17,20-Lyase inhibitors. Part 4: Design, synthesis and structure-activity relationships of naphthylmethylimidazole derivatives as novel 17,20-lyase inhibitors

Article abstract of DOI:10.1016/j.bmc.2011.01.017

A novel series of naphthylmethylimidazole derivatives and related compounds have been investigated as selective 17,20-lyase inhibitors. Optimization of the substituent at the 6-position on the naphthalene ring was performed to yield a methylcarbamoyl derivative, which exhibited potent inhibitory activity against human 17,20-lyase and promising selectivity (>200-fold) for 17,20-lyase over CYP3A4. Further modifications of the methylcarbamoyl derivative led to the discovery of the corresponding tricyclic compound, which showed highly potent activity against human 17,20-lyase (IC₅₀ 19 nM) and good selectivity (>1000-fold) for inhibition of 17,20-lyase over CYP3A4. Additional biological evaluation revealed that the tricyclic compound had potent in vivo efficacy in monkeys and favorable pharmacokinetic profiles when administered in rats. Asymmetric synthesis of the selective tricyclic inhibitor was also achieved using a chiral α-hydroxy ketone.

Full text of DOI:10.1016/j.bmc.2011.01.017

Bioorganic & Medicinal Chemistry 19 (2011) 1751–1770
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
17,20-Lyase inhibitors. Part 4: Design, synthesis and structure–activity
relationships of naphthylmethylimidazole derivatives as novel
17,20-lyase inhibitors
Tomohiro Kaku a, , Nobuyuki Matsunaga a, Akio Ojida e, Toshimasa Tanaka b, Takahito Hara c,
⇑
Masuo Yamaoka c, Masami Kusaka c, Akihiro Tasaka d
a Medicinal Chemistry Research Laboratories, Takeda Pharmaceutical Company, Ltd, 17-85, Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
b Discovery Research Center, Takeda Pharmaceutical Company, Ltd, 17-85, Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
c Pharmacology Research Laboratories, Takeda Pharmaceutical Company, Ltd, 17-85, Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
d Environment and Safety Department, Takeda Pharmaceutical Company, Ltd, 17-85, Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
e Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
A novel series of naphthylmethylimidazole derivatives and related compounds have been investigated as
selective 17,20-lyase inhibitors. Optimization of the substituent at the 6-position on the naphthalene ring
was performed to yield a methylcarbamoyl derivative, which exhibited potent inhibitory activity against
human 17,20-lyase and promising selectivity (>200-fold) for 17,20-lyase over CYP3A4. Further modifica-
tions of the methylcarbamoyl derivative led to the discovery of the corresponding tricyclic compound,
which showed highly potent activity against human 17,20-lyase (IC50 19 nM) and good selectivity
(>1000-fold) for inhibition of 17,20-lyase over CYP3A4. Additional biological evaluation revealed that
the tricyclic compound had potent in vivo efficacy in monkeys and favorable pharmacokinetic profiles
when administered in rats. Asymmetric synthesis of the selective tricyclic inhibitor was also achieved
Received 27 November 2010
Revised 7 January 2011
Accepted 11 January 2011
Available online 15 January 2011
Keywords:
17,20-Lyase
11-Hydroxylase
Testosterone
Prostate cancer
using a chiral a-hydroxy ketone.
Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction
decrease serum androgen levels secreted not only by the testes
but also by the adrenal glands.7–9
Prostate cancer is one of the most prevalent cancers among men
in the USA and Europe.1 In most cases, growth, maintenance and
progression of prostate cancer is androgen-dependent.2,3 Therefore,
the current first-line treatment for prostate cancer is hormone ther-
apy, such as surgical castration or medical castration via administra-
tion of a luteinizing hormone-releasing hormone (LH-RH) agonist,
which reduces the production of testosterone secreted by the testes.
However, resistance to this therapy eventually occurs and this clin-
ical condition is referred to as castration-resistant prostate cancer
(CRPC).4 Despite very many studies in this field, the mechanism of
progression to CRPC has not been fully understood. However, recent
studies have suggested that residual adrenal androgen dehydroepi-
androsterone (DHEA) after surgical castration could be responsible
for the development of CRPC.5,6
In recent years, several groups have reported the development
of steroidal and non-steroidal inhibitors of 17,20-lyase,10–44 such
as YM-11627 and abiraterone acetate,11 which have been evaluated
in clinical studies, and we have also disclosed the design of
17,20-lyase inhibitors such as compounds 1a45 and 1b (Kaku et
al., manuscript in preparation), as shown in Figure 1.
We have previously reported that the introduction of a small
alkoxy group such as methoxy or ethoxy group at the 6-position
of the naphthalene ring of these compounds slightly increased
17,20-lyase inhibition. Moreover, docking studies of 1a using a
homology model for human 17,20-lyase suggested that the
methoxy group at the 6-position on the naphthalene ring might
form a hydrogen bond with threonine 101 (Thr101) in the active
site of the enzyme. Unfortunately, compound 1a was found to also
be a potent inhibitor of CYP3A4, with an IC50 value of less than
1000 nM, as shown in Table 1. Therefore, we continued further
modification of this series of compounds, aiming to improve the
selectivity for 17,20-lyase over CYP3A4. In this report, we discuss
the synthesis and structure–activity relationships (SAR) of novel
naphthylmethylimidazole derivatives and related compounds as
17,20-lyase inhibitors. Additionally, asymmetric synthesis of the
Thus one possible target for CRPC treatment is the enzyme
17,20-lyase, which plays a crucial role in androgen biosynthesis.
This is because inhibition of 17,20-lyase would be expected to
⇑
Corresponding author. Tel.: +81 6 6300 6546; fax: +81 6 6300 6306.
E-mail address: Kaku_Tomohiro@takeda.co.jp (T. Kaku).
0968-0896/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2011.01.017

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T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
Figure 1. Chemical structures of previously developed 17,20-lyase inhibitors.
Table 1
The syntheses of 10a and 10b are shown in Scheme 2. Conversion
of bromide 4 into 7 was performed by Buchwald’s method using
tris(dibenzylideneactone)dipalladium (Pd2(dba)2), 2,20-bis(diphen-
ylphosphino)-1,10-binaphthyl (BINAP), sodium tert-butoxide
(tert-BuONa) and benzophenonimine, to provide good yields of 7.
The resulting imine 7 was deprotected to give 8, which was then
treated with acetic anhydride or phenyl chloroformate, followed
by methylamine hydrochloride to yield 9a and 9b, respectively.
Subsequent deprotections of 9a and 9b were performed by
treatment with pyridine hydrochloride to give 10a and 10b,
respectively.
The syntheses of the trisubstituted naphthalene derivatives
11b–d are shown in Scheme 3. 6-Bromo-2-naphthol was chlori-
nated at the 1-position with sulfuryl chloride to give a moderate
yield of 11b. After Wolff–Kishner reduction of 1-formyl-2-naph-
thol, 12 was treated with bromine to give 6-brominated 11c in
high yield. Trimethoxyborane-catalyzed reduction of 13 with lith-
ium borohydride gave alcohol 14. The alcohol 14 was successively
oxidized with manganese dioxide (MnO2) to produce 15 in high
yield (in two steps). After Wolff–Kishner reduction of the aldehyde
15, conversion of the methoxy group of 16 with BBr3 was carried
out to give a high yield of phenol 11d.
Effect of R substituent on inhibition of rat and human 17,20-lyase and human CYP3A4
HO
N
N
H
R
Compound No.
R
Enzyme inhibition IC50 (nM)
Ratioa
17,20-Lyase
CYP3A4
Rat
Human
1a
6
10a
10b
22
OMe
Ac
NHAc
21
14
29
11
43
6
28
28
39
36
24
16
<1000
1400
<1000
<1000
1400
<36
50
<26
<28
58
NHCONHMe
COOMe
CONHMe
24b
3600
225
a
Ratio is given by IC50 value of CYP3A4 inhibition/IC50 value of human
17,20-lyase inhibition.
selected compound using the chiral
achieved and is described in detail.
a-hydroxy ketone was
The syntheses of 22 and 24a–24h are shown in Scheme 4. Phe-
nols 11a–d were protected with tert-butyldimethylsilyl chloride
(TBSCl), the resulting silyl ethers were treated with n-BuLi at
ꢀ78 °C, followed by addition of ketone 3 to produce excellent
yields of 18a–d, respectively. Removal of the tert-butyldimethylsi-
lyl (TBS) group with tetrabutylammonium fluoride (TBAF)
provided phenols 19a–d, which were allowed to react with triflu-
oromethansulfonic anhydride (Tf2O) to give 20a–d, respectively.
Methoxycarbonylation of 20a–d using palladium(II) acetate
(Pd(OAc)2) and 1,10-bis(diphenylphosphino)ferrocene (dppf) in
MeOH and N,N-dimethylformamide (DMF) under CO atmosphere
gave the corresponding esters, which underwent hydrolysis, fol-
lowed by treatment with diphenylphosphoryl azide (DPPA) and
ammonium bicarbonate or 1-ethyl-3-(3-dimethylaminopropyl)
2. Chemistry
The synthesis of ketone 6 is outlined in Scheme 1. As reported
previously,46 conversion of 6-bromo-2-naphthol to dibromide 2
was achieved by treatment with triphenylphosphine (PPh3) and
bromine at 70–300 °C. Treating dibromide 2 with a sub-stoichiom-
etric amount of n-butyllithium (n-BuLi) in tetrahydrofuran (THF)
followed by the addition of ketone 3, gave bromide 4 in high yield.
Sequential treatment of bromide 4 with n-BuLi generated the
lithium dianion, to which Weinreb’s amide was added at ꢀ78 °C
to give a moderate yield of ketone 5. Finally, removal of the trityl
group with pyridine hydrochloride in methanol (MeOH) provided
the targeted ketone 6.
HO
a
b
c
N
N
Br
Br
Br
O
Br
HO
Trt
N
N
2
4
Trt
3
HO
HO
d
N
N
N
Me
Me
N
H
Trt
O
O
5
6
Scheme 1. Reagents and conditions: (a) (1) PPh3, Br2, CH3CN, 70 °C, then 300 °C, 29%; (b) (1) n-BuLi, THF, ꢀ50 °C; (2) 3, THF, ꢀ50 °C, 93%; (c) (1) n-BuLi, THF, ꢀ70 °C; (2) N-
methoxy-N-methylacetamide, THF, ꢀ70 °C, 54%; (d) pyridine hydrochloride, MeOH, CHCl3, 60 °C, 81%.

T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
1753
Scheme 2. Reagents and conditions: (a) benzophenoneimine, Pd2(dba)2, BINAP, tert-BuONa, toluene, 80 °C, 87%; (b) NH2OHꢁHCl, AcONa, THF, MeOH, rt; (c) Ac2O, pyridine, rt;
(d) (1) phenyl chloroformate, pyridine, THF, 0 °C, then (2) MeNH2ꢁHCl, 10 N NaOH, DMSO, rt; (e) pyridine hydrochloride, MeOH, CHCl3, 60 °C, 31–80% in three steps.
Scheme 3. Reagents and conditions: (a) SO2Cl2, Et2O, 0 °C to rt, 51%; (b) hydrazine monohydrate, KOH, triethyleneglycol, 170–190 °C, 89%; (c) Br2, AcOH, 10–20 °C, 99%; (d)
LiBH4, cat.B(OMe)3, THF; refluxed; (e) MnO2, CH2Cl2, refluxed, 94% in two steps; (f) hydrazine monohydrate, KOH, triethyleneglycol, 160–180 °C, 98%; (g) BBr3, CH2Cl2, ꢀ70 °C
to rt, 89%.
carbodiimide hydrochloride (EDCIꢁHCl) and alkylamine to provide
carbamoyl derivatives 23a–h in good yield. Deprotections of 21a
and 23a–h were performed according to a similar method as
described for 6 to give the desired compounds 22 and 24a–h,
respectively.
The syntheses of 27a and 27b are shown in Scheme 5. Substi-
tuted naphthalene 21c was brominated using N-bromosuccinimide
(NBS) and 2,20-azobis(2-methylpropionitrile) (AIBN) to yield 25,
which was subjected to lactam cyclization to form 26a and 26b,
respectively. Deprotections of each compound yielded the desired
27a and 27b. The regioisomers 30a and 30b were also synthesized
from 21d in a similar manner, as shown in Scheme 6.
To examine the stereochemical requirement at the chiral cen-
ters of these inhibitors, optical resolutions of 27a and 27b into
(ꢀ)-27a and (+)-27a, and (ꢀ)-27b and (+)-27b, respectively, were
performed using preparative HPLC with a Chiralpak AD column.
Additionally, as shown in Scheme 7, (+)-27b was converted to
the 4-bromobenzenesulfonyl derivative 31 and the absolute con-
figuration of (+)-27b was confirmed to be R by X-ray crystallo-
graphic analysis of 31, as shown in Figure 2.
2.1. Asymmetric synthesis of compound (ꢀ)-27b
The asymmetric synthesis of (ꢀ)-27b is shown in Scheme 8.
Diastereoselective Grignard reactions are versatile and effective
methods for providing chiral tertiary alcohols.47–49 Our group has
previously reported the application of this method to substrates
with an
a-hydroxy ketone and established effective methods to
synthesize chiral hydroxymethylimidazole derivatives utilizing
diastereoselective Grignard reactions.50,51 To construct the chiral
center of (ꢀ)-27b, we used our previously reported method using
a-hydroxy ketone 34b. The key intermediate 34b was easily pre-
pared from the known morpholine amide 33.52 The synthesized
33 was treated with lithium species generated from 32b and
n-BuLi to give 34a, which was followed by deprotection of the
TBS group with TBAF to afford moderate yield of the desired 34b.
Treatment of 34b with isopropylmagnesium bromide gave the
crude (1S,2R)-diol 35 in a diastereoselective manner together with
some by-products, followed by crystallization to give (1S,2R)-diol
35 with 95% purity; this was used without further purification in
the next step. ortho lithiation of 35 followed by the addition of

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T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
HO
c
R2
b
R2
a
R2
Br
Br
N
N
HO
TBSO
TBSO
O
R1
R1
Trt
R1
N
N
11a: R1=H, R2=H
11b: R1=Cl, R2=H
17a: R1=H, R2=H
17b: R1=Cl, R2=H
17c: R1=Me, R2=H
18a: R1=H, R2=H
18b: R1=Cl, R2=H
18c: R1=Me, R2=H
18d: R1=H, R2=Me
3
Trt
11c: R1=Me, R2=H
11d: R1=H, R2=Me
17d: R1=H, R2=Me
HO
HO
HO
e
d
R2
HO
R2
R2
N
N
N
N
N
N
R3
TfO
R1
MeO2C
R1
R1
Trt
Trt
19a: R1=H, R2=H
19b: R1=Cl, R2=H
19c: R1=Me, R2=H
19d: R1=H, R2=Me
21a: R1=H, R2=H, R3=Trt
20a: R1=H, R2=H
20b: R1=Cl, R2=H
20c: R1=Me, R2=H
20d: R1=H, R2=Me
21b: R1=Cl, R2=H, R3=Trt
21c: R1=Me, R2=H, R3=Trt
21d: R1=H, R2=Me, R3=Trt
22: R1=R2=R3=H
f
HO
HO
g
h
R2
R3HNOC
R2
N
N
N
R3HNOC
N
H
R1
R1
Trt
23a: R1=H, R2=H, R3=H
24a: R1=H, R2=H, R3=H
24b: R1=H, R2=H, R3=Me
24c: R1=H, R2=H, R3=Et
24d: R1=H, R2=H, R3=Pr
24e: R1=H, R2=H, R3=i-Pr
24f: R1=Cl, R2=H, R3=Me
24g: R1=Me, R2=H, R3=Me
24h: R1=H, R2=Me, R3=Me
23b: R1=H, R2=H, R3=Me
23c: R1=H, R2=H, R3=Et
23d: R1=H, R2=H, R3=Pr
23e: R1=H, R2=H, R3=i-Pr
23f: R1=Cl, R2=H, R3=Me
23g: R1=Me, R2=H, R3=Me
23h: R1=H, R2=Me, R3=Me
Scheme 4. Reagents and conditions: (a) TBSCl, imidazole, DMF, 0 °C to rt, 85–98%; (b) (1) n-BuLi, THF, ꢀ70 °C; (2) 3, 84–93%; (c) TBAF, THF, 0 °C to rt, 89–98%; (d) Tf2O,
pyridine, 0 °C, 61–94%; (e) CO, Pd(OAc)2, dppf, Et3N, DMF, MeOH, 70 °C, 81–95%; (f) pyridine hydrochloride, MeOH, CHCl3, 60 °C, 94%; (g) (1) 4 N NaOH, THF, MeOH, 60 °C,
then (2) for 23a, NH4HCO3, DPPA, Et3N, DMF, rt, quant., for 23b–h, R3NH2, EDCIꢁHCl, HOBtꢁH2O, Et3N, DMF, rt, 75% to quant.; (h) pyridine hydrochloride, MeOH, CHCl3, 60 °C,
73–93%.
Scheme 5. Reagents and conditions: (a) NBS, AIBN, CCl4, refluxed, 59% as a mixture of 25 and 21c (25:21c = ca. 7:1); (b) for 26a, saturated NH3 in MeOH, THF, 0 °C to rt, 26%;
(c) for 26b, 40% NH2Me in MeOH, rt, quant.; (d) pyridine hydrochloride, MeOH, CHCl3, 60 °C, 75–90%.
DMF gave a mixture of 36a and 36b (36a:36b = ca. 6:1), which was
then treated with methylamine under reductive amination condi-
tions to yield a mixture of 37a and 37b. Subsequent internal cycli-
zation of a mixture of 37a and 37b using lithium diisopropylamide
(LDA), followed by recrystallization gave a mixture of the regioi-
somers such as 38a and 38b (38a:38b = 93:7) in moderate yield.
Swern oxidation of a mixture of 38a and 38b, and subsequent
recrystallization of the product gave 39 with >99% purity, which
was then subjected to the -bromination condition using pyridini-
um bromide perbromide to give -bromoketone 40.
Since the direct conversion from 40 to (ꢀ)-27b gave insufficient
yield of (ꢀ)-27b with 2% (not shown in Scheme 8), imidazole ring
closure was performed after protection of 40 with a trimethylsilyl
group by N,O-bis(trimethylsilyl)acetamide. The obtained 41 was
a
a

