 6.43–6.54 (m, 4H), 6.59 (m, 2H),

6.64–6.71 (m, 2H), 6.84 (d, 1H), 7.10–7.19 (m, 3H). MS

(EI): 457 (M⁺), 124, 98. HR-MS; calcd for C₃₀H₃₆NO₃

(M+H⁺) 458.2695, found 458.2679.

1-(2-chloroethyl)pyrrolidine

hydrochloride

(0.38 g,

2.23mmol) and sodium iodide (0.01 g, 0.07 mmol) in dry

acetone (100 mL). The crude product was recrystallized

from ethanol to give 7i as colorless needles; 0.67 g (yield

72%), mp 110.5–111.5 ^ꢁC. H NMR (CDCl₃, 300 MHz)

1

d: 1.70–1.88 (m, 4H), 2.53–2.67 (m, 4H), 2.85 (t, 2H),

3.55 (ddd, 1H), 3.64 (s, 3H), 3.80 (s, 3H), 4.00 (t, 2H),

4.18–4.27 (m, 2H), 4.39 (dd, 1H), 6.19 (m, 1H), 6.29

(dm, 1H), 6.45 (dd, 1H), 6.48–6.58 (m, 3H), 6.58–6.67

(m, 2H), 6.71 (dm, 1H), 6.85 (d, 1H), 7.07 (dd, 1H). MS

(EI): 459 (M⁺), 84. HR-MS; calcd for C₂₉H₃₄NO₄

(M+H⁺) 460.2488, found 460.2464. Elemental analy-

sis; calcd for C₂₉H₃₃NO₄; C, 75.79; H, 7.24; N, 3.05%;

found C, 75.48; H, 7.24; N, 2.93%.

(ꢀ)-cis-7-Methoxy-4-(4-(2-piperidinoethoxy)phenyl)-3-

(4-(triﬂuoromethyl)phenyl)chromane (7m). The title

compound was prepared as described for 7b from (ꢀ)-

cis-4-(4-hydroxyphenyl)-7-methoxy-3-(4-(triﬂuorometh-

yl)phenyl)chromane, (6c, 0.80 g, 2.0 mmol), potassium

carbonate (2.76 g, 20.0 mmol), 1-(2-chloroethyl)piper-

idine hydrochloride (0.41 g, 2.23 mmol) and sodium

iodide (0.01 g, 0.07 mmol) in dry acetone (100 mL). The

crude product was puriﬁed by recrystallization from

ethanol to give the colorless solid, 7m; 0.97 g (95%

yield), mp 119–120.5 ^ꢁC. ¹H NMR (CDCl₃, 300 MHz) d:

1.35–1.50 (m, 2H), 1.50–1.65 (m, 4H), 2.40–2.55 (m,

4H), 2.71 (t, 2H), 3.62 (ddd, 1H), 3.81 (s, 3H), 4.10 (t,

(ꢀ)-cis-7-Methoxy-3-(3-methylphenyl)-4-(4-(2-pyrrolidi-

noethoxy)phenyl)chromane hydrochloride (7j). The title

compound was prepared as described for 7b from (ꢀ)-

cis-4-(4-hydroxyphenyl)-7-methoxy-3-(3-methylphenyl)-

chromane, (6j, 0.69 g, 2.0 mmol), potassium carbonate

(2.76 g, 20 mmol), 1-(2-chloroethyl)pyrrolidine hydro-

chloride (0.38 g, 2.23 mmol) and sodium iodide (0.01 g,

0.07 mmol) in dry acetone (100 mL). The crude product

was puriﬁed by column chromatography on silica gel

(5% methanol in CH₂Cl₂eluent) to give a yellow gum,

which was dissolved in ether and an excess of an ether

solution of hydrochloric acid added. The solvents were

140

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

2H), 4.18–4.28 (m, 2H), 4.44 (dd, 1H), 6.43–6.56 (m,

4H), 6.62 (dm, 2H), 6.79 (dm, 2H), 6.84 (d, 1H), 7.40

(dm, 2H). MS (EI): 511 (M⁺), 98. HR-MS; calcd for

C₃₀H₃₃F₃NO₃(M+H⁺) 512.2412, found 512.2406.

Elemental analysis; calcd for C₃₀H₃₂F₃NO₃; C, 70.43;

H, 6.30; N, 2.74%; found C, 70.32; H, 6.51; N, 2.64%.

(À)-(3S,4R)-7-Methoxy-3-phenyl-4-(4-(2-pyrrolidinoe-

thoxy)phenyl)chromane [(À)-7a]. A mixture of (ꢀ)-cis-7

-methoxy-3-phenyl-4-(4-(2-pyrrolidinoethoxy)phenyl)-

chromane, [(ꢀ)-7a, 85.92 g, 0.20 mol] and (À)-di-p-

toluoyl-l-tartaric acid (85.92 g, 0.22 mol) in 1-butanol

(1.9 L) was heated to 60 ^ꢁC and ﬁltered to remove inso-

luble material. The resulting solution was stirred for 2 h,

cooling slowly to room temperature, and the pre-

cipitated solid collected by ﬁltration. The solid was re-

dissolved in fresh 1-butanol (1.6 L) heated to 75 ^ꢁC, and

the solution again slowly cooled to room temperature

over 2 h. The resulting precipitated solid, (À)-7a (À)-di-

p-toluoyl-l-tartrate salt, was collected by ﬁltration,

washed with ice-cold ethanol, and vacuum dried. The

solid was partitioned between water (400 mL) and a

mixture of toluene (400 mL) and ethyl acetate (300 mL).

The aqueous layer was basiﬁed to pH 11 with 10 M

sodium hydroxide, separated and extracted with ethyl

acetate (300 mL). The combined organic phases were

dried (MgSO₄), and evaporated to give an oﬀ-white

solid, which was recrystallized from aqueous ethanol to

give the product, (À)-7a as a colorless powder, which

contained both water (0.2 mol equiv) and ethanol (0.4

mol equiv) of crystallization; 18.32 g (40% yield), mp

(ꢀ)-cis-7-Methoxy-3-(4-methylphenyl)-4-(4-(2-piperidi-

noethoxy)phenyl)chromane (7n). The title compound was

prepared as described for 7b from (ꢀ)-cis-4-(4-hydro-

xyphenyl)-7-methoxy-3-(4-methylphenyl)chromane (6e,

0.69 g, 2.0 mmol), potassium carbonate (2.76 g,

20.0 mmol), 1-(2-chloroethyl)piperidine hydrochloride

(0.41 g, 2.23 mmol) and sodium iodide (0.01 g,

0.07 mmol) in dry acetone (100 mL). The crude product

was puriﬁed by recrystallization from ethanol to give the

colorless solid, 7n; 0.82 g (85% yield), mp 109–110.5 ^ꢁC.

