C17,20-lyase inhibitors I. Structure-based de novo design and SAR study of C17,20-lyase inhibitors.

Article abstract of DOI:10.1016/j.bmc.2004.02.007

Novel nonsteroidal C(17,20)-lyase inhibitors were synthesized using de novo design based on its substrate, 17 alpha-hydroxypregnenolone, and several compounds exhibited potent C(17,20)-lyase inhibition. However, in vivo activities were found to be short-lasting, and in order to improve the duration of action, a series of benzothiophene derivatives were evaluated. As a result, compounds 9h, (S)-9i, and 9k with nanomolar enzyme inhibition (IC(50)=4-9 nM) and 9e (IC(50)=27 nM) were identified to have powerful in vivo efficacy with extended duration of action. The key structural determinants for the in vivo efficacy were demonstrated to be the 5-fluoro group on the benzothiophene ring and the 4-imidazolyl moiety. Superimposition of 9k and 17 alpha-hydroxypregnenolone demonstrated their structural similarity and enabled rationalization of the pharmacological results. In addition, selected compounds were also identified to be potent inhibitors of human enzyme with IC(50) values of 20-30 nM.

Full text of DOI:10.1016/j.bmc.2004.02.007

Bioorganic & Medicinal Chemistry 12 (2004) 2251–2273
C17;20-Lyase inhibitors I. Structure-based de novo design and
SAR study of C17;20-lyase inhibitors
Nobuyuki Matsunaga,a,* Tomohiro Kaku,a Fumio Itoh,a Toshimasa Tanaka,a
Takahito Hara,b Hiroshi Miki,c Masahiko Iwasaki,d Tetsuya Aono,a Masuo Yamaoka,b
Masami Kusakab and Akihiro Tasakaa
aMedicinal Chemistry Research Laboratories, Pharmaceutical Research Division: Takeda Chemical Industries, Ltd, 17-85,
Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
bPharmacology Research Laboratories I, Pharmaceutical Research Division: Takeda Chemical Industries, Ltd, 17-85,
Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
cPharmaceutical Discovery Center, Pharmaceutical Research Division: Takeda Chemical Industries, Ltd, 17-85,
Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
dDrug Analysis and Pharmacokinetics Research Laboratories, Pharmaceutical Research Division: Takeda Chemical Industries, Ltd,
17-85, Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan
Received 6 January 2004; revised 6 February 2004; accepted 8 February 2004
Abstract—Novel nonsteroidal C17;20-lyase inhibitors were synthesized using de novo design based on its substrate, 17a-hydroxy-
pregnenolone, and several compounds exhibited potent C17;20-lyase inhibition. However, in vivo activities were found to be
short-lasting, and in order to improve the duration of action, a series of benzothiophene derivatives were evaluated. As a result,
compounds 9h, (S)-9i, and 9k with nanomolar enzyme inhibition (IC50 ¼ 4–9 nM) and 9e (IC50 ¼ 27 nM) were identified to have
powerful in vivo efficacy with extended duration of action. The key structural determinants for the in vivo efficacy were demon-
strated to be the 5-fluoro group on the benzothiophene ring and the 4-imidazolyl moiety. Superimposition of 9k and 17a-
hydroxypregnenolone demonstrated their structural similarity and enabled rationalization of the pharmacological results. In
addition, selected compounds were also identified to be potent inhibitors of human enzyme with IC50 values of 20–30 nM.
ꢀ 2004 Elsevier Ltd. All rights reserved.
1. Introduction
gen blockade (CAB), although to date none of the
androgen antagonists achieve effective therapeutic
results due to suboptimal pharmacokinetic properties or
substantial efficacy-limiting adverse effects. Further-
more, androgen antagonists lead to the selection for
androgen receptor mutations in prostate cancers, which
recognize the antagonists as agonists.3–6
Prostate cancer is now the most prevalent cancer in
males in the U.S. and Europe. The prostate cancer in
about 80% of these patients grows androgen depen-
dently and responds to first-line endocrine therapy. At
present, the standard treatment includes orchidectomy
and its medical equivalent, the administration of gona-
dotropin-releasing hormone (GnRH) analogues, which
abolish the production of testosterone in the testes.
However, these treatments do not inhibit adrenal
androgen production and therefore are frequently
combined with an androgen receptor antagonist to
block the action of residual adrenal androgens.1;2 This
combination strategy is recognized as combined andro-
An alternative target would be C17;20-lyase, which is one
of the key enzymes responsible for the biosynthesis of
androgens, and the mechanism of this reaction has been
studied in some detail.7–9 This enzyme catalyzes the
conversion of 17a-hydroxypregnenolone and 17a-
hydroxyprogesterone into the weak androgens, dehy-
droepiandrosterone and androstenedione, respectively,
in testes and adrenal glands. These weak androgens are
subsequently converted into more potent androgens
such as testosterone and dihydrotestosterone in prostate
cancer cells. The inhibition of C17;20-lyase could prevent
initial androgen production and consequently prevent
Keywords: C17;20-Lyase; Androgen; Testosterone; Benzo[b]thiophene.
* Corresponding author. Tel.: +81-06-6300-6706; fax: +81-06-6300-
6306; e-mail: matsunaga_nobuyuki@takeda.co.jp
0968-0896/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2004.02.007

2252
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
subsequent production of the more potent androgens.
Therefore, the use of C17;20-lyase inhibitors may offer a
promising therapeutic approach either as a single agent
or in combination with castration, for the treatment of
androgen-dependent prostate cancer.10;11
marked in vivo efficacy, as well as potent in vitro
activity, derivatives containing variations of the fused
ring system in the place of the naphthalene ring were
synthesized. Among these, the benzothiophene deriva-
tive was identified as a new lead and a series of benzo-
thiophene derivatives (8 and 9) were synthesized.
Several categories of steroidal and nonsteroidal C17;20
-
lyase inhibitors have been reported,12–42 and of these
compounds, only ketoconazole had been used clinically
in the treatment of patients suffering advanced prostate
cancer (Fig. 1).12–14 However, ketoconazole was with-
drawn from clinical use because of the significant
adverse effects due to inhibition of other P450 enzymes
at clinical doses.15 In recent years, other nonsteroidal
C17;20-lyase inhibitors have entered clinical trials,
including CB-7630 (British Technology Group),16;17
GI-111924 (GlaxoSmithKline)18 and YM-116 (Yama-
nouchi).19
This paper describes the de novo design, synthesis, and
pharmacological activities of these C17;20-lyase inhibi-
tors. The pharmacological activities include inhibitory
activity of rat C17;20-lyase and inhibitory effects on tes-
tosterone biosynthesis in male rats. Furthermore,
selected compounds were evaluated for inhibitory
activity of recombinant human C17;20-lyase.
2. Chemistry
At the beginning of this study, no lead compound was
available therefore the initial target molecules (1–6) were
designed as mimetics of the substrate, 17a-hydroxy-
pregnenolone (Fig. 2). In the known C17;20-lyase inhibi-
tors, the critical structures for enzyme inhibition were
thought to be the lone pair of the nitrogen atom in the
imidazole or pyridine ring, which should be able to
interact with the heme iron in C17;20-lyase. Thus the
imidazole ring was combined with a steroid mimetic ring
system such as trans-stilbenes (1, 2: A–D ring of the
steroid), cis-stilbene (3: A–C ring), biphenyl (4: A–C
ring), and naphthalene (5: B–C ring, 6: A–B ring).
Because 6 was found to be a lead compound exhibiting
Synthesis of the trans-stilbene derivatives 1 and 2 is
shown in Scheme 1. Diethyl benzylphosphonate (10) and
3-bromobenzaldehyde (11) were subjected to Horner–
Emmons olefination to give the trans-stilbene 12, which
was reacted with imidazole in the presence of NaH and
CuO to give 1. Reaction of 3-bromobenzyl bromide (13)
and imidazole gave the benzylimidazole 14, which was
followed by Heck reaction with styrene affording 2.
Synthesis of the cis-stilbene derivative 3 is shown in
Scheme 2. Sonogashira reaction of methyl 3-bromo-
benzoate (15) with phenylacetylene gave 16, which was
N
Cl
Cl
H
F
N
N
N
N
N
N
H
N
H
O
O
CH3
O
O
N
N
AcO
YM-116 (Yamanouchi)
GI-111924 (GlaxoSmithKline)
CB-7630 (BTG)
Ketoconazole
Figure 1. Structures of some known C17;20-lyase inhibitors.
N
N
N
N
N
20
17
18
O
OH
16
N
n
N
N
12
( )
D
11
9
19
C 13
D
15
1
C
C
C
B
2
14
A 10
8
3
B
A
A
7
HO
5
A
4
6
17α-Hydroxypregnenolone
1: n=0
2: n=1
5
4
3
R2
N
N
N
R1
N
imidazole
R3 R4
S
Fused
Ring
Benzo[b]thiophenes (8, 9)
A
B
8: 1-Imidazolyl
9: 4-Imidazolyl
7
6
Figure 2. Design of target compounds for C17;20-lyase inhibitors.

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2253
N
Br
N
Br
NaH
imidazole, NaH
OEt
OEt
P
O
+
THF
38%
CuO, DMF
84%
OHC
11
12
1
10
N
N
N
Br
PhCH=CH2
N
Pd(OAc)2, P(o-tolyl)3
imidazole
Et3N, THF
22%
Br
DMF
81%
Br
13
14
2
Scheme 1.
OH
N
CO2Me
1) H2, Pd/BaSO4
quinoline, MeOH
2) SOCl2
N
• HCl
CO2Me
DIBAL
toluene
72%
3) imidazole
4) HCl
Br
PdCl2(PPh3)2
CuI, Et3N
89%
15
16
17
37%
3
Scheme 2.
converted into the alcohol 17 with diisobutylaluminium
hydride (DIBAL). Compound 17 was converted into 3
as follows: catalytic hydrogenation of the acetylene,
chlorination of the hydroxyl group, nucleophilic sub-
stitution with imidazole, and then treatment with HCl.
ethyl (or methyl) diethylphosphonoacetate afforded the
corresponding (E)-olefins 19. Reduction of the esters
with DIBAL provided the alcohols 20. Chlorination or
methanesulfonylation of the hydroxyl group followed
by displacement by imidazole gave 6, 7a–d, 8a–d, 8f and
8h.
The biphenyl derivative 4 and the naphthalene deriva-
tive 5 were prepared by chlorination of 4-biphenyl-
methanol or 2-naphthylmethanol, respectively, followed
by treatment with imidazole (schemes not shown).
Preparation of benzothiophene intermediates were
shown in Scheme 4. Benzothiophene skeletons were
constructed by a known procedure43 as follows. Starting
thiophenols 21 were alkylated with a-chloroketones or
bromoacetaldehyde diethylacetal in the presence of
potassium carbonate, and the resulting products were
Scheme 3 shows the synthesis of the fused ring deriva-
tives. Horner–Emmons olefination of aldehydes 18 with
N
1) SOCl2
or MsCl, Et3N
OH
CO2R
N
(EtO)2P(O)CH2CO2R
DIBAL
O
Fused Ring
H
Fused Ring
NaH
55%-quant.
Fused Ring
2) imidazole
14-75%
Fused Ring
44%-quant.
19
20
6, 7, 8
18
R2
R1
Fused Ring =
S
N
7d: R1=R2=H
6
7a
8a: R1=4-F, R2=H
8b: R1=5-F, R2=H
8c: R1=6-F, R2=H
8d: R1=7-F, R2=H
8f: R1=5-Cl, R2=H
O
O
7c
7b
8h: R1=5-CH3O, R2=CH3
Scheme 3.

2254
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2
1) ClCH COR
2
R2
R2
4
or
BrCH CH(OEt)
5
6
3
1) n-BuLi, THF
2
2
R1
R1
R1
2
CHO
2) DMF
S
S
SH
K CO , DMF
2 3
7
53%-quant.
1
2
1
2
18i: R =4-F, R =H
22i: R =4-F, R =H
2) PPA, toluene
24-80%
21
1
2
1
2
18ii: R =5-F, R =H
22ii: R =5-F, R =H
1
2
1
2
18iii: R =6-F, R =H
22iii: R =6-F, R =H
1
2
1
2
18iv: R =7-F, R =H
22iv: R =7-F, R =H
1
2
1
2
18v: R =5-F, R =CH
3
22v: R =5-F, R =CH
3
1
2
1
2
18vi: R =5-Cl, R =H
22vi: R =5-Cl, R =H
1
2
1
2
18vii: R =5-Cl, R =CH
3
22vii: R =5-Cl, R =CH
3
1
2
1
2
18viii: R =5-CH O, R =CH
3
3
22viii: R =5-CH O, R =CH
3
2
3
1
22ix: R =5-F, R =(CH ) C
3 3
1
2
22x: R =5,7-F , R =CH
2
3
1) KOH aq, EtOH
2) Cu, quinoline
20-83% from 23
CHO
F
HSCH CO Et
2
2
F
F
CO2Et
S
K CO , DMF
2
3
1
2
24i: R =4-F, R =H
23
1
2
24ii: R =5-F, R =H
1
2
24iii: R =6-F, R =H
24iv: R =7-F, R =H
1
2
Scheme 4.
cyclized by heating with polyphosphoric acid (PPA) in
toluene to give benzothiophenes 22v–x. However, these
procedures resulted in poor yields for the reaction of
fluorothiophenols (21, R1 ¼ F) with bromoacetaldehyde
diethylacetal, and thus preparation of fluorobenzothio-
phenes 22i–iv (R1 ¼ F, R2 ¼ H) was achieved by the
alternative procedures.44;45 The reaction of difluoro-
benzaldehydes 23 and ethyl thioglycolate in the presence
of potassium carbonate provided the benzothiophene
esters 24i–iv. Alkaline hydrolysis of the esters followed
by decarboxylation of the resulting carboxyl group in
the presence of Cu in quinoline provided 22i–iv. Com-
pounds 22i–viii were converted to the corresponding
aldehydes 18i–viii by lithiation with n-BuLi followed by
addition to DMF.
Crafts acylation of benzothiophenes 22v,vii with 3-
chloropropionyl chloride afforded the 2-acylated com-
pounds 25, which were substituted with imidazole to
provide the 1-imidazolyl compounds 26. Reduction of
the ketones with NaBH4 gave alcohols 27, and these
compounds were dehydrated by heating with p-tolu-
enesulfonic acid monohydrate (TsOHÆH2O) in toluene
to furnish 8e and 8g.
The benzothiophene derivatives bearing a 4-imidazolyl
moiety were synthesized by two general strategies based
on the same intermediates 22. In the first approach
(Scheme 6), benzothiophenes 22i–v,ix,x were lithiated by
n-BuLi and reacted with aldehydes 28 or 32 to afford
compound 33. Dehydration and detritylation of 33 were
accomplished by heating with TsOHÆH2O to give 9a–h.
Compound 2846 was prepared from urocainic acid
according to known procedures, and 32 was prepared
The benzothiophene derivatives bearing a 1-imidazolyl
moiety were prepared as shown in Scheme 5. Friedel–
R2
R2
R2
Cl
Cl
imidazole
O
R1
R1
N
R1
Cl
N
S
S
S
AlCl , CS
3
DMF
2
O
O
73-97%
74-83%
22v, vii
25
26
R2
R2
NaBH
TsOH•H O
2
4
R1
R1
N
N
N
N
S
S
toluene
92-99%
THF, MeOH
97-98%
OH
1
2
8e: R =5-F, R =CH
27
3
1
2
8g: R =5-Cl, R =CH
3
Scheme 5.