T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
1755
Scheme 6. Reagents and conditions: (a) NBS, AIBN, CCl4, refluxed, quant.; (b) for 29a, saturated NH3 in MeOH, THF, 0 °C to rt; (c) for 29b, 40% NH2Me in MeOH, rt; (d) pyridine
hydrochloride, MeOH, CHCl3, 60 °C, 22–64% in two steps.
Scheme 7. Reagents and conditions: (a) optical resolution using preparative HPLC on a Chiralpak AD column; (b) 4-bromobenzenesulfonyl chloride, Et3N, DMF, rt, 88%.
Figure 2. ORTEP drawing of 31.
then subjected to the reaction conditions using formamidine
acetate in saturated NH3 solution, shown in Scheme 8 to give (ꢀ)-
27b in moderate chemical yield with excellent ee (>99%ee). In sum-
mary, an 11-step method was developed for asymmetric synthesis
of the selected (ꢀ)-27b from 6-bromo-2-naphthoic acid 32a using
the diastereoselective Grignard reaction as a key step to construct
the chiral center of (ꢀ)-27b.
3. Results and discussion
3.1. SARs for 17,20-lyase, CYP3A4, and 11-hydroxylase
All compounds synthesized as racemates were tested in vitro
for inhibition of rat 17,20-lyase, human 17,20-lyase and CYP3A4.
Selected compounds were resolved by HPLC and the resultant

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T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
O
b
R
HO
1S
Br
d
2R
R
R
(i-Pr)2NOC
OH
O
(i-Pr)2NOC
R
N
32a: R=CO2H
32b: R=CON(i-Pr)2
35
a
O
OTBS
34a: R=OTBS
34b: R=OH
c
33
HO
HO
e
HO
g
R2
(i-Pr)2NOC
+
OH
Me
N
O
OH
OH
N
O
Me
R1
38b
38a
( 38a:38b = 93:7 )
36a+36b; 36a:R1=CHO, R2=H,36b:R1=H, R2=CHO
f
37a+37b; 37a:R1=CH2NHMe, R2=H,37b:R1=H, R2=CH2NHMe
TMSO
HO
HO
h
i
j
Br
OTMS
Br
O
O
O
Me
O
O
Me
N
N
N
Me
39
41
40
HO
N
k
N
H
O
Me
N
(-)-27b
Scheme 8. Reagents and conditions: (a) (1) SOCl2, DMF, THF, 60 °C; (2) diisopropylamine, Et3N, THF, 0 °C–rt; 88%; (b) (1) n-BuLi, toluene, THF, ꢀ70 °C; (2) 33, THF, ꢀ78 °C; (c)
TBAF, THF, ꢀ10 to 0 °C, 58% from 33; (d) isopropylmagnesium bromide, THF, ꢀ10 to 0 °C, 54%; (e) n-BuLi, TMEDA, DMF, THF, ꢀ70 °C; (f) 2 M MeNH2 in THF, NaBH(OAc)3,
AcOH, CH2Cl2, rt; (g) LDA, THF, ꢀ70 to ꢀ10 °C, 42% as a mixture of 38a and 38b; (h) DMSO, (COCl)2, Et3N, CH2Cl2, ꢀ70 to ꢀ20 °C, 33%; (i) pyridinium bromide perbromide, THF,
0 °C to rt; (j) N,O-bis(trimethylsilyl)acetamide, cat. TBAF, DMF, rt, 54% from 39; (k) formamidine acetate, saturated NH3 in MeOH, THF, ꢀ15 °C to rt, 54%, >99% ee.
optical isomers were further examined in vitro for inhibition of rat
11-hydroxylase, which is responsible for the biosynthesis of gluco-
corticoid and mineralocorticoid.
Table 2
Effect of R1, R2, R3 substituents on inhibition of rat and human 17,20-lyase and human
CYP3A4
As previously described,45 we have shown that the substituents
at the 6-position of the naphthalene ring are likely to have an
important role in hydrogen bond formation with Thr101 in the en-
zyme. Therefore, a number of modifications to optimize the substi-
tuent at the 6-position of the naphthalene ring were investigated.
The results of a SAR study on replacement of the substituent at
the 6-position of the naphthalene ring are shown in Table 1. On the
basis of a docking study of 1a, hydrogen bond acceptors were
examined as replacements for the methoxy group of compound
1a. Although replacing the methoxy group (1a) with an acetyl
group (6) or a methoxycarbonyl group (22) had little effect on po-
tency against human 17,20-lyase with slightly improved selectivity
between human 17,20-lyase and CYP3A4, replacing the methoxy
group (1a) with an acetamide group (10a) or a methylureido group
(10b) led to slightly decreased inhibitory activity against human
17,20-lyase without improved selectivity between human 17,20-
lyase and CYP3A4. Replacement of the methoxy group (1a) with
a methylcarbamoyl group (24b), on the other hand, resulted in
both increased inhibitory activity against human 17,20-lyase and
a promising improvement in selectivity between the two enzymes.
These results indicate that the methylcarbamoyl group on the
naphthalene ring is optimal in terms of both inhibition of
17,20-lyase and selectivity between 17,20-lyase and CYP3A4.
We then focused on modification of the methylcarbamoyl group
and the introduction of a substituent at the 5- or 7-position of the
naphthalene ring. The results are shown in Table 2. Replacement of
HO
R2
N
R3 HNOC
N
H
R1
R3
Compound No.
R1
R2
Enzyme inhibition IC50 (nM)
17,20-Lyase
Human
CYP3A4
Rat
24a
24b
24c
24d
24e
24f
H
H
H
H
H
Cl
H
H
H
H
H
H
H
Me
Et
<10
6
30
16
46
38
75
200
160
39
3700
3600
5700
3400
9300
>10000
>10000
3600
11
13
12
91
200
12
Pr
iPr
Me
Me
Me
24g
24h
Me
H
H
Me
the methylcarbamoyl group (24b) with a carbamoyl (24a) or other
small alkyl carbamoyl group (24c, 24d and 24e) resulted in a 2–5-
fold loss in potency against human 17,20-lyase and a 2–3-fold de-
crease in selectivity for human 17,20-lyase over CYP3A4. The intro-
duction of a substituent at the 5-position of the naphthalene ring
also resulted in decreased potency. For example, incorporation of
a chlorine substitution (24f) at the 5-position resulted in a de-
crease in potency of more than an order of magnitude when com-

T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
1757
Table 5
pared with the unsubstituted 24b. Even a relatively small methyl
group (24g) led to marked reductions in potency against human
17,20-lyase. On the other hand, introduction of a methyl group at
the 7-position of the naphthalene ring (24h) resulted in only a
slight decrease in inhibition of human 17,20-lyase and no change
in inhibition of CYP3A4 compared with 24b. These results sug-
gested that the methylcarbamoyl group (24b) was optimum in size
and the bulkiness at the 5- or 7-position may have some effect on
fixing the conformation of the carbamoyl group.
Inhibitory effect of (ꢀ)-27b on marker enzyme activities in microsomes expressing
human CYP isoforms
Compound No.
Enzyme inhibition IC50 (nM)
Human CYP isoforms
17,20-Lyase
Rat
<10
Human
19
CYP2C8
28000
CYP2C9
<3000
CYP2D6
>30000
CYP3A4
27000
(ꢀ)-27b
Therefore, fixing the angle of the carbamoyl group seemed to be
a promising strategy for further development, and tricyclic com-
pounds such as 27a, 27b, 30a and 30b were prepared to make
the conformation of the carbonyl group more rigid. As a result,
all of these tricyclic compounds had reduced inhibitory activity
against CYP3A4 compared with 24b, but maintained activity
against 17,20-lyase, shown in Table 3. Among them, 27b had the
best selectivity for 17,20-lyase over CYP3A4 by more than 400-
fold.
Further investigations regarding the stereochemical require-
ment at the chiral center of these inhibitors were performed using
optical isomers such as (ꢀ)-27a, (+)-27a, (ꢀ)-27b, and (+)-27b,
respectively, as shown in Table 4. As expected, each isomer exhib-
ited markedly different potencies against 17,20-lyase, as well as
selectivity between 17,20-lyase and CYP3A4. Each (ꢀ)-isomer
had potent inhibitory activity against 17,20-lyase and selectivity
by more than 500-fold for 17,20-lyase over CYP3A4. These data
indicate that the orientation of the isopropyl group at the benzyl
moiety may be critical for binding to targeted 17,20-lyase.
Table 3
Effect of R1 substituent on inhibition of rat and human 17,20-lyase and human
CYP3A4
Figure 3. Docking of (ꢀ)-27b in the 17,20-lyase homology model.
HO
HO
N
N
R1
N
Compounds (ꢀ)-27a, (+)-27a, (ꢀ)-27b, and (+)-27b were also
tested for their ability to inhibit rat 11-hydroxylase. Compounds
(ꢀ)-27a and (+)-27a showed highly potent inhibitory activity
against 11-hydroxylase, while (ꢀ)-27b and (+)-27b showed low
levels of 11-hydroxylase inhibition at concentrations of up to
1000 nM.
N
N
H
O
H
O
N
R1
27a,b
R1
30a,b
Enzyme inhibition IC50 (nM)
17,20-Lyase CYP3A4
Human
Compound No.
3.2. Enzyme selectivity
Rat
27a
27b
30a
30b
H
Me
H
<10
15
42
18
22
36
19
6700
>10000
>10000
5400
During a series of in vitro studies, (ꢀ)-27b was further investi-
gated against other P450 enzymes such as CYP2D6, CYP2C8, and
CYP2C9, which have been identified as important P450 enzymes
involved in drug metabolism.53–56 As shown in Table 5, (ꢀ)-27b
demonstrated specific inhibition of CYP2C9 versus CYP2C8,
CYP2D6, and CYP3A4; however, it also showed good selectivity
(>1000-fold) for inhibition of human 17,20-lyase over CYP2C8,
CYP2D6 and CYP3A4.
Me
70
Table 4
Stereochemical requirement for inhibitory activities of ( )-27a and ( )-27b against rat
and human 17,20-lyase, rat 11-hydroxylase and human CYP3A4 enzymes
HO
N
Table 6
N
In vivo effects of (ꢀ)-27b on serum testosterone and DHEA levels after single oral
O
H
dosing (1 mg/kg) in monkeys
N
R1
Compound
% of average 0 h values, mean SD
Serum testosterone Serum DHEA
27a,b
Enzyme inhibition IC50 (nM)
Compound No.
R1
4 h
8 h
4 h
8 h
17,20-Lyase
Rat Human
11-Hydroxylase
CYP3A4
Vehicle
(ꢀ)-27b (1 mg/kg)
89.1 15.6
13.2 7.5b
68.5 27.3
9.8 4.9a
105.7 4.2
16.8 7.0c
38.5 18.4
7.7 4.3a
(ꢀ)-27a
(+)-27a
(ꢀ)-27b
(+)-27b
H
H
Me
Me
<10
180
<10
110
15
60
19
13
220
>1000
>1000
>10000
7400
>10000
>10000
n = 3.
a
b
c
P <0.05 versus vehicle (Dunnett test).
P <0.005 versus vehicle (Dunnett test).
P <0.001 versus vehicle (Dunnett test).
270

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T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
Table 7
Selected pharmacokinetic data for compound (ꢀ)-27b after oral or intravenous (IV) administration in rats
Dosage route
Dose (mg/kg)
Tmax (h)
Cmax
(
l
g/mL)
AUCa
(l
g h/mL)
Bioavailability (%)
127.7 38.1
Oral
IV
10
1
0.42 0.14
2.943 0.611
7.315 2.148
0.573 0.030
Mean SD (n = 3).
a
0–24 h.
3.3. Docking experiments
taken using a SHIMADZU FT-IR-8200PC spectrometer. 1H NMR
spectra were recorded using Varian Gemini-200, Varian
a
The docking of (ꢀ)-27b was studied using a homology model of
17,20-lyase. In the docking experiment it was postulated that
(ꢀ)-27b should be connected to the catalytic heme iron via the
nitrogen of the imidazole ring moiety, and the proposed binding
mode of (ꢀ)-27b is shown in Figure 3. Results of docking studies
indicated that the tricyclic ring of (ꢀ)-27b occupied a hydrophobic
region in the active site of the enzyme and the carbonyl moiety on
the lactam ring formed a hydrogen bond with Thr101. These find-
ings are consistent with our previous results on the docking study
of 1a.45 Furthermore, an additional hydrogen bond between the
hydroxyl group at the linker position between the tricyclic and
imidazole rings of (ꢀ)-27b with Thr306 was also observed in this
model.
Mercury-300 spectrometer, or a Bruker AVANCE-300 spectrome-
ter. 13C NMR spectra were recorded using a Bruker AVANCE-300
spectrometer; chemical shifts are given in ppm with tetramethyl-
silane as an internal standard, and coupling constants (J) are mea-
sured in hertz (Hz). The following abbreviations are used:
s = singlet, d = doublet, t = triplet, m = multiplet, br s = broad sin-
glet. LCMS was performed on the Agilent1200Sl and Agi-
lent6130MS apparatus with 5 mM aqueous AcONH4 solution/
acetonitrile mobile phase. Reactions were followed by TLC on Silica
Gel 60 F254 precoated TLC plates (Merck, Darmstadt, Germany).
Column chromatography was performed using Silica Gel 60 (E.
Merck, Darmstadt, Germany). Compounds 3 (Kaku, T. et al., manu-
script in preparation) and 1357 were prepared in the same manner
as described previously.
3.4. In vivo efficacy
5.1. 2,6-Dibromonaphthalene (2)
Based on the in vitro profiles, (ꢀ)-27b was selected for further
biological investigation. In a monkey model both testicular andro-
gen testosterone and adrenal androgen DHEA levels were exam-
ined to evaluate in vivo potency of (ꢀ)-27b. As shown in Table 6,
(ꢀ)-27b markedly reduced serum testosterone and DHEA levels
at 4 and 8 h after administration of an oral dose (1 mg/kg) in
monkeys. These results indicate that compound (ꢀ)-27b could be
useful for the treatment of both hormone-dependent and castra-
tion-resistant prostate cancer.
Bromine (78.8 g, 493 mmol) was added dropwise to a cooled
(0 °C) solution of triphenylphosphine (129 g, 493 mmol) in anhy-
drous CH3CN (200 mL) and the solution was stirred for 30 min at
rt. A solution of 6-bromo-2-naphthol (100 g, 448 mmol) in anhy-
drous acetonitrile (CH3CN) (200 mL) was added, and the reaction
mixture was stirred for a further 2 h at 70 °C. After removal of
the solvent (bath temp was increased to 140 °C), the residue was
heated to 300 °C for 1 h. After being cooled to 100 °C, the black
tar was dissolved in toluene (100 mL), and cooled to rt while stir-
ring. The resulting solution was washed with 1 N NaOH and water,
followed by drying over MgSO4. The solvent was removed in vacuo
and the residue was dissolved in MeOH (50 mL). The precipitate
was filtered and washed with MeOH (200 mL) and diisopropyle-
ther (iPr2O), successively, to give 2 (37.2 g, 29%) as a grey powder.
The analytical sample was obtained by recrystallization from
AcOEt (light brown plates). 1H NMR (CDCl3) d: 7.51–7.62 (4H, m),
7.94 (2H, s). IR (KBr): 1568, 1481, 1175, 1134, 1065, 885, 853,
816 cmꢀ1. Anal. Calcd for C10H6Br2: C, 42.00; H, 2.11. Found: C,
42.28; H, 2.18.
3.5. Pharmacokinetics
Pharmacokinetic studies of (ꢀ)-27b were performed in rats (not
evaluated in monkeys). As shown in Table 7, (ꢀ)-27b demon-
strated good pharmacokinetic profiles with large oral AUC and
excellent bioavailability values; these results are encouraging for
the further development of (ꢀ)-27b as a therapeutic agent.
4. Conclusions
We have successfully synthesized a new class of potent and
selective 17,20-lyase inhibitors. Replacement of the substituent
at the 6-position of the naphthalene ring showed that a methylcar-
bamoyl group was optimal in terms of potency and selectivity. Fur-
ther modifications aimed at fixing the orientation of the carbonyl
group of the inhibitor yielded tricyclic compounds 27a and 27b
that were potent and selective human 17,20-lyase inhibitors.
Among them (ꢀ)-27b showed good selectivity (>1000-fold) for
the inhibition of 17,20-lyase over CYP3A4, while showing potent
inhibitory activity against 17,20-lyase. Additional biological evalu-
ation revealed that (ꢀ)-27b exhibited potent in vivo efficacy at an
oral dose of 1 mg/kg in monkeys and showed favorable pharmaco-
kinetic profiles when administered to rats. Further evaluation on
this series is ongoing, with the aim of identifying a new potent
and highly selective 17,20-lyase inhibitor.
5.2. 1-(6-Bromo-2-naphthyl)-2-methyl-1-(1-trityl-1H-imidazol-
4-yl)-1-propanol (4)
n-BuLi (1.6 M; 59.0 mL, 94.4 mmol) was added dropwise to a
cooled (ꢀ50 °C) solution of 2 (27.0 g, 94.4 mmol) in anhydrous
THF (1300 mL) , and the solution was stirred for 20 min at
ꢀ50 °C. A solution of 3 (23.9 g, 62.9 mmol) in anhydrous THF
(200 mL) was added dropwise over 20 min, and the reaction mix-
ture was stirred for 20 min at ꢀ50 °C. After dilution with water,
the organic phase was separated. The aqueous phase was extracted
with AcOEt. The extracts were washed with brine and dried over
MgSO4, and then concentrated in vacuo. The residue was washed
with hot AcOEt to give 4 (34.4 g, 93%) as a light brown powder.
The analytical sample was obtained by recrystallization from
THF–hexane (colorless powder). 1H NMR (CDCl3) d: 0.72 (3H, d,
J = 6.7 Hz), 0.95 (3H, d, J = 6.7 Hz), 2.45–2.58 (1H, m), 3.75 (1H, s),
6.80 (1H, d, J = 1.4 Hz), 7.10–7.15 (6H, m), 7.29–7.35 (10H, m),
7.50 (1H, dd, J = 1.8, 8.7 Hz), 7.57 (1H, dd, J = 1.8, 8.8 Hz),
5. Experimental
Melting points were determined using a BUCHI Melting Point
B-545 apparatus and are uncorrected. Infrared (IR) spectra were