¹H NMR (CDCl₃, 300 MHz) d: 1.38–1.50 (m, 2H), 1.50–

1.78 (m, 4H), 2.29 (s, 3H), 2.40–2.55 (m, 4H), 2.72 (t,

2H), 3.53 (ddd, 1H), 3.80 (s, 3H), 4.01 (t, 2H), 4.16–4.24

(m, 2H), 4.39 (dd, 1H), 6.40–6.65 (m, 8H), 6.84 (d, 1H),

6.95 (dm, 2H). MS (EI): 457 (M⁺), 98. HR-MS; calcd for

C₃₀H₃₆NO₃(M+H⁺) 458.2695, found 458.2685. Ele-

mental analysis; calcd for C₃₀H₃₅NO₃; C, 78.74; H, 7.71;

N, 3.06%; found C, 78.37; H, 7.92; N, 2.93%.

56–60 ^ꢁC. H NMR (CDCl₃, 300 MHz) d: 1.24 (t, 1.2H,

1

ethanol), 1.58 (bs, water+ethanol), 1.73–1.85 (m, 4H),

2.54–2.65 (m, 4H), 2.84 (t, 2H), 3.58 (ddd, 1H), 3.72 (q,

0.8H, ethanol), 3.81 (s, 3H), 4.01 (t, 2H), 4.19–4.28 (m,

2H), 4.43 (dd, 1H), 6.42–6.55 (m, 4H), 6.58–6.72 (m,

4H), 6.85 (d, 1H), 7.10–7.20 (m, 3H). MS (EI): 429

(M⁺), 84. Chiral HPLC: ChiraDex 5 m, 250ꢂ4 mm

(Merck) column; eluent, 7:3 methanol/0.25% triethy-

lammonium acetate buﬀer, pH=5.2; ﬂow, 0.5 mL/min;

UV 220 nm; R_t=17.3 min, 95%ee. Elemental analysis:

(ꢀ)-cis-3-(4-Fluorophenyl)-7-methoxy-4-(4-(3-piperidino-

propoxy)phenyl)chromane (7o). The title compound was

prepared as described for 7b from (ꢀ)-cis-3-(4-ﬂuoro-

phenyl)-4-(4-hydroxyphenyl)-7-methoxychromane, (6b,

0.708 g, 2.0 mmol), potassium carbonate (2.76 g,

20.0 mmol), 1-(3-chloropropyl)piperidine hydrochloride

(0.44 g, 2.22 mmol) and sodium iodide (0.01 g,

0.07 mmol) in dry acetone (100 mL). The crude product

was puriﬁed by recrystallization from aqueous acetone

to give the product, 7k as colorless needles; 0.777 g

(81% yield), mp 92–94.5 ^ꢁC. ¹H NMR (CDCl₃,

300 MHz) d: 1.38–1.50 (m, 2H), 1.50–1.65 (m, 4H), 1.92

(pentet, 2H), 2.30–2.50 (m, 6H), 3.55 (ddd, 1H), 3.81 (s,

3H), 3.91 (t, 2H), 4.15–4.24 (m, 2H), 4.28 (dd, 1H),

6.42–6.54 (m, 4H), 6.57–6.66 (m, 4H), 6.80–6.89 (m,

3H). MS (EI): 475 (M⁺), 124, 98. HR-MS; calcd for

C₃₀H₃₅FNO₃(M+H⁺) 476.2601, found 484.2604.

ꢄ

calcd for C₂₈H₃₁NO₃0.4C₂H₅OH^ꢄ0.2H₂O; C, 76.60; H,

7.54; N, 3.10; water, 0.80%; found C, 76.50; H, 7.25; N,

3.07; water, 0.73%. [a]²_D⁰=À329.5^ꢁ(c=1%, 95:5

methanol/DMSO).

(À)-cis-7-Methoxy-4-(4-(2-pyrrolidinoethoxy)phenyl)-3-

(4-(triﬂuoromethyl)phenyl)chromane [(À)-7c]. A mixture

of (ꢀ)-cis-7-methoxy-4-(4-(2-pyrrolidinoethoxy)phen-

yl)-3-(4-(triﬂuoromethyl)phenyl)chromane

[(ꢀ)-7c,

14.9 g, 0.03 mol] and (À)-di-p-toluoyl-l-tartaric acid

(20.86 g, 0.054 mol) in 1-butanol (300 mL) was heated to

50 ^ꢁC and ﬁltered to remove insoluble material. The

resulting solution was cooled slowly to room tempera-

ture, and the precipitated solid collected by ﬁltration.

The solid was re-dissolved at 75 ^ꢁC in 1-butanol

(200 mL), the solution again cooled to room tempera-

ture, and the resulting precipitated solid, (À)-7c (À)-di-

p-toluoyl-l-tartrate salt, was collected by ﬁltration,

washed with ice-cold ethanol, and dried. The solid was

partitioned between water (100 mL) and ethyl acetate

(150 mL), and the aqueous layer basiﬁed to pH 12 with

10 M sodium hydroxide. The aqueous layer was sepa-

rated, extracted twice with ethyl acetate (100 mL), and

the combined organic phases dried (MgSO₄) and eva-

porated to give a gum, which was dissolved in hot 4:1

ethanol/water (80 mL) and cooled slowly to give the

product, (À)-7c as colorless needles, which were col-

lected by ﬁltration and vacuum dried. The mother

liquors from the crystallization were evaporated to give

(ꢀ)-cis-7-Methoxy-3-(3-methoxyphenyl)-4-(4-(3-piperidi-

nopropoxy)phenyl)chromane (7p). The title compound

was prepared as described for 7b from (ꢀ)-cis-4-(4-hydro-

xyphenyl)-7-methoxy-3-(3-methoxyphenyl)chromane (6i,

3.62g, 9.99 mmol), potassium carbonate (13.8 g,

99.9mmol), 1-(3-chloropropyl)piperidine hydrochloride

(2.22 g, 11.2 mmol) and sodium iodide (0.01 g,

0.07 mmol) in dry acetone (100 mL). The crude product

was puriﬁed by recrystallization from aqueous ethanol

to give the product, 7p as colorless platelets; 4.61 g (94%

yield), mp 112–113 ^ꢁC. H NMR (CDCl₃, 300 MHz) d:

1

1.37–1.49 (m, 2H), 1.50–1.63 (m, 4H), 1.92 (pentet,

2H), 2.30–2.48 (m, 6H), 3.54 (ddd, 1H), 3.63 (s, 3H),

3.80 (s, 3H), 3.90 (t, 2H), 4.18–4.26 (m, 2H), 4.39 (dd,

1H), 6.19 (m, 1H), 6.30 (dm, 1H), 6.45 (dd, 1H), 6.48–

6.56 (m, 3H), 6.61 (dm, 2H), 6.72 (dm, 1H), 6.84 (d,

1H), 7.07 (dd, 1H). MS (EI): 487 (M⁺), 98. HR-MS;

calcd for C₃₁H₃₈NO₄(M+H⁺) 488.2801, found

488.2795.