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2255
H
N
R2
Tr
R2
R2
N
1) n-BuLi, THF
TsOH • H O
2
R1
R1
R1
N
N
S
S
S
R3
2)
OH R3
16-84% from 22
Tr
1
2
3
N
9a: R =4-F, R =R =H
22i-v, ix, x
33
1
2
3
9b: R =5-F, R =R =H
N
CHO
1
2
3
9c: R =6-F, R =R =H
R3
1
2
3
9d: R =7-F, R =R =H
3
3
1
2
3
28 (R =H) or 32 (R =CH )
9e: R =5-F, R =CH , R =H
3
3
1
2
3
9f: R =5-F, R =(CH ) C, R =H
3 3
1
2
3
DIBAL, THF, 80%
9g: R =5,7-F , R =CH , R =H
2
3
1
2
3
9h: R =5-F, R =H, R =CH
3
Tr
N
Tr
N
Tr
N
1)
(EtO) P(O)CH CO Et
NaH, THF, 91%
2
2
2
1) MeMgBr, 98%
2) MnO , 85%
N
CH3
N
CO2Et
N
CHO
2
2)
3)
CH3
H , Pd-C, AcOEt, THF
2
TrCl, Et N, DMF, 80%
O
3
29
30
31
Scheme 6.
from 1-trityl-1H-imidazole-4-carboxaldehyde (29).47
Grignard reaction of 29 with methylmagnesium bromide
followed by oxidation with MnO2 gave the acetylimid-
azole 30. Subsequent Horner–Emmons olefination, cat-
alytic hydrogenation, and re-protection of the partially
detritylated imidazole afforded the branched compound
31. Reduction of 31 with DIBAL then provided 32. The
second approach is shown in Scheme 7. Friedel–Crafts
acylation of 22v with acetyl chloride afforded the 2-
acetylbenzothiophene 34. Claisen–Schmidt reaction of
34 and 29 followed by removal of the trityl group using
TsOHÆH2O yielded the a,b-unsaturated ketone 35,
which upon treatment with methylmagnesium bromide
gave a mixture of isomers. These were separated by
column chromatography on silica gel to provide the
desired Michael adduct 36 and the 1,2-adduct 37. A
similar procedure employing isopropylmagnesium
chloride provided 38 and 39. Compounds 36 and 38
were converted to 9i and 9j, respectively, by NaBH4
reduction followed by dehydration. Optical resolution
of the racemic compound 9i into enantiomers (S)-9i and
(R)-9i was accomplished by HPLC using Chiralcelꢁ OD.
H
CH3
CH3
N
CH3
F
CH COCl
F
F
3
29, NaOH, quant.
1)
2)
N
CH3
S
S
S
AlCl , CS
3
59%
2
O
TsOH • H O, 86%
2
O
35
22v
34
H
H
N
CH3
CH3
N
F
CH MgBr
3
F
+
N
N
S
S
or
R3 OH
O
R3
(CH ) CHMgCl
3 2
3
3
37: R =CH (25%)
36: R =CH (66%)
3
3
3
3
39: R =(CH ) CH (23%)
38: R =(CH ) CH (38%)
3 2
3 2
1) NaBH , 2) TsOH • H O
4
2
H
N
CH3
F
N
S
R3
3
9i: R =CH (77%)
3
3
9j: R =(CH ) CH (80%)
3 2
H
N
H
CH3
CH3
N
F
F
R
R
CHIRALCEL OD
+
N
S
N
9i
S
S
CH3
CH3
(R)-9i
(S)-9i
Scheme 7.

2256
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
3. Results and discussion
3.1. Enzyme inhibitory activity (in vitro study)
Test compounds were evaluated in vitro for the inhibi-
tion of rat microsomal C17;20-lyase, which was prepared
from rat testes. Inhibitory activity was measured
using the radiometric assay described by Brodie and
co-workers27 with some modifications.
3.2. Inhibitory effects on testosterone biosynthesis in
rats (in vivo study)
Test compounds were orally administrated to male rats
(n ¼ 5) at a dose of 25 mg/kg. After 2 and 5 h, the serum
testosterone concentrations were measured by a specific
radioimmunoassay and expressed as percent values of
the control.
Figure 3. Crystal structure of (R)-9i as the fumarate.
3.3. Screening of steroid mimetic ring systems
The stereochemistry of (S)-9i and (R)-9i was determined
by single-crystal X-ray analysis of (R)-9i as the fumarate
(Fig. 3).
Table 1 shows pharmacological activities of the initial
target compounds possessing a steroid mimetic ring
system. In the in vitro assay, the A–C ring mimetics (3
and 4), B-C ring mimetic (5) and the A–B ring mimetic
(6) were found to be potent inhibitors with IC50 values
of 10–53 nM. The A–D ring mimetics (1 and 2) were
moderate inhibitors. The most potent inhibitor was
biphenyl derivative 449 with an IC50 value of 10 nM. In
the in vivo evaluation, 4 reduced the serum testosterone
concentration to 8% of the control at 2 h after treatment,
but showed poor efficacy at 5 h (63% of the control). The
most active compound at 5 h was the naphthalene
derivative 6, which reduced the testosterone concentra-
tion to 8% and 26% of the control at 2 and 5 h, res-
pectively. Since compound 6 exhibited superior in vitro
and in vivo activities to those of ketoconazole, it was
identified as the lead compound. It is noteworthy that
the propenyl group is an important structure for the
duration of in vivo action because compound 45 with an
IC50 value of 42 nM showed potent testosterone reduc-
Scheme 8 shows the synthesis of the benzothiophene
derivative possessing a gem-dimethyl group adjacent to
the imidazole. Compound 24ii was converted to the
phosphonate 40 by the following procedures: reduction
using LiAlH4, chlorination of the resulting hydroxyl
group with thionyl chloride, and phosphonylation with
triethyl phosphite. Horner–Emmons olefination of 40
with 44 followed by detritylation with pyridinium
chloride in methanol then furnished 9k. Preparation of
the imidazole intermediate 44 started with the reaction
of the a-bromoketone 4148 and formamide to construct
the imidazole 42. Protection of the imidazole was
accomplished by the treatment with chloro-
triphenylmethane (TrCl) in the presence of triethylamine
to afford the tritylated imidazole 43, which was reduced
by DIBAL to yield 44.
Tr
N
H
N
O
TrCl, Et N
NH CHO
3
2
N
CO2Et
CH3
Br
CO2Et
CH3
N
CO2Et
CH3
20%
H3C
DMF
88%
H3C
H3C
43
42
41
DIBAL, THF, 67%
Tr
N
N
CHO
H
N
H3C CH3
1) LiAlH , THF, 96%
4
F
F
2) SOCl , THF, 69%
F
O
P
1) 44
NaH, 92%
2
N
OEt
OEt
CO2Et
S
S
S
H3C CH3
3) P(OEt) , 89%
2) pyridinium chloride
MeOH, 98%
3
9k
40
24ii
Scheme 8.

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2257
Table 1. Pharmacological activities of initial target compounds
were probably due to cancellation of the negative feed-
back control caused by transient suppression of the
testosterone levels as previously reported.17;32;33
N
N
N
N
( )n
Variations of the fused ring system in the place of the
naphthalene ring were evaluated, and 2H-chromene,
benzofuran and benzothiophene derivatives (7b, 7c, and
7d) exhibited potent inhibitory activity with IC50 values
of 16–39 nM, while quinoline derivative 7a showed
moderate inhibition. In vivo evaluation revealed that 7d
had more potent efficacy than 6, in reducing the serum
testosterone concentration to 5% and 17% of the control
at 2 and 5 h after treatment, respectively. These data
suggested that benzothiophene derivative 7d had an
attractive scaffold and additional targets were designed
focusing on benzothiophene analogues.
1: n=0
2: n=1
3
N
N
N
N
5
4
3.4. Pharmacological activities of benzothiophene
derivatives
N
Fused
Ring
=
N
N
3.4.1. Effects of R1 and R2. The in vivo efficacy of 7d was
sufficient at 2 h after treatment, but extended duration of
action even at 5 h was required. Several benzothiophene
compounds were reported to be metabolized in vivo by a
pathway involving the hydroxylation of the benzothio-
phene nuclei, followed by conversion to O-glucuro-
nides.50 This knowledge led us to synthesize derivatives
carrying a metabolically resistant substituent such as a
fluoro or a chloro group on the benzothiophene ring
(Table 2). The data revealed that substituents on the
benzothiophene ring (R1 and R2) showed no significant
difference in the inhibitory activity. For example, a flu-
oro, chloro, or methoxy group at the 5-position showed
the same range of activity as the unsubstituted derivative
(comparison of 8e–h and 7d; IC50 ¼ 16–33 nM). Intro-
duction of a methyl group at the R2 position had no
influence on activity (comparison of 8b and 8e, 8f and
8g). The substitution position of a fluoro group on
the benzothiophene had only a minor effect on activity
(8a–d; IC50 ¼ 10–26 nM). We also explored the effects of
7a
6
Fused
Ring
S
O
O
7c
7d
7b
N
N
45
Compd no.
C17;20-Lyase
inhibition IC50
(nM)
T concn (in vivo)c % of
control
Rat
2 h
5 h
1
270
91
24
10
53
26
95
29
39
16
42
240
nt
nt
nt
2
3a
nt
8
135
63
55
26
nt
4
8
13
8
5
6
Table 2. Pharmacological activities of 1-imidazolyl derivatives
7a
7b
7cb
7d
45b
nt
14
15
5
R2
28
86
17
226
115
4
5
6
N
R1
N
S
14
28
7
Ketoconazole
7d, 8a-h
R2 C17;20-Lyase inhi- T concn (in vivo)a
nt: Not tested.
a HCl salt.
b Fumarate.
Compd R1
no.
%
bition IC50 (nM)
of control
c Test compounds and ketoconazole were administrated orally at a
dose of 25 mg/kg to male rats. After 2 and 5 h, the serum testosterone
(T) concentration was measured by radioimmunoassay and shown as
the % values of that of control.
Rat
2 h
5 h
7d
8a
8b
8c
8d
8e
8f
H
H
H
H
H
H
16
20
25
26
10
5
28
14
17
17
2
17
52
10
22
23
8
4-F
5-F
6-F
7-F
5-F
5-Cl
5-Cl
tion at 2 h after treatment (14% of the control) but led to
an increase of the testosterone concentration above the
control at 5 h (226% of the control). Similarly, com-
pound 3 increased the testosterone concentration at 5 h
(135% of the control) in spite of comparable testoster-
one reduction to 6 at 2 h after treatment. These increases
CH3 25
29
CH3 26
H
8
29
30
70
8g
8h
7
13
5-CH3O CH3 33
a 25 mg/kg (po).

2258
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
the substituent on the benzothiophene ring in 4-imid-
azolyl series (Table 3). As was observed for the 1-imid-
azolyl derivatives, the position of the fluoro group at R1
and the methyl group at R2 did not have a marked
influence on enzyme inhibition (9a–e,g; IC50 ¼ 19–
32 nM), although a bulky tert-butyl group at R2 such as
9f led to a reduced activity.
group at R3 led to nanomolar inhibitors as illustrated by
9h and 9i with IC50 values of 4 and 9 nM, respectively.
The bulky isopropyl group such as 9j resulted in a
modest decrease in the activity relative to their unsub-
stituted compound. The enantiomers of 9i were sepa-
rated to establish, which enantiomer of 9i (and by
analogy 9h) was responsible for the excellent activity.
The enzyme inhibitory activity of (S)-9i and (R)-9i, with
IC50 values of 9 and 8 nM, respectively, indicated that
both the b-methyl group in (S)-9i and the a-methyl
group in (R)-9i were able to confer potent inhibitory
activity. The gem-dimethyl group (9k) also exhibited
increased inhibitory activity with an IC50 value of 6 nM.
In the in vivo assay, all the tested compounds showed a
reduction in the serum testosterone concentration at 2 h
after treatment, although to different extents, and the
differences in the duration became clear at 5 h after
treatment. The substituent at R1 in 1-imidazolyl inhibi-
tors had a major influence on the in vivo efficacy (Table
2). The 5-fluoro derivatives (8b and 8e) reduced the serum
testosterone concentration more effectively than 4-, 6-,
and 7-fluoro compounds (8a, 8c, and 8d), 5-chloro
compound (8f and 8g), and 5-methoxy compound (8h) at
5 h after treatment. In the case of 4-imidazolyl com-
pounds as well as 1-imidazolyl analogues, the 5-fluoro
group was critical for the extended duration of in vivo
efficacy, and compounds 9b and 9e reduced the testo-
sterone concentration to 4% and 2% of the control,
respectively, even at 5 h after treatment (Table 3). These
results clearly demonstrate that the 5-fluoro group on the
benzothiophene ring is the key structural determinant for
the duration of the in vivo action. In addition, the ori-
entation of the imidazole ring appears to be important for
in vivo potency, with 4-imidazolyl compounds displaying
more potent testosterone reduction than 1-imidazolyl
analogues (comparison of 8b and 9b, 8e and 9e).
These nanomolar inhibitors 9h, 9i, and 9k also had
strong in vivo efficacy, and their effects at 5 h after
treatment were comparable with that of 9e. The most
potent in vivo efficacy at 5 h in this study was achieved
by (S)-9i, which was more effective than the other
enantiomer (R)-9i, in reducing in the testosterone con-
centration to 1% of the control.
3.5. Structural comparison of 9k with 17a-hydroxy-
pregnenolone
The superimposition of 9k (bold line) with 17a-
hydroxypregnenolone (thin line) and the steroidal
inhibitor CB-7630 (dotted line) is shown in Figure 4,
which shows that the benzothiophene ring and the
propenyl linker in 9k overlap the steroid nucleus of the
substrate. Furthermore, the superimposition might
explain the increase in the enzyme inhibition by the
methyl groups in the propenyl linker. It is clear that the
a-methyl group in 9k and the C-16 methylene group in
3.4.2. Effects of R3 and R4. The effects of substituents at
the R3 and R4 were investigated (Table 3). The methyl
Table 3. Pharmacological activities of 4-imidazolyl derivatives
H
H
N
CH3
H
N
R2
CH3
4
F
N
F
5
R
N
S
R1
6
N
N
S
S
S
CH3
R3 R4
CH3
7
(S)-9i
(R)-9i
9
Compd no.
R1
R2
R3
R4
C17;20-Lyase
inhibition
IC50 (nM)
T concn (in vivo)a % of control
Rat
2 h
5 h
9a
9b
4-F
5-F
6-F
7-F
5-F
5-F
H
H
H
H
H
H
H
H
H
H
H
H
19
23
27
25
27
300
32
4
7
12
14
5
25
4
H
H
9c
9d
H
H
23
16
2
H
CH3
H
9e
H
3
9f
9g
(CH3)3C
CH3
H
H
nt
26
7
nt
46
2
5,7-F2
5-F
5-F
H
9h
9i
CH3
CH3
(CH3)2CH
CH3
CH3
CH3
H
9
5
2
9j
9k
5-F
5-F
140
6
nt
12
8
nt
3
CH3
(S)-9i
(R)-9i
(S)-Enantiomer of 9i
(R)-Enantiomer of 9i
9
1
10
8
13
nt: Not tested.
a 25 mg/kg (po).