T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
1759
7.63–7.69 (2H, m), 7.94 (1H, d, J = 1.8 Hz), 8.02 (1H, s). IR (KBr):
3241, 2967, 1493, 1445, 1169, 1017, 826, 812, 756, 747, 700 cm
ꢀ1. Anal. Calcd for C36H31N2OBr: C, 73.59; H, 5.32; N, 4.77. Found:
C, 73.89; H, 5.11; N, 4.63.
1163, 1005, 812, 748 cmꢀ1. Anal. Calcd for C49H41N3Oꢁ0.3THF: C,
84.98; H, 6.17; N, 5.92. Found: C, 84.87; H, 6.27; N, 5.74.
5.6. 1-(6-Amino-2-naphthyl)-2-methyl-1-(1-trityl-1H-imidazol-
4-yl)-1-propanol (8)
5.3. 1-{6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-2-naphthyl}-1-ethanone (5)
Sodium acetate (4.02 g, 49.0 mmol) and hydroxylamine hydro-
chloride (2.52 g, 36.3 mmol) were added to a solution of
7
n-BuLi (1.6 M; 16.4 mL, 26.2 mmol) was added dropwise to a
cooled (ꢀ70 °C) solution of 4 (7.0 g, 11.9 mmol) in anhydrous
THF (150 mL) , and the solution was stirred for 20 min at ꢀ70 °C.
A solution of N-methoxy-N-methylacetamide (2.45 g, 23.8 mmol)
in anhydrous THF (10 mL) was added, and the reaction mixture
was stirred for 20 min at ꢀ70 °C. After dilution with water, the
resulting mixture was extracted with AcOEt (ꢂ2). The combined
organic layers were washed with brine, dried over MgSO4, and con-
centrated in vacuo. The residue was purified by column chroma-
tography on silica gel (hexane/THF = 6:1–3:1) to give 5 (3.53 g,
54%) as a colorless powder. The analytical sample was obtained
by recrystallization from i-Pr2O (colorless powder). 1H NMR
(CDCl3) d: 0.74 (3H, d, J = 6.8 Hz), 0.97 (3H, d, J = 6.8 Hz), 2.48–
2.61 (1H, m), 2.72 (3H, s), 3.75 (1H, br s), 6.83 (1H, d, J = 1.4 Hz),
7.10–7.17 (6H, m), 7.30–7.37 (10H, m), 7.65 (1H, dd, J = 1.6,
8.8 Hz), 7.84 (1H, d, J = 8.8 Hz), 7.87 (1H, d, J = 8.8 Hz), 8.01 (1H,
dd, J = 1.6, 8.8 Hz), 8.07 (1H, s), 8.42 (1H, s). IR (KBr): 3519, 2963,
(14.0 g, 20.4 mmol) in anhydrous THF (100 mL) and MeOH
(100 mL) and the mixture was stirred for 40 min at rt. After con-
centration in vacuo, the residue was diluted with 0.2 N NaOH,
and the resulting mixture was extracted with AcOEt (ꢂ2). The
combined organic layers were washed with brine and dried over
MgSO4 followed by concentration in vacuo to give 8 (orange-col-
ored oil), which was used in the next reaction without further puri-
fication. The analytical sample was obtained by recrystallization
from AcOEt (pale yellow powder). 1H NMR (CDCl3) d: 0.75 (3H, d,
J = 6.8 Hz), 0.93 (3H, d, J = 6.8 Hz), 2.44–2.57 (1H, m), 3.62 (1H, br
s), 6.79 (1H, d, J = 1.4 Hz), 6.89–6.94 (2H, m), 7.11–7.18 (6H, m),
7.29–7.36 (10H, m), 7.44 (1H, dd, J = 1.8, 8.8 Hz), 7.50 (1H, d,
J = 8.8 Hz), 7.61 (1H, d, J = 8.4 Hz), 7.86 (1H, d, J = 1.2 Hz). IR
(KBr): 3370, 3092, 2963, 1634, 1485, 1445, 760, 747, 700 cmꢀ1
.
Anal. Calcd for C36H33N3Oꢁ0.2AcOEt: C, 81.66; H, 6.44; N, 7.76.
Found: C, 81.55; H, 6.51; N, 7.66.
1671, 1275, 1231, 1140, 747, 700 cmꢀ1. Anal. Calcd for C38
34N2O2: C, 82.88; H, 6.22; N, 5.09. Found: C, 82.96; H, 6.17; N,
-
5.7. N-{6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-2-naphthyl}acetamide (9a)
H
5.37.
Pyridine (5.0 mL, 61.2 mmol) and acetic anhydride (3.9 mL,
40.8 mmol) were added to a crude mixture of 8 in anhydrous
CH2Cl2 (100 mL) and stirred for 40 min at rt. After dilution with
saturated NaHCO3 (200 mL), the mixture was extracted with
CH2Cl2 (ꢂ3). The combined organic layers were dried over MgSO4
and concentrated in vacuo. The residue was recrystallized from
AcOEt to give 9a (10.9 g, 95% from 7) as a pale yellow powder.
1H NMR (CDCl3 + CD3OD) d: 0.75 (3H, d, J = 6.7 Hz), 0.95 (3H, d,
J = 6.7 Hz), 2.20 (3H, s), 2.57–2.71 (1H, m), 6.87 (1H, d, J = 1.4 Hz),
7.10–7.15 (6H, m), 7.32–7.54 (12H, m), 7.68–7.77 (2H, m), 7.92
(1H, s), 8.15 (1H, s), 9.60 (1H, br s). IR (KBr): 3058, 2969, 1686,
5.4. 1-{6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-2-
naphthyl}-1-ethanone (6)
A mixture of 5 (350 mg, 0.64 mmol) and pyridine hydrochloride
(148 mg, 1.28 mmol) in MeOH (4 mL) and CHCl3 (2 mL) was stirred
at 60 °C for 3 h. The mixture was diluted with aq NaHCO3 solution
and the resulting mixture was extracted with AcOEt. The combined
organic layers were washed with brine, dried over MgSO4. After
removing the solvent, the residue was purified by column chroma-
tography on silica gel (CH2Cl2/MeOH = 20:1–10:1) to give 6
(159 mg, 81%) as a colorless powder. The analytical sample was ob-
tained by recrystallization from AcOEt as a colorless powder. Mp
180.0–182.0 °C. 1H NMR (CDCl3 + CD3OD) d: 0.81 (3H, d,
J = 6.7 Hz), 1.02 (3H, d, J = 6.7 Hz), 2.73–2.86 (4H, m), 7.05 (1H, d,
J = 1.1 Hz), 7.56 (1H, d, J = 1.1 Hz), 7.73 (1H, dd, J = 1.7, 8.7 Hz),
7.89 (1H, d, J = 8.7 Hz), 7.92 (1H, d, J = 8.7 Hz), 7.99 (1H, dd,
J = 1.7, 8.7 Hz), 8.11 (1H, s), 8.46 (1H, s). IR (KBr): 3235, 2969,
1672, 1306, 1289, 1044, 895, 824, 789 cmꢀ1. LCMS (API): m/z
309.2 [M+H]+. Anal. Calcd for C19H20N2O2ꢁ0.1AcOEt: C, 73.46; H,
6.61; N, 8.83. Found: C, 73.29; H, 6.57; N, 8.84.
1493, 1298, 1011, 747, 700 cmꢀ1
. Anal. Calcd for C38H35-
N3O2ꢁ0.3AcOEt: C, 79.51; H, 6.37; N, 7.10. Found: C, 79.50; H,
6.47; N, 7.28.
5.8. N-{6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-2-
naphthyl}acetamide (10a)
Compound 10a was prepared in the same manner as described
for the preparation of 6. Yield 84%, colorless powder. Mp 186.0–
188.0 °C. 1H NMR (CDCl3 + CD3OD) d: 0.79 (3H, d, J = 6.8 Hz), 1.0
(3H, d, J = 6.8 Hz), 2.17 (3H, s), 2.63–2.76 (1H, m), 6.99 (1H, s),
7.43–7.54 (3H, m), 7.65–7.74 (2H, m), 7.91 (1H, s), 8.11 (1H, s).
5.5. 1-[6-[(Diphenylmethylene)amino]-2-naphthyl]-2-methyl-
1-(1-trityl-1H-imidazol-4-yl)-1-propanol (7)
IR (KBr): 3248, 2971, 1669, 1557, 1495, 1391, 1296, 818 cmꢀ1
.
LCMS (API): m/z 324.2 [M+H]+. Anal. Calcd for C19H21N3O2: C,
A mixture of 4 (14.0 g, 23.8 mmol), benzophenoneimine (5.18 g,
28.6 mmol), tert-BuONa (5.72 g, 59.5 mmol), Pd2(dba)3 (440 mg,
0.48 mmol), and R-(+)-BINAP (872 mg, 1.40 mmol) in anhydrous
toluene (140 mL) was heated at 80 °C for 18 h under Ar atmo-
sphere. After dilution with AcOEt, the resulting mixture was passed
through Celite. The filtrate was concentrated in vacuo, and the res-
idue was purified by column chromatography on silica gel (hex-
ane/THF = 1:1) and recrystallized from AcOEt–hexane (ꢂ2) to
give 7 (14.3 g, 87%) as a yellow powder. 1H NMR (CDCl3) d: 0.74
(3H, d, J = 6.7 Hz), 0.93 (3H, d, J = 6.7 Hz), 2.42–2.56 (1H, d), 3.65
(1H, br s), 6.79 (1H, d, J = 1.4 Hz), 6.87 (1H, dd, J = 2.0, 8.6 Hz),
7.10–7.57 (28H, m), 7.76 (1H, d, J = 2.0 Hz), 7.80 (1H, d,
J = 1.4 Hz), 7.86 (1H, s). IR (KBr): 3453, 2969, 1493, 1445, 1256,
70.57; H, 6.55; N, 12.99. Found: C, 70.58; H, 6.90; N, 12.94.
5.9. N0-{6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-2-
naphthyl}-N-methylurea (10b)
Phenyl chloroformate (0.50 mL, 4.01 mmol) was added drop-
wise to a cooled (0 °C) solution of 8 (1.40 g, 2.67 mmol) and pyri-
dine (0.65 mL, 8.01 mmol) in anhydrous THF (10 mL) and stirred
for 30 min at 0 °C. After pouring into phosphate buffer (pH 7.0),
the resulting mixture was extracted with AcOEt (ꢂ2). The com-
bined organic layers were washed with brine and dried over
MgSO4, followed by concentrating in vacuo to give the carbamate
(red viscous oil) which was used for the next reaction without

1760
T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
further purification. Methylamine hydrochloride (360 mg,
5.34 mmol) and 10 N NaOH (0.54 mL, 5.4 mmol) were added to a
stirred solution of the carbamate in DMSO (5 mL), and the reaction
mixture was stirred for 1 h at rt. After dilution with 0.5 N NaOH,
the resulting mixture was extracted with AcOEt (ꢂ2). The com-
bined organic layers were washed with brine and dried over
MgSO4 followed by concentrating in vacuo. The residue was puri-
fied by column chromatography on silica gel (hexane/AcOEt =
1:2–1:4) to give 9b (984 mg) as a pale yellow powder, which con-
tained a small amount of impurities. 9b (850 mg) was used as a
starting material. Using the same procedure as described for the
synthesis of 6, 10b (278 mg, 31% from 8) was obtained as colorless
amorphous solid. 1H NMR (CDCl3 + CD3OD) d: 0.79 (3H, d,
J = 6.9 Hz), 0.97 (3H, d, J = 6.9 Hz), 2.74–2.87 (1H, m), 2.79 (3H, s),
7.03 (1H, s), 7.38 (1H, dd, J = 2.2, 8.8 Hz), 7.55–7.66 (3H, m), 7.72
(1H, d, J = 9.0 Hz), 7.87 (1H, d, J = 2.0 Hz), 7.94 (1H, s). IR (KBr):
3320, 2971, 1655, 1555, 1493, 1248 cmꢀ1. LCMS (API): m/z 339.2
[M+H]+. Anal. Calcd for C19H22N4O2ꢁH2O: C, 64.03; H, 6.79; N,
15.72. Found: C, 64.06; H, 6.72; N, 15.63.
810 cmꢀ1. Anal. Calcd for C11H9OBr: C, 55.72; H, 3.83. Found: C,
55.70; H, 3.81.
5.13. (7-Bromo-3-methoxy-2-naphthyl)methanol (14)
Trimethoxyborane (1.60 mL, 13.6 mmol) was added dropwise
to a solution of lithium borohydride (2.96 g, 136 mmol) and 1356
(40.0 g, 136 mmol) in anhydrous THF (150 mL), and the solution
was refluxed for 90 min. After cooling to 0 °C, water was carefully
added, and the mixture was acidified with 6 N HCl followed by
extraction with AcOEt (ꢂ2). The combined organic layers were
washed with 1 N NaOH (ꢂ2) and brine, and then dried over MgSO4.
The solvent was removed in vacuo to give 14 as a colorless powder,
which was used for the next reaction without further purification.
The analytical sample was obtained by recrystallization from
AcOEt–hexane (colorless needles). 1H NMR (CDCl3) d: 3.97 (3H,
s), 4.82 (2H, s), 7.09 (1H, s), 7.49 (1H, dd, J = 1.8, 8.8 Hz), 7.60
(1H, d, J = 8.8 Hz), 7.65 (1H, s), 7.91 (1H, d, J = 1.8 Hz). IR (KBr):
3239, 1497, 1248, 1215, 1065, 1049, 839 cmꢀ1. Anal. Calcd for
C12H11O2Br: C, 53.96; H, 4.15. Found: C, 53.76; H, 3.93.
5.10. 6-Bromo-1-chloro-2-naphthol (11b)
5.14. 7-Bromo-3-methoxy-2-naphthaldehyde (15)
Sulfuryl chloride (6.48 mL, 80.7 mmol) was added dropwise to a
cooled (0 °C) solution of 6-bromo-2-naphthol (15.0 g, 67.2 mmol)
in anhydrous Et2O (80 mL) and stirred for 1 h at rt. After removal
of the solvent in vacuo, the residue was diluted with AcOEt. The
solution was washed with water and brine, and then dried over
MgSO4. After concentration in vacuo, the residue was recrystallized
from i-Pr2O–hexane (ꢂ2) to give 11b (8.89 g, 51%) as a light brown
powder. 1H NMR (CDCl3) d: 5.90 (1H, s), 7.27 (1H, d, J = 9.0 Hz),
7.61 (1H, d, J = 9.0 Hz), 7.63 (1H, dd, J = 2.2, 9.0 Hz), 7.92 (1H, d,
J = 9.0 Hz), 7.94 (1H, d, J = 2.2 Hz). IR (KBr): 3491, 3432, 1589,
1200, 1184, 939, 806 cmꢀ1. Anal. Calcd for C10H6OBrCl: C, 46.64;
H, 2.35. Found: C, 46.44; H, 2.35.
A suspension of 14 and MnO2 (200 g) in CH2Cl2 (600 mL) was
refluxed for 1 h. The mixture was filtered through Celite, and the
filtrate was concentrated in vacuo to give 15 (33.9 g, 94% from
13) as a yellow powder. The analytical sample was obtained by
recrystallization from AcOEt–hexane (colorless plates). 1H NMR
(CDCl3) d: 4.01 (3H, s), 7.13 (1H, s), 7.58 (2H, s), 7.98 (1H, s), 8.20
(1H, s), 10.55 (1H, s). IR (KBr): 2882, 1680, 1620, 1250, 1157 cm
ꢀ1. Anal. Calcd for C12H9O2Br: C, 54.37; H, 3.42. Found: C, 54.41;
H, 3.46.
5.15. 6-Bromo-2-methoxy-3-methylnaphthalene (16)
5.11. 1-Methyl-2-naphthol (12)
A mixture of 15 (13.0 g, 49.0 mmol), hydrazine monohydrate
(7.13 mL, 147 mmol) and KOH (13.0 g) in triethyleneglycol
(100 mL) was slowly heated to 160 °C in a round-bottomed flask
equipped with Dean-Stark apparatus. Evolution of N2 gas started
at 100 °C. The mixture was heated at 160 °C for 20 min and then
at 180 °C for a further 10 min. After cooling to rt, the mixture
was poured into water. The precipitate was washed with water
and dried in vacuo to give 16 (12.1 g, 98%) as pale yellow plates.
The analytical sample was obtained by recrystallization from
AcOEt–hexane (colorless plates). 1H NMR (CDCl3) d: 2.35 (3H, s),
3.91 (3H, s), 7.01 (1H, s), 7.40–7.45 (2H, m), 7.56 (1H, d,
J = 8.4 Hz), 7.82 (1H, s). IR (KBr): 2978, 1590, 1490, 1256, 1157,
1119, 1019, 903, 851 cmꢀ1. Anal. Calcd for C12H11OBr: C, 57.39;
H, 4.42. Found: C, 57.27; H, 4.47.
A mixture of 2-hydroxy-1-naphthaldehyde (20.0 g, 116 mmol),
hydrazine monohydrate (16.9 mL, 348 mmol) and KOH (20 g) in
triethyleneglycol (150 mL) was slowly heated to 170 °C in a
round-bottomed flask equipped with Dean-Stark apparatus. The
mixture was then heated at 170 °C for 90 min and at 190 °C for a
further 20 min. After cooling to rt, the mixture was poured into
water and acidified with concentrated HCl. The precipitate was fil-
tered, washed with water, and dried in vacuo to give 12 (16.3 g,
89%) as a pale yellow powder. The analytical sample was obtained
by recrystallization from i-Pr2O–hexane (colorless needles). 1H
NMR (CDCl3) d: 2.52 (3H, s), 4.91 (1H, br s), 7.04 (1H, d,
J = 8.8 Hz), 7.29–7.37 (1H, m), 7.44–7.52 (1H, m), 7.60 (1H, d,
J = 8.8 Hz), 7.75 (1H, d, J = 8.0 Hz), 7.90 (1H, d, J = 8.4 Hz). IR
(KBr): 3295, 1514, 1354, 1227, 1213, 806, 742 cmꢀ1. Anal. Calcd
for C11H10O: C, 83.51; H, 6.37. Found: C, 83.55; H, 6.46.
5.16. 6-Bromo-3-methyl-2-naphthol (11d)
BBr3 (1 M solution in CH2Cl2; 55.0 mL) was added dropwise to a
cooled (ꢀ70 °C) solution of 16 (11.5 g, 45.8 mmol) in anhydrous
CH2Cl2 (120 mL), and the mixture was slowly heated to rt. After
stirring for 2 h at rt, the reaction was quenched with water at
0 °C. The resulting mixture was extracted with CH2Cl2 (ꢂ2). The
combined organic layers were washed with brine, dried over
MgSO4, and then concentrated in vacuo. The residue was purified
by column chromatography on silica gel (hexane/AcOEt = 2:1)
and washed with hexane to give 11d (9.67 g, 89%) as a pale yellow
powder. The analytical sample was obtained by recrystallization
from AcOEt–hexane (pale yellow prisms). 1H NMR (CDCl3) d: 2.40
(3H, s), 5.12 (1H, s), 7.02 (1H, s), 7.40 (1H, dd, J = 1.8, 8.8 Hz),
7.46–7.50 (2H, m), 7.82 (1H, s). IR (KBr): 3562, 1589, 1512, 1232,
5.12. 6-Bromo-1-methyl-2-naphthol (11c)
A solution of bromine (16.1 g, 101 mL) in AcOH (30 mL) was
added dropwise to
a cooled (10 °C) solution of 12 (16.0 g,
101 mmol) in AcOH (50 mL); the temperature of the solution was
maintained at 10–20 °C. After stirring for 15 min at 15–20 °C, the
mixture was poured into water. The precipitate was filtered,
washed with water, and dried in vacuo to give 11c (23.7 g, 99%)
as a reddish powder. 1H NMR (CDCl3) d: 2.49 (3H, s), 4.94 (1H, s),
7.05 (1H, d, J = 8.8 Hz), 7.50 (1H, d, J = 8.8 Hz), 7.52 (1H, dd,
J = 2.2, 9.0 Hz), 7.76 (1H, d J = 9.0 Hz), 7.89 (1H, d, J = 2.2 Hz). IR
(KBr): 3245, 1591, 1497, 1356, 1341, 1198, 1080, 893, 878,