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

141

a small amount of a colorless gum, which was repeat

crystallized from aqueous ethanol, giving a second crop

of colorless needles, which was mixed with the ﬁrst crop

to give the combined product (À)-7c; 3.11 g (21% com-

bined yield), mp 146–147 ^ꢁC. ¹H NMR (CDCl₃,

300 MHz) d: 1.75–1.85 (m, 4H), 2.55–2.65 (m, 4H), 2.85

(t, 2H), 3.62 (ddd, 1H), 3.81 (s, 3H), 4.01 (t, 2H), 4.19–

4.28 (m, 2H), 4.44 (dd, 1H), 6.44–6.55 (m, 4H), 6.64

(dm, 2H), 6.78 (dm, 2H), 6.84 (d, 1H), 7.40 (dm, 2H).

MS (EI): 497 (M⁺), 84. Chiral HPLC: ChiraDex 5m,

250ꢂ4 mm (Merck) column; eluent, 7:3 methanol/

0.25% triethylammonium acetate buﬀer, pH=5.2; ﬂow,

0.5 mL/min; UV 220 nm; R_t33.0 min, 90%ee. HR-MS;

calcd for C₂₉H₃₁F₃NO₃(M+H⁺) 498.2256, found

498.2251. Elemental analysis: calcd for C₂₉H₃₀F₃NO₃;

C, 70.01; H, 6.08; N, 2.82; found C, 69.88; H, 6.08; N,

2.77%. [a]²_D⁰=À273.8^ꢁ(c=0.6%, methanol).

dried over sodium sulfate and evaporated to give a dark

colored gum, which was puriﬁed by column chromato-

graphy on silica gel (7% methanol in CH₂Cl₂eluent),

giving the product as a colorless glass. This was dis-

solved in a minimum of acetone (5 mL), then petroleum

ether (50 mL) was added to precipitate the product, 8b

as an oﬀ-white amorphous solid, which was vacuum

dried; 0.632 g (72% yield), mp 164–167 ^ꢁC. H NMR

1

(DMSO-d₆, 300 MHz) d: 1.55–1.80 (m, 4H), 2.40–2.60

(m, 4H), 2.70 (t, 2H), 3.50–3.61 (m, 1H), 3.93 (t, 2H),

4.13–4.25 (m, 2H), 4.29 (dd, 1H), 6.25–6.35 (m, 2H),

6.46 (d, 2H), 6.60–6.70 (m, 3H), 6.74–6.81 (m, 2H), 6.98

(t, 2H), 9.30 (s, 1H). MS (EI) 433 (M⁺), 84. HR-MS;

calcd for C₂₇H₂₉FNO₃(M+H⁺) 434.2131, found

434.2110. Elemental analysis; calcd for C₂₇H₂₈FNO₃; C,

74.81; H, 6.51; N, 3.23%; found C, 74.79; H, 6.78; N,

3.08%.

(ꢀ)-cis-7-Hydroxy-3-phenyl-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane hydrochloride (8a). Pyridine (9.5 mL)

was added carefully to concentrated hydrochloric acid

(10 mL), the solution heated to reﬂux, and water (5 mL)

removed by distillation until the mixture reached

140 ^ꢁC. (ꢀ)-cis-7-Methoxy-3-phenyl-4-(4-(2-pyrrolidi-

noethoxy)phenyl)chromane (7a, 2.0 g, 4.66 mmol) was

added, and the temperature of the resulting melt raised

to 150 ^ꢁC. The mixture was stirred at 150 ^ꢁC for 6 h,

then water (30 mL) was added and the resulting solution

cooled to 30 ^ꢁC. Toluene (30 mL) was added, and the

mixture basiﬁed to pH 12 with 32.5 wt% sodium

hydroxide solution. The organic phase was separated,

washed with water (20 mL), dried (K₂CO₃) and evapo-

rated. The residue was dissolved in ethanol (5 mL) and

water (20 mL), and the solution acidiﬁed to pH 3 with

concentrated hydrochloric acid. The resulting pre-

cipitated solid was collected, and recrystallized from hot

ethanol (10 mL) to give a colorless solid which was col-

lected, washed with cold ethanol and vacuum dried to

give 8a as its hydrochloride salt; 1.0 g (47% yield), mp

(ꢀ)-cis-7-Hydroxy-4-(4-(2-pyrrolidinoethoxy)phenyl)-3-

(4-(triﬂuoromethyl)phenyl)chromane (8c). The title com-

pound was prepared as described for 8b from (ꢀ)-cis-7-

methoxy-4-(4-(2-pyrrolidinoethoxy)phenyl)-3-(4-(tri-

ﬂuoromethyl)phenyl)chromane, (7c, 0.30 g, 0.60 mmol)

and pyridine hydrochloride (3.5 g, 30.3 mmol). The

crude product was puriﬁed by column chromatography

on silica gel (6% methanol in CH₂Cl₂eluent) giving the

product, 8c as a colorless powder; 0.20 g (68% yield),

mp 100 ^ꢁC (dec). ¹H NMR (DMSO-d₆, 300 MHz) d:

1.80–1.95 (m, 4H), 2.65–2.82 (m, 4H), 2.82–2.94 (m,

1H), 3.0–3.12 (m, 1H), 3.62 (ddd, 1H), 3.77–4.08 (m,

2H), 4.16 (dd, 1H), 4.21 (d, 1H), 4.38 (dd, 1H), 6.36 (dd,

1H), 6.41 (d, 1H), 6.41–6.45 (m, 4H), 6.72–6.79 (m, 3H),

7.37–7.44 (m, 2H), phenol OH not observed. MS (EI)

483 (M⁺), 84. HR-MS; calcd for C₂₈H₂₉F₃NO₃

(M+H⁺) 484.2099, found 484.2084.

(ꢀ)-cis-7-Hydroxy-3-(4-hydroxyphenyl)-4-(4-(2-pyrroli-

dinoethoxy)phenyl)chromane (8d). The title compound

was prepared as described for 8b from (ꢀ)-cis-7-meth-

oxy-3-(4-methoxyphenyl)-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane (7d, 0.23 g, 0.50 mmol) and pyridine

hydrochloride (3.0 g, 26 mmol). The crude product was

puriﬁed by column chromatography on silica gel (15%

methanol in CH₂Cl₂eluent) giving the product, 8d as a

243–245 ^ꢁC. H NMR (DMSO-d₆, 400 MHz) d: 1.77–

1

2.05 (m, 4H), 2.98–3.13 (m, 2H), 3.45–3.60 (m, 5H),

4.13–4.30 (m, 4H), 4.32 (dd, 1H), 6.30 (dd, 1H), 6.34 (d,

1H), 6.49 (d, 2H), 6.62–6.72 (m, 3H), 6.73–6.81 (m, 2H),

7.10–7.18 (m, 2H), 9.37 (s, 1H), 10.75 (bs, 1H). MS (EI):

415 (free base M⁺), 84. Elemental analysis; calcd for

C₂₇H₃₀ClNO₃; C, 71.75; H, 6.69; N, 3.10; Cl, 7.84%;

found C, 71.92; H, 6.97; N, 2.91; Cl, 7.58%.

colorless solid; 0.158 g (73% yield), mp 112–116 ^ꢁC. H

1

NMR (CD₃OD, 300 MHz) d: 1.85–2.00 (m, 4H), 2.88–

3.04 (m, 4H), 3.15 (t, 2H), 3.44 (ddd, 1H), 4.11 (t, 2H),

4.06–4.20 (m, 2H), 4.32 (dd, 1H), 6.29 (dd, 1H), 6.34 (d,

1H), 6.47–6.59 (m, 6H), 6.64–6.72 (m, 3H), phenolic OH

not observed. MS (EI) 431 (M⁺), 84. HR-MS; calcd for

C₂₇H₃₀NO₄(M+H⁺) 432.2175, found 432.2156.