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2259
Table 4. IC50 values of selected compounds toward human C17;20-lyase
F
AcO
HO
Compd no.
C17;20-Lyase inhibition IC50 (nM)
Human
S
6
7d
26
30
25
22
21
20
21
29
29
9b
9e
N
HO
O
9h
9i
N
N
(S)-9i
(R)-9i
9k
9k
17α-Hydroxypregnenolone
CB-7630
(IC50 ¼ 27 nM) and potent in vivo efficacy with extended
duration. The key structural features required for potent
in vivo efficacy were demonstrated to be the 5-fluoro
group on the benzothiophene ring and the 4-imidazolyl
moiety. Selected compounds were found to be potent
inhibitors of human enzyme with IC50 values of 20–
30 nM and these results suggest that some benzothio-
phene inhibitors described in this paper may be
promising agents for the treatment of prostate cancer.
5. Experimental
5.1. Chemistry
Figure 4. Superimposition of 9k (bold line) with 17a-hydroxypregne-
nolone (thin line) and CB-7630 (dotted line).
Melting points were determined on a Yanaco MP-500V
micro melting point apparatus and are uncorrected.
Infrared (IR) spectra were taken on a Shimadzu FTIR-
8200PC spectrometer. Proton nuclear magnetic reso-
nance (1H NMR) spectra were recorded on a Varian
Gemini-200 (200 MHz) spectrometer. Chemical shifts
are given in ppm with tetramethylsilane as the internal
standard, and coupling constants (J) are given in Hertz
(Hz). The following abbreviations are used: s ¼ singlet,
d ¼ doublet, t ¼ triplet, q ¼ quartet, m ¼ multiplet,
br ¼ broad. Column chromatography was carried out
on Kieselgel 60 (230–400 mesh, Merck). Solutions in
organic solvents were dried over anhydrous magnesium
sulfate unless otherwise noted.
17a-hydroxypregnenolone share the same regions of
space. Also, the b-methyl group in 9k and the C-18
methyl group in 17a-hydroxypregnenolone occupy
similar regions of space. Thus the methyl groups may
contribute to more precise mimicry of the steroid
nucleus, and consequently enhance the hydrophobic
interactions of the molecule and C17;20-lyase leading to a
increased enzyme inhibitory activity. From the results of
9h, (S)-9i, (R)-9i, and 9k, the insertion of either the
b-methyl group or the a-methyl group in the propenyl
group would be needed for nanomolar enzyme inhibi-
tion.
3.6. Human enzyme inhibitory activity (in vitro study)
5.2. 1-Bromo-3-[(E)-2-phenylethenyl]benzene (12)
Selected compounds were evaluated for inhibitory
activity of human recombinant C17;20-lyase. The potent
inhibitors for rat enzyme also had potent human enzyme
inhibitory activity with IC50 values of 20–30 nM (Table
4).
To a suspension of NaH (60% dispersion in oil, 0.63 g,
15.8 mmol) in THF (80 mL) was added diethyl benzyl-
phosphonate (10, 3.04 g, 14.6 mmol) with ice cooling,
and the mixture was stirred for 1 h. 3-Bromobenzalde-
hyde (11, 2.50 g, 13.5 mmol) was added, and the mixture
was stirred for an additional 24 h at room temperature
and then quenched with saturated aqueous NH4Cl.
After the separation of the layers, the organic layer was
dried and concentrated. The residue was chromato-
graphed on silica gel using hexane–AcOEt (1:1) as an
eluent, followed by recrystallization from CH2Cl2–
AcOEt to give 12 (1.33 g, 38%) as colorless prisms. Mp
4. Conclusions
We have discovered novel and potent C17;20-lyase
inhibitors through structure-based de novo design. To
improve the duration of the in vivo action, a series of
benzothiophene derivatives were examined, which
resulted in the identification of 9h, (S)-9i, and 9k with
nanomolar enzyme inhibition (IC50 ¼ 4–9 nM) and 9e
87–89 ꢂC. IR (KBr): 3024, 1585, 1425, 1073, 967 cmꢀ1
.
1H NMR (CDCl3) d: 7.00 (1H, d, J ¼ 16:3 Hz), 7.11
(1H, d, J ¼ 16:3 Hz), 7.17–7.54 (8H, m), 7.67 (1H, t,

2260
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
J ¼ 1:8 Hz). Anal. Calcd for C14H11Br: C, 64.89; H,
catalyst was filtered off and the filtrate was evaporated.
The residue was chromatographed on silica gel using
hexane–AcOEt (3:1) as an eluent, followed by recrystal-
lization from hexane–CH2Cl2 to give 16 (10.77 g, 89%).
Mp 77–79 ꢂC. IR (KBr): 1726, 1440, 1255, 1145 cmꢀ1. 1H
NMR (CDCl3) d: 3.94 (3H, s), 7.31–7.60 (6H, m), 7.71
(1H, m), 8.00 (1H, m), 8.22 (1H, m). Anal. Calcd for
C16H12O2: C, 81.34; H, 5.12. Found: C, 81.31; H, 5.19.
4.28. Found: C, 64.99; H, 4.31.
5.3. 1-{3-[(E)-2-Phenylethenyl]phenyl}-1H-imidazole (1)
To a suspension of NaH (60% dispersion in oil, 0.329 g,
8.22 mmol) in DMF (3 mL) was added imidazole
(610 mg, 8.96 mmol), and the mixture was stirred for
10 min. Then 12 (712 mg, 2.75 mmol) and CuO (77 mg,
0.968 mmol) were added, and the mixture was heated at
150 ꢂC for 7 h, cooled, and partitioned between CH2Cl2
and water. The organic layer was separated, dried, and
concentrated, and the residue was chromatographed on
silica gel using CH2Cl2–AcOEt (1:1) as an eluent, fol-
lowed by recrystallization from hexane–CH2Cl2 to give
1 (569 mg, 84%) as a colorless powder. Mp 78–79 ꢂC. IR
5.7. [3-(2-Phenylethynyl)phenyl]methanol (17)
To a solution of 16 (10.45 g, 44.2 mmol) in CH2Cl2
(200 mL) was added dropwise diisobutylaluminum
hydride (1.5 M solution in toluene, 65 mL, 97.5 mmol) at
)70 ꢂC. The mixture was stirred for 2 h, cautiously
quenched with 1 N HCl, and allowed to warm up to
room temperature. After the separation of the layers, the
aqueous layer was further extracted with AcOEt and the
organic layers were combined, dried and concentrated.
The residue was chromatographed on silica gel using
hexane–AcOEt (5:1) as an eluent, followed by recrys-
tallization from hexane gave 17 (6.60 g, 72%). Mp 41–
43 ꢂC. IR (KBr): 3263, 1604, 1494, 1041 cmꢀ1. 1H NMR
(CDCl3) d: 4.71 (2H, s), 7.30–7.60 (9H, m). Anal. Calcd
for C15H12O: C, 86.51; H, 5.81. Found: C, 86.30; H, 5.78.
1
(KBr): 1605, 1503, 1306, 1059 cmꢀ1. H NMR (CDCl3)
d: 7.12 (1H, d, J ¼ 16:2 Hz), 7.17–7.59 (12H, m), 7.91
(1H, s). Anal. Calcd for C17H14N2: C, 82.90; H, 5.73; N,
11.37. Found: C, 82.85; H, 5.67; N, 11.25.
5.4. 1-(3-Bromobenzyl)-1H-imidazole (14)
A mixture of 3-bromobenzyl bromide (13, 25.0 g,
0.100 mol) and imidazole (14.97 g, 0.220 mol) in DMF
(100 mL) was stirred at 100 ꢂC for 2 h. After removal of
the solvent, the residue was diluted with water and
extracted with CH2Cl2. The organic layer was dried and
concentrated, and the residue was chromatographed on
silica gel using CH2Cl2–MeOH (10:1) as an eluent
to give 14 (19.10 g, 81%) as a colorless oil. IR (Neat):
5.8. 1-{3-[(Z)-2-Phenylethenyl]benzyl}-1H-imidazole
hydrochloride (3)
A mixture of 17 (1.76 g, 8.47 mmol), 5% Pd/BaSO4
(43 mg) and quinoline (45 mg, 0.348 mmol) in MeOH
(20 mL) was stirred at room temperature for 50 min
under a hydrogen atmosphere. The catalyst was filtered
off and the solvent was evaporated to give a colorless oil
(1.78 g, quant.). The oil was dissolved in CH2Cl2
(20 mL) and the solution was cooled with an ice bath.
Thionyl chloride (1.8 mL, 24.7 mmol) was added and the
mixture was refluxed for 2 h and concentrated. The
residue was diluted with AcOEt, and the solution was
washed with aqueous NaHCO3, dried, and concen-
trated. The residue was heated at 100 ꢂC for 2 h with
imidazole (1.40 g, 20.5 mmol) in DMF (20 mL). After
removal of the solvent, the residue was diluted with
AcOEt, and the solution was washed with water, dried,
and concentrated. The residue was chromatographed on
silica gel using AcOEt as an eluent, and the product was
treated with 4 N HCl–AcOEt. The precipitate was col-
lected by filtration and washed with AcOEt to give 3
(1.55 g, 37%) as colorless crystals. Mp 112–114 ꢂC
1
3110, 1505, 1231, 1074 cmꢀ1. H NMR (CDCl3) d: 5.09
(2H, s), 6.90 (1H, s), 7.01–7.32 (4H, m), 7.45 (1H, d,
J ¼ 8:0 Hz), 7.54 (1H, m).
5.5. 1-{3-[(E)-2-Phenylethenyl]benzyl}-1H-imidazole (2)
A mixture of 14 (1.05 g, 4.43 mmol), styrene (1.2 mL,
10.5 mmol), palladium(II) acetate (93 mg, 0.414 mmol),
tris(2-methylphenyl)phosphine (1.45 g, 4.75 mmol), and
Et3N (2.0 mL, 14.3 mmol) in THF (25 mL) was refluxed
for 18 h under an argon atmosphere. The insoluble
material was filtered off and the filtrate was concen-
trated. The residue was chromatographed on silica gel
using CH2Cl2–MeOH (20:1) as an eluent to give 2 as
crystals (254 mg, 22%). Mp 141–142 ꢂC (CH2Cl2–cyclo-
hexane). IR (KBr): 1601, 1510, 1231, 1076, 963 cmꢀ1. 1H
NMR (CDCl3) d: 5.15 (2H, s), 6.94 (1H, t, J ¼ 1:4 Hz),
7.08 (4H, m), 7.25–7.43 (5H, m), 7.45–7.62 (4H, m).
Anal. Calcd for C18H16N2Æ0.1H2O: C, 72.90; H, 5.17; N,
9.45. Found: C, 72.79; H, 5.12; N, 9.31.
(AcOEt). IR (KBr): 3064, 1567, 1446, 1278, 1075 cmꢀ1
.
1H NMR (DMSO-d6) d: 5.37 (2H, s), 6.63 (1H, d,
J ¼ 12:2 Hz), 6.70 (1H, d, J ¼ 12:2 Hz), 7.08–7.40 (9H,
m), 7.68 (2H, m), 9.22 (1H, s). Anal. Calcd for
C18H17N2ClÆ0.1H2O: C, 72.40; H, 5.81; N, 9.38. Found:
C, 72.30; H, 5.72; N, 9.46.
5.6. Methyl 3-(2-phenylethynyl)benzoate (16)
To a mixture of methyl 3-bromobenzoate (15, 11.07 g,
51.5 mmol), CuI (112 mg, 1.24 mmol), PdCl2(PPh3)2
(1.0 g, 1.42 mmol) in Et3N (300 mL) was added phenyl
acetylene (6.0 mL, 54.6 mmol), and the mixture was
stirred at 50 ꢂC for 24 h under an argon atmosphere. The
5.9. 1-([1,10-Biphenyl]-4-ylmethyl)-1H-imidazole (4)
To a solution of 4-biphenylmethanol (0.91 g, 4.9 mmol)
in THF (10 mL) was added thionyl chloride (1.5 mL,