T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
1761
1186, 1153, 1103, 920, 905, 860 cmꢀ1. Anal. Calcd for C11H9OBr: C,
55.72; H, 3.83. Found: C, 55.65; H, 3.63.
8.6 Hz), 7.60 (1H, d, J = 8.6 Hz), 7.68 (1H, d, J = 8.8 Hz), 7.94 (1H,
s). IR (KBr): 3158, 2955, 2930, 1601, 1480, 1260, 843, 700 cmꢀ1
.
Anal. Calcd for C42H46N2O2Si: C, 78.95; H, 7.26; N, 4.38. Found: C,
79.05; H, 7.26; N, 4.47. Compounds 18b–d were prepared using
the same method as described for the preparation of 18a.
5.17. 2-Bromo-6-(tert-butyldimethylsilyloxy)naphthalene (17a)
TBSCl (37.0 g, 246 mmol) was added to a cooled (0 °C) solution
of 6-bromo-2-naphthol (50.0 g, 224 mmol) and imidazole (22.9 g,
336 mmol) in DMF (200 mL), and the solution was stirred for 2 h
at rt. After dilution with water, the resulting mixture was extracted
with AcOEt (ꢂ2). The combined organic layers were washed with
water and brine, and then dried over MgSO4. After removal of
the solvent in vacuo, the residue was recrystallized from MeOH
(20 mL) to give 17a (71.3 g, 94%) as colorless plates. 1H NMR
(CDCl3) d: 0.24 (6H, s), 1.01 (9H, s), 7.08 (1H, dd, J = 2.4, 8.8 Hz),
7.15 (1H, d, J = 2.4 Hz), 7.46 (1H, dd, J = 1.8, 8.8 Hz), 7.54 (1H, d,
J = 8.8 Hz), 7.61 (1H, d, J = 8.8 Hz), 7.90 (1H, d, J = 1.8 Hz). IR
(KBr): 2957, 2930, 2857, 1256, 874, 797, 783 cmꢀ1. Anal. Calcd
for C16H21OBrSi: C, 56.97; H, 6.27; Br, 23.69. Found: C, 56.94; H,
6.26. Compounds 17b–d were prepared using the same method
as described for the preparation of 17a.
5.22. 1-(6-{[tert-Butyl(dimethyl)silyl]oxy}-5-chloro-2-naphthyl)-
2-methyl-1-(1-trityl-1H-imidazol-4-yl)propan-1-ol (18b)
Yield 84%, colorless powder. 1H NMR (CDCl3) d: 0.25 (6H, s), 0.74
(3H, d, J = 6.8 Hz), 0.95 (3H, d, J = 6.6 Hz), 1.07 (9H, s), 2.45–2.59 (1H,
m), 3.70 (1H, s), 6.80 (1H, d, J = 1.2 Hz), 7.07–7.16 (7H, m), 7.29–7.34
(10H, m), 7.59 (1H, dd, J = 1.8, 8.8 Hz), 7.61 (1H, d, J = 8.8 Hz), 7.99
(1H, d, J = 1.8 Hz), 8.07 (1H, d, J = 8.8 Hz). IR (KBr): 3155, 2957,
1599, 1474, 1360, 1252, 1020, 964, 841, 700 cmꢀ1
.
5.23. 1-(6-{[tert-Butyl(dimethyl)silyl]oxy}-5-methyl-2-naph-
thyl)-2-methyl-1-(1-trityl-1H-imidazol-4-yl)propan-1-ol (18c)
Yield 89%, colorless powder. 1H NMR (CDCl3) d: 0.22 (6H, s), 0.75
(3H, d, J = 6.6 Hz), 0.95 (3H, d, J = 6.6 Hz), 1.05 (9H, s), 2.44–2.60
(4H, m), 3.64 (1H, s), 6.80 (1H, d, J = 1.2 Hz), 7.03 (1H, d,
J = 8.8 Hz), 7.10–7.16 (6H, m), 7.28–7.34 (10H, m), 7.55 (1H, d,
J = 8.8 Hz), 7.56 (1H, dd, J = 1.8, 9.0 Hz), 7.81 (1H, d, J = 9.0 Hz),
7.92 (1H, d, J = 1.8 Hz). IR (KBr): 3200, 2961, 1472, 1242, 839,
702 cmꢀ1. Anal. Calcd for C43H48N2O2Si: C, 79.10; H, 7.41; N,
4.29. Found: C, 79.11; H, 7.44; N,4.40.
5.18. 6-Bromo-2-[(tert-butyldimethylsilyl)oxy]-1-chloronaph-
thalene (17b)
Yield 98%, pale yellow oil. 1H NMR (CDCl3) d: 0.27 (6H, s), 1.07
(9H, s), 7.14 (1H, d, J = 8.8 Hz), 7.56 (1H, d, J = 8.8 Hz), 7.60 (1H, dd,
J = 2.0, 9.0 Hz), 7.93 (1H, d, J = 2.0 Hz), 8.07 (1H, d, J = 9.0 Hz). IR
(KBr): 2930, 1588, 1487, 1352, 1271, 1246, 960, 839 cmꢀ1
.
5.24. 1-(6-{[tert-Butyl(dimethyl)silyl]oxy}-7-methyl-2-naph-
thyl)-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-1-propanol (18d)
5.19. 6-Bromo-2-[(tert-butyldimethylsilyl)oxy]-1-methylnaph-
thalene (17c)
Yield 93%, pale yellow powder. 1H NMR (CDCl3) d: 0.27 (6H, s),
0.75 (3H, d, J = 6.6 Hz), 0.94 (3H, d, J = 6.6 Hz), 1.05 (9H, s), 2.35
(3H, s), 2.45–2.58 (1H, m), 3.67 (1H, s), 6.80 (1H, d, J = 1.2 Hz),
7.06 (1H, s), 7.11–7.15 (6H, m), 7.30–7.7.33 (10H, m), 7.44 (1H,
dd, J = 1.8, 8.6 Hz), 7.53–7.57 (2H, m), 7.86 (1H, s). IR (KBr): 3198,
1472, 1445, 1250, 1163, 1124, 914, 700 cmꢀ1. Anal. Calcd for
Yield 85%, pale yellow plates. 1H NMR (CDCl3) d: 0.23 (6H, s),
1.05 (9H, s), 2.49 (3H, s), 7.07 (1H, d, J = 8.8 Hz), 7.48 (1H, d,
J = 8.8 Hz), 7.51 (1H, dd, J = 2.2, 9.2 Hz), 7.77 (1H, d, J = 9.2 Hz),
7.89 (1H, d, J = 2.2 Hz). IR (KBr): 2926, 1460, 1258, 928, 841,
781 cmꢀ1. Anal. Calcd for C17H23OBrSi: C, 58.11; H, 6.60; Br,
22.74. Found: C, 57.97; H, 6.56.
C43H48N2O2Si: C, 79.10; H, 7.41; N, 4.29. Found: C, 79.12; H, 7.39;
N, 4.44.
5.20. 6-Bromo-2-[(tert-butyldimethylsilyl)oxy]-3-methylnaph-
thalene (17d)
5.25. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-2-naphthol (19a)
Yield 98%, pale yellow powder. 1H NMR (CDCl3) d: 0.28 (6H, s),
1.04 (9H, s), 2.35 (3H, s), 7.05 (1H, s), 7.40 (1H, dd, J = 2.0, 8.6 Hz),
7.48–7.52 (2H, m), 7.81 (1H, d, J = 1.8 Hz). IR (KBr): 2928, 2856,
1587, 1460, 1254, 840, 781 cmꢀ1. Anal. Calcd for C17H23OBrSi: C,
58.11; H, 6.60; Br, 22.74. Found: C, 58.23; H, 6.64.
Tetrabutylammonium fluoride (1 M in THF; 100 mL) was added
to a cooled (0 °C) solution of 18a (35.0 g, 54.8 mmol) in anhydrous
THF (100 mL), and the reaction mixture was stirred for 1 h at rt.
After removal of the solvent in vacuo, the residue was diluted with
water. The precipitate was filtered, washed with water and AcOEt,
and then dried in vacuo (100 °C) to give 19a (28.3 g, 98%) as a
colorless powder. The analytical sample was obtained by recrystal-
lization from THF–hexane (colorless powder). 1H NMR (CDCl3 +
CD3OD) d: 0.76 (3H, d, J = 6.8 Hz), 0.95 (3H, d, J = 6.6 Hz),
2.27–2.71 (1H, m), 6.86 (1H, d, J = 1.4 Hz), 7.05–7.17 (7H, m),
7.31–7.38 (11H, m), 7.48 (1H, dd, J = 1.8, 8.6 Hz), 7.58 (1H, d,
J = 8.8 Hz), 7.67 (1H, d, J = 8.6 Hz), 7.85 (1H, s). IR (KBr): 3598,
2965, 1603, 1445, 1250, 1223, 1171, 702 cmꢀ1. LCMS (API): m/z
523.1 [MꢀH]ꢀ. Anal. Calcd for C36H32N2O2ꢁ0.5H2Oꢁ0.5THF: C,
80.11; H, 6.55; N, 4.92. Found: C, 80.27; H, 6.55, N, 4.92. Com-
pounds 19b–d were prepared using the same method as described
for the preparation of 19a.
5.21. 1-(6-tert-Butyldimethylsilyloxy-2-naphthyl)-2-methyl-1-
(1-trityl-1H-imidazol-4-yl)-1-propanol (18a)
n-BuLi (1.6 M; 55.6 mL, 88.9 mmol) was added dropwise to a
cooled (ꢀ70 °C) solution of 17a (30.0 g, 88.9 mmol) in anhydrous
THF (300 mL), and the solution was stirred for 20 min at ꢀ70 °C.
A solution of 3 (22.6 g, 59.3 mmol) in anhydrous THF (150 mL)
was added dropwise over 30 min, and the reaction mixture was
stirred for 20 min at ꢀ70 °C. After dilution with water, the organic
phase was separated and the aqueous phase was extracted with
AcOEt. The extracts were washed with brine and dried over MgSO4.
After removal of the solvent in vacuo, the residue was purified by
column chromatography on silica gel (hexane/AcOEt = 1:1) and
recrystallized from iPr2O–hexane to give 18a (34.8 g, 92%) as a col-
orless powder. 1H NMR (CDCl3) d: 0.23 (6H, s), 0.75 (3H, d,
J = 6.8 Hz), 0.95 (3H, d, J = 6.6 Hz), 1.02 (9H, s), 2.45–2.59 (1H, m),
3.66 (1H, s), 6.80 (1H, d, J = 1.4 Hz), 7.04 (1H, dd, J = 2.4, 8.8 Hz),
7.11–7.16 (6H, m), 7.30–7.34 (11H, m), 7.49 (1H, dd, J = 1.6,
5.26. Chloro-6-[1-hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-
yl)propyl]-2-naphthol (19b)
Yield 89%, colorless powder. 1H NMR (CDCl3 + CD3OD) d: 0.73
(3H, d, J = 7.0 Hz), 0.97 (3H, d, J = 6.6 Hz), 2.48–2.61 (1H, m), 6.86