(ꢀ)-cis-3-(4-Fluorophenyl)-7-hydroxy-4-(4-(2-pyrrolidi-

noethoxy)phenyl)chromane (8b). A mixture of (ꢀ)-cis-3-

(4-ﬂuorophenyl)-7-methoxy-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane (7b, 0.90 g, 2.01 mmol) and anhydrous

pyridine hydrochloride (11.60 g, 100 mmol) was heated

to 150–155 ^ꢁC as a melt/fusion for 18 h. The mixture

was cooled to room temperature, and the resulting

orange colored wax dissolved in a mixture of water

(100 mL), hot ethanol (20 mL) and dichloromethane

(150 mL). The aqueous layer was basiﬁed to pH 14 by

addition of 10 M sodium hydroxide, then 1 M hydro-

chloric acid was added until pH 8–9. The organic layer

was collected, and the aqueous layer further extracted

with dichloromethane (2ꢂ150 mL). The combined

organics were washed with saturated sodium chloride,

(ꢀ)-cis-7-Hydroxy-3-(4-methylphenyl)-4-(4-(2-pyrrolidi-

noethoxy)phenyl)chromane (8e). The title compound was

prepared as described for 8b from (ꢀ)-cis-7-methoxy-3-

(4 - methylphenyl) - 4 - (4 - (2 - pyrrolidinoethoxy)phenyl)-

chromane (7e, 0.444 g, 1.0 mmol) and pyridine hydro-

chloride (5.8 g, 50 mmol). The crude product was

puriﬁed by column chromatography on silica gel (5–7%

methanol in CH₂Cl₂eluent) giving the product as a

colorless glass. This was triturated with a mixture of

ethanol, CH₂Cl₂and petroleum ether to give the ﬁrst

crop of colorless solid. The triturate was evaporated and

142

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

the resulting solid repeat triturated with ethanol,

CH₂Cl₂and petroleum ether to give a second crop of

solid. The two crops were combined to give the product,

8e as a colorless solid; 0.30 g (71% yield), mp 161–

165 ^ꢁC. ¹H NMR (CD₃OD, 300 MHz) d: 1.80–1.95 (bm,

4H), 2.30 (s, 3H), 2.64–2.80 (m, 4H), 2.81–2.92 (m, 1H),

2.97–3.10 (m, 1H), 3.52 (ddd, 1H), 3.96–4.06 (m, 2H),

4.08–4.19 (m, 2H), 4,32 (dd, 1H), 6.34 (dd, 1H), 6.39 (d,

1H), 6.40–6.49 (m, 4H), 6.50–6.56 (m, 2H), 6.75 (d, 1H),

6.92–6.98 (m, 2H), phenol OH not observed. MS (EI)

429 (M⁺), 84. HR-MS; calcd for C₂₈H₃₂NO₃(M+H⁺)

430.2382, found 430.2366.

2H), 3.50–3.60 (m, 1H), 4.00–4.10 (m, 2H), 4.10–4.23

(m, 2H), 4.32 (dd, 1H), 6.30–6.55 (m, 8H), 6.74 (d, 1H),

6.80–6.90 (m, 1H), 7.05–7.17 (m, 1H), phenol OH not

observed. MS (EI) 433 (M⁺), 84. HR-MS; calcd for

C₂₇H₂₉FNO₃(M+H⁺) 434.2131, found 434.2131.

(ꢀ)-cis-7-Hydroxy-3-(3-hydroxyphenyl)-4-(4-(2-pyrroli-

dinoethoxy)phenyl)chromane (8i). The title compound

was prepared as described for 8b from (ꢀ)-cis-7-meth-

oxy-3-(3-methoxyphenyl)-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane (7i, 0.345 g, 0.75 mmol) and pyridine

hydrochloride (4.34 g, 37.5 mmol). The crude product

was puriﬁed by column chromatography on silica gel

(10% methanol in CH₂Cl₂eluent) giving the product, 8i

as a colorless solid; 0.25 g (77% yield), mp 126 ^ꢁC (dec).

¹H NMR (DMSO-d₆, 300 MHz) d: 1.65–1.80 (m, 4H),

2.60–2.80 (m, 4H), 2.85–3.00 (m, 2H), 3.30–3.60 (m, 1H

plus water from solvent), 4.00 (t, 2H), 4.12–4.30 (m,

3H), 6.17–6.22 (m, 2H), 6.22–6.34 (m, 2H), 6.44–6.60

(m, 3H), 6.0–6.70 (m, 3H), 6.92 (t, 1H), 9.20 (s, 1H),

9.30 (s, 1H). MS (EI) 431 (M⁺), 84. HR-MS; calcd for

C₂₇H₃₀NO₄(M+H⁺) 432.2175, found 432.2175.

(ꢀ)-cis-3-(4-Biphenyl)-7-hydroxy-4-(4-(2-pyrrolidinoeth-

oxy)phenyl)chromane (8f). The title compound was pre-

pared as described for 8b from (ꢀ)-cis-3-(4-biphenyl)-7-

methoxy - 4 - (4 - (2 - pyrrolidinoethoxy)phenyl)chromane

(7f, 0.202 g, 0.399 mmol) and pyridine hydrochloride

(2.5 g, 21.6 mmol). The crude product was puriﬁed by

column chromatography on silica gel (5% methanol in

CH₂Cl₂eluent) giving the product, 8f as an oﬀ-white

solid; 43 mg (22% yield). ¹H NMR (DMSO-d₆,

300 MHz) d: 1.70–1.90 (m, 4H), 2.90–3.10 (m, 4H),

3.15–3.25 (m, 2H), 3.55–3.65 (m, 1H), 4.05–4.15 (m,

2H), 4.20–4.45 (m, 3H), 6.27–6.37 (m, 2H), 6.50–6.58

(m, 2H), 6.62–6.75 (m, 3H), 6.82–6.90 (m, 2H), 7.29–

7.40 (m, 1H), 7.40–7.52 (m, 4H), 7.57–7.66 (m, 2H), 9.30

(s, 1H)1.85-2.00 (m, 4H), 2.88–3.04 (m, 4H), 3.15 (t,

2H), 3.44 (ddd, 1H), 4.11 (t, 2H), 4.06–4.20 (m, 2H),

4.32 (dd, 1H), 6.29 (dd, 1H), 6.34 (d, 1H), 6.47–6.59 (m,

6H), 6.64–6.72 (m, 3H), phenolic OH not observed. MS

(EI) 491 (M⁺), 84. HR-MS; calcd for C₃₃H₃₄NO₃

(M+H⁺) 492.2538, found 492.2523.