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2261
20 mmol) with ice cooling. The mixture was stirred at
70 ꢂC (hexane). IR (KBr): 2972, 1704, 1274, 1191 cmꢀ1
.
room temperature for 5 h and concentrated, and the
residue was heated at 100 ꢂC for 2 h with imidazole
(2.72 g, 40 mmol) in DMF (10 mL). The mixture was
diluted with AcOEt, and the solution was washed with
water, dried, and concentrated. The residue was crys-
tallized from AcOEt–hexane to give 4 as colorless
crystals (0.65 g, 56%). Mp 143.5–145 ꢂC. IR (KBr): 3108,
1H NMR (CDCl3) d: 1.32 (3H, t, J ¼ 7:2 Hz), 4.24 (2H,
q, J ¼ 7:2 Hz), 4.96 (2H, s), 5.76 (1H, d, J ¼ 16:2 Hz),
6.72 (1H, s), 6.85 (1H, d, J ¼ 8:4 Hz), 6.89 (1H, m), 7.06
(1H, dd, J ¼ 7:7, 1.8 Hz), 7.17 (1H, dt, J ¼ 7:7, 1.8 Hz),
7.37 (1H, d, J ¼ 16:2 Hz). Anal. Calcd for C14H14O3: C,
73.03; H, 6.13. Found: C, 72.80; H, 6.19.
1
1508, 1487, 1233, 745 cmꢀ1. H NMR (CDCl3) d: 5.17
(2H, s), 6.95 (1H, t, J ¼ 1:2 Hz), 7.12 (1H, s), 7.23 (2H,
d, J ¼ 8:2 Hz), 7.34–7.50 (3H, m), 7.53–7.61 (5H, m).
Anal. Calcd for C16H14N2: C, 82.02; H, 6.02; N, 11.96.
Found: C, 81.94; H, 6.00; N, 11.88.
5.11.4. Ethyl (E)-3-(benzo[b]furan-2-yl)-2-propenoate.
63% yield from benzo[b]furan-2-carboxaldehyde. Mp
73–76 ꢂC (hexane–AcOEt). IR (KBr): 2982, 1713, 1638,
1451, 1264, 1173 cmꢀ1. 1H NMR (CDCl3) d: 1.35 (3H, t,
J ¼ 7:1 Hz), 4.28 (2H, q, J ¼ 7:1 Hz), 6.58 (1H, d,
J ¼ 15:7 Hz), 6.93 (1H, s), 7.24 (1H, dt, J ¼ 1:4, 6.8 Hz),
7.36 (1H, dt, J ¼ 1:4, 7.6 Hz), 7.46 (1H, m), 7.55 (1H, d,
J ¼ 15:7 Hz), 7.59 (1H, m). Anal. Calcd for C13H12O3:
C, 72.21; H, 5.59. Found: C, 71.93; H, 5.53.
5.10. 1-(2-Naphthylmethyl)-1H-imidazole (5)
Prepared from 2-naphthylmethanol in 62% yield by the
method described for 4. Mp 82–85 ꢂC (hexane–AcOEt).
1
IR (KBr): 3057, 1502, 1225, 1074, 820 cmꢀ1. H NMR
(CDCl3) d: 5.28 (2H, s), 6.94 (1H, t, J ¼ 1:3 Hz), 7.12
(1H, t, J ¼ 1:3 Hz), 7.26 (1H, dd, J ¼ 8:4, 1.8 Hz), 7.45–
7.63 (4H, m), 7.74–7.88 (3H, m). Anal. Calcd for
C14H12N2: C, 80.74; H, 5.81; N, 13.45. Found: C, 80.78;
H, 5.55; N, 13.52.
5.11.5. Ethyl 3-(benzo[b]thiophen-2-yl)-2-propenoate.
98% yield from benzo[b]thiophene-2-carboxaldehyde.
Mp 48–50 ꢂC (EtOH). IR (KBr): 1701, 1630, 1269, 1167,
1038, 955, 824, 747, 727 cmꢀ1. 1H NMR (CDCl3) d: 1.35
(3H, t, J ¼ 7:2 Hz), 4.28 (2H, q, J ¼ 7:2 Hz), 6.30 (1H,
d, J ¼ 15:6 Hz), 7.32–7.41 (2H, m), 7.46 (1H, s), 7.73–
7.82 (2H, m), 7.87 (1H, d, J ¼ 15:6 Hz).
5.11. Synthesis of 1-[(E)-3-aryl-2-propen-1-yl]-1H-imid-
azoles (6, 7, 8): General procedure for the synthesis of 19
5.11.6. Ethyl 3-(4-fluorobenzo[b]thiophen-2-yl)-2-pro-
penoate. 80% yield from 18i. Mp 81.5–83 ꢂC (EtOH).
IR (KBr): 1701, 1628, 1568, 1466, 1456, 1264, 1159, 984,
To a suspension of sodium hydride (60% dispersion in
oil, 1.56 g, 39.0 mmol) in THF (100 mL) was added
methyl diethylphosphonoacetate or ethyl diethyl-
phosphonoacetate (39.0 mmol) with ice cooling, and the
mixture was stirred for 1 h. A solution of the aldehyde
18 (commercially available or prepared in Scheme 4,
38.4 mmol) in THF (30 mL) was added, and the mixture
was stirred for 1 h, diluted with water, and extracted
with AcOEt. The extract was dried and concentrated,
and the residue was chromatographed on silica gel using
hexane–AcOEt as an eluent to give 19.
849, 772 cmꢀ1
.
1H NMR (CDCl3) d: 1.35 (3H, t,
J ¼ 7:2 Hz), 4.28 (2H, q, J ¼ 7:2 Hz), 6.31 (1H, d,
J ¼ 15:8 Hz), 7.02 (1H, dd, J ¼ 10:0, 8.0 Hz), 7.34 (1H,
dt, J ¼ 5:2, 8.0 Hz), 7.56 (1H, d, J ¼ 8:0 Hz), 7.56 (1H,
s), 7.86 (1H, d, J ¼ 15:8 Hz). Anal. Calcd for
C13H11FO2S: C, 62.38; H, 4.43. Found: C, 62.45; H, 4.42.
5.11.7. Ethyl 3-(5-fluorobenzo[b]thiophen-2-yl)-2-pro-
penoate. 94% yield from 18ii. Mp 90–91 ꢂC (EtOH). IR
(KBr): 1701, 1636, 1443, 1314, 1177, 957, 806, 517 cmꢀ1
.
1H NMR (CDCl3) d: 1.35 (3H, t, J ¼ 7:0 Hz), 4.28 (2H,
q, J ¼ 7:0 Hz), 6.31 (1H, d, J ¼ 15:8 Hz), 7.14 (1H, dt,
J ¼ 2:6, 8.8 Hz), 7.41 (1H, s), 7.43 (1H, dd, J ¼ 8:8,
2.6 Hz), 7.72 (1H, dd, J ¼ 8:8, 4.8 Hz), 7.85 (1H, d,
J ¼ 15:8 Hz). Anal. Calcd for C13H11FO2S: C, 62.38; H,
4.43. Found: C, 62.52; H, 4.20.
5.11.1. Methyl (E)-3-(2-naphthyl)-2-propenoate. 84%
yield. Mp 80–83 ꢂC (hexane–cyclohexane). IR (KBr):
1
1735, 1436, 1315, 1172, 985 cmꢀ1. H NMR (CDCl3) d:
3.84 (3H, s), 6.56 (1H, d, J ¼ 16:0 Hz), 7.51 (2H, m), 7.67
(1H, dd, J ¼ 8:8, 1.6 Hz), 7.86 (5H, m). Anal. Calcd for
C14H12O2: C, 79.23; H, 5.70. Found: C, 79.11; H, 5.69.
5.11.8. Ethyl 3-(6-fluorobenzo[b]thiophen-2-yl)-2-pro-
penoate. Quantitative yield from 18iii. Mp 87–88 ꢂC
(EtOH). IR (KBr): 1711, 1634, 1267, 1169, 1146,
835 cmꢀ1. 1H NMR (CDCl3) d: 1.35 (3H, t, J ¼ 7:0 Hz),
4.27 (2H, q, J ¼ 7:0 Hz), 6.26 (1H, d, J ¼ 15:8 Hz), 7.11
(1H, dt, J ¼ 2:4, 8.8 Hz), 7.41 (1H, s), 7.48 (1H, dd,
J ¼ 8:8, 2.4 Hz), 7.71 (1H, dd, J ¼ 8:8, 5.2 Hz), 7.84
(1H, d, J ¼ 15:8 Hz). Anal. Calcd for C13H11FO2S: C,
62.38; H, 4.43. Found: C, 62.36; H, 4.42.
5.11.2. Ethyl (E)-3-(3-quinolinyl)-2-propenoate. 44%
yield from quinoline-3-carboxaldehyde. Mp 87–88 ꢂC
(CH2Cl2–cyclohexane). IR (KBr): 1706, 1635, 1185,
751 cmꢀ1. 1H NMR (CDCl3) d: 1.38 (3H, t, J ¼ 7:1 Hz),
4.32 (2H, q, J ¼ 7:1 Hz), 6.68 (1H, d, J ¼ 16:2 Hz), 7.60
(1H, t, J ¼ 7:5 Hz), 7.77 (3H, m), 8.12 (1H, d,
J ¼ 8:4 Hz), 8.25 (1H, d, J ¼ 2:2 Hz), 9.10 (1H, d,
J ¼ 2:2 Hz). Anal. Calcd for C14H13NO2: C, 73.99; H,
5.77; N, 6.16. Found: C, 73.89; H, 5.72; N, 6.16.
5.11.9. Ethyl 3-(7-fluorobenzo[b]thiophen-2-yl)-2-pro-
penoate. Quantitative yield from 18iv. Mp 55.5–56.5 ꢂC
(EtOH). IR (KBr): 1717, 1628, 1470, 1298, 1269, 1169,
5.11.3. Ethyl (E)-3-(2H-chromen-3-yl)-2-propenoate. 73%
yield from 2H-chromene-3-carboxaldehyde. Mp 68–

2262
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
831 cmꢀ1 ; 1H NMR (CDCl3) d: 1.35 (3H, t, J ¼ 7:2 Hz),
4.28 (2H, q, J ¼ 7:2 Hz), 6.34 (1H, d, J ¼ 15:8 Hz), 7.08
(1H, dd, J ¼ 9:6, 8.0 Hz), 7.32 (1H, dt, J ¼ 5:0, 8.0 Hz),
7.48 (1H, d, J ¼ 3:4 Hz), 7.56 (1H, d, J ¼ 8:0 Hz), 7.86
(1H, d, J ¼ 15:8 Hz). Anal. Calcd for C13H11FO2S: C,
62.38; H, 4.43. Found: C, 62.33; H, 4.15.
2908, 1486, 1039 cmꢀ1. 1H NMR (CDCl3) d: 4.28 (2H, t,
J ¼ 5:3 Hz), 4.96 (2H, s), 5.74 (1H, dt, J ¼ 5:7, 16.2 Hz),
6.36 (2H, m), 6.85 (2H, m), 7.01 (1H, dd, J ¼ 1:8,
7.4 Hz), 7.11 (1H, dt, J ¼ 1:8, 7.5 Hz). Anal. Calcd for
C12H12O2: C, 76.57; H, 6.43. Found: C, 76.67; H, 6.47.
5.12.4. (E)-3-(Benzo[b]furan-2-yl)-2-propen-1-ol. 87%
yield. Mp 55–59 ꢂC (AcOEt–hexane). IR (KBr): 3335,
5.11.10. Ethyl 3-(5-chlorobenzo[b]thiophen-2-yl)-2-pro-
penoate. Quantitative yield from 18vi. Mp 100 ꢂC
(EtOH). IR (KBr): 1711, 1630, 1319, 1173, 1152, 957,
795 cmꢀ1; 1H NMR (CDCl3) d: 1.35 (3H, t, J ¼ 7:0 Hz),
4.28 (2H, q, J ¼ 7:0 Hz), 6.31 (1H, d, J ¼ 15:6 Hz), 7.33
(1H, dd, J ¼ 8:6, 2.0 Hz), 7.39 (1H, s), 7.70 (1H, d,
J ¼ 8:6 Hz), 7.74 (1H, d, J ¼ 2:0 Hz), 7.84 (1H, d,
J ¼ 15:6 Hz). Anal. Calcd for C13H11ClO2S: C, 58.54; H,
4.16. Found: C, 58.52; H, 4.10.
1
1678, 1557, 1453, 1254, 955 cmꢀ1. H NMR (CDCl3) d:
4.38 (2H, d, J ¼ 2:2 Hz), 6.59 (3H, m), 7.14–7.32 (2H,
m), 7.40–7.55 (2H, m). Anal. Calcd for C11H10O: C,
75.84; H, 5.79. Found: C, 76.01; H, 5.83.
5.12.5. (E)-3-(Benzo[b]thiophen-2-yl)-2-propen-1-ol. 96%
yield. Mp 116–120 ꢂC (diisopropylether). IR (KBr):
3281, 1088, 1005, 953, 741, 725 cmꢀ1. 1H NMR (CDCl3)
d: 4.35 (2H, dd, J ¼ 5:6, 1.6 Hz), 6.29 (1H, d, J ¼ 15:4,
5.6 Hz), 6.86 (1H, d, J ¼ 15:4 Hz), 7.15 (1H, s), 7.24–
7.35 (2H, m), 7.65–7.78 (2H, m). Anal. Calcd for
C11H10OS: C, 69.44; H, 5.30. Found: C, 69.10; H, 5.18.
5.11.11. Ethyl 3-(5-methoxy-3-methylbenzo[b]thiophen-2-
yl)-2-propenoate. 98% yield from 18viii. Mp 108 ꢂC
(EtOH). IR (KBr): 1709, 1628, 1460, 1308, 1171,
833 cmꢀ1. 1H NMR (CDCl3) d: 1.35 (3H, t, J ¼ 7:0 Hz),
2.49 (3H, s), 3.89 (3H, s), 4.28 (2H, q, J ¼ 7:0 Hz), 6.26
(1H, d, J ¼ 15:6 Hz), 7.04 (1H, dd, J ¼ 8:8, 2.4 Hz), 7.12
(1H, d, J ¼ 2:4 Hz), 7.63 (1H, d, J ¼ 8:8 Hz), 8.03 (1H,
d, J ¼ 15:6 Hz). Anal. Calcd for C15H16O3S: C, 65.19;
H, 5.84. Found: C, 65.15; H, 5.95.
5.12.6. (E)-3-(4-Fluorobenzo[b]thiophen-2-yl)-2-propen-1-
ol. Quantitative yield. Mp 89 ꢂC (AcOEt). IR (KBr):
3235, 1462, 1221, 1013, 963, 766 cmꢀ1
.
1H NMR
(CDCl3) d: 4.36 (2H, d, J ¼ 5:4 Hz), 6.30 (1H, dt,
J ¼ 15:8, 5.4 Hz), 6.86 (1H, d, J ¼ 15:8 Hz), 6.98 (1H,
dd, J ¼ 10:2, 8.0 Hz), 7.23 (1H, dt, J ¼ 5:0, 8.0 Hz), 7.25
(1H, s), 7.52 (1H, d, J ¼ 8:0 Hz). Anal. Calcd for
C11H9FOS: C, 63.44; H, 4.36. Found: C, 63.72; H, 4.53.
5.12. General procedure for the synthesis of 20
To a solution of 19 (11.2 mmol) in THF (50 mL) was
added diisobutylaluminum hydride (DIBAL, 1.5 M
solution in toluene, 18.0 mL, 27.0 mmol) at )78 ꢂC. The
reaction mixture was stirred for 2 h, cautiously quenched
by the addition of water, diluted with 1 N HCl, and al-
lowed to warm to room temperature. The mixture was
extracted with AcOEt, and the extract was washed with
aqueous NaHCO3, dried and concentrated to give 20.
5.12.7. (E)-3-(5-Fluorobenzo[b]thiophen-2-yl)-2-propen-1-
ol. 98% yield. IR (KBr): 3285, 1443, 1177, 955, 868 cmꢀ1
.
1H NMR (CDCl3) d: 4.35 (1H, d, J ¼ 5:4 Hz), 6.30 (1H,
dt, J ¼ 15:8, 5.4 Hz), 6.85 (1H, d, J ¼ 15:8 Hz), 7.05
(1H, dt, J ¼ 2:6, 8.8 Hz), 7.10 (1H, s), 7.34 (1H, dd,
J ¼ 9:2, 2.6 Hz), 7.67 (1H, dd, J ¼ 8:8, 4.8 Hz). Anal.
Calcd for C11H9FOS: C, 63.44; H, 4.36. Found: C,
63.43; H, 4.26.
5.12.1. (E)-3-(2-Naphthyl)-2-propen-1-ol. 86% yield. Mp
112–114 ꢂC (CH2Cl2–cyclohexane). IR (KBr): 3267,
1089, 965 cmꢀ1. 1H NMR (CDCl3) d: 4.38 (2H, br), 6.48
(1H, dt, J ¼ 5:6, 16.0 Hz), 6.78 (1H, d, J ¼ 16:0 Hz),
7.45 (2H, m), 7.60 (1H, dd, J ¼ 8:8, 1.8 Hz), 7.79 (4H,
m). Anal. Calcd for C13H12O: C, 83.93; H, 6.45. Found:
C, 83.99; H, 6.45.
5.12.8. (E)-3-(6-Fluorobenzo[b]thiophen-2-yl)-2-propen-1-ol.
Quantitative yield. Mp 135–137 ꢂC (diisopropylether).
IR (KBr): 3299, 1566, 1468, 1254, 1086, 951, 856,
588 cmꢀ1. 1H NMR (CDCl3) d: 4.35 (2H, d, J ¼ 5:6 Hz),
6.24 (1H, dt, J ¼ 15:8, 5.6 Hz), 6.84 (1H, d,
J ¼ 15:8 Hz), 7.06 (1H, dt, J ¼ 2:2, 8.8 Hz), 7.10 (1H, s),
7.44 (1H, dd, J ¼ 8:8, 2.2 Hz), 7.61 (1H, dd, J ¼ 8:8,
5.2 Hz). Anal. Calcd for C11H9FOS: C, 63.44; H, 4.36.
Found: C, 63.36; H, 4.23.
5.12.2. (E)-3-(3-Quinolinyl)-2-propen-1-ol. 55% yield.
Mp 102–103 ꢂC (AcOEt–CH2Cl2). IR (KBr): 3232, 1498,
1
1340, 1100, 782 cmꢀ1. H NMR (CDCl3) d: 3.03 (1H,
br), 4.40 (2H, d, J ¼ 4:6 Hz), 6.75 (1H, dt, J ¼ 5:0,
16.1 Hz), 6.76 (1H, d, J ¼ 16:1 Hz), 7.52 (1H, t,
J ¼ 7:3 Hz), 7.66 (1H, m), 7.76 (1H, d, J ¼ 8:0 Hz), 8.00
(1H, d, J ¼ 1:8 Hz), 8.07 (1H, d, J ¼ 8:4 Hz), 8.96 (1H,
d, J ¼ 2:2 Hz). Anal. Calcd for C12H11NO: C, 77.81; H,
5.99; N, 7.56. Found: C, 77.58; H, 5.91; N, 7.48.
5.12.9. (E)-3-(7-Fluorobenzo[b]thiophen-2-yl)-2-propen-1-ol.
Quantitative yield. Mp 81.5–83 ꢂC (AcOEt). IR (KBr)
3299, 1466, 1086, 953, 781, 710 cmꢀ1. 1H NMR (CDCl3)
d: 4.37 (2H, d, J ¼ 5:4 Hz), 6.33 (1H, dt, J ¼ 15:8,
5.4 Hz), 6.87 (1H, d, J ¼ 15:8 Hz), 6.99 (1H, dd, J ¼ 9:8,
8.0 Hz), 7.17 (1H, d, J ¼ 3:6 Hz), 7.27 (1H, dt, J ¼ 5:2,
8.0 Hz), 7.47 (1H, d, J ¼ 8:0 Hz). Anal. Calcd for
C11H9FOS: C, 63.44; H, 4.36. Found: C, 63.57; H, 4.42.
5.12.3. (E)-3-(2H-Chromen-3-yl)-2-propen-1-ol. 91%
yield. Mp 96–98 ꢂC (AcOEt–hexane). IR (KBr): 3240,