1762
T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
(1H, d, J = 1.4 Hz), 6.90 (1H, d, J = 9.2 Hz), 7.12–7.17 (6H, m), 7.31–
7.47 (12H, m), 7.85 (1H, s), 7.94 (1H, d, J = 9.2 Hz). IR (KBr): 3533,
2971, 1485, 1350, 1310, 1001, 758, 702 cmꢀ1. LCMS (API): m/z
557.1 [MꢀH]ꢀ. Anal. Calcd for C36H31N2O2Clꢁ0.5THF: C, 76.69; H,
5.93; N, 4.71. Found: C, 76.51; H, 5.92; N, 4.62.
5.31. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-1-methyl-2-naphthyl trifluoromethanesulfonate (20c)
Yield 61%, colorless powder. 1H NMR (CDCl3) d: 0.73 (3H, d,
J = 6.6 Hz), 0.96 (3H, d, J = 6.6 Hz), 2.48–2.63 (1H, m), 2.67 (3H, s),
3.70 (1H, s), 6.82 (1H, d, J = 1.4 Hz), 7.10–7.16 (6H, m), 7.29–7.35
(11H, m), 7.69–7.74 (2H, m), 7.95 (1H, d, J = 8.8 Hz), 8.07 (1H, d,
J = 1.8 Hz). IR (KBr): 3208, 2973, 1408, 1219, 1140, 897, 702 cm
ꢀ1. Anal. Calcd for C38H33N2O4SF3: C, 68.05; H, 4.96; N, 4.18. Found:
C, 68.22; H, 4.97; N, 4.19.
5.27. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-1-methyl-2-naphthol (19c)
Yield 95%, colorless powder. 1H NMR (CDCl3) d: 0.69 (3H, d,
J = 6.6 Hz), 1.03 (3H, d, J = 6.6 Hz), 2.30–2.43 (1H, m), 2.43 (3H, s),
3.89 (1H, s), 6.04 (1H, d, J = 8.8 Hz), 6.49 (1H, d, J = 8.8 Hz), 6.85–
6.93 (2H, m), 7.21–7.25 (6H, m), 7.37–7.48 (10H, m), 7.55 (1H, d,
J = 8.8 Hz), 7.56 (1H, d, J = 1.0 Hz). IR (KBr): 3511, 2976, 1485,
1445, 1348, 1169, 1001, 758, 702 cmꢀ1. LCMS (API): m/z 539.1
[M+H]+. Anal. Calcd for C37H34N2O2ꢁ0.5THF: C, 81.50; H, 6.66; N,
4.87. Found: C, 81.54; H, 6.67; N, 4.82.
5.32. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-3-methyl-2-naphthyl trifluoromethanesulfonate (20d)
Yield 74%, yellow powder. 1H NMR (CDCl3) d: 0.72 (3H, d,
J = 7.0 Hz), 0.96 (3H, d, J = 7.0 Hz), 2.46–2.59 (1H, m), 2.51 (3H, s),
3.72 (1H, s), 6.80 (1H, d, J = 1.6 Hz), 7.09–7.16 (6H, m), 7.29–7.36
(10H, m), 7.56 (1H, dd, J = 1.8, 8.6 Hz), 7.67–7.73 (3H, m), 8.02
(1H, s). IR (KBr): 3219, 2966, 1408, 1215, 1140, 1055, 895, 748,
700 cmꢀ1. Anal. Calcd for C38H33N2O4SF3: C, 68.05; H, 4.96; N,
4.18. Found: C, 68.16; H, 4.98; N, 4.01.
5.28. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-3-methyl-2-naphthol (19d)
Yield 98%, colorless plates. 1H NMR (DMSO-d6) d: 0.61 (3H, d,
J = 6.8 Hz), 0.71 (3H, d, J = 6.6 Hz), 2.27 (3H, s), 2.54–2.64 (1H, m),
5.04 (1H, s), 6.83 (1H, d, J = 1.4 Hz), 7.03–7.08 (6H, m), 7.29 (1H,
d, J = 1.4 Hz), 7.33–7.41 (10H, m), 7.45–7.50 (2H, m), 7.69 (1H,
dd, J = 1.4, 8.8 Hz), 7.84 (1H, s), 9.26 (1H, br s). IR (KBr): 3603,
2966, 1670, 1447, 1244, 1159, 760, 748, 704 cmꢀ1. Anal. Calcd
for C37H34N2O2ꢁ0.6DMF: C, 80.00; H, 6.61; N, 6.25. Found: C,
80.03; H, 6.59; N, 6.19.
5.33. Methyl-6-[1-hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-
yl)propyl]-2-naphthoate (21a)
A degassed solution of 20a (15.0 g, 22.8 mmol) and triethyl-
amine (6.36 mL, 45.6 mmol) in anhydrous DMF (90 mL) and MeOH
(30 mL) was added to Pd(OAc)2 (256 mg, 1.14 mmol) and dppf
(632 mg, 1.14 mmol), and vigorously stirred for 14 h at 70 °C under
CO atmosphere (1 atm). After dilution with water, the resulting
mixture was extracted with AcOEt (ꢂ2). The combined organic lay-
ers were washed with water and brine, and then dried over MgSO4.
After removal of the solvent in vacuo, the residue was purified by
column chromatography on silica gel (hexane/THF = 1:2) and
recrystallized from hexane–AcOEt to give 21a (12.3 g, 95%) as a
light brown powder. 1H NMR (CDCl3) d: 0.74 (3H, d, J = 7.0 Hz),
0.97 (3H, d, J = 6.6 Hz), 2.47–2.61 (1H, m), 3.75 (1H, s), 3.97 (3H,
s), 6.82 (1H, d, J = 1.2 Hz), 7.10–7.16 (6H, m), 7.29–7.35 (10H, m),
7.62 (1H, dd, J = 1.8, 8.6 Hz), 7.81 (1H, d, J = 3.2 Hz), 7.85 (1H, d,
J = 3.2 Hz), 8.02 (1H, dd, J = 1.8 Hz, 8.6 Hz), 8.07 (1H, s), 8.55 (1H,
5.29. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-2-naphthyl trifluoromethanesulfonate (20a)
Trifluoromethanesulfonic anhydride (9.1 mL, 54.1 mmol) was
added dropwise to
a cooled (0 °C) solution of 19a (27.0 g,
51.5 mmol) in anhydrous pyridine (200 mL) and stirred for 1 h at
0 °C. After dilution with water, the resulting mixture was extracted
with AcOEt (ꢂ2). The combined organic layers were washed with
brine, dried over MgSO4, and then concentrated in vacuo. The res-
idue was purified by column chromatography on silica gel (hex-
s). IR (KBr): 3542, 2965, 1707, 1441, 1279, 1231, 747, 700 cmꢀ1
.
ane/AcOEt
= 1:1) and recrystallized from i-Pr2O to give 23
Anal. Calcd for C38H34N2O3ꢁ0.1AcOEt: C, 80.41; H, 6.09; N, 4.87.
Found: C, 80.07; H, 6.06; N, 4.95. Compounds 21b–d were prepared
using the same method as described for the preparation of 21a.
(26.1 g, 77%) as a colorless powder. The mother liquor was
concentrated, and the residue was recrystallized from i-Pr2O to
give 20a (3.54 g, 10%) as a colorless powder. 1H NMR (CDCl3) d:
0.73 (3H, d, J = 6.6 Hz), 0.96 (3H, d, J = 6.6 Hz), 2.47–2.60 (1H, m),
3.72 (1H, br s), 6.82 (1H, d, J = 1.4 Hz), 7.10–7.17 (6H, m),
7.30–7.35 (11H, m), 7.65 (1H, dd, J = 1.7, 8.6 Hz), 7.70 (1H, d,
J = 2.6 Hz), 7.77 (1H, d, J = 8.6 Hz), 7.88 (1H, d, J = 9.0 Hz), 8.11
(1H, s). IR (KBr): 3164, 2965, 1431, 1412, 1242, 1211, 1142, 909,
897, 748, 702 cmꢀ1. Anal. Calcd for C37H31N2O4SF3: C, 67.67; H,
4.76; N, 4.27. Found: C, 67.75; H, 4.51; N, 4.34. Compounds
20b–d were prepared using the same method as described for
the preparation of 20a.
5.34. Methyl-1-chloro-6-[1-hydroxy-2-methyl-1-(1-trityl-1H-
imidazol-4-yl)propyl]-2-naphthoate (21b)
Yield 89%, colorless powder. 1H NMR (CDCl3) d: 0.72 (3H, d,
J = 7.0 Hz), 0.97 (3H, d, J = 6.0 Hz), 2.44–2.61 (1H, m), 3.79 (1H, s),
3.98 (3H, s), 6.82 (1H, d, J = 1.4 Hz), 7.09–7.14 (6H, m), 7.31–7.38
(10H, m), 7.70 (1H, dd, J = 1.8, 9.0 Hz), 7.75 (s, 2H), 8.09 (1H, d,
J = 1.4 Hz), 8.34 (1H, d, J = 9.2 Hz). IR (KBr): 3162, 1732, 1240,
1012, 747, 700 cmꢀ1. Anal. Calcd for C38H33N2O3Cl: C, 75.92; H,
5.53; N, 4.66. Found: C, 75.88; H, 5.58; N, 4.65.
5.30. 1-Chloro-6-[1-hydroxy-2-methyl-1-(1-trityl-1H-imidazol-
4-yl)propyl]-2-naphthyl trifluoromethanesulfonate (20b)
5.35. Methyl-6-[1-hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-
yl)propyl]-1-methyl-2-naphthoate (21c)
Yield 94%, colorless powder. 1H NMR (CDCl3) d: 0.72 (3H, d,
J = 6.6 Hz), 0.97 (3H, d, J = 6.6 Hz), 2.48–2.61 (1H, m), 3.75 (1H, s),
6.82 (1H, d, J = 1.6 Hz), 7.09–7.16 (6H, m), 7.30–7.37 (10H, m),
7.40 (1H, d, J = 9.2 Hz), 7.75 (1H, dd, J = 1.8, 8.8 Hz), 7.81 (1H, d,
J = 9.2 Hz), 8.15 (1H, d, J = 1.8 Hz), 8.19 (1H, d, J = 8.8 Hz). IR
(KBr): 3194, 2965, 1422, 1221, 1134, 828, 702 cmꢀ1. Anal. Calcd
for C37H30N2O4SClF3: C, 64.30; H, 4.37; N, 4.05. Found: C, 64.03;
H, 4.19; N, 4.03.
Yield 81%, colorless powder. 1H NMR (CDCl3) d: 0.74 (3H, d,
J = 7.0 Hz), 0.76 (3H, d, J = 6.0 Hz), 2.48–2.62 (1H, m), 2.91 (3H, s),
3.74 (1H, s), 3.94 (3H, s), 6.82 (1H, d, J = 1.4 Hz), 7.10–7.15 (6H,
m), 7.30–7.34 (10H, m), 7.64–7.70 (2H, m), 7.80 (1H, d,
J = 8.8 Hz), 8.02 (1H, d, J = 1.4 Hz), 8.08 (1H, d, J = 9.2 Hz). IR
(KBr): 3162, 2969, 1719, 1445, 1240, 1173, 747, 700 cmꢀ1. Anal.

T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
1763
Calcd for C39H36N2O3: C, 80.66; H, 6.25; N, 4.82. Found: C, 80.47; H,
6.26; N, 4.72.
HOBtꢁH2O (2.59 g, 16.9 mmol) and triethylamine (2.36 mL,
16.9 mmol) in anhydrous DMF (80 mL) was stirred for 12 h at rt.
After dilution with water, the mixture was extracted with AcOEt
(ꢂ2). The combined organic layers were washed with water and
brine, and then dried over MgSO4. After removal of the solvent in
vacuo, the residue was washed with AcOEt to give 23b (8.0 g,
quant.) as a pale yellow powder. The analytical sample was ob-
tained by recrystallization from THF–hexane (pale yellow powder).
1H NMR (CDCl3 + CD3OD) d: 0.75 (3H, d, J = 6.6 Hz), 0.97 (3H, d,
J = 7.0 Hz), 2.60–2.74 (1H, m), 3.01 (3H, d, J = 4.4 Hz), 6.89 (1H, s),
7.10–7.14 (6H, m), 7.27–7.38 (10H, m), 7.65 (1H, dd, J = 1.4,
8.8 Hz), 7.82–7.86 (3H, m), 8.03 (1H, s), 8.28 (1H, s). IR (KBr):
3345, 2969, 1657, 1443, 1302, 1011, 747, 700 cmꢀ1. Anal. Calcd
for C38H35N3O2ꢁ0.3THF: C, 80.03; H, 6.58; N, 7.14. Found: C,
79.81; H, 6.46; N, 7.05. Compounds 23c–h were prepared using
the same method as described for the preparation of 23b.
5.36. Methyl-6-[1-hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-
yl)propyl]-3-methyl-2-naphthoate (21d)
Yield 88%, pale yellow powder. 1H NMR (CDCl3) d: 0.73 (3H, d,
J = 6.8 Hz), 0.95 (3H, d, J = 6.6 Hz), 2.45–2.59 (1H, m), 2.71 (3H, s),
3.73 (1H, s), 3.94 (3H, s), 6.80 (1H, d, J = 1.6 Hz), 7.10–7.16 (6H,
m), 7.29–7.36 (10H, m), 7.54 (1H, dd, J = 1.6, 8.6 Hz), 7.61 (1H, s),
7.76 (1H, d, J = 8.6 Hz), 7.96 (1H, s), 8.44 (1H, s). IR (KBr): 3223,
2968, 1724, 1445, 1283, 1267, 748, 700 cmꢀ1. Anal. Calcd for
C
39H36N2O3ꢁ0.4AcOEt: C, 79.17; H, 6.41; N, 4.55. Found: C, 79.17;
H, 6.23; N, 4.61.
5.37. Methyl 6-[1-hydroxy-1-(1H-imidazol-4-yl)-2-methylpro-
pyl]-2-naphthoate (22)
5.40. N-Ethyl-6-[1-hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-
yl)propyl]-2-naphthamide (23c)
Compound 21a (1.40 g, 2.47 mmol) was used as a starting mate-
rial. Using the same procedure described for the synthesis of 6, 22
(751 mg, 94%) was obtained as a pale yellow powder after recrys-
tallization from AcOEt. Mp 167.0–169.0 °C. 1H NMR (CDCl3 +
CD3OD) d: 0.80 (3H, d, J = 7.0 Hz), 1.02 (3H, d, J = 6.6 Hz), 2.69–
2.82 (1H, m), 3.97 (3H, s), 7.02 (1H, d, J = 1.2 Hz), 7.52 (1H, d,
J = 1.2 Hz), 7.68 (1H, dd, J = 1.0, 8.4 Hz), 7.87 (2H, d, J = 8,4 Hz),
8.01 (1H, dd, J = 1.0, 8.4 Hz), 8.08 (1H, s), 8.55 (1H, s). IR (KBr):
3542, 2965, 1707, 1441, 1279, 1231, 747, 700 cmꢀ1. LCMS (API):
m/z 325.1 [M+H]+. Anal. Calcd for C19H20N2O3ꢁ0.2AcOEt: C, 69.54;
H, 6.37; N, 8.19. Found: C, 69.53; H, 6.43; N, 8.26.
Yield 83%, colorless powder. 1H NMR (CDCl3) d: 0.73 (3H, d,
J = 3.3 Hz), 0.96 (3H, d, J = 6.6 Hz), 1.28 (3H, t, J = 7.2 Hz), 2.47–
2.60 (1H, m), 3.48–3.61 (2H, m), 3.79 (1H, s), 6.32 (1H, t,
J = 5.5 Hz), 6.82 (1H, d, J = 1.4 Hz), 7.09–7.16 (6H, m), 7.28–7.34
(10H, m), 7.61 (1H, dd, J = 1.8, 8.8 Hz), 7.75–7.84 (3H, m), 8.05
(1H, s), 8.23 (1H, s). IR (KBr): 3308, 2967, 1638, 1535, 1308,
1009, 747, 700 cmꢀ1. Anal. Calcd for C39H37N3O2ꢁ0.1AcOEt: C,
80.41; H, 6.47; N, 7.14. Found: C, 80.26; H, 6.54; N, 7.09.
5.41. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-N-propyl-2-naphthamide (23d)
5.38. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-2-naphthamide (23a)
Yield 92%, colorless powder. 1H NMR (CDCl3) d: 0.73 (3H, d,
J = 6.8 Hz), 0.96 (3H, d, J = 6.8 Hz), 1.02 (3H, t, J = 7.2 Hz), 1.60–
1.78 (2H, m), 2.53 (1H, quintet, J = 6.8 Hz), 3.48 (2H, q, J = 7.2 Hz),
3.76 (1H, s), 6.28 (1H, t, J = 7.2 Hz), 6.81 (1H, d, J = 1.4 Hz), 7.07–
7.20 (6H, m), 7.28–7.37 (10H, m), 7.62 (1H, dd, J = 1.8, 8.6 Hz),
7.75–7.86 (3H, m), 8.06 (1H, s), 8.23 (1H, s). IR (KBr): 3326, 2967,
A solution of 21a (2.0 g, 3.53 mmol) in THF (20 mL) and MeOH
(4 mL) and 4 N NaOH (4 mL) was stirred for 2 h at 60 °C. After cool-
ing to 0 °C, the solution was neutralized with concentrated HCl and
extracted with AcOEt (ꢂ2). The combined organic layers were
washed with brine and concentrated in vacuo. The residue was
dried with toluene azeotropically (ꢂ2) to give the carboxylate as
a light brown powder, which was used for the next reaction with-
out further purification. A mixture of the carboxylate, ammonium
bicarbonate (558 mg, 7.06 mmol), DPPA (0.91 mL, 4.24 mmol)
and triethylamine (0.98 mL, 7.06 mmol) in anhydrous DMF
(10 mL) was stirred for 12 h at rt. After dilution with water, the
mixture was extracted with AcOEt (ꢂ2). The combined organic lay-
ers were washed with water and brine, and then dried over MgSO4.
After removal of the solvent in vacuo, the residue was purified by
column chromatography on silica gel (hexane/THF = 1:2) and
washed with hexane–AcOEt to give 23a (1.96 g, quant.) as a color-
less powder. The analytical sample was obtained by recrystalliza-
ion from THF–hexane (colorless powder). 1H NMR (CDCl3 +
CD3OD) d: 0.74 (3H, d, J = 7.0 Hz), 0.97 (3H, d, J = 7.0 Hz),
2.55–2.68 (1H, m), 6.86 (1H, d, J = 1.2 Hz), 7.09–7.14 (6H, m),
7.27–2.38 (10H, m), 7.63 (1H, d, J = 1.7, 8.5 Hz), 7.82–7.85 (3H,
m), 8.04 (1H, s), 8.33 (1H, s). IR (KBr): 3407, 3189, 2965, 1644,
1642, 1599, 1541, 1445, 1308, 1157 cmꢀ1
40H39N3O2: C, 80.91; H, 6.62; N, 7.08. Found: C 80.84; H, 6.86;
N, 7.08.
. Anal. Calcd for
C
5.42. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-N-isopropyl-2-naphthamide (23e)
Yield 91%, colorless powder. 1H NMR (CDCl3) d: 0.73 (3H, d,
J = 6.8 Hz), 0.96 (3H, d, J = 6.8 Hz), 1.31 (6H, d, J = 6.6 Hz), 2.53
(1H, quintet, J = 6.8 Hz), 3.76 (1H, s), 4.27–4.43 (1H, m), 6.06 (1H,
d, J = 7.4 Hz), 6.81 (1H, d, J = 1.4 Hz), 7.07–7.18 (6H, m), 7.28–
7.38 (10H, m), 7.61 (1H, dd, J = 1.8, 8.6 Hz), 7.74–7.85 (3H, m),
8.06 (1H, s), 8.22 (1H, s). IR (KBr): 3301, 2971, 1640, 1601, 1537,
1447, 1289, 1171 cmꢀ1. Anal. Calcd for C40H39N3O2ꢁ0.25H2O: C,
81.30; H, 6.65; N, 7.02. Found: C, 80.33; H, 6.68; N, 6.88.
1443, 748, 700 cmꢀ1
.
Anal. Calcd for C37H33N3O2ꢁ1.0THF: C,
5.43. 1-Chloro-6-[1-hydroxy-2-methyl-1-(1-trityl-1H-imidazol-
4-yl)propyl]-N-methyl-2-naphthamide (23f)
78.94; H, 6.62; N, 6.74. Found: C, 78.83; H, 6.57; N, 6.94.
Yield 75%, colorless powder. 1H NMR (CDCl3) d: 0.71 (3H, d,
J = 7.0 Hz), 0.96 (3H, d, J = 6.6 Hz), 2.46–2.60 (1H, m), 3.07 (3H,
d, J = 4.8 Hz), 3.81 (1H, s), 6.24 (1H, d, J = 4.8 Hz), 6.82 (1H, d,
J = 0.6 Hz), 7.09–7.14 (6H, m), 7.31–7.34 (10H, m), 7.57 (1H,
d, J = 8.4 Hz), 7.69–7.73 (2H, m), 8.05 (1H, s), 8.22 (1H, d,
J = 8.8 Hz). IR (KBr): 3376, 2969, 1634, 1157, 1134, 702 cmꢀ1. Anal.
Calcd for C38H34N3O2Cl: C, 76.05; H, 5.71; N, 7.00. Found: C, 75.87;
H, 5.71; N, 6.97.
5.39. General procedure for the synthesis of the carbamoyl
derivatives: 6-[1-hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-
yl)propyl]-N-methyl-2-naphthamide (23b)
Using the same procedure as described for the synthesis of 23a,
21a (8.0 g, 14.1 mmol) was hydrolyzed to give the carboxylate
(light brown powder). A solution of the carboxylate, methylamine
(2 M solution in THF; 8.45 mL), EDCIꢁHCl (3.24 g, 16.9 mmol),