(ꢀ)-cis-7-Hydroxy-3-(3-methylphenyl)-4-(4-(2-pyrrolidi-

noethoxy)phenyl)chromane (8j). The title compound was

prepared as described for 8b from (ꢀ)-cis-7-methoxy-3-

(3 - methylphenyl) - 4 - (4 - (2 - pyrrolidinoethoxy)phenyl)-

chromane (7j, 0.360 g, 0.75 mmol) and pyridine hydro-

chloride (4.35 g, 37.6 mmol). The crude product was

puriﬁed by column chromatography on silica gel (7%

methanol in CH₂Cl₂eluent) giving the product, 8j as a

colorless solid; 0.228 g (70% yield), mp 85–90 ^ꢁC. ¹H

NMR (CDCl₃, 300 MHz) d: 1.85–2.00 (m, 4H), 2.20 (s,

3H), 2.75–2.90 (m, 4H), 2.90–3.03 (m, 1H), 3.03–3.17

(m, 1H), 3.52 (ddd, 1H), 4.00–4.10 (m, 2H), 4.10–4.20

(m, 2H), 4.32 (dd, 1H), 6.32–6.52 (m, 8H), 6.72 (d, 1H),

6.94–7.06 (m, 2H), phenol OH not observed. MS (EI)

429 (M⁺), 84. HR-MS; calcd for C₂₈H₃₀NO₃(M+H⁺)

430.2382, found 430.2363.

(ꢀ)-cis-7-Hydroxy-4-(4-(2-pyrrolidinoethoxy)phenyl)-3-

(3-(triﬂuoromethyl)phenyl)chromane (8g). The title com-

pound was prepared as described for 8b from (ꢀ)-cis-7-

methoxy-4-(4-(2-pyrrolidinoethoxy)phenyl)-3-(3-(tri-

ﬂuoromethyl)phenyl)chromane (7g, 0.25 g, 0.50 mmol)

and pyridine hydrochloride (2.90 g, 25 mmol). The crude

product was puriﬁed by column chromatography on

silica gel (7% methanol in CH₂Cl₂eluent) giving the

product 8g as an oﬀ-white solid; 0.131 g (53% yield), mp

(ꢀ)-cis-7-Hydroxy-3-phenyl-4-(4-(2-piperidinoethoxy)-

phenyl)chromane (8k). The title compound was pre-

pared as described for 8b from (ꢀ)-cis-7-methoxy-3-

phenyl-4-(4-(2-piperidinoethoxy)phenyl)chromane, (7k,

0.89 g, 2.01 mmol), and pyridine hydrochloride (11.6 g,

100 mmol). The crude product was puriﬁed by column

chromatography on silica gel (7% methanol in CH₂Cl₂

eluent) giving an oﬀ-white solid, which was recrys-

tallized from aqueous ethanol to give the product, 8k as

colorless needles; 0.424 g (49% yield), mp 168–170 ^ꢁC.

¹H NMR (DMSO-d₆, 300 MHz) d: 1.30–1.40 (m, 2H),

1.40–1.55 (m, 4H), 2.35–2.45 (m, 4H), 2.60 (t, 2H), 3.53

(ddd, 1H), 3.72 (t, 2H), 4.15–4.26 (m, 2H), 4.13 (dd,

1H), 6.28 (dd, 1H), 6.31 (d, 1H), 6.44 (d, 2H), 6.61 (d,

2H), 6.66 (d, 1H), 6.71–6.80 (m, 2H), 7.10–7.20 (m, 3H),

9.30 (s, 1H). MS (EI) 429 (M⁺), 98. Elemental analysis;

calcd for C₂₈H₃₁NO₃; C, 78.29; H, 7.27; N, 3.26%;

found C, 78.46; H, 7.26; N, 3.21%. HR-MS; calcd for

C₂₈H₃₂NO₃(M+H⁺) 430.2382, found 430.2381.

87–89 ^ꢁC. H NMR (CDCl₃, 300 MHz) d: 1.85–2.00 (m,

1

4H), 2.75–2.90 (m, 4H), 2.90–3.01 (m, 1H), 3.04–3.16

(m, 1H), 3.55–3.66 (m, 1H), 3.77–4.21 (m, 4H), 4.34 (m,

1H), 6.30–6.48 (m, 6H), 6.72 (d, 1H), 6.79 (d, 1H), 6.82

(s, 1H), 7.20–7.30 (m,1H), 7.40 (d, 1H), phenol OH not

observed. MS (EI) 483 (M⁺), 84. HR-MS; calcd for

C₂₈H₂₉F₃NO₃(M+H⁺) 484.2099, found 484.2090.

(ꢀ)-cis-3-(3-Fluorophenyl)-7-hydroxy-4-(4-(2-pyrrolidi-

noethoxy)phenyl)chromane (8h). The title compound

was prepared as described for 8b from (ꢀ)-cis-3-(3-

ﬂuorophenyl)-7-methoxy-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane (7h, 0.224 g, 0.50 mmol) and pyridine

hydrochloride (2.90 g, 25 mmol). The crude product was

puriﬁed by column chromatography on silica gel (7%

methanol in CH₂Cl₂eluent) giving a sticky gum, which

was triturated with CH₂Cl₂and petroleum ether to give

the product, 8h as an oﬀ-white solid; 0.107 g (49%

(ꢀ)-cis-7-Hydroxy-3-phenyl-4-(4-(3-piperidinopropoxy)-

phenyl)chromane (8l). The title compound was prepared

as described for 8b from (ꢀ)-cis-7-methoxy-3-phenyl-4-

ꢁ

1

yield), mp 146–150 C. H NMR (CDCl₃, 300 MHz) d:

1.85–2.00 (m, 4H), 2.65–2.88 (m, 4H), 2.88–3.14 (m,

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

143

(4-(3-piperidinopropoxy)phenyl)chromane (7l, 0.114 g,

0.25 mmol), and pyridine hydrochloride (0.60 g,

5.19 mmol). The crude product was puriﬁed by column

chromatography on silica gel (7% methanol in CH₂Cl₂

eluent) giving the product, 8l as an oﬀ-white solid; 52 mg

6.42–6.52 (m, 2H), 6.58–6.69 (m, 3H), 6.73–6.83 (m,

2H), 6.91–7.03 (m, 2H), 9.30 (s, 1H). MS (EI) 461 (M⁺),

98. HR-MS; calcd for C₂₉H₃₃FNO₃(M+H⁺) 462.2444,

found 462.2431.