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2263
5.12.10. (E)-3-(5-Chlorobenzo[b]thiophen-2-yl)-2-propen-
1-ol. 83% yield, mp 148–150 ꢂC (AcOEt). IR (KBr):
Anal. Calcd for C15H13N3: C, 76.57; H, 5.57; N, 17.86.
Found: C, 76.40; H, 5.54; N, 17.78.
1
3293, 1078, 1009, 806 cmꢀ1. H NMR (CDCl3) d: 4.33–
4.38 (2H, br m), 6.30 (1H, dt, J ¼ 15:6, 5.4 Hz), 6.85
(1H, d, J ¼ 15:6 Hz), 7.08 (1H, s), 7.25 (1H, dd, J ¼ 8:6,
2.2 Hz), 7.65 (1H, d, J ¼ 8:6 Hz), 7.65 (1H, d,
J ¼ 2:2 Hz). Anal. Calcd for C11H9ClOS: C, 58.80; H,
4.04. Found: C, 58.69; H, 4.13.
5.13.5. 1-[(E)-3-(2H-Chromen-3-yl)-2-propen-1-yl]-1H-
imidazole (7b). 20% yield. Mp 115–117 ꢂC (CH2Cl2–
AcOEt–hexane). IR (KBr): 3107, 1506, 1486, 1045 cmꢀ1
.
1H NMR (CDCl3) d: 4.28 (2H, t, J ¼ 5:3 Hz), 4.96 (2H,
s), 5.74 (1H, dt, J ¼ 5:7, 16.2 Hz), 6.36 (2H, m), 6.85
(2H, m), 7.01 (1H, dd, J ¼ 7:4, 1.8 Hz), 7.11 (1H, dt,
J ¼ 1:8, 7.5 Hz). Anal. Calcd for C15H14N2O: C, 75.61;
H, 5.92; N, 11.76. Found: C, 75.49; H, 5.79; N, 11.69.
5.12.11. (E)-3-(5-Methoxy-3-methylbenzo[b]thiophen-2-yl)-
2-propen-1-ol. Quantitative yield. Mp 80 ꢂC (diisopror-
ylether). IR (KBr): 3376, 1597, 1458, 1229, 949,
837 cmꢀ1. 1H NMR (CDCl3) d: 1.26 (1H, s), 2.37 (3H, s),
3.88 (3H, s), 4.36 (1H, dd, J ¼ 5:6, 1.4 Hz), 6.25 (1H, dt,
J ¼ 15:6, 5.6 Hz), 6.92–7.02 (2H, m), 7.07 (1H, d,
J ¼ 2:4 Hz), 7.60 (1H, d, J ¼ 8:8 Hz). Anal. Calcd for
C13H14O2S: C, 66.64; H, 6.02. Found: C, 66.52; H, 6.09.
5.13.6. 1-[(E)-3-(Benzo[b]furan-2-yl)-2-propen-1-yl]-1H-
imidazole (7c). 14% yield as the fumarate. Mp 121–
124 ꢂC (MeOH). IR (KBr): 3086, 1698, 1451, 1254, 1184,
754 cmꢀ1. 1H NMR (CDCl3) d: 4.86 (2H, d, J ¼ 4:4 Hz),
6.51 (2H, m), 6.63 (2H, s), 6.90 (1H, s), 6.99 (1H, m),
7.16–7.36 (3H, m), 7.46–7.64 (2H, m), 7.77 (1H, s). Anal.
Calcd for C18H16N2O5Æ0.1H2O: C, 63.19; H, 4.77; N,
8.19. Found: C, 63.13; H, 4.67; N, 8.31.
5.13. General procedure for the synthesis of 6, 7, and 8
5.13.1. For 6, 7d, 8a–d, 8f and 8h. To a solution of 20
(9.6 mmol) in CH2Cl2 (50 mL) was added thionyl chlo-
ride (2.1 mL, 28.8 mmol). The mixture was refluxed for
2 h and concentrated, and the residue was heated at
100 ꢂC for 2 h with imidazole (1.10 g, 16.2 mmol) in
DMF (20 mL). The mixture was diluted with water and
extracted with AcOEt, and the extract was washed with
water, dried, and concentrated. The residue was chro-
matographed on silica gel using CH2Cl2–MeOH (9:1) as
an eluent to give 6, 7d, 8a–d, 8f and 8h.
5.13.7. 1-[(E)-3-(Benzo[b]thiophen-2-yl)-2-propen-1-yl]-
1H-imidazole (7d). 60% yield. Mp 130–132 ꢂC (AcOEt).
IR (KBr): 1503, 1433, 1223, 1074, 953, 758, 665 cmꢀ1
.
1H NMR (CDCl3) d: 4.74 (2H, d, J ¼ 6:0 Hz), 6.20 (1H,
dt, J ¼ 15:4, 6.0 Hz), 6.68 (1H, d, J ¼ 15:4 Hz), 6.98
(1H, s), 7.13 (1H, s), 7.16 (1H, s), 7.29–7.36 (2H, m),
7.56 (1H, s), 7.67–7.78 (2H, m). Anal. Calcd for
C14H12N2S: C, 69.97; H, 5.03; N, 11.66. Found: C,
69.88; H, 4.83; N, 11.80.
5.13.2. For 7a, 7b and 7c. To a mixture of 20 (6.5 mmol)
and triethylamine (1.81 mL, 13.0 mmol) in CH2Cl2
(20 mL) was added methanesulfonyl chloride (0.77 mL,
10.0 mmol). The mixture was stirred at room tempera-
ture for 6 h, washed with water, dried and concentrated,
and the residue was heated at 100 ꢂC with imidazole
(0.89 g, 13.0 mmol) in DMF (10 mL) for 4 h. The mix-
ture was diluted with AcOEt, and the solution was
washed with water, dried and concentrated. The residue
was chromatographed on silica gel using CH2Cl2–
MeOH (9:1) as an eluent to give 7a, 7b, and 7c.
5.13.8.
1-[(E)-3-(4-Fluorobenzo[b]thiophen-2-yl)-2-pro-
pen-1-yl]-1H-imidazole (8a). 75% yield. Mp 116–117 ꢂC
(AcOEt). IR (KBr): 1566, 1503, 1468, 1426, 1242, 1209,
1074, 949, 916, 802, 764, 660 cmꢀ1. 1H NMR (CDCl3) d:
4.75 (2H, d, J ¼ 5:8 Hz), 6.22 (1H, dt, J ¼ 15:8, 5.8 Hz),
6.69 (1H, d, J ¼ 15:8 Hz), 6.95–7.04 (2H, m), 7.13 (1H,
s), 7.22–7.32 (2H, m), 7.53 (1H, d, J ¼ 8:0 Hz), 7.57 (1H,
s). Anal. Calcd for C14H11FN2S: C, 65.09; H, 4.29; N,
10.84. Found: C, 65.06; H, 4.25; N, 10.85.
5.13.9.
1-[(E)-3-(5-Fluorobenzo[b]thiophen-2-yl)-2-pro-
pen-1-yl]-1H-imidazole (8b). 75% yield. Mp 123 ꢂC
(AcOEt). IR (KBr): 3102, 1508, 1441, 1175, 963, 872,
5.13.3. 1-[(E)-3-(2-Naphthyl)-2-propen-1-yl]-1H-imidaz-
ole (6). 50% yield. Mp 112–113 ꢂC (CH2Cl2–hexane).
IR (KBr): 1506, 1226, 977, 825 cmꢀ1. 1H NMR (CDCl3)
d: 4.76 (2H, d, J ¼ 6:2 Hz), 6.40 (1H, dt, J ¼ 15:7,
6.2 Hz), 6.68 (1H, d, J ¼ 15:7 Hz), 7.00 (1H, s), 7.49 (4H,
m), 7.78 (4H, m). Anal. Calcd for C16H14N2: C, 82.02; H,
6.02; N, 11.96. Found: C, 81.77; H, 5.82; N, 11.73.
804, 748 cmꢀ1 1H NMR (CDCl3) d: 4.74 (2H, dd,
.
J ¼ 5:8, 1.4 Hz), 6.22 (1H, dt, J ¼ 15:8, 5.8 Hz), 6.65
(1H, dd, J ¼ 15:8, 1.4 Hz), 6.98 (1H, s), 7.07 (1H, dt,
J ¼ 2:4, 8.8 Hz), 7.11 (1H, s), 7.35 (1H, dd, J ¼ 9:4,
2.4 Hz), 7.55 (1H, s), 7.67 (1H, dd, J ¼ 8:8, 5.2 Hz), 7.13
(1H, s). Anal. Calcd for C14H11FN2S: C, 65.09; H, 4.29;
N, 10.84. Found: C, 64.98; H, 4.47; N, 10.81.
5.13.4. 1-[(E)-3-(3-Quinolinyl)-2-propen-1-yl]-1H-imidaz-
ole (7a). 15% yield. Mp 146–148 ꢂC (AcOEt). IR (KBr):
5.13.10. 1-[(E)-3-(6-Fluorobenzo[b]thiophen-2-yl)-2-pro-
pen-1-yl]-1H-imidazole (8c). 64% yield. Mp 108–109 ꢂC
(AcOEt). IR (KBr): 1505, 1466, 1250, 1221, 1073, 955,
3105, 1506, 1494, 1425, 1226, 807 cmꢀ1
.
1H NMR
(CDCl3) d: 4.80 (2H, d, J ¼ 4:8 Hz), 6.50 (1H, m), 6.63
(1H, d, J ¼ 16:2 Hz), 7.01 (1H, s), 7.15 (1H, s), 7.55 (2H,
m), 7.74 (2H, m), 8.05 (2H, m), 8.97 (1H, d, J ¼ 2:2 Hz).
1
855, 820, 752, 665 cmꢀ1. H NMR (CDCl3) d: 4.74 (2H,
d, J ¼ 6:0 Hz), 6.16 (1H, dt, J ¼ 15:8, 6.0 Hz), 6.64 (1H,