1764
T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
5.44. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-N,1-dimethyl-2-naphthamide (23g)
J = 6.6 Hz), 1.58–1.77 (2H, m), 2.68 (1H, quintet, J = 7.2 Hz), 3.40–
3.52 (2H, m), 3.49 (1H, s), 6.44 (1H, t, J = 5.5 Hz), 6.99 (1H, s),
7.45 (1H, s), 7.59–7.80 (4H, m), 8.05 (1H, s), 8.1 7 (1H, s). IR
Yield 95%, colorless powder. 1H NMR (CDCl3) d: 0.72 (3H, d,
J = 6.6 Hz), 0.95 (3H, d, J = 6.6 Hz), 2.47–2.61 (1H, m), 2.70 (3H, s),
3.02 (3H, d, J = 4.8 Hz), 3.75 (1H, s), 5.89 (1H, br s), 6.81 (1H, d,
J = 1.2 Hz), 7.09–7.14 (6H, m), 7.28–7.35 (10H, m), 7.59–7.68 (2H,
m), 7.93–7.99 (2H, m). IR (KBr): 3407, 3250, 2971, 1634, 1495,
1157, 816, 702 cmꢀ1. Anal. Calcd for C39H37N3O2: C, 80.80; H,
6.43; N, 7.25. Found: C, 80.41; H, 6.33; N, 7.18.
(KBr): 3400–3100, 2967, 1640, 1601, 1539, 1464, 1308, 1144 cm
.
ꢀ1
LCMS (API): m/z 352.3 [M+H]+. Anal. Calcd for
C
21H25N3O2ꢁ0.2H2O: C, 71.04; H, 7.21; N, 11.83. Found: C, 70.83;
H, 7.29; N, 11.78.
5.50. 6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-N-
isopropyl-2-naphthamide (24e)
5.45. 6-[1-Hydroxy-2-methyl-1-(1-trityl-1H-imidazol-4-yl)-
propyl]-N,3-dimethyl-2-naphthamide (23h)
Yield 73%, colorless amorphous solid. 1H NMR (CDCl3) d: 0.77
(3H, d, J = 6.8 Hz), 1.00 (3H, d, J = 6.8 Hz), 1.29 (6H, d, J = 6.6 Hz),
2.67 (1H, quintet, J = 6.8 Hz), 3.48 (1H, s), 4.26–4.42 (1H, m), 6.23
(1H, d, J = 7.8 Hz), 6.97 (1H, d, J = 1.2 Hz), 7.41 (1H, d, J = 1.2 Hz),
7.57–7.80 (4H, m), 8.04 (1H, s), 8.14 (1H, s). IR (KBr): 3400–3100,
2973, 1626, 1601, 1537, 1456, 1294, 1173 cmꢀ1. LCMS (API): m/z
352.3 [M+H]+. Anal. Calcd for C21H25N3O2ꢁ0.15H2O: C, 71.22; H,
7.20; N, 11.87. Found: C, 71.05; H, 7.34; N, 11.81.
Yield 86%, colorless powder. 1H NMR (CDCl3 + CD3OD) d: 0.72
(3H, d, J = 6.6 Hz), 0.95 (3H, d, J = 6.6 Hz), 2.54 (3H, s), 2.52–2.65
(1H, m), 2.99 (3H, d, J = 4.0 Hz), 6.85 (1H, d, J = 1.6 Hz), 7.10–7.15
(6H, m), 7.32–7.38 (10H, m), 7.53 (1H, dd, J = 1.6, 8.6 Hz), 7.58
(1H, s), 7.69 (1H, d, J = 8.6 Hz), 7.78 (1H, s), 7.89 (1H, s). IR (KBr):
3412, 3277, 2966, 1645, 1011, 746, 702 cmꢀ1. Anal. Calcd for
C
39H37N3O2ꢁ0.1AcOEt: C, 80.41; H, 6.47; N, 7.14. Found: C, 80.36;
5.51. 1-Chloro-6-[1-hydroxy-1-(1H-imidazol-4-yl)-2-methyl-
propyl]-N-methyl-2-naphthamide (24f)
H, 6.31; N, 7.14. Compounds 24a–h were prepared using the meth-
od as described for the preparation of 6.
Yield 93%, pale yellow amorphous solid. 1H NMR (CDCl3 +
CD3OD) d: 0.76 (3H, d, J = 6.6 Hz), 0.99 (3H, d, J = 6.6 Hz), 2.64–
2.78 (1H, m), 3.01 (3H, d, J = 1.4 Hz), 6.98 (1H, s), 7.41 (1H, dd,
J = 1.4, 8.6 Hz), 7.42 (1H, s), 7.69 (1H, d, J = 7.8 Hz), 7.72 (1H, dd,
J = 1.4, 7.8 Hz), 8.01 (1H, s), 8.19 (1H, d, J = 8.6 Hz). IR (KBr):
3242, 2970, 1630, 1553, 1333, 824 cmꢀ1. LCMS (API): m/z 358.1
[M+H]+. Anal. Calcd for C19H20N3O2ꢁ0.5H2O: C, 62.21; H, 5.77; N,
11.45. Found: C, 62.10; H, 5.84; N, 11.37.
5.46. 6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-2-
naphthamide (24a)
Yield 88%, a colorless amorphous solid. 1H NMR (CDCl3 +
CD3OD) d: 0.78 (3H, d, J = 6.6 Hz), 1.00 (3H, d, J = 7.0 Hz), 2.66–
2.80 (1H, m), 7.00 (1H, d, J = 1.0 Hz), 7.49 (1H, d, J = 1.0 Hz), 7.63
(1H, d, J = 1.8, 8.8 Hz), 7.77–7.81 (3H, m), 8.04 (1H, s), 8.29 (1H,
s). IR (KBr): 3200, 2969, 1659, 1393, 816 cmꢀ1. LCMS (API): m/z
310.1 [M+H]+. Anal. Calcd for C18H19N3O2ꢁH2O: C, 66.04; H, 6.47;
N, 12.84. Found: C, 66.65; H, 6.45; N, 12.86.
5.52. 6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-N,1-
dimethyl-2-naphthamide (24g)
5.47. 6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-N-
methyl-2-naphthamide (24b)
Yield 91%, colorless amorphous solid. 1H NMR (CDCl3 + CD3OD)
d: 0.78 (3H, d, J = 7.0 Hz), 0.99 (3H, d, J = 6.6 Hz), 2.65 (3H, s), 2.65–
2.78 (1H, m), 2.98 (3H, s), 6.97 (1H, d, J = 1.2 Hz), 7.31 (1H, d,
J = 8.4 Hz), 7.42 (1H, d, J = 1.2 Hz), 7.61–7.67 (2H, m), 7.93–7.97
Yield 88%, colorless powder. Mp 217.0–219.0 °C. 1H NMR
(CDCl3 + CD3OD) d: 0.78 (3H, d, J = 7.0 Hz), 1.01 (3H, d, J = 6.6 Hz),
2.67–2.80 (1H, m), 3.00 (3H, s), 7.00 (1H, d, J = 1.2 Hz), 7.49 (1H, d,
J = 1.0 Hz), 7.63 (1H, dd, J = 1.8, 8.8 Hz), 7.74–7.79 (2H, m), 7.83
(1H, d, J = 8.4 Hz), 8.03 (1H, s), 8.22 (1H, s). 13C NMR (DMSO-d6) d:
16.7, 17.4, 26.3, 36.6, 77.4, 112.0, 123.1, 123.8, 125.9, 126.7, 127.5,
127.9, 130.6, 131.1, 133.6, 134.2, 147.2, 147.5, 166.7. IR (KBr):
(2H, m). IR (KBr): 330, 2975, 1634, 1559, 1410, 1159, 822 cmꢀ1
.
LCMS
(API):
m/z
338.2
[M+H]+.
Anal.
Calcd
for
C
20H23N3O2ꢁ0.75H2O: C, 68.45; H, 7.04; N, 11.97. Found: C, 68.20;
H, 7.15; N, 11.83.
5.53. 6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-N,3-
dimethyl-2-naphthamide (24h)
3565, 3351, 3318, 2973, 1638, 1628, 1549, 1308, 993, 812 cmꢀ1
.
LCMS (API): m/z 324.2 [M+H]+. Anal. Calcd for C19H21N3O2: C,
70.57; H, 6.55; N, 12.99. Found: C, 70.46; H, 6.67; N, 12.87.
Yield 84%, pale yellow amorphous solid. 1H NMR (CDCl3 +
CD3OD) d: 0.77 (3H, d, J = 7.0 Hz), 0.99 (3H, d, J = 6.6 Hz), 2.48
(3H, s), 2.61–2.74 (1H, m), 2.98 (3H, d, J = 3.0 Hz), 6.95 (1H, d,
J = 1.2 Hz), 7.37 (1H, d, J = 1.2 Hz), 7.50 (1H, dd, J = 1.8, 8.8 Hz),
7.54 (1H, s), 7.64 (1H, d, J = 8.8 Hz), 7.72 (1H, s), 7.88 (1H, s). IR
5.48. N-Ethyl-6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpro-
pyl]-2-naphthamide (24c)
Yield 92%, pale yellow amorphous solid. 1H NMR (CDCl3 +
CD3OD) d: 0.77 (3H, d, J = 7.0 Hz), 1.00 (3H, d, J = 7.0 Hz), 1.26
(3H, t, J = 7.2 Hz), 2.63–2.77 (1H, m), 3.42–3.56 (2H, m), 6.98 (1H,
d, J = 1.2 Hz), 7.22 (1H, t, J = 5.5 Hz), 7.44 (1H, d, J = 1.2 Hz), 7.59
(1H, dd, J = 1.6, 8.6 Hz), 7.70–7.76 (3H, m), 8.01 (1H, s), 8.19 (1H,
s). IR (KBr): 3310, 2971, 1638, 1561, 1306, 1146, 816 cmꢀ1. LCMS
(API): m/z 338.2 [M+H]+. Anal. Calcd for C20H23N3O2ꢁ0.75H2O: C,
68.45; H, 7.04; N, 11.97. Found: C, 68.62; H, 7.08; N, 11.93.
(KBr): 3192, 2968, 1643, 1539, 1408, 1304, 1155, 908, 818 cmꢀ1
.
LCMS (API): m/z 338.2 [M+H]+. Anal. Calcd for C20H23
-
N3O2ꢁ0.75H2O: C, 68.45; H, 7.04; N, 11.97. Found: C, 68.56; H,
7.12; N, 11.79.
5.54. Methyl-1-(Bromomethyl)-6-[1-hydroxy-2-methyl-1-(1-tri-
phenylmethyl-1H-imidazol-4-yl)propyl]-2-naphthoate (25)
A mixture of 21c (34.61 g, 59.6 mmol), N-bromosuccinimide
(12.28 g, 69.0 mmol) and 2,20-azobisisobutyronitrile (0.99 g,
6.0 mmol) in CCl4 (800 mL) was refluxed for 21 h. After removing
the solvent, the mixture was diluted with aq NaHCO3 solution.
The resulting mixture was extracted with AcOEt–THF and the com-
bined organic layers were washed with brine, dried over MgSO4,
5.49. 6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-N-
propyl-2-naphthamide (24d)
Yield 77%, colorless amorphous powder solid. 1H NMR (CDCl3)
d: 0.78 (3H, d, J = 6.6 Hz), 1.00 (3H, t, J = 7.2 Hz), 1.00 (3H, d,

T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
1765
and concentrated under reduced pressure. The residue was puri-
fied by column chromatography on silica gel (AcOEt) to give a
crude mixture of 21c and 25 (21c:25 = 1:7, 23.1 g, 59%). The analyt-
ical sample was obtained by recrystallization from THF–AcOEt as a
colorless powder. Mp 195 °C decomp. 1H NMR (CDCl3) d: 0.74 (3H,
d, J = 6.8 Hz), 0.98 (3H, d, J = 6.8 Hz), 2.55 (1H, septet, J = 6.8 Hz),
3.78 (1H, s), 3.99 (3H, s), 5.43 (1H, d, J = 9.8 Hz), 5.47 (1H, d,
J = 9.8 Hz), 6.82 (1H, d, J = 1.4 Hz), 7.10–7.35 (16H, m), 7.72 (1H,
dd, J = 8.8, 1.8 Hz), 7.81 (1H, d, J = 8.8 Hz), 7.92 (1H, d, J = 8.8 Hz),
8.10 (1H, d, J = 1.8 Hz), 8.18 (1H, d, J = 8.8 Hz). IR (KBr): 1725,
1238, 702 cmꢀ1. Anal. Calcd for C39H35N2O3Br: C, 71.01; H, 5.35;
N, 4.25; Br, 12.11. Found: C, 70.86; H, 5.42; N, 4.19.
obtained as a colorless powder. The analytical sample was ob-
tained by recrystallization from THF–MeOH (colorless powder).
Mp 250 °C decomp. 1H NMR (CDCl3 + CD3OD) d: 0.80 (3H, d,
J = 7.0 Hz), 1.02 (3H, d, J = 7.0 Hz), 2.78 (1H, septet, J = 7.0 Hz),
3.29 (3H, s), 4.73 (2H, s), 7.04 (1H, d, J = 1.2 Hz), 7.54 (1H, d,
J = 1.2 Hz), 7.76–7.94 (4H, m), 8.17 (1H, s). 13C NMR (DMSO-d6) d:
16.7, 17.4, 29.0, 36.7, 50.6, 77.4, 112.0, 119.0, 122.5, 124.3, 125.9,
126.5, 128.6, 129.0, 133.9, 134.2, 140.5, 147.1, 147.7, 168.1. IR
(KBr): 3193, 1667, 1003 cmꢀ1. LCMS (API): m/z 336.2 [M+H]+. Anal.
Calcd for C20H21N3O2ꢁ0.1H2O: C, 71.24; H, 6.34; N, 12.46. Found: C,
71.09; H, 6.48; N, 12.23.
5.59. Methyl-3-(bromomethyl)-6-[1-hydroxy-2-methyl-1-(1-
5.55. 7-[1-Hydroxy-2-methyl-1-(1-triphenylmethyl-1H-imidazol-
4-yl)propyl]-1,2-dihydro-3H-benzo[e]isoindol-3-one (26a)
triphenylmethyl-1H-imidazol-4-yl)propyl]-2-naphthoate (28)
Using 21d (5.93 g, 10.2 mmol) as the starting material and the
same procedure as described for the synthesis of 25, crude 28
(6.70 g, quant.) was obtained as a brown amorphous solid. 1H
NMR (CDCl3) d: 0.73 (3H, d, J = 6.6 Hz), 0.97 (3H, d, J = 6.6 Hz),
2.53 (1H, septet, J = 6.6 Hz), 3.74 (1H, s), 4.00 (3H, s), 5.12 (1H, d,
J = 10.4 Hz), 5.15 (1H, d, J = 10.4 Hz), 6.81 (1H, d, J = 1.0 Hz), 7.09–
7.38 (16H, m), 7.65 (1H, dd, J = 8.4, 1.6 Hz), 7.78–7.84 (2H, m),
A solution of saturated NH3 in MeOH (50 mL) was added to a
cooled (0 °C) solution of 25 (5.58 g, crude 8.5 mmol) in THF
(50 mL), and stirred for 1 h at rt. After removal of the solvent, the
residue was diluted with aq NaHCO3 solution. The resulting mix-
ture was extracted with AcOEt–THF and the combined organic lay-
ers were washed with brine, dried over MgSO4, and concentrated
under reduced pressure. The residue was purified by column chro-
matography on silica gel (AcOEt/MeOH = 20:1) to give 26a (1.22 g,
8.02 (1H, s), 8.50 (1H, s). IR (KBr): 2969, 1717, 1287, 702 cmꢀ1
.
Anal. Calcd C39H35N2O3Brꢁ2H2O: C, 67.34; H, 5.65; N, 4.03; Br,
26%) as
a
colorless powder. Mp 250 °C decomp. 1H NMR
12.11.Found: C, 67.38; H, 5.50; N, 4.34.
(CDCl3 + CD3OD) d: 0.74 (3H, d, J = 6.6 Hz), 0.98 (3H, d, J = 6.6 Hz),
2.59 (1H, septet, J = 6.6 Hz), 4.73 (2H, s), 6.85 (1H, s), 7.10–7.38
(16H, m), 7.78–7.90 (4H, m), 8.11 (1H, s). IR (KBr): 1690, 745,
702 cmꢀ1. Anal. Calcd for C38H33N3O2ꢁ0.5H2O: C, 79.69; H, 5.98;
N, 7.34. Found: C, 79.57; H, 6.27; N, 7.07.
5.60. 6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-2,3-
dihydro-1H-benzo[f]isoindol-1-one (30a)
Using 28 (5.00 g, 7.3 mmol) as the starting material and the
same procedure as described for the synthesis of 27a, 30a
(1.46 g, 64%) was obtained as a colorless power. The analytical
sample was obtained by recrystallization from EtOH as a colorless
powder. Mp 204.0–208.0 °C. 1H NMR (CDCl3 + CD3OD) d: 0.80 (3H,
d, J = 7.0 Hz), 1.02 (3H, d, J = 7.0 Hz), 2.76 (1H, septet, J = 7.0 Hz),
4.56 (2H, s), 7.03 (1H, d, J = 1.2 Hz), 7.53 (1H, d, J = 1.2 Hz), 7.65
(1H, dd, J = 8.4, 1.6 Hz), 7.90–7.96 (2H, m), 8.13 (1H, s), 8.31 (1H,
s). IR (KBr): 3208, 1671 cmꢀ1. LCMS (API): m/z 322.1 [M+H]+. Anal.
Calcd for C19H19N3O2ꢁC2H5OH: C, 68.64; H, 6.86; N, 11.44. Found: C,
68.30; H, 6.84; N, 11.29.
5.56. 7-[1-Hydroxy-2-methyl-1-(1-triphenylmethyl-1H-imida-
zol-4-yl)propyl]-2-methyl-1,2-dihydro-3H-benzo[e]isoindol-3-
one (26b)
Using 25 (0.80 g, 1.2 mmol) was used as the starting material
and the same procedure described for the synthesis of 26a with
40% methylamine solution, 26b (0.77 g, quant.) was obtained as a
colorless powder. The analytical sample was obtained by recrystal-
lization from THF as a colorless powder. Mp 250 °C decomp. 1H
NMR (CDCl3) d: 0.74 (3H, d, J = 6.6 Hz), 0.97 (3H, d, J = 6.6 Hz),
2.56 (1H, septet, J = 6.6 Hz), 3.29 (3H, s), 3.69 (1H, br s), 4.68 (2H,
s), 6.83 (1H, d, J = 1.4 Hz), 7.10–7.36 (16H, m), 7.76 (2H, s), 7.83
(2H, s), 8.11 (1H, s). IR (KBr): 3409, 1680, 704 cmꢀ1. Anal. Calcd
for C39H35N3O2: C, 81.08; H, 6.11; N, 7.27. Found: C, 80.69; H,
6.11; N, 7.12.
5.61. 6-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-2-
methyl-2,3-dihydro-1H-benzo[f]isoindol-1-one (30b)
Using 28 (0.99 g, 1.5 mmol) as the starting material and the
same procedure as described for the synthesis of 27a, 30b
(0.11 g, 22%) was obtained as a colorless power. The analytical
sample was obtained by recrystallization from EtOH (colorless
powder). Mp 260 °C decomp. 1H NMR (CDCl3 + CD3OD) d: 0.81
(3H, d, J = 6.6 Hz), 1.02 (3H, d, J = 6.6 Hz), 2.70–2.90 (1H, m), 3.27
(3H, s), 4.59 (2H, s), 7.04 (1H, s), 7.54 (1H, s), 7.65–7.73 (1H, m),
7.92–7.96 (2H, m), 8.14 (1H, s), 8.27 (1H, s). 13C NMR (DMSO-d6)
d: 16.7, 17.4, 29.1, 36.6, 51.1, 77.4, 112.0, 121.8, 121.9, 123.4,
125.5, 128.0, 130.0, 130.8, 134.1, 134.1, 134.2, 136.5, 147.2,
5.57. 7-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-1,2-
dihydro-3H-benzo[e]isoindol-3-one (27a)
Compound 26a (1.17 g, 2.1 mmol) was used as a starting mate-
rial. Using the same procedure described for the synthesis of 6, 27a
(0.50 g, 75%) was obtained as a colorless powder. The analytical sam-
ple was obtained by recrystallization from EtOH–H2O as a colorless
powder. Mp 230 °C decomp. 1H NMR (CDCl3 + CD3OD) d: 0.79 (3H, d,
J = 6.6 Hz), 1.02 (3H, d, J = 6.6 Hz), 2.76 (1H, septet, J = 6.6 Hz), 4.68
(2H, s), 7.04 (1H, s), 7.55 (1H, s), 7.70–7.77 (3H, m), 7.88 (1H, d,
J = 8.4 Hz), 8.15 (1H, s). IR (KBr): 1684, 1472, 747 cmꢀ1. LCMS
(API): m/z 322.1 [M+H]+. Anal. Calcd for C19H19N3O2: C, 71.01; H,
5.96; N, 13.08. Found: C, 70.76; H, 6.04; N, 12.78.
147.4, 167.1. IR (KBr): 3167, 1663, 1400, 1150, 810, 625 cmꢀ1
.
LCMS (API): m/z 336.2 [M+H]+. Anal. Calcd for C20H21N3O2: C,
71.62; H, 6.31; N, 12.53. Found: C, 71.22; H, 6.61; N, 12.46.
5.62. Optical resolution of 27a
Optical resolution of 27a (13.1 g) was performed using prepara-
tive HPLC on a Chiralpak AD column (50 mmID ꢂ 500 mmL, eluent:
hexane/EtOH/diethylamine = 85:15:0.1, flow rate: 80–100 mL/min,
temperature: 35 °C) to yield (ꢀ)-27a (5.27 g, 99.9% enantiomeric
excess [ee]) as a colorless powder and (+)-27a (5.39 g, 99.7% ee)
as colorless amorphous solid. (ꢀ)-27a: Mp 220.0–222.0 °C. 1H
5.58. 7-[1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-2-
methyl-1,2-dihydro-3H-benzo[e]isoindol-3-one (27b)
Using 26b was used as the starting material and the same pro-
cedure as described for the synthesis of 27a, 27b (0.28 g, 90%) was