1

(47% yield). H NMR (CDCl₃, 300 MHz) d: 1.45–1.60

(ꢀ)-cis-7-Hydroxy-3-(3-hydroxyphenyl)-4-(4-(3-piperidi-

nopropoxy)phenyl)chromane (8p). The title compound

was prepared as described for 8b from (ꢀ)-cis-7-meth-

oxy-3-(3-methoxyphenyl)-4-(4-(3-piperidinopropoxy)-

phenyl)chromane (7p, 0.49 g, 1.0 mmol), and pyridine

hydrochloride (5.8 g, 50 mmol). The crude product was

puriﬁed by column chromatography on silica gel (10%

methanol in CH₂Cl₂eluent) to give the product, 8p as a

yellow solid; 0.28 g (58% yield), mp 117–119 ^ꢁC. ¹H

NMR (DMSO-d₆, 300 MHz) d: 1.30–1.42 (m, 2H),

1.42–1.54 (m, 4H), 1.80 (pentet, 2H), 2.25–2.44 (m, 6H),

3.40 (ddd, 1H), 3.87 (t, 2H), 4.00–4.32 (m, 3H), 6.15–

6.22 (m, 2H), 6.27 (dd, 1H), 6.31 (d, 1H), 6.47 (dm, 2H),

6.54 (dm, 1H), 6.57–6.69 (m, 3H), 6.93 (dd, 1H), 9.15

(bs, 1H), 9.28 (s, 1H). MS (EI) 459 (M⁺), 98. HR-MS;

calcd for C₂₉H₃₄NO₄(M+H⁺) 460.2488, found

460.2469.

(m, 2H), 1.70–1.85 (m, 4H), 2.05–2.20 (m, 2H), 2.65–2.85

(m, 6H), 3.54 (ddd, 1H), 3.86 (t, 2H), 4.14–4.23 (m, 2H),

4.37 (dd, 1H), 6.39 (dd, 1H), 6.42–6.56 (m, 5H), 6.61–

6.68 (m, 2H), 6.72 (d, 1H), 6.70–6.90 (bs, 1H), 7.10–7.20

(m, 3H). MS (EI) 443 (M⁺), 98. HR-MS; calcd for

C₂₉H₃₄NO₃(M+H⁺) 444.2538, found 444.2523.

(ꢀ)-cis-7-Hydroxy-4-(4-(2-piperidinoethoxy)phenyl)-3-

(4-(triﬂuoromethyl)phenyl)chromane (8m). The title com-

pound was prepared as described for 8b from (ꢀ)-cis-7-

methoxy - 4 - (4 - (2 - piperidinoethoxy)phenyl)- 3 - (4 - (tri-

ﬂuoromethyl)phenyl)chromane (7m, 0.512 g, 1.0 mmol),

and pyridine hydrochloride (5.80 g, 50 mmol). The crude

product was puriﬁed by column chromatography on

silica gel (5–7% methanol in CH₂Cl₂eluent) to give an

orange gum, which was triturated with ether to give the

product, 8m as an oﬀ-white powder; 0.30 g (61% yield),

mp 117–119 ^ꢁC. ¹H NMR (DMSO-d₆, 300 MHz) d:

1.30–1.60 (m, 6H), 2.35–2.45 (m, 4H), 2.55–2.65 (m,

2H), 3.60–3.72 (m, 1H), 3.87–4.0 (m, 2H), 4.19–4.42 (m,

3H), 6.25–6.35 (m, 2H), 6.43–6.52 (m, 2H), 6.60–6.70

(m, 3H), 6.95–7.03 (m, 2H), 7.46–7.55 (m, 2H), 9.35 (s,

1H). MS (EI) 497 (M⁺), 98. HR-MS; calcd for

C₂₉H₃₁F₃NO₃(M+H⁺) 498.2256, found 498.2241.

(À)-(3S,4R)-7-Hydroxy-3-phenyl-4-(4-(2-pyrrolidinoe-

thoxy)phenyl)chromane (3,=9a). A mixture of (À) -

(3S,4R)-7-methoxy-3-phenyl-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane [(À)-7a, 3.43 g, 8.0 mmol], pyridine

(20 mL) and concentrated hydrochloric acid (24 mL)

was heated to reﬂux and water removed by distillation

until the temperature of the mixture reached 150 ^ꢁC.

The resulting melt was stirred for 5 h at 150 ^ꢁC, cooled

to room temperature, and diluted with water (30 mL),

toluene (30 mL) and basiﬁed to pH 10 with 32.5 wt%

sodium hydroxide solution. The aqueous phase was

separated, extracted with toluene (30 mL), and the

combined organic phases dried (K₂CO₃) and evapo-

rated. The resulting solid residue was dissolved in etha-

nol (200 mL) and water (20 mL), acidiﬁed to pH 2 with

concentrated hydrochloric acid and the solution ﬁltered

through activated charcoal. The solvents were evapo-

rated, the residue dissolved in ethanol (20 mL), the

solution ﬁltered, diluted with more ethanol (100 mL)

and neutralized to pH 7 with 32.5 wt% sodium hydrox-

ide. The resulting precipitated solid was collected, tritu-

rated with water (30 mL), collected again by ﬁltration,

and vacuum dried to give the colorless powder 3, which

contained 0.25 mol equiv of ethanol of crystallization;

(ꢀ)-cis-7-Hydroxy-3-(4-methylphenyl)-4-(4-(2-piperidi-

noethoxy)phenyl)chromane (8n). The title compound

was prepared as described for 8b from (ꢀ)-cis-7-meth-

oxy-3-(4-methylphenyl)-4-(4-(2-piperidinoethoxy)phen-

yl)chromane (7n, 0.458 g, 1.0 mmol) and pyridine

hydrochloride (5.8 g, 50 mmol). The crude product was

puriﬁed by column chromatography on silica gel (7%

methanol in CH₂Cl₂eluent) to give a colorless foam,

which was triturated with CH₂Cl₂and petroleum ether

to give the product, 8n as an oﬀ-white powder; 0.315 g

(70% yield), mp 146–147 ^ꢁC. ¹H NMR (CDCl₃,

300 MHz) d: 1.45–1.55 (m, 2H), 1.64–1.75 (m, 4H), 2.32

(s, 3H), 2.50–2.70 (m, 4H), 2.70–2.82 (m, 1H), 2.82–2.95

(m, 1H), 3.53 (ddd, 1H), 3.96–4.10 (m, 2H), 4.10–4.20

(m, 2H), 4.33 (dd, 1H), 6.37 (dd, 1H), 6.40 (d, 1H),

6.41–6.50 (m, 4H), 6.50–6.58 (m, 2H), 6.77 (d, 1H),

6.92–7.00 (m, 2H), phenol OH not observed. MS (EI)

443 (M⁺), 98. HR-MS; calcd for C₂₉H₃₄NO₃(M+H⁺)

444.2538, found 444.2532.