2264
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
d, J ¼ 15:8 Hz), 6.98 (1H, s), 7.02–7.13 (3H, m), 7.44
(1H, dd, J ¼ 8:8, 2.2 Hz), 7.56 (1H, s), 7.63 (1H, dd,
J ¼ 8:8, 5.2 Hz). Anal. Calcd for C14H11FN2S: C, 65.09;
H, 4.29; N, 10.84. Found: C, 65.22; H, 4.33; N, 10.86.
chloroacetone (21.1 mL, 265.0 mmol) in DMF (250 mL)
was added potassium carbonate (71.87 g, 520 mmol)
with ice cooling. The mixture was stirred for 2 h, diluted
with AcOEt, and washed with water. The organic
solution was dried and concentrated, and the residue
was heated with polyphosphoric acid (145 g) in toluene
(400 mL) at 100 ꢂC for 12 h. The mixture was concen-
trated, carefully neutralized with aqueous potassium
carbonate with ice cooling, and extracted with AcOEt.
The extract was dried and concentrated, and the residue
was purified by distillation (73–74 ꢂC/0.4 mmHg) to give
22v (28.71 g, 66%) as a colorless oil. IR (neat): 1603,
5.13.11. 1-[(E)-3-(7-Fluorobenzo[b]thiophen-2-yl)-2-prop-
en-1-yl]-1H-imidazole (8d). 68% yield. Mp 125 ꢂC
(AcOEt). IR (KBr): 1526, 1464, 1426, 1416, 1231, 1078,
947, 843, 812, 789, 756, 714, 660 cmꢀ1
.
1H NMR
(CDCl3) d: 4.76 (2H, d, J ¼ 5:8 Hz), 6.27 (1H, dt,
J ¼ 15:6, 5.8 Hz), 6.65 (1H, d, J ¼ 15:6 Hz), 6.98–7.07
(2H, m), 7.14 (1H, s), 7.18 (1H, d, J ¼ 3:6 Hz), 7.29 (1H,
dt, J ¼ 5:0, 8.0 Hz), 7.49 (1H, d, J ¼ 8:0 Hz), 7.60 (1H,
s). Anal. Calcd for C14H11FN2S: C, 65.09; H, 4.29; N,
10.84. Found: C, 65.09; H, 4.33; N, 10.93.
1
1445, 1250, 1204 cmꢀ1. H NMR (CDCl3) d: 2.41 (3H,
s), 7.10 (1H, dt, J ¼ 2:2, 8.8 Hz), 7.15 (1H, s), 7.37 (1H,
dd, J ¼ 9:6, 2.2 Hz), 7.76 (1H, dd, J ¼ 8:8, 4.8 Hz).
Compounds described below were prepared similarly
from the corresponding thiophenol with chloroacetone,
bromoacetaldehyde diethylacetal, or 1-chloro-3,3-di-
methyl-2-butanone.
5.13.12. 1-[(E)-3-(5-Chlorobenzo[b]thiophen-2-yl)-2-prop-
en-1-yl]-1H-imidazole (8f). 74% yield. Mp 150 ꢂC
(AcOEt). IR (KBr): 3090, 1431, 1074, 949, 866, 843, 812,
756 cmꢀ1. 1H NMR (CDCl3) d: 4.74 (2H, d, J ¼ 5:8 Hz),
6.23 (1H, dt, J ¼ 15:8, 5.8 Hz), 6.65 (1H, d,
J ¼ 15:8 Hz), 6.98 (1H, s), 7.09 (1H, s), 7.13 (1H, s), 7.27
(1H, dd, J ¼ 8:8, 2.0 Hz), 7.56 (1H, s), 7.66 (1H, d,
J ¼ 8:8 Hz), 7.67 (1H, d, J ¼ 2:0 Hz). Anal. Calcd for
C14H11ClN2S: C, 61.20; H, 4.04; N, 10.20. Found: C,
61.33; H, 4.02; N, 10.10.
5.14.2. 5-Chlorobenzo[b]thiophene (22vi). Yield 29%. A
colorless crystals. H NMR (CDCl3) d: 7.26–7.33 (2H,
1
m), 7.50 (1H, d, J ¼ 5:6 Hz), 7.77–7.81 (2H, m).
5.14.3. 5-Chloro-3-methylbenzo[b]thiophene (22vii). Yield
80%. A colorless oil. IR (neat): 1076, 831 cmꢀ1 1H
.
NMR (CDCl3) d: 2.41 (3H, s), 7.13 (1H, s), 7.31 (1H, dd,
J ¼ 8:4, 2.0 Hz), 7.69 (1H, d, J ¼ 2:0 Hz), 7.75 (1H, d,
J ¼ 8:4 Hz).
5.13.13. 1-[(E)-3-(5-Methoxy-3-methylbenzo[b]thiophen-
2-yl)-2-propen-1-yl]-1H-imidazole (8h). 31% yield. Mp
133–135 ꢂC (AcOEt). IR (KBr): 1595, 1458, 1427, 1227,
1
1202, 833, 665 cmꢀ1. H NMR (CDCl3) d: 2.34 (3H, s),
3.88 (3H, s), 4.75 (2H, dd, J ¼ 6:0, 1.4 Hz), 6.16 (1H, dt,
J ¼ 15:6, 6.0 Hz), 6.81 (1H, dt, J ¼ 15:6, 1.4 Hz), 6.98
(1H, dd, J ¼ 8:8, 2.6 Hz), 6.99 (1H, s), 7.07 (1H, d,
J ¼ 2:6 Hz), 7.12 (1H, s), 7.57 (1H, s), 7.60 (1H, d,
J ¼ 8:8 Hz). Anal. Calcd for C16H16N2OS: C, 67.58; H,
5.67; N, 9.85. Found: C, 67.51; H, 5.68; N, 9.87.
5.14.4. 5-Methoxy-3-methylbenzo[b]thiophene (22viii).
Yield 24%. A colorless oil. IR (neat): 1599, 1456, 1262,
1227 cmꢀ1
.
1H NMR (CDCl3) d: 2.41 (3H, d,
J ¼ 1:2 Hz), 3.90 (3H, s), 7.01 (1H, dd, J ¼ 8:8, 2.4 Hz),
7.09 (1H, d, J ¼ 1:2 Hz), 7.15 (1H, d, J ¼ 2:4 Hz), 7.71
(1H, d, J ¼ 8:8 Hz).
5.13.14.
1-[3-(2-Naphthyl)propan-1-yl]-1H-imidazole
5.14.5. 5-Fluoro-3-tert-butylbenzo[b]thiophene (22ix).
Yield 25%. A colorless oil. IR (neat): 2965, 1443, 1227,
fumarate (45). A mixture of 6 (0.73 g, 3.1 mmol) and
10% Pd–C (0.30 g) in ethanol (15 mL) was stirred at room
temperature for 16 h under a hydrogen atmosphere. The
catalyst was filtered off, and the filtrate was concentrated
to give an oil, which was treated with fumaric acid
(0.30 g) in AcOEt–MeOH to give 45 as colorless crystals
(0.75 g, 68%). Mp 130–132 ꢂC (AcOEt). IR (KBr): 3139,
1
1127 cmꢀ1. H NMR (CDCl3) d: 1.44 (9H, s), 6.98 (1H,
s), 7.00 (1H, dt, J ¼ 2:6, 8.8 Hz), 7.32 (1H, dd, J ¼ 9:4,
2.6 Hz), 7.67 (1H, dd, J ¼ 8:8, 5.2 Hz).
5.14.6. 5,7-Difluoro-3-methylbenzo[b]thiophene (22x).
Yield 33%. Crystals. IR (KBr): 1624, 1576, 1418, 1111,
1694, 1287, 1269 cmꢀ1. H NMR (CDCl3) d: 2.14 (2H,
1
1
m), 2.71 (2H, t, J ¼ 7:5 Hz), 4.03 (2H, t, J ¼ 7:1 Hz),
6.63 (2H, s), 6.95 (1H, s), 7.25 (1H, s), 7.34–7.54 (3H, m),
7.66–7.77 (2H, m), 7.80–7.92 (2H, m), 8.31 (1H, s). Anal.
Calcd for C20H20N2-O4Æ0.1H2O: C, 67.82; H, 5.75; N,
7.91. Found: C, 67.71; H, 5.58; N, 7.95.
984, 839 cmꢀ1. H NMR (CDCl3) d: 2.40 (3H, s), 6.88
(1H, dt, J ¼ 2:2, 9.2 Hz), 7.18 (1H, s), 7.21 (1H, dd,
J ¼ 9:2, 2.2 Hz).
5.15. From 2-fluorobenzaldehydes: Synthesis of 24
5.14. General procedures for the synthesis of benzo[b]thio-
phenes (22): From thiophenols
5.15.1. Ethyl 5-fluorobenzo[b]thiophene-2-carboxylate
(24ii). To a mixture of 2,5-difluorobenzaldehyde
(23.81 g, 167.5 mmol) and potassium carbonate (30.16 g,
218.2 mmol) in DMF (250 mL) was added ethyl thio-
glycolate (18.4 mL, 167.5 mmol) dropwise with ice
5.14.1. 5-Fluoro-3-methylbenzo[b]thiophene (22v). To a
mixture of 4-fluorothiophenol (33.50 g, 261.4 mmol) and

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2265
cooling. The mixture was stirred at room temperature
for 14 h and at 60 ꢂC for 6 h, poured into water, and
extracted with AcOEt. The extract was washed with
water, dried, and concentrated, and the residue was
suspended in EtOH and collected by filtration to give
24ii as crystals (20.10 g, 53%). Mp 90–91 ꢂC (EtOH). IR
(120 mL) was added n-BuLi (1.59 M solution in hexane,
28.0 mL, 44.5 mmol) at )78 ꢂC, and the mixture was
stirred for 1 h. DMF (6.20 mL, 80.1 mmol) was added,
and the mixture was stirred for an additional 1 h,
quenched by the addition of aqueous NH4Cl, and
allowed to warm to room temperature. After the sepa-
ration of the layers, the aqueous layer was further
extracted with AcOEt. The organic layers were com-
bined, dried, and concentrated to give 18ii as colorless
crystals (6.77 g, 99%). Mp 122 ꢂC (EtOH). IR (KBr):
1
(KBr): 1715, 1530, 1260, 1206, 889, 808, 750 cmꢀ1. H
NMR (CDCl3) d: 1.42 (3H, t, J ¼ 7:2 Hz), 4.42 (2H, q,
J ¼ 7:2 Hz), 7.23 (1H, dt, J ¼ 2:6, 9.0 Hz), 7.54 (1H, dd,
J ¼ 9:0, 2.6 Hz), 7.81 (1H, dd, J ¼ 9:0, 4.8 Hz), 8.01
(1H, s). Anal. Calcd for C11H9FO2S: C, 58.91; H, 4.05.
Found: C, 58.93; H, 3.86.
1
1671, 1522, 1169, 660 cmꢀ1. H NMR (CDCl3) d: 7.29
(1H, dt, J ¼ 2:4, 8.8 Hz), 7.61 (1H, dd, J ¼ 8:8, 2.4 Hz),
7.86 (1H, dd, J ¼ 8:8, 4.6 Hz), 7.99 (1H, s), 10.11 (1H,
s). Anal. Calcd for C9H5FOS: C, 59.99; H, 2.80. Found:
C, 60.14; H, 2.82.
5.16. Synthesis of 22
5.16.1. 5-Fluorobenzo[b]thiophene (22ii). A mixture of
24ii (18.90 g, 84.3 mmol), potassium hydroxide (25.81 g,
460 mmol), water (200 mL), and EtOH (200 mL) was
heated at reflux for 1.5 h. The mixture was concentrated,
acidified with 2 N HCl, and extracted with AcOEt–THF,
and the extract was dried and concentrated to give 5-
fluorobenzo[b]thiophene-2-carboxylic acid as colorless
crystals (16.43 g, 99%).A mixture of this carboxylic acid
(16.10 g, 82.1 mmol), powdered copper (1.70 g), and
quinoline (75 mL) was heated at 185 ꢂC for 2 h. The
reaction mixture was cooled and diluted with AcOEt
and 2 N HCl. After the insoluble material was filtered
off, the organic layer was separated, dried, and con-
centrated. The residue was chromatographed on silica
gel using hexane as an eluent to give 22ii (11.47 g, 92 %)
5.17.2. 4-Fluorobenzo[b]thiophen-2-carboxaldehyde (18i).
Quantitative yield. Mp 73 ꢂC (EtOH). IR (KBr): 1671,
1559, 1470, 1223, 1179, 1132, 779 cmꢀ1
.
1H NMR
(CDCl3) d: 7.10 (1H, dd, J ¼ 9:8, 8.0 Hz), 7.48 (1H, dt,
J ¼ 5:0, 8.0 Hz), 7.68 (1H, d, J ¼ 8:0 Hz), 8.15 (1H, s),
10.12 (1H, s). Anal. Calcd for C9H5FOS: C, 59.99; H,
2.80. Found: C, 59.85; H, 2.87.
5.17.3. 6-Fluorobenzo[b]thiophen-2-carboxaldehyde (18iii).
Yield 53%. Mp 106 ꢂC (diisopropylether). IR (KBr):
1
1667, 1601, 1518, 1258, 1190, 1130, 858, 660 cmꢀ1. H
NMR (CDCl3) d: 7.21 (1H, dt, J ¼ 2:4, 8.8 Hz), 7.59
(1H, dd, J ¼ 8:8, 2.4 Hz), 7.92 (1H, dd, J ¼ 8:8, 5.0 Hz),
8.01 (1H, s), 10.08 (1H, s). Anal. Calcd for C9H5FOS: C,
59.99; H, 2.80. Found: C, 60.07; H, 2.78.
1
as a colorless oil. IR (neat): 1424, 1248, 1127 cmꢀ1. H
NMR (CDCl3) d: 7.11 (1H, dt, J ¼ 2:6, 8.8 Hz), 7.29
(1H, d, J ¼ 5:4 Hz), 7.49 (1H, dd, J ¼ 9:6, 2.6 Hz), 7.53
(1H, d, J ¼ 5:4 Hz), 7.80 (1H, dd, J ¼ 8:8, 4.8 Hz).
5.17.4. 7-Fluorobenzo[b]thiophen-2-carboxaldehyde (18iv).
Quantitative yield. Mp 79–81.5 ꢂC (EtOH). IR (KBr):
5.16.2. 4-Fluorobenzo[b]thiophene (22i). 66% yield from
the 2,6-difluorobenzaldehyde. A colorless oil. IR (neat):
1
1661, 1468, 1248, 1140, 775, 708, 660 cmꢀ1. H NMR
1
1564, 1456, 1420, 1337, 1242, 918, 745, 689 cmꢀ1. H
(CDCl3) d: 7.22 (1H, dd, J ¼ 9:6, 8.0 Hz), 7.42 (1H, dt,
J ¼ 4:8, 8.0 Hz), 7.76 (1H, d, J ¼ 8:0 Hz), 8.06 (1H, d,
J ¼ 3:4 Hz), 10.13 (1H, s). Anal. Calcd for C9H5FOS: C,
59.99; H, 2.80. Found: C, 59.83; H, 2.86.
NMR (CDCl3) d: 7.03 (1H, ddd, J ¼ 10:2, 8.0, 0.8 Hz),
7.24–7.35 (1H, dt, J ¼ 5:0, 8.0 Hz), 7.45 (2H, s), 7.65
(1H, d, J ¼ 8:0 Hz).
5.16.3. 6-Fluorobenzo[b]thiophene (22iii). 20% yield from
2,4-difluorobenzaldehyde. A colorless oil. IR (neat):
5.17.5. 5-Fluoro-3-methylbenzo[b]thiophene-2-carboxal-
dehyde (18v). Yield 90%. Mp 150–152 ꢂC (EtOH). IR
1470, 912 cmꢀ1 1H NMR (CDCl3) d: 7.12 (1H, dt,
.
1
(KBr): 1653, 1534, 1445, 1169, 853, 662 cmꢀ1. H NMR
J ¼ 2:6, 8.8 Hz), 7.30 (1H, d, J ¼ 5:4 Hz), 7.39 (1H, d,
J ¼ 5:4 Hz), 7.56 (1H, dd, J ¼ 8:4, 2.6 Hz), 7.75 (1H, dd,
J ¼ 8:8, 5.2 Hz).
(CDCl3) d: 2.76 (3H, s), 7.28 (1H, dt, J ¼ 2:6, 8.8 Hz),
7.54 (1H, dd, J ¼ 9:6, 2.6 Hz), 7.82 (1H, dd, J ¼ 8:8,
4.8 Hz), 10.33 (1H, s). Anal. Calcd for C10H7FOS: C,
61.84; H, 3.63. Found: C, 61.94; H, 3.54.
5.16.4. 7-Fluorobenzo[b]thiophene (22iv). 83% yield from
2,3-difluorobenzaldehyde. A colorless oil. IR (neat):
1
1559, 1507, 1458, 1399, 1247, 1011, 787, 689 cmꢀ1. H
5.17.6. 5-Chlorobenzo[b]thiophene-2-carboxaldehyde (18vi).
Yield 83%, mp 135 ꢂC (EtOH). IR (KBr): 1678, 1516,
NMR (CDCl3) d: 7.04 (1H, dd, J ¼ 9:6, 8.0 Hz), 7.28–
7.39 (2H, m), 7.48 (1H, d, J ¼ 5:4 Hz), 7.62 (1H, d,
J ¼ 8:0 Hz).
1
1140 cmꢀ1. H NMR (CDCl3) d: 7.48 (1H, dd, J ¼ 8:8,
2.0 Hz), 7.84 (1H, d, J ¼ 8:8 Hz), 7.94 (1H, d,
J ¼ 2:0 Hz), 7.97 (1H, s), 10.12 (1H, s). Anal. Calcd for
C9H5ClOS: C, 54.97; H, 2.56. Found: C, 54.89; H, 2.52.
5.17. General procedure for the synthesis of 18
5.17.1. 5-Fluorobenzo[b]thiophene-2-carboxaldehyde (18ii).
To a solution of 22ii (5.80 g, 38.1 mmol) in THF
5.17.7.
5-Chloro-3-methylbenzo[b]thiophene-2-carbox-
aldehyde (18vii). Yield 65%. Mp 176–179 ꢂC (AcOEt).