1766
T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
NMR (DMSO-d6) d: 0.66 (3H, d, J = 6.8 Hz), 0.75–0.97 (3H, m), 2.67–
2.86 (1H, m), 4.71 (2H, s), 5.18 (1H, br s), 7.02 (1H, br s), 7.56 (1H,
br s), 7.64 (1H, d, J = 8.3 Hz), 7.82–8.10 (3H, m), 8.25 (1H, br s), 8.58
(1H, s), 11.82 (1H, br s). IR (KBr): 3185, 2976, 1686 cmꢀ1. LCMS
(API): m/z 322.1 [M+H]+. Anal. Calcd for C19H19N3O2ꢁ0.5H2O: C,
69.07; H, 6.10; N, 12.72. Found: C, 69.37; H, 6.11; N, 12.68.
crystal. 1H NMR (CDCl3) d: 1.36 (12H, br s), 3.71 (2H, br s), 7.44
(1H, dd, J = 1.2 Hz, 8.6 Hz), 7.58 (1H, dd, J = 2.2 Hz, 8.8 Hz), 7.70–
7.79 (3H, m), 8.01 (1H, d, J = 1.2 Hz). IR (KBr): 2968, 1620, 1435,
1369, 1333, 895, 814 cmꢀ1. LCMS (API): m/z 334.1 [M+H]+. Anal.
Calcd for C17H20NOBr: C, 61.09; H, 6.03; N, 4.19; Br, 23.91. Found:
C, 61.22; H, 6.08; N, 4.12.
½
a 2D0
ꢃ
¼ ꢀ41:2 (c 0.9520, MeOH). (+)-27a: The spectral data of (+)-
27a were identical to those of the (ꢀ)-27a except for elemental
analysis and optical rotation. LCMS (API): m/z 322.1 [M+H]+. Anal.
Calcd for C19H19N3O2ꢁ1.25H2Oꢁ0.25AcOEt: C, 65.65; H, 6.47; N,
5.66. 6-[(2R)-2-(tert-Butyldimethylsilyloxy)propanoyl]-N,N-di-
isopropyl-2-naphthamide (34a)
11.48. Found: C, 65.40; H, 6.68; N, 11.36. ½a D20
¼ þ35:4 (c 1.0085,
ꢃ
Solution 32b (46.80 g, 140.0 mmol) in THF (400 mL) was added
dropwise to a cooled (ꢀ70 °C) solution of n-BuLi (1.6 mol/L in hex-
ane; 96.3 mL, 154 mmol) in toluene (900 mL) and the mixture was
stirred at ꢀ70 °C for 30 min. A solution of 33 (34.45 g, 126.0 mmol)
in toluene (50 mL) was added to the mixture and the solution was
stirred at ꢀ78 °C for 30 min. The reaction was quenched with aq
NH4Cl and the mixture was warmed to rt. After extraction with
AcOEt, the combined organic layers were dried over MgSO4 and
evaporated to give 34a as a pale yellow oil. This compound was di-
rectly used without further purification in the next step. 1H NMR
(CDCl3) d: 0.06 (3H, s), 0.12 (3H, s), 0.91 (9H, s), 1.10–1.60 (12H,
m), 1.60 (3H, d, J = 7.0 Hz), 3.50–4.00 (2H, br m), 5.04 (1H, q,
J = 7.0 Hz), 7.50 (1H, dd, J = 8.4, 1.4 Hz), 7.83 (1H, s), 7.91 (1H, d,
J = 8.4 Hz), 7.99 (1H, d, J = 8.4 Hz), 8.14 (1H, d, J = 8.4, 1.4 Hz),
MeOH).
5.63. Optical resolution of 27b
Optical resolution of 27b (2.40 g) was performed using prepara-
tive HPLC on a Chiralpak AD column (50 mmID ꢂ 500 mmL, eluent:
hexane/EtOH = 40:60, flow rate: 60 mL/min, temperature: rt) to
yield (ꢀ)-27b (1.10 g, 99.9% ee) as a colorless powder and (+)-27b
(1.00 g, 99.8% ee) as a colorless powder. (ꢀ)-27b: Mp 207.0–
209.0 °C. 1H NMR (DMSO-d6) d: 0.65 (3H, d, J = 6.6 Hz), 0.83 (3H, d,
J = 6.6 Hz), 2.65–2.87 (1H, m), 3.14 (3H, s), 4.78 (2H, s), 5.17 (1H, s),
7.04 (1H, s), 7.42–7.76 (2H, m), 7.80–8.08 (3H, m), 8.26 (1H, s),
11.83 (1H, br s). The 13C NMR spectral data of (ꢀ)-27b was identical
to those of the 27b. IR (KBr): 3148, 2971, 1669 cmꢀ1. LCMS (API): m/z
336.2 [M+H]+. Anal. Calcd for C20H21N3O2ꢁ0.75H2O: C, 68.85; H, 6.50;
8.72 (1H, s). IR (KBr): 1694, 1630, 1441, 1335, 835 cmꢀ1
.
N, 12.04. Found: C, 68.71; H, 6.38; N, 11.99. ½a D20
¼ ꢀ33:4 (c 0.226,
ꢃ
5.67. 6-[(2R)-2-Hydroxypropanoyl]-N,N-diisopropyl-2-naphth-
amide (34b)
MeOH). (+)-27b: The spectral data of (+)-27b were identical to those
of the (ꢀ)-27b except for elemental analysis and optical rotation. Mp
207.0–209.0 °C. LCMS (API): m/z 336.1 [M+H]+. Anal. Calcd for
TBAF (41.01 g, 157 mmol) was added to a cooled (ꢀ10 °C) solu-
tion of 34a (25.7 g, 74.9 mmol) in THF (900 mL) and the mixture
was stirred at 0 °C for 1 h. The mixture was diluted with brine
and the aqueous phase was extracted with AcOEt. The combined
organic layers were washed with brine and dried over MgSO4. After
removal of the solvent in vacuo, the residue was chromatographed
on silica gel (hexane/AcOEt = 2:1–2:3) and washed with diethyl-
ether to give 34b (24.00 g, 58% from 33) as a colorless solid. Mp
C
20H21N3O2ꢁ0.75H2O: C, 68.85; H, 6.50; N, 12.04. Found: C, 68.99;
H, 6.45; N, 11.95. ½a D20
¼ þ34:5 (c 0.258, MeOH).
ꢃ
5.64. 7-[(1R)-1-{1-[(4-Bromophenyl)sulfonyl]-1H-imidazol-4-yl}-
1-hydroxy-2-methylpropyl]-2-methyl-1,2-dihydro-3H-benzo[e]-
isoindol-3-one (31)
4-Bromobenzenesulfonyl chloride (460 mg, 1.8 mmol) was
added to a solution of (+)-27b (503 mg, 1.5 mmol) in DMF
(12 mL) and the mixture was stirred at rt for 3 h. The mixture
was poured into water and the aqueous phase extracted with
AcOEt. The combined organic layer was washed with 10% citric
acid solution, H2O and brine, dried over MgSO4 and evaporated.
The residue was crystallized from AcOEt–i-Pr2O to give 31
(730 mg, 88%). Analytical sample was obtained by recrystallization
174 °C. ½a 2D0
ꢃ
¼ þ38:2 (c 0.726, MeOH). 1H NMR (CDCl3) d: 1.10–
1.70 (12H, br m), 1.52 (3H, d, J = 6.9 Hz), 3.40–3.90 (2H, br), 3.84
(1H, d, J = 6.9 Hz), 5.32 (1H, quint, J = 6.9 Hz), 7.52 (1H, dd, J = 8.4,
1.8 Hz), 7.84 (1H, s), 7.95 (1H, d, J = 8.4 Hz), 8.00–8.04 (2H, m),
8.45 (1H, s). IR (KBr): 3493, 1678, 1628, 1117, 826 cmꢀ1. LCMS
(API): m/z 328.1 [M+H]+. Anal. Calcd for C20H25NO3: C, 73.37; H,
7.70; N, 4.28. Found: C, 73.24; H, 7.60; N, 4.21.
from THF–MeOH. Mp 170 °C. IR (KBr): 3345, 1671, 745, 635 cmꢀ1
.
1H NMR (CDCl3) d: 0.76 (3H, d, J = 6.6 Hz), 0.91 (3H, d, J = 6.6 Hz),
2.79 (1H, septet, J = 6.6 Hz), 2.96 (1H, s), 3.27 (3H, s), 4.66 (2H, s),
7.31 (1H, d, J = 1.4 Hz), 7.64–7.88 (8H, m), 7.94 (1H, d, J = 1.4 Hz),
8.14 (1H, s). Anal. Calcd for C26H24BrN3O4SꢁMeOH: C, 55.29; H,
4.81; N, 7.13. Found: C, 55.48; H, 4.75; N, 6.98.
5.68. 6-[(1S,2R)-1,2-Dihydroxy-1-isopropylpropyl]-N,N-
diisopropyl-2-naphthamide (35)
A solution of i-propylmagnesium bromide (0.7 M in THF;
500 mL, 350 mmol) was added dropwise over 2 h to a cooled
(ꢀ10 °C) solution of 34b (20.08 g, 61.3 mmol) in THF (300 mL)
and the mixture was stirred at 0 °C for 1 h. The reaction was
quenched with satd aq NH4Cl and the aqueous layer was extracted
with AcOEt. The combined organic layers were dried over MgSO4
and concentrated in vacuo. The residue was crystallized from i-
Pr2O to give 35 (12.35 g, 54%) as a colorless solid. The purity of
the obtained 35 was >95% as determined by HPLC using a Chiralpak
AD column. The analytical sample was obtained by recrystalliza-
5.65. 6-Bromo-N,N-diisopropyl-2-naphthamide (32b)
A solution of 6-bromo-2-naphthoic acid 32a (100 g, 398 mmol),
thionylchloride (37.7 mL, 517 mmol) and DMF (0.5 mL) in THF
(1000 mL) was stirred at 60 °C for 90 min. After cooling to rt, the
solvent and excess amount of thionylchloride was evaporated.
The resulting residue was dissolved in dry THF (400 mL) and the
solution was added dropwise to a cooled (0 °C) solution of diiso-
propylamine (112 mL, 799 mmol) and triethylamine (112 mL,
804 mmol) in THF (800 mL). After being stirred at rt for 1 h, about
50% of the solvent was evaporated. Then the mixture was diluted
with AcOEt and the organic phase was washed with H2O, 1 N NaOH
solution and brine, dried over MgSO4 and evaporated. The residue
was washed with i-Pr2O to give 32b (117 g, 88%) as a colorless
tion from AcOEt. Mp 200 °C. ½a D20
ꢃ
¼ þ19:9 (c 0.545, MeOH). 1H
NMR (CDCl3) d: 0.87 (3H, d, J = 6.6 Hz), 0.95 (3H, d, J = 6.6 Hz),
1.06 (3H, d, J = 6.6 Hz), 1.00–1.70 (12H, br m), 1.65 (1H, d,
J = 4.2 Hz), 2.45 (1H, septet, J = 6.6 Hz), 2.61 (1H, s), 3.50–4.00
(2H, br), 4.37 (1H, dq, J = 4.2, 6.6 Hz), 7.41 (1H, dd, J = 8.4, 1.8 Hz),
7.48 (1H, dd, J = 8.4, 1.8 Hz), 7.77–7.90 (4H, m). IR (KBr): 3511,
2971, 1617, 1443, 1372, 1341 cmꢀ1
. LCMS (API): m/z 372.2