0.90 g (27% yield), mp 221–223 ^ꢁC. H NMR (DMSO-

1

d₆, 400 MHz) d: 1.60–1.73 (m, 4H), 2.40–2.50 (m, 4H),

2.69 (t, 2H), 3.47–3.57 (m, 1H), 3.92 (t, 2H), 4.14–4.25

(m, 2H), 4.32 (dd, 1H), 6.27 (dd, 1H), 6.30 (d, 1H), 6.44

(d, 2H), 6.60 (d, 2H), 6.65 (d, 1H), 6.70–6.80 (m, 2H),

7.09–7.20 (m, 3H), 9.25 (s, 1H). MS (EI): 415 (M⁺), 84.

HR-MS; calcd for C₂₇H₃₀NO₃(M+H⁺) 416.2225,

found 416.2198. HR-MS; calcd for C₂₈H₃₂NO₃

(M+H⁺) 430.2382, found 430.2376. Chiral HPLC:

Chiradex A, 5m, 250ꢂ4 mm (Merck) column; eluent, 6:4

methanol/0.2% aqueous triethylammonium acetate

buﬀer, pH=5.2; ﬂow, 0.5 mL/min; UV 220 nm;

R_t=19.2 min, >98%ee. Elemental analysis; calcd for

(ꢀ)-cis-3-(4-Fluorophenyl)-7-hydroxy-4-(4-(3-piperidino-

propoxy)phenyl)chromane (8o). The title compound was

prepared as described for 8b from (ꢀ)-cis-3-(4-ﬂuoro-

phenyl)-7-methoxy-4-(4-(3-piperidinopropoxy)phenyl)-

chromane (7o, 0.476 g, 1.0 mmol), and pyridine

hydrochloride (5.80 g, 50 mmol). The crude product was

puriﬁed by column chromatography on silica gel (7%

methanol in CH₂Cl₂eluent) to give the product, 8o as

an oﬀ-white solid; 0.264 g (57% yield), mp 78–84 ^ꢁC. ¹H

NMR (DMSO-d₆, 300 MHz) d: 1.30–1.60 (m, 6H),

1.75–7.90 (m, 2H), 2.30–2.60 (m, 6H), 3.50–3.60 (m,

1H), 3.86 (t, 2H), 4.05–4.35 (m, 3H), 6.25–6.35 (m, 2H),

ꢄ

C₂₇H₂₉NO₃0.25C₂H₅OH; C, 77.35; H, 7.20; N, 3.28%;

found C, 77.39; H, 7.29; N, 3.12%. [a]²_D⁰=À283^ꢁ

(c=1.004% in ethanol/3M HCl, 80:20).

144

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

(À)-cis-7-Hydroxy-4-(4-(2-pyrrolidinoethoxy)phenyl)-3-

(4-(triﬂuoromethyl)phenyl)chromane (9c). The title com-

pound was prepared from (À)-cis-7-methoxy-4-(4-(2-

pyrrolidinoethoxy)phenyl)-3-(4-(triﬂuoromethyl)phen-

yl)chromane, [(À)-7c, 0.50 g, 1.00 mmol] and pyridine

hydrochloride (5.81 g, 50.3 mmol) using the method

described for the preparation of 8b. The crude product

was puriﬁed by column chromatography on silica gel

(10% methanol in CH₂Cl₂eluent) giving the product, 9c

as a oﬀ-white solid; 0.236 g (48% yield), mp 92–96 ^ꢁC.

¹H NMR (CDCl₃, 300 MHz) d: 1.82–1.95 (m, 4H), 2.65–

2.84 (m, 4H), 2. 92 (dt, 1H), 3.02 (dt, 1H), 3.62 (m, 1H),

4.04 (t, 2H), 4.12–4.22 (m, 2H), 4.40 (dd, 1H), 6.35 (dd,

1H), 6.40–6.50 (m, 5H), 6.70–6.80 (m, 3H), 7.38–7.46 (m,

2H), phenol OH not observed. MS (EI) 483 (M⁺), 84.

HR-MS; calcd for C₂₈H₂₉F₃NO₃(M+H⁺) 484.2099,

found 484.2093. [a]²_D⁰=À234.8^ꢁ(c=1.00% in methanol).

evaporated to give a yellow gum, which was puriﬁed by

column chromatography on silica gel (30% ethyl acetate

in petroleum ether eluent) to give 13 as a yellow solid;

0.12 g (19% yield), mp 144.5–147.5 ^ꢁC. ¹H NMR

(CDCl₃, 300 MHz) d: 3.74 (s, 3H), 6.30 (bs, 1H), 6.92

(dm, 2H), 7.01 (d, 1H), 7.10 (d, 1H), 7.13 (dd, 1H), 7.68

(dm, 2H), 11.50 (s, 1H). MS (EI) 244 (M⁺), 150.

4-(4-Acetoxyphenyl)-3-phenyl-6-methoxychromen-2-one

(14).

benzophenone (13, 0.59 g, 2.42 mmol), acetic anhydride

(1.15 mL, 12.1 mmol), triethylamine (0.44 mL,

A

mixture of 2,4⁰-dihydroxy-5-methoxy-

3.16 mmol), and phenylacetic acid (0.33 g, 2.42 mmol)

was stirred at 135 ^ꢁC for 18 h. The resulting orange

colored solution was poured into water (20 mL), stirred

for 3 h, and the resulting mixture diluted with ethyl

acetate (20 mL). The aqueous layer was separated, and

extracted with ethyl acetate (2ꢂ20 mL). The combined

organic layers were washed with water, brine, dried over

sodium sulfate and evaporated to give a yellow/orange

gum, which was dissolved in a minimum of ether. Pet-

roleum ether was then added to precipitate the product,

which was collected by ﬁltration and vacuum dried to

General method for the small-scale separation of com-

pounds 9a–o and 10a–o. Small quantities of the com-

pounds 9a–o and 10a–o (approximately 3 mg of each)

were isolated by means of preparative chiral HPLC

separation of 10–15 mg quantities of compounds 8a–o.

Table 1 gives details of the separations, including the

type of chiral column used, the ﬂow rate, the eluents

employed, and the collection retention times (R_t) of the

diﬀerent enantiomers.

1

give 14 as an oﬀ white powder; 0.49 g (52% yield). H

NMR (CDCl₃, 300 MHz) d: 2.28 (s, 3H), 3.72 (s, 3H),

6.70 (d, 1H), 7.04–7.25 (m, 10H), 7.48 (d, 1H). MS (EI)

386 (M⁺), 344, 327, 316, 43.