2266
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
1
IR (KBr): 1655, 1202, 1078, 870, 806 cmꢀ1. H NMR
(CDCl3) d: 2.77 (3H, s), 7.47 (1H, dd, J ¼ 8:6, 2.0 Hz),
7.80 (1H, d, J ¼ 8:6 Hz), 7.87 (1H, d, J ¼ 2:0 Hz), 10.33
(1H, s). Anal. Calcd for C10H7ClOS: C, 57.01; H, 3.35.
Found: C, 57.14; H, 3.28.
J ¼ 6:4 Hz), 4.44 (2H, t, J ¼ 6:4 Hz), 7.00 (1H, s), 7.05
(1H, s), 7.28 (1H, dt, J ¼ 2:2, 8.8 Hz), 7.52 (1H, dd,
J ¼ 9:4, 2.2 Hz), 7.58 (1H, s), 7.78 (1H, dd, J ¼ 8:8,
4.8 Hz). Anal. Calcd for C15H13FN2OS: C, 62.48; H,
4.54; N, 9.72. Found: C, 62.47; H, 4.63; N, 9.74.
5.17.8. 5-Methoxy-3-methylbenzo[b]thiophene-2-carbox-
aldehyde (18iii). Yield 60%. Mp 146 ꢂC (EtOH). IR
5.19.2. 1-(5-Chloro-3-methylbenzo[b]thiophen-2-yl)-3-(1H-
imidazol-1-yl)propan-1-one. 73% yield. Mp 106 ꢂC
(AcOEt). IR (KBr): 1671, 1508, 1356, 1285, 1225, 1194,
1094, 1078, 804 cmꢀ1. 1H NMR (CDCl3) d: 2.73 (3H, s),
3.39 (2H, t, J ¼ 6:4 Hz), 4.44 (2H, t, J ¼ 6:4 Hz), 6.99
(1H, s), 7.05 (1H, s), 7.47 (1H, dd, J ¼ 8:8, 1.8 Hz), 7.58
(1H, s), 7.76 (1H, d, J ¼ 8:8 Hz), 7.85 (1H, d,
J ¼ 1:8 Hz). Anal. Calcd for C15H13ClN2OS: C, 59.11;
H, 4.30; N, 9.19. Found: C, 59.13; H, 4.24; N, 9.24.
(KBr): 1653, 1460, 1198, 829, 667 cmꢀ1 1H NMR
.
(CDCl3) d: 2.76 (3H, s), 3.91 (3H, s), 7.17 (1H, dd,
J ¼ 8:8, 2.6 Hz), 7.25 (1H, d, J ¼ 2:6 Hz), 7.73 (1H, d,
J ¼ 8:8 Hz). Anal. Calcd for C11H10O2S: C, 64.05; H,
4.89. Found: C, 63.95; H, 4.96.
5.18. Preparation of 25
5.18.1. 3-Chloro-1-(5-fluoro-3-methylbenzo[b]thiophen-2-
yl)propan-1-one. To a mixture of 22v (9.97 g, 60.0 mmol)
and 3-chloropropionyl chloride (7.45 mL, 78.0 mmol) in
carbon disulfide (100 mL) was added AlCl3 (16.00 g,
120.0 mmol) with ice cooling. The mixture was stirred at
room temperature for 2 h, poured onto crushed ice,
diluted with 1 N HCl, and extracted with AcOEt. The
extract was washed with water and aqueous NaHCO3,
dried, and concentrated, and the residue was suspended
in EtOH and collected by filtration to give the title
compound as colorless crystals (12.75 g, 83%). Mp 110–
112 ꢂC (EtOH). IR (KBr): 1649, 1518, 1368, 1289, 1179,
5.20. Preparation of 27
5.20.1. 1-(5-Fluoro-3-methylbenzo[b]thiophen-2-yl)-3-(1H-
imidazol-1-yl)propan-1-ol. To a solution of 1-(5-fluoro-3-
methylbenzo[b]thiophen-2-yl)-3-(1H-imidazol-1-yl)pro-
pan-1-one (9.00 g, 31.2 mmol) in THF–MeOH (1:1,
120 mL) was added NaBH4 (1.18 g, 31.2 mmol) with ice
cooling. The mixture was stirred for 0.5 h, concentrated,
diluted with water, and extracted with AcOEt. The
extract was dried and concentrated to give the title
compound as colorless crystals (8.92 g, 98%). mp 100–
102 ꢂC (AcOEt). IR (KBr): 3144, 1445, 1179, 1078, 922,
1
1
1152, 876, 820 cmꢀ1. H NMR (CDCl3) d: 2.74 (3H, s),
745, 656 cmꢀ1. H NMR (CDCl3) d: 2.00–2.42 (2H, m),
3.42 (2H, t, J ¼ 6:6 Hz), 3.93 (2H, t, J ¼ 6:6 Hz), 7.28
(1H, dt, J ¼ 2:2, 8.8 Hz), 7.53 (1H, dd, J ¼ 9:4, 2.2 Hz),
7.79 (1H, dd, J ¼ 8:8, 4.8 Hz). Anal. Calcd for
C12H10ClFOS: C, 56.14; H, 3.93. Found: C, 56.11; H,
3.92.
2.17 (3H, s), 4.03–4.37 (2H, m), 4.87 (1H, dd, J ¼ 9:4,
2.4 Hz), 6.95 (1H, s), 7.02 (1H, s), 7.08 (1H, dt, J ¼ 2:6,
8.8 Hz), 7.28 (1H, dd, J ¼ 9:6, 2.6 Hz), 7.51 (1H, s), 7.72
(1H, dd, J ¼ 8:8, 5.2 Hz). Anal. Calcd for
C15H15FN2OS: C, 62.05; H, 5.21; N, 9.65. Found: C,
62.03; H, 5.18; N, 9.75.
5.18.2. 3-Chloro-1-(5-chloro-3-methylbenzo[b]thiophen-2-
yl)propan-1-one. 74% yield from 22vii. Mp 93 ꢂC
(EtOH). IR (KBr): 1667, 1510, 1346, 1179, 1080,
804 cmꢀ1. 1H NMR (CDCl3) d: 2.75 (3H, s), 3.42 (2H, t,
J ¼ 6:6 Hz), 3.93 (2H, t, J ¼ 6:6 Hz), 7.47 (1H, dd,
J ¼ 8:4, 2.2 Hz), 7.78 (1H, d, J ¼ 8:4 Hz), 7.87 (1H, d,
J ¼ 2:2 Hz). Anal. Calcd for C12H10Cl2OS: C, 52.76; H,
3.69. Found: C, 52.86; H, 3.61.
5.20.2. 1-(5-Chloro-3-methylbenzo[b]thiophen-2-yl)-3-(1H-
imidazol-1-yl)propan-1-ol. 97% yield. Mp 160 ꢂC
(AcOEt). IR (KBr): 3146, 1514, 1449, 1080, 802,
1
745 cmꢀ1. H NMR (CDCl3) d: 2.13 (3H, s), 2.04–2.40
(2H, m), 4.00–4.14 (1H, m), 4.25–4.40 (1H, m), 4.78 (1H,
dd, J ¼ 9:6, 4.8 Hz), 6.93 (1H, s), 6.95 (1H, s), 7.27 (1H,
dd, J ¼ 8:4, 2.0 Hz), 7.49 (1H, s), 7.58 (1H, d,
J ¼ 2:0 Hz), 7.70 (1H, d, J ¼ 8:4 Hz). Anal. Calcd for
C15H15ClN2OS: C, 58.72; H, 4.93; N, 9.13. Found: C,
58.64; H, 4.76; N, 9.14.
5.19. Preparation of 26
5.19.1. 1-(5-Fluoro-3-methylbenzo[b]thiophen-2-yl)-3-(1H-
imidazol-1-yl)propan-1-one. To a solution of 3-chloro-1-
(5-fluoro-3-methylbenzo[b]thiophen-2-yl)propan-1-one
(10.97 g, 42.7 mmol) in DMF (100 mL) was added
imidazole (11.64 g, 171.0 mmol), and the mixture was
stirred at room temperature for 1 h, poured into water,
and extracted with AcOEt. The extract was washed with
water, dried, and concentrated, and the residue was
chromatographed on silica gel using AcOEt–EtOH
(10:1) as an eluent to give the title compound as color-
less crystals (12.00 g, 97%). Mp 122–125 ꢂC (AcOEt). IR
5.21. 1-[(E)-3-(5-Fluoro-3-methylbenzo[b]thiophen-2-yl)-
2-propen-1-yl]-1H-imidazole (8e)
A mixture of 1-(5-fluoro-3-methylbenzo[b]thiophen-2-
yl)-3-(1H-imidazol-1-yl)propan-1-ol (5.00 g, 17.2 mmol)
and p-toluenesulfonic acid monohydrate (9.83 g,
51.7 mmol) in toluene (150 mL) was heated at reflux for
3 h. The mixture was concentrated, diluted with aqueous
NaHCO3, and extracted with AcOEt, and the extract
was washed with brine, dried, and concentrated to give
8e as pale brown crystals (4.65 g, 99%). Mp 132–134 ꢂC
(AcOEt). IR (KBr): 1443, 1225, 1169, 959, 860, 828,
(KBr): 1667, 1508, 1433, 1175, 1084, 853, 739, 662 cmꢀ1
1H NMR (CDCl3) d: 2.72 (3H, s), 3.39 (2H, t,
.