T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
1767
[M+H]+. Anal. Calcd for C23H33NO3: C, 74.36; H, 8.95; N, 3.77.
Found: C, 74.39; H, 8.77; N, 3.73.
2.20 (3H, s), 2.97 (1H, septet, J = 6.9 Hz), 3.29 (3H, s), 4.63 (1H, s),
4.70 (2H, s), 7.77 (1H, dd, J = 8.7, 1.8 Hz), 7.84–7.92 (3H, m), 8.17
(1H, d, J = 1.8 Hz). IR (KBr): 3335, 1705, 1667, 1171, 748 cmꢀ1
.
5.69. 7-[(1S,2R)-1,2-Dihydroxy-1-isopropylpropyl]-2-methyl-
1,2-dihydro-3H-benzo[e]isoindol-3-one (38a)
LCMS (API): m/z 312.2 [M+H]+. Anal. Calcd for C19H21NO3ꢁ0.6AcOEt:
C, 70.57; H, 7.14; N, 3.85. Found: C, 70.60; H, 7.16; N, 4.12.
n-BuLi (1.6 mol/L, 103.8 mL, 166 mmol) was added dropwise to
a cooled (ꢀ70 °C) solution of 35 (12.35 g, 33.2 mmol) and tetra-
methylethylenediamine (TMEDA) (60 mL) in THF (250 mL) and
the mixture was stirred at ꢀ70 °C for 2.5 h. To the mixture, DMF
(25 mL) was added dropwise, and the reaction mixture was further
stirred at ꢀ70 °C for 1 h. After diluting with aq NH4Cl solution, the
aqueous layer was extracted with AcOEt. The combined organic
layers were washed with H2O and brine, dried over MgSO4. Re-
moval of the solvent in vacuo gave a crude product of 36a and
36b (36a:36b = ca. 6:1) as amorphous solid. The crude product of
36a and 36b was dissolved in CH2Cl2 (250 mL) and methylamine
(2 M in THF, 67.5 mL, 135 mmol) was added. After adjusting the
pH of the reaction mixture to 6–7 with acetic acid (ca. 9 mL), NaB-
H(OAc)3 (59.3 g, 280 mmol) was added dropwise to the reaction
mixture, which was then stirred at rt for 62 h. After being diluted
with 2 N HCl, the aqueous layer was washed with AcOEt. The aque-
ous layer was then made alkaline with 10 N NaOH solution and ex-
tracted with AcOEt. The combined organic layers were dried over
MgSO4 and evaporated in vacuo to give a crude product of 37a
and 37b.
n-BuLi (1.6 M in hexane; 104 ml, 166 mmol) was added drop-
wise to a cooled (ꢀ60 °C) solution of diisopropylamine (24.5 mL,
175 mmol) in THF (250 mL) and the mixture was stirred at
ꢀ70 °C for 10 min to prepare the LDA solution. A solution of the
crude product of 37a and 37b in THF (70 mL) was then added drop-
wise, and the reaction mixture was allowed to warm to 0 °C over
2 h. After being diluted with aq NH4Cl solution, the aqueous layer
was extracted with AcOEt. The combined organic layers were dried
over MgSO4 and evaporated. The residue was purified by column
chromatography on silica gel (AcOEt) and crystallized from
THF–AcOEt to yield a mixture of 38a and 38b (4.33 g, 42%,
38a:38b = 93:7) as a colorless solid. The ratio of the obtained 38a
and 38b was determined by HPLC using Chiralpak AD column. 1H
NMR (CDCl3) d: 0.89 (3H, d, J = 6.9 Hz), 0.95 (3H, d, J = 6.9 Hz),
1.07 (3H, d, J = 6.3 Hz), 1.82 (1H, d, J = 6.3 Hz), 2.46 (1H, septet,
J = 6.9 Hz), 2.69 (1H, s), 3.29 (3H, s), 4.41 (1H, quint, J = 6.3 Hz),
4.70 (2H, s), 7.61 (1H, dd, J = 8.7, 1.8 Hz), 7.80–7.97 (3H, m), 8.01
(1H, d, J = 1.8 Hz). IR (KBr): 3420, 1686, 826, 747 cmꢀ1. LCMS
(API): m/z 314.2 [M+H]+. Anal. Calcd for C19H23NO3ꢁ0.1AcOEt: C,
72.32; H, 7.45; N, 4.35. Found: C, 72.37; H, 7.61; N, 4.32.
5.71. 7-[(1S)-3-Bromo-1-hydroxy-1-isopropyl-2-oxopropyl]-2-
methyl-1,2-dihydro-3H-benzo[e]isoindol-3-one (40)
Pyridinium bromide perbromide (3.17 g, 9.9 mmol) was added
to a cooled (0 °C) solution of 39 (2.80 g, 9.0 mmol) in THF
(35 mL) and the mixture was stirred at rt for 66 h. The reaction
mixture was diluted with aqueous sodium thiosulfate solution
and the aqueous phase was extracted with AcOEt. The combined
organic layers were washed with 10% aq citric acid solution and
aq NaHCO3 solution, and dried over MgSO4. After removal of the
solvent in vacuo, the residue was chromatographed on silica gel
(hexane/AcOEt = 1:1–1:2) to give 40 (2.97 g, 85%) including start-
ing material 39 as a colorless solid. This compound was used with-
out further purification in the next step. 1H NMR (CDCl3) d: 0.80
(3H, d, J = 6.6 Hz), 1.04 (3H, d, J = 6.6 Hz), 2.99 (1H, septet,
J = 6.6 Hz), 3.28 (3H, s), 3.97 (1H, s), 4.27 (1H, d, J = 15.0 Hz), 4.34
(1H, d, J = 15.0 Hz), 4.68 (2H, s), 7.72–7.91 (4H, m), 8.19 (1H, d,
J = 1.4 Hz). IR (KBr): 1670 cmꢀ1
.
5.72. 7-{(1S,2Z)-3-Bromo-1-isopropyl-1,2-bis[(trimethylsilyl)-
oxy]prop-2-enyl}-2-methyl-1,2-dihydro-3H-benzo[e]isoindol-
3-one (41)
TBAF (1 M solution in THF, 32 mL, 0.032 mmol) was added to a
solution of 40 (0.63 g, 1.6 mmol) and N,O-bis(trimethylsilyl)acet-
amide (2.4 mL, 9.7 mmol) in DMF (8 mL) and the reaction mixture
was stirred at rt for 16 h. After being diluted with AcOEt, the mix-
ture was washed with H2O, followed by brine, before drying over
MgSO4. After removal of the solvent in vacuo, the residue was chro-
matographed on silica gel (hexane/AcOEt = 13:7–7:13) to give 41
(0.55 g, 54% from 39) as colorless amorphous solid. 1H NMR (CDCl3)
d: ꢀ0.14 (9H, s), 0.09 (9H, s), 0.85 (3H, d, J = 6.9 Hz), 1.00 (3H, d,
J = 6.9 Hz), 2.59 (1H, septet, J = 6.9 Hz), 3.31 (3H, s), 4.72 (2H, s),
5.90 (1H, s), 7.64 (1H, dd, J = 9.0, 4.8 Hz), 7.78–7.94 (4H, m). IR
(KBr): 1690, 1252, 843 cmꢀ1. LRMS (FAB): m/z 534 [M+H]+.
5.73. 7-[(1S)-1-Hydroxy-1-(1H-imidazol-4-yl)-2-methylpropyl]-
2-methyl-1,2-dihydro-3H-benzo[e]isoindol-3-one [(ꢀ)-27b]
Saturated ammonia solution in MeOH (1.5 mL) and formami-
dine acetate (31 mg, 0.3 mmol) was added to a cooled (ꢀ15 °C)
solution of 41 (160 mg, 0.30 mmol) in THF (0.5 mL) and the result-
ing mixture was stirred at ꢀ15 °C for 30 min. The reaction mixture
was allowed to warm to rt over 3 h and stirred at rt for a further
90 h. After removing excess NH3 and MeOH, the residue was di-
luted with brine. The aqueous layer was extracted with AcOEt/
THF (1:1) and the combined organic layer was dried over MgSO4.
After removal of the solvent in vacuo, the residue was chromato-
graphed on silica gel (CH2Cl2/MeOH = 30:1–6:1) to give (ꢀ)-27b
(54 mg, 54%). The optical purity of the obtained (ꢀ)-27b was
>99% ee as determined by HPLC using a Chiralpak AD column.
5.70. 7-[(1S)-1-Acetyl-1-hydroxy-2-methylpropyl]-2-methyl-
1,2-dihydro-3H-benzo[e]isoindol-3-one (39)
Dimethyl sulfoxide (DMSO) (3.63 mL, 51.1 mmol) was added
dropwise to
a
cooled (ꢀ70 °C) solution of oxalylchloride
(2.22 mL, 25.5 mmol) in CH2Cl2 (40 mL) and the mixture was stir-
red at ꢀ70 °C for 1 h. A solution of 38a (4.00 g, 12.8 mmol,
38a:38b = 93:7) in CH2Cl2/DMSO (1:1, 12 mL) was added dropwise,
and the reaction mixture was warmed to ꢀ20 °C over 1 h. After
cooling to ꢀ70 °C, triethylamine (10.7 mL, 76.6 mmol) was added
dropwise to the mixture and the solution was allowed to warm
to rt and stirred for a further 2 h. The resulting mixture was diluted
with H2O and the combined organic layers were washed with H2O
and dried over MgSO4. After removal of the solvent in vacuo, the
resulting solid was washed with i-Pr2O and recrystallized from
AcOEt to give 39 (3.10 g, 33% from 35) as a colorless solid. The pur-
ity of the obtained 39 was >99% as determined by HPLC using a
5.74. Homology modeling
Homology models of 17,20-lyase (CYP17) were constructed
based on the crystal structure of mammalian CYP2C5 (PDB co-
de:1DT6) using the Insight II homology module (v2000, Accelrys
Inc.). Using the Search/Generate-Loops function of Insight II, con-
formations of the insertions and deletions in the alignment were
obtained with reference to the known 3-D structures. After some
Chiralpak AD column. Mp 171 °C. ½a D20
¼ ꢀ22:9 (c 0.615, MeOH).
ꢃ
1H NMR (CDCl3) d: 0.94 (3H, d, J = 6.9 Hz), 0.96 (3H, d, J = 6.9 Hz),

1768
T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
manual adjustments to remove large steric hindrances, the struc-
ture was subjected to 1000 steps of energy minimization with
the steepest descent minimizer, followed by 5000 steps with the
analyzer (FUJIX). The concentrations of the test compounds re-
quired to reduce the concentration of the products by 50% (IC50
were calculated.
)
conjugate gradient minimizer, to
a maximum gradient of
0.1 kcal/molꢀ1 Åꢀ1, using the Discover-ESFF force field (v980,
Accelrys Inc.). During the minimization procedure, the dielectric
constant was set to 4 ⁄ r, where r is the distance between two
interacting atoms, and the force constant of tethering constraints
for the backbone of structurally conserved regions and heme was
set to 40 kcal/Å2 to prevent a large movement from the initial
positions.
5.78. Inhibition of human 17,20-lyase in vitro
Inhibition of human enzymes was determined as above. The
reaction mixture consisted of 75 mM phosphate buffer (pH 7.4),
1 mM magnesium chloride, 0.5 pmol recombinant P450c17 (Bio-
technology Laboratories, Takeda), 0.5 pmol recombinant cyto-
chrome b5 (Pan Vera), 20.8 ng recombinant NADPH-cytochrome
P450 reductase (Pan Vera), 10 nM [1,2-3H]-17
a
-hydroxypregneno-
lone (Amersham), 5 mM NADPH (Oriental Yeast), and 1–1000 nM
test compound in a total volume of 20 L. The test compounds
were serially diluted with dimethylformamide, and then diluted
fivefold with distilled water before 5 L of the solution was added
to the reaction mixture. The reaction was terminated by the addi-
tion of 40 L of ethyl acetate after 15 min (17,20-lyase) incubation
at 37 °C, then vortexing for 30 s and briefly centrifuging. Organic
phases (30 L) were applied to silica gel thin layer chromatography
5.75. Docking of inhibitors
l
Covalent bonding models of imidazole were constructed by full
energy minimization using the Discover-ESFF force field. The resid-
ual parts of compounds were connected to the imidazole. Using the
Search—Compare module of Insight II, the stable binding mode of
each compound was investigated by systematic bond rotation
within the ligand, including of some side chains around the ligand.
Energy minimization was continued using the Discover-ESFF force
field. The energy minimization conditions were the same as those
used for the homology modeling.
l
l
l
plates (Whatman, LHPK). The substrate and product DHEA were
separated using the cyclohexane–ethyl acetate (3:2) solvent
system.
5.76. X-ray crystallographic analysis of compound 31
5.79. Screening for the inhibition of CYP3A4 in vitro (Tables 1–4)
A single crystal (0.40 ꢂ 0.40 ꢂ 0.16 mm) of 31 was obtained by
recrystallization from THF/MeOH. Reflection data were collected
using a Rigaku AFC5R diffractometer with graphite monochromated
The reaction mixture consisted of 50 mM phosphate buffer (pH
7.4), 10 pmol/mL recombinant CYP3A4 (Gentest), 100 lM testos-
terone, NADPH regenerating system (0.5 mM NADP; Oriental
Yeast), 5 mM glucose-6-phosphate (Oriental Yeast), 1 mM MgCl2,
1.5 unit/mL G-6-P dehydrogenase (Oriental Yeast)), and 1 or
Cu K
a
radiation. The structure was determined by direct methods
SIR92), and refined using the full-matrix least-squares techniques
SHELXL-97) with anisotropic temperature factors for the non-hydro-
(
(
10 lM test compound in a total volume of 200 lL. The total micro-
gen atoms. Hydrogen atoms were included using a riding model. The
crystal contained two host (31) molecules and two methanol
molecules in the asymmetric unit. The absolute configuration was
determined by the Flack parameter of ꢀ0.03 (3). Crystal data:
some protein content was adjusted by control microsome protein
(Gentest). The concentration of reagents was expressed as the final
concentration in the reaction mixture. The reaction mixture was
incubated for 30 min at 37 °C and terminated by adding 200
lL
C
26H24BrN3O4SꢁCH3OH; M = 586.50; monoclinic; space group P21
acetonitrile. After adding 400 L water, the reaction mixture was
l
(#4); cell constants a = 14.684(2) Å, b = 10.318(1) Å, c =
centrifuged at 14,000 rpm for 10 min. The 6-hydroxytestosterone
content in the supernatant was determined by HPLC analysis (Shi-
madzu LC-10, column: Inertsil ODS-3 (4.6 ꢂ 150 mm) (GL
Sciences)).
18.927(2) Å, b = 112.256(7)°, V = 2653.9(5) Å3; Z = 4; Dc = 1.468 g/
cm3; unique reflections, 9180; observed reflections [I > 2
r(I)],
5158; R1 = 0.072, wR2 = 0.241. Further details of the X-ray structure
data are available on request from the Cambridge Crystallographic
Data Centre (deposition number CCDC 781827).
5.80. Inhibition of rat 11-hydroxylase in vitro
5.77. Inhibition of rat 17,20-lyase in vitro
Adrenal glands excised from SD rats were homogenized, and the
mitochondrial fraction was prepared through a series of centrifu-
gation steps. Rat 11-hydroxylase activity was measured according
to the method described for side-chain cleavage activity by Uzgiris
et al.59 with some modifications. The reaction mixture contained
200 mM mannitol, 4.5 mM HEPES, 2.3 mM potassium phosphate
(pH 7.4), 0.1 mM EDTAꢁ2 K, 0.03% BSA (crystallized, Miles),
Inhibitory activity against rat enzymes was determined accord-
ing to a previously described method58 with some modifications.
Testes excised from 13-week-old male Sprague-Dawley (SD) rats
were homogenized and testicular microsomes were prepared by
centrifugation. The reaction mixture consisted of 75 mM phos-
phate buffer (pH 7.4),
[1,2-3H]-17
-hydroxyprogesterone (NEN), 5 mM NADPH (Oriental
Yeast), and 1–1000 nM test compound in a total volume of 20 L.
7 lg the microsome protein, 10 nM
4.5 mM NADPH (Oriental Yeast), 11 mM calcium chloride, 4 lg
a
mitochondria protein, 10 nM [1,2-3H]-hydroxy-11-deoxycorticos-
terone (11-deoxycortisol) (NEN, dissolved in 0.02% Tween-80),
l
The concentration of reagents was expressed as the final concen-
tration in the reaction mixture. The test compounds were serially
diluted with dimethylformamide, and then diluted fivefold with
and 1–1000 nM test compound in a total volume of 150
test compounds were serially diluted with dimethylformamide,
and 1.5 L samples were directly added to the reaction mixture.
lL. The
l
distilled water before 5
lL samples were added to the reaction
The concentration of reagents was expressed as the final concen-
tration in the reaction mixture. The reaction was terminated by
mixture. The reaction was terminated with the addition of 40
of ethyl acetate after 15 min (17,20-lyase) incubation at 37 °C, fol-
lowed by vortexing for 30 s and a brief centrifugation. Samples
(30 lL) of the organic phase were applied to silica gel TLC plates
(Whatman, LHPK). The substrate and products, androstenedione
and testosterone, were separated using the toluene–acetone (7:2)
solvent system. Detection of the spots and measurement of the
radioactivity as PSL were performed using a BAS2000 Bio-image
l
L
the addition of 400
after 30 min incubation at 37 °C, followed by vortexing for 30 s
and a brief centrifugation. Organic phase (300 L) was transferred
to a new tube, and evaporated until dry with nitrogen gas. The ste-
roids were dissolved with 30 L ethyl acetate. The whole volume
was applied to silica gel TLC plates (Whatman, LHPK). The sub-
lL ethyl acetate and 100 lL distilled water
l
l

T. Kaku et al. / Bioorg. Med. Chem. 19 (2011) 1751–1770
1769
strate and the products, 11-deoxycortisol and cortisol, were sepa-
Acknowledgments
rated using the toluene–acetone (7:2) solvent system.
The authors thank Dr. S. Furuya for helpful discussions through-
out this work, Ms. K. Higashikawa for single-crystal X-ray analysis,
Mr. A. Furuta for pharmacokinetic studies, Ms. H. Shinohara and
Mr. T. Masaki for technical support and Dr. F. W. Dahlquist (Univer-
sity of Oregon) for kindly providing vector pCWori. This work was
funded by Millennium Pharmaceuticals, Inc. The authors would
also like to acknowledge FireKite for editorial assistance in the
development of this manuscript, which was supported by funding
from Millennium Pharmaceuticals, Inc.
5.81. Effect of (ꢀ)-27b on metabolic activities of CYP-expressing
microsomes (Table 5)
The effect of (ꢀ)-27b on CYP isoforms was assessed by incubat-
ing a marker substrate with the microsomes expressing each
human CYP isoform in the presence of 3, 10, and 30 lmol/L of
(ꢀ)-27b. The incubation mixture contained 10 mmol/L MgCl2,
3.2 mg/mL glucose-6-phosphate, 0.8 mg/mL b-NADP+ and
4 units/mL glucose-6-phosphate dehydrogenase in 80 mmol/L
phosphate buffer (pH 7.4). In the case of 2C9, 80 mmol/L Tris–HCl
buffer (pH 7.4) was used instead of phosphate buffer. After prein-
cubation of (ꢀ)-27b and CYP isoform-specific substrate in the
mixture at 37 °C for 5 min, the reaction was initiated by the
addition of microsomes derived from specific CYP-expressing hu-
man B-lymphoblastoid cells. The concentration of the substrates
was referenced from the data sheet from GENTEST Corp. [( )-buf-
uralol 10-hydroxylation for CYP2D6 and testosterone 6b-hydroxyl-
ation activity for CYP3A4] or published reports (tolbutamide
hydroxylation for CYP2C8 and 2C9)60,61 with slight modifications.
The marker reactions specific for CYP isoforms except for
CYP3A4, were measured by published analytical methods60,62–66
with slight modifications. Testosterone 6b-hydroxylation activity
for CYP3A4 was analyzed under the following HPLC conditions:
Inertsil ODS-2 column (150 ꢂ 4.6 mm I.D.; GL Science, Tokyo, Ja-
pan), detection wavelength 254 nm, flow rate 1.0 mL/min, column
temperature 50 °C, and mobile phase 10 mmol/L acetate buffer
(pH4.3)/acetonitrile = 7/3. Control marker enzymatic activities
were measured for the preincubation samples in the presence of
methanol alone without (ꢀ)-27b.
References and notes
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5.82. Effects of (ꢀ)-27b on serum testosterone and DHEA
concentrations in male cynomolgus monkeys
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Discuss. 1995, 13, 27.
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Adult male cynomolgus monkeys housed in a temperature-
controlled room (23 2 °C) with a 12:12 h light/dark cycle (illumi-
nation from 7:00 am to 7:00 pm) were used for the single dosing
experiments. All procedures were performed according to proto-
cols approved by the Institutional Animal Care and Use Committee
of Pharmaceutical Research Division, Takeda. The test compound
(ꢀ)-27b was suspended in 0.5% methylcellulose and orally admin-
istered at a dose of 1 mg/kg. Blood samples were collected just
before dosing, and 4 and 8 h after the dosing. Serum was stored
at ꢀ30 °C until assayed by radioimmunoassay (RIA). Concentra-
tions of testosterone were determined using a Testosterone I-125
kit (Dia Sorin s.r.l., Italy), according to the manufacturer’s
directions.
5.83. Pharmacokinetic studies
Compound (ꢀ)-27b was administered to non-fasted
Crl:CD(SD)IGS rats (male, 8 weeks old, n = 3) intravenously at a
dose of 1 mg/kg and orally at a dose of 10 mg/kg. Blood samples
were collected at 5, 10, 15, and 30 min and 1, 2, 4, 8, 24 h after
intravenous administration, or at 15 and 30 min and 1, 2, 4, 8,
24 h after oral administration. The blood samples were centrifuged
to obtain the plasma fraction. The plasma samples were deprotei-
nized with acetonitrile. After centrifugation, the supernatant was
dried under N2. The residue was reused with HPLC mobile phase
(A:B = 90:10) and analyzed by HPLC. The analytical conditions
using HPLC were: column, L-column ODS (4.6 mm ꢂ 250 mm);
mobile phase, (A) 0.01 mol/L ammonium acetate:(B) acetoni-
trile = 78:22; flow rate, 1.0 mL/min; column temperature, 40 °C.
33. Hartmann, R. W.; Hector, M.; Wachall, B. G.; Paluszcak, A.; Palzer, M.; Huch, V.;
Veith, M. J. Med. Chem. 2000, 43, 4437.
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