4⁰-Benzyloxy-2,5-dimethoxybenzophenone (12). Butyl-

lithium (2.0 M in hexanes, 6.6 mL, 13.2 mmol) was

added dropwise at À78 ^ꢁC to a stirred THF (20 mL) solu-

tion of 4-benzyloxybromobenzene (3.15 g, 11.97 mmol) to

give a yellow colored suspension, which was stirred for

10 min. A THF (10 mL) solution of N,N-dimethyl 2,5-

dimethoxybenzamide (11, 2.09 g, 9.99 mmol) was then

added slowly, and the resulting mixture warmed to room

temperature over 20 h. The mixture was diluted with 1 M

aqueous hydrochloric acid (50 mL) and the product

extracted into dichloromethane (4ꢂ50 mL). The com-

bined extracts were washed with brine, dried over

sodium sulfate and evaporated. The crude product was

puriﬁed by column chromatography on silica gel (20%

ethyl acetate in petroleum ether eluent), to give a color-

less solid, which was recrystallized from ethanol to give

12 as colorless platelets; 1.61 g (46% yield), mp 111–

(ꢀ)-cis-6-Methoxy-3-phenyl-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane (15). Lithium aluminium hydride

(0.96 g, 2.54 mmol) was added in small portions to a

stirred solution of 4-(4-acetoxyphenyl)-3-phenyl-6-

methoxychromen-2-one (14, 0.49 g, 1.27 mmol) in tetra-

hydrofuran (75 mL) and the resulting mixture stirred for

30 min. Hydrochloric acid (6 M, 4 mL) was then added

dropwise, and the resulting mixture heated to 65 ^ꢁC for

3 h. The resulting solution was cooled to room tem-

perature, diluted with water (100 mL) and the products

extracted into ethyl acetate (2ꢂ100 mL). The combined

extracts were washed with brine, dried over sodium sul-

fate and evaporated to give crude 4-(4-hydroxyphenyl)-

6-methoxy-3-phenyl-2H-chromene as a yellow gum.

This gum was dissolved in ethanol (100 mL), palladium

(5 wt% on activated carbon, 0.045 g, 0.02 mmol) added,

and the mixture stirred under a hydrogen atmosphere

for 18 h. The palladium catalyst was removed by ﬁltra-

tion through Celite¹and the solvents evaporated to

give crude (ꢀ)-cis-4-(4-hydroxyphenyl)-6-methoxy-3-

phenylchromane. This chromane was dissolved in dry

acetone (20 mL), potassium carbonate (1.87 g,

13.50 mmol), 1-(2-chloroethyl)pyrrolidine hydrochloride

(0.257 g, 1.51 mmol) and sodium iodide (0.01 g,

0.07 mmol) were added, and the mixture heated to 60 ^ꢁC

for 20 h. The solid inorganic products were removed by

ﬁltration, and the solvent evaporated to give an orange

gum, which was puriﬁed by column chromatography on

silica gel (10% methanol in CH₂Cl₂eluent). This gave

ꢁ

1

113 C. H NMR (CDCl₃, 300 MHz) d: 3.70 (s, 3H),

3.78 (s, 3H), 5.13 (s, 2H), 6.85–7.02 (m, 5H), 7.30–7.47

(m, 5H), 7.82 (dm, 2H). MS (EI) 348 (M⁺), 257, 91.

HR-MS; calcd for C₂₂H₂₁O₄(M+H⁺) 349.1440, found

349.1450.

2,4⁰-Dihydroxy-5-methoxybenzophenone (13). Hydrogen

bromide (33% w/w in acetic acid, 0.70 mL, 3.94 mmol) was

added to a stirred acetic acid (5 mL) solution of (4-benzy-

loxyphenyl)-(2,5-dimethoxyphenyl)-methanone (12, 0.87 g,

2.50 mmol) and the resulting mixture heated to 75 ^ꢁC for

4 h. The mixture was diluted with water (10 mL) and the

solution stirred at room temperature for 18 h, diluted

with CH₂Cl₂(50 mL) and water (40 mL), and neu-

tralized to pH 7 by addition of 2 M sodium hydroxide.

The aqueous layer was separated and extracted with

CH₂Cl₂(50 mL). The combined organic layers were

washed with brine, dried over magnesium sulfate, and

1

15 as a pale orange gum; 0.34 g (62% yield). H NMR

(CDCl₃, 300 MHz) d: 1.70–1.90 (m, 4H), 2.55–2.70 (m,

4H), 2.85 (t, 2H), 3.56 (ddd, 1H), 3.69 (s, 3H), 4.02 (t,

2H), 4.15–4.28 (m, 2H), 4.40 (dd, 1H), 6.45–6.55 (m,

3H), 6.55–6.72 (m, 4H), 6.79 (dd, 1H), 6.90 (d, 1H),

7.10–7.20 (m, 3H).

P. S. Bury et al. / Bioorg. Med. Chem. 10 (2002) 125–145

145

(ꢀ)-cis-6-Hydroxy-3-phenyl-4-(4-(2-pyrrolidinoethoxy)-

phenyl)chromane (16). A mixture of (ꢀ)-cis-6-methoxy-

3-phenyl-4-(4-(2-pyrrolidinoethoxy)phenyl)chromane (15,

0.34 g, 0.79 mmol) and pyridine hydrochloride (0.91 g,

7.9 mmol) was stirred at 135 ^ꢁC for 18 h, cooled to room

temperature and the resulting dark solid dissolved in a

mixture of methanol (10 mL), water (50 mL) and

CH₂Cl₂(50 mL). The aqueous layer was separated and

further extracted with 4:1 CH₂Cl₂/methanol (50 mL).

The combined organic layers were washed with brine,

dried over magnesium sulfate, and evaporated to an

orange gum, which was puriﬁed by column chromato-

graphy on silica gel (5% methanol in CH₂Cl₂eluent) to

give a yellow solid. This solid was dissolved in CH₂Cl₂,

washed with sodium hydrogen carbonate solution, brine,

dried over magnesium sulfate and evaporated to give 16

as a pale yellow solid; 70 mg (21% yield). ¹H NMR

(CDCl₃, 200 MHz) d: 1.70–1.90 (m, 4H), 2.55–2.75 (m,

4H), 2.85 (t, 2H), 3.55 (ddd, 1H), 3.90–4.10 (m, 2H),

4.15–4.28 (m, 2H), 4.40 (dd, 1H), 6.38 (d, 1H), 6.42–6.60

(m, 4H), 6.60–6.75 (m, 3H), 6.85 (d, 1H), 7.05–7.25 (m,

3H), phenol OH not observed. HR-MS; calcd for

C₂₇H₃₀NO₃(M+H⁺) 416.2225, found 416.2230.

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Acknowledgements

We would like to thank Alice Ravn, Lene Skrubbel-

trang, Martin Wenkens, Eric Fischer, Minna Susanne

Møller, Bent Høegh, Aase Vinterby, Susanne Dam

Høiberg, Marianne Barfoed, Jesper Damgaard, Jette

Møller, Frank Nygaard and Rikke Burgdorf for their

superb technical assistance.

17. Sharma, I.; Ray, S. Indian J. Chem., Sect. B 1988, 27, 374.

18. Bury, P. S., Nygaard, F. B., and Larsen, S. Unpublished

results, manuscript in preparation.

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Article Doi

Synthesis and pharmacological evaluation of novel cis-3,4-Diaryl-hydroxychromanes as high affinity partial agonists for the estrogen receptor

DOI: 10.1016/S0968-0896(01)00257-7

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