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2267
797 cmꢀ1. 1H NMR (CDCl3) d: 2.34 (3H, s), 4.76 (2H, d,
J ¼ 6:2 Hz), 6.19 (1H, dt, J ¼ 15:4, 6.2 Hz), 6.80 (1H, d,
J ¼ 15:4 Hz), 6.99 (1H, s), 7.08 (1H, dt, J ¼ 2:4, 8.8 Hz),
7.13 (1H, s), 7.29 (1H, dd, J ¼ 9:6, 2.4 Hz), 7.56 (1H, s),
7.65 (1H, dd, J ¼ 8:8, 4.8 Hz). Anal. Calcd for
C15H13FN2S: C, 66.15; H, 4.81; N, 10.29. Found: C,
66.10; H, 4.75; N, 10.21.
and refluxed for 18 h, diluted with water, and extracted
with AcOEt. The extract was dried and concentrated to
give ethyl 3-(1-triphenylmethyl-1H-imidazol-4-yl)-2-
methyl-2-propenoate (21.83 g, 91%). This compound
was dissolved in THF–AcOEt (1:1, 400 mL) and 10%
Pd–C (20.00 g) was added, and the mixture was stirred
at room temperature for 4 h under a hydrogen atmo-
sphere. The catalyst was filtered through Celite pad and
the filtrate was concentrated. The residue was dissolved
in DMF (250 mL) and the solution was cooled with ice
bath. Triethylamine (7.2 mL, 52.0 mmol) and chlorotri-
phenylmethane (14.50 g, 52.0 mmol) were added, and the
mixture was stirred at room temperature for 96 h,
washed with water, and extracted with AcOEt. The
extract was dried and concentrated, and the residue was
chromatographed on silica gel eluting with hexane–
AcOEt (4:1) to AcOEt to give 31 as colorless crystals
(17.56 g, 80%). Mp 100–102 ꢂC (AcOEt–hexane). IR
5.22. 1-[(E)-3-(5-Chloro-3-methylbenzo[b]thiophen-2-yl)-
2-propen-1-yl]-1H-imidazole (8g)
92% yield. Mp 145 ꢂC (AcOEt). IR (KBr): 3106, 1507,
1437, 1231, 1074, 951, 839, 804 cmꢀ1. 1H NMR (CDCl3)
d: 2.34 (3H, s), 4.77 (2H, dd, J ¼ 6:0, 1.4 Hz), 6.19 (1H,
dt, J ¼ 15:6, 6.0 Hz), 6.80 (1H, dt, J ¼ 15:6, 1.4 Hz),
7.00 (1H, s), 7.13 (1H, s), 7.29 (1H, dd, J ¼ 8:4, 2.2 Hz),
7.57 (1H, s), 7.61 (1H, d, J ¼ 2:2 Hz), 7.65 (1H, d,
J ¼ 8:4 Hz). Anal. Calcd for C15H13ClN2S: C, 62.38; H,
4.54; N, 9.70. Found: C, 62.43; H, 4.48; N, 9.66.
1
(KBr): 1726, 762, 702 cmꢀ1. H NMR (CDCl3) d: 1.19
(3H, t, J ¼ 7:0 Hz), 1.27 (3H, d, J ¼ 7:0 Hz), 2.44 (1H,
dd, J ¼ 15:0, 8.0 Hz), 2.73 (1H, dd, J ¼ 15:0, 6.6 Hz),
3.20–3.28 (1H, m), 4.07 (2H, q, J ¼ 7:0 Hz), 6.54 (1H, s),
7.08–7.35 (16H, m). Anal. Calcd for C28H28N2O2: C,
79.22; H, 6.65; N, 6.60. Found: C, 79.24; H, 6.67; N,
6.66.
5.23. 4-Acetyl-1-triphenylmethyl-1H-imidazole (30)
To a solution of 2947 (30.52 g, 90.2 mmol) in THF
(500 mL) was added methylmagnesium bromide (3.0 M
solution in ether, 32.0 mmol, 96.0 mmol) with ice cool-
ing, and the mixture was stirred for 1 h. The reaction
was quenched with aqueous NH4Cl, layers were sepa-
rated, and the aqueous phase was further extracted with
AcOEt. The organic layers were combined, dried, and
concentrated, and the residue was suspended in ether
and collected by filtration to give 1-(1-triphenylmethyl-
1H-imidazol-4-yl)ethanol as colorless crystals (31.40 g,
5.25. 3-(1-Triphenylmethyl-1H-imidazol-4-yl)butanal (32)
To a solution of 31 (17.59 g, 41.4 mmol) in THF
(260 mL) was added DIBAL (0.96 M solution in hexane,
43.0 mL, 41.3 mmol) at )78 ꢂC, and the reaction mixture
was stirred for 1 h. DIBAL (0.96 M solution in hexane,
40.0 mL, 38.4 mmol) was additionally added, and the
mixture was stirred for an additional 45 min, quenched
by the addition of EtOH (20 mL) followed by water
(20 mL), and allowed to warm to room temperature.
The insoluble material was filtered through Celite pad
and the filtered cake was washed with AcOEt. The fil-
trate was concentrated and the residue was chromato-
graphed on silica gel using hexane–AcOEt (1:1) as an
eluent to give 32 as colorless crystals (12.45 g, 80%). mp
105.5–106 ꢂC (AcOEt–hexane). IR (KBr): 1721, 1491,
98%). IR (KBr): 1493, 1445, 1133, 1088, 750, 702 cmꢀ1
.
1H NMR (CDCl3) d: 1.48 (3H, d, J ¼ 6:6 Hz), 4.85 (1H,
q, J ¼ 6:6 Hz), 6.72 (1H, s), 7.09–7.40 (16H, m). Anal.
Calcd for C24H22N2O: C, 81.33; H, 6.26; N, 7.90.
Found: C, 81.30; H, 6.14; N, 7.91.This compound
(31.00 g, 87.5 mmol) was dissolved in CH2Cl2 (300 mL)
and manganese(IV) oxide (8.0 g) was added, and the
mixture was stirred at room temperature for 12 h. The
insoluble material was filtered through Celite pad and
the filtered cake was washed with CH2Cl2, and the fil-
trate was concentrated. The residue was suspended in
EtOH and collected by filtration to give 30 as colorless
crystals (26.35 g, 85%). mp 166–167 ꢂC (EtOH). IR
1
1441, 754, 702 cmꢀ1. H NMR (CDCl3) d: 1.28 (3H, d,
J ¼ 7:0 Hz), 2.58 (1H, ddd, J ¼ 16:2, 7.0, 2.2 Hz), 2.82
(1H, ddd, J ¼ 16:2, 7.0, 2.2 Hz), 3.34 (1H, sextet,
J ¼ 7:0 Hz), 6.55 (1H, s), 7.08–7.17 (6H, m), 7.29–7.37
(10H, m), 9.76 (1H, t, J ¼ 2:2 Hz). Anal. Calcd for
C26H24N2O: C, 82.07; H, 6.36; N, 7.36. Found: C, 81.82;
H, 6.22; N, 7.39.
(KBr): 1669, 1534, 1179, 754, 700 cmꢀ1 1H NMR
.
(CDCl3) d: 2.56 (3H, s), 7.09–7.16 (6H, m), 7.30–7.37
(9H, m), 7.44 (1H, d, J ¼ 1:4 Hz), 7.58 (1H, d,
J ¼ 1:4 Hz). Anal. Calcd for C24H20N2O: C, 81.79; H,
5.72; N, 7.95. Found: C, 81.65; H, 5.57; N, 8.04.
5.26. Synthesis of 4-[(E)-3-(benzo[b]thiophen-2-yl)-2-pro-
pen-1-yl]-1H-imidazoles (9a–h): General procedure for
the synthesis of 33
5.24. Ethyl 3-(1-triphenylmethyl-1H-imidazol-4-yl)butyl-
ate (31)
5.26.1. 1-(5-Fluorobenzo[b]thiophen-2-yl)-3-(1-triphenyl-
methyl-1H-imidazol-4-yl)-propan-1-ol. To a solution of
22ii (2.50 g, 16.4 mmol) in THF (50 mL) was added n-
BuLi (1.59 M solution in hexane, 10.3 mL, 16.4 mmol) at
)78 ꢂC, and the mixture was stirred for 1 h. A solution
of 28 (6.01 g, 16.4 mmol) in THF (10 mL) was added,
and the mixture was stirred for 1 h, allowed to warm up
To a suspension of sodium hydride (60% dispersion in
oil, 3.60 g, 90.0 mmol) in THF (100 mL) was added ethyl
diethylphosphonoacetate (20.18 g, 90.0 mmol) with ice
cooling, and the mixture was stirred for 1 h. A solution
of 30 (20.00 g, 56.8 mmol) in THF (100 mL) was added,
and the mixture was stirred at room temperature for 2 h

2268
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
to )50 ꢂC over 1 h, quenched by the addition of aqueous
NH4Cl. After the separation of layers, the aqueous layer
was further extracted with AcOEt. The organic layer
was combined, dried, and concentrated, and the
residue was crystallized from acetone to give the title
compound as colorless crystals (4.62 g, 55%). mp 206–
208 ꢂC (AcOEt–hexane). IR (KBr): 3063, 1447, 1138,
1128, 1088, 1001, 862, 756, 747, 704, 658 cmꢀ1. 1H NMR
(CDCl3) d: 2.16–2.33 (2H, m), 2.65–2.90 (2H, m), 5.17
(1H, dd, J ¼ 6:6, 4.6 Hz), 6.56 (1H, d, J ¼ 1:2 Hz), 7.01
(1H, dt, J ¼ 2:6, 8.8 Hz), 7.11–7.18 (7H, m), 7.31–7.39
(11H, m), 7.70 (1H, dd, J ¼ 8:8, 4.8 Hz). Anal. Calcd for
C33H27FN2OS: C, 76.42; H, 5.25; N, 5.40. Found: C,
76.16; H, 5.21; N, 5.40.
5.27.3. 4-[(E)-3-(6-Fluorobenzo[b]thiophen-2-yl)-2-prop-
en-1-yl]-1H-imidazole (9c). 19% yield from 22iii. Mp
171 ꢂC (AcOEt). IR (KBr): 3069, 2830, 1566, 1468, 1250,
1
949, 856, 816 cmꢀ1. H NMR (CDCl3) d: 3.56 (2H, d,
J ¼ 6:6 Hz), 6.24 (1H, dt, J ¼ 15:6, 6.6 Hz), 6.65 (1H, d,
J ¼ 15:6 Hz), 6.86 (1H, s), 7.01 (1H, s), 7.03 (1H, dt,
J ¼ 2:2, 8.8 Hz), 7.40 (1H, dd, J ¼ 8:8, 2.2 Hz), 7.57
(1H, dd, J ¼ 8:8, 5.2 Hz), 7.61 (1H, s). Anal. Calcd for
C14H11FN2S: C, 65.09; H, 4.29; N, 10.84. Found: C,
64.99; H, 4.26; N, 10.86.
5.27.4. 4-[(E)-3-(7-Fluorobenzo[b]thiophen-2-yl)-2-prop-
en-1-yl]-1H-imidazole (9d). 62% yield from 22iv. Mp
119 ꢂC (AcOEt). IR (KBr): 1464, 1238, 945, 818, 777,
1
710 cmꢀ1. H NMR (CDCl3+CD3OD) d: 3.55 (2H, d,
5.27. General procedure for the synthesis of 9a–h
J ¼ 6:6 Hz), 6.33 (1H, dt, J ¼ 15:6, 6.6 Hz), 6.68 (1H, d,
J ¼ 15:6 Hz), 6.83 (1H, s), 6.97 (1H, dd, J ¼ 9:8,
8.0 Hz), 7.10 (1H, d, J ¼ 3:8 Hz), 7.25 (1H, dt, J ¼ 4:8,
8.0 Hz), 7.45 (1H, d, J ¼ 8:0 Hz), 7.61 (1H, s). Anal.
Calcd for C14H11FN2S: C, 65.09; H, 4.29; N, 10.84.
Found: C, 65.01; H, 4.50; N, 10.83.
5.27.1. 4-[(E)-3-(5-Fluorobenzo[b]thiophen-2-yl)-2-prop-
en-1-yl]-1H-imidazole (9b). A mixture of 1-(5-fluoro-
benzo[b]thiophen-2-yl)-3-(1-triphenylmethyl-1H-imidazol-
4-yl)-propan-1-ol (11.27 g, 21.7 mmol), p-toluene- sulfonic
acid monohydrate (12.44 g, 65.4mmol), water (0.77 mL,
43mmol), and 1,2-dimethoxyethane (500 mL) was heated
at reflux for 2 h. The mixture was concentrated, diluted
with aqueous NaHCO3, and extracted with AcOEt–THF.
The extract was concentrated, and the residue was chro-
matographed on silica gel using CH2Cl2–MeOH (40:1 to
8:1) as an eluent to give 9b as colorless crystals (0.49g, 9%)
and 1-(5-fluorobenzo[b]thiophen-2-yl)-3-(1H-imidazol-4-
yl)propan-1-ol as a colorless amorphous solid (4.50 g). The
propan-1-ol was heated at reflux for 1 h with p-toluene-
sulfonic acid monohydrate (4.00 g, 21.0 mmol) in toluene
(450 mL). The mixture was concentrated, diluted with
aqueous NaHCO3, and extracted with AcOEt–THF. The
extract was concentrated and the residue was chromato-
graphed on silica gel using CH2Cl2–MeOH (20:1) as an
eluent, followed by crystallization with ether to give 9b as
colorless crystals (2.73 g, 65%). mp 196–197ꢂC (AcOEt).
5.27.5. 4-[(E)-3-(5-Fluoro-3-methylbenzo[b]thiophen-2-yl)-
2-propen-1-yl]-1H-imidazole (9e). 70% yield from 22v.
Mp 170–171 ꢂC (AcOEt). IR (KBr): 1599, 1445, 955,
1
810, 625 cmꢀ1. H NMR (CDCl3) d: 2.32 (3H, s), 3.60
(2H, d, J ¼ 7:0 Hz), 6.27 (1H, dt, J ¼ 15:4, 7.0 Hz), 6.81
(1H, d, J ¼ 15:4 Hz), 6.87 (1H, s), 7.03 (1H, dt, J ¼ 2:4,
8.8 Hz), 7.25 (1H, dd, J ¼ 10:0, 2.4 Hz), 7.62 (1H, dd,
J ¼ 8:8, 4.6 Hz), 7.63 (1H, s). Anal. Calcd for
C15H13FN2S: C, 66.15; H, 4.81; N, 10.29. Found: C,
65.96; H, 4.88; N, 10.14.
5.27.6. 4-[(E)-3-(3-tert-Butyl-5-fluorobenzo[b]thiophen-2-
yl)-2-propen-1-yl]-1H-imidazole (9f). 16% yield from
22ix. An amorphous solid. IR (KBr): 2963, 1570, 1449,
1229, 1182, 970, 820, 797 cmꢀ1. 1H NMR (CDCl3) d: 1.44
(9H, s), 3.66 (2H, d, J ¼ 6:6 Hz), 6.58 (1H, dt, J ¼ 15:8,
6.6 Hz), 6.77 (1H, d, J ¼ 15:8 Hz), 6.89 (1H, s), 6.99 (1H,
dd, J ¼ 11:0, 8.8 Hz), 7.23 (1H, d, J ¼ 11:0 Hz), 7.53
(1H, dd, J ¼ 8:8, 4.4 Hz), 7.62 (1H, s).
1
IR (KBr): 1441, 1175, 955, 868, 835, 806 cmꢀ1. H NMR
(CDCl3) d: 3.58 (2H, d, J ¼ 6:8 Hz), 6.31 (1H, dt,
J ¼ 15:8, 6.8 Hz), 6.68 (1H, d, J ¼ 15:8 Hz), 6.87 (1H, s),
7.02 (1H, dt, J ¼ 2:6, 8.8 Hz), 7.02 (1H, s), 7.31 (1H, dd,
J ¼ 9:2, 2.6 Hz), 7.63 (1H, s), 7.64 (1H, dd, J ¼ 8:8,
5.2Hz). Anal. Calcd for C14H11FN2S: C, 65.10; H, 4.29; N,
10.84. Found: C, 65.06; H, 4.35; N, 10.82.
5.27.7. 4-[(E)-3-(5,7-Difluoro-3-methylbenzo[b]thiophen-
2-yl)-2-propen-1-yl]-1H-imidazole (9g). 37% yield from
22x. Mp 152–153 ꢂC (AcOEt). IR (KBr): 3086, 2822,
Compounds 9a and 9c–h were prepared from the cor-
responding 22 with 28 (for 9a and 9c–g) or 32 (for 9h) by
similar procedures.
1
2640, 1422, 972, 839, 818, 623 cmꢀ1. H NMR (CDCl3)
d: 2.37 (3H, s), 3.63 (2H, d, J ¼ 6:0 Hz), 6.58–6.79 (2H,
m), 6.89 (1H, s), 7.12–7.21 (2H, m), 7.64 (1H, s). Anal.
Calcd for C15H12F2N2S: C, 62.05; H, 4.17; N, 9.65.
Found: C, 62.00; H, 4.18; N, 9.52.
5.27.2. 4-[(E)-3-(4-Fluorobenzo[b]thiophen-2-yl)-2-prop-
en-1-yl]-1H-imidazole (9a). 84% yield from 22i. Mp
131–132 ꢂC (AcOEt). IR (KBr): 1568, 1462, 1248, 1211,
955, 774 cmꢀ1. 1H NMR (CDCl3+CD3OD) d: 3.55 (2H,
d, J ¼ 6:8 Hz), 6.29 (1H, dt, J ¼ 15:4, 6.8 Hz), 6.69 (1H,
d, J ¼ 15:4 Hz), 6.83 (1H, s), 6.96 (1H, dd, J ¼ 10:4,
8.0 Hz), 7.18 (1H, s), 7.22 (1H, dt, J ¼ 4:8, 8.0 Hz), 7.50
(1H, d, J ¼ 8:0 Hz), 7.61 (1H, s). Anal. Calcd for
C14H11FN2S: C, 65.09; H, 4.29; N, 10.84. Found: C,
65.18; H, 4.31; N, 10.86.
5.27.8. 4-[(E)-4-(5-Fluorobenzo[b]thiophen-2-yl)-3-buten-
2-yl]-1H-imidazole (9h). 41% yield from 22ii. Mp 153–
154 ꢂC (AcOEt). IR (KBr): 1447, 1177, 955, 868, 804,
627 cmꢀ1. 1H NMR (CDCl3) d: 1.47 (3H, d, J ¼ 7:0 Hz),
3.69 (1H, quint, J ¼ 7:0 Hz), 6.28 (1H, dd, J ¼ 15:6,
7.0 Hz), 6.63 (1H, d, J ¼ 15:6 Hz), 6.81 (1H, s), 7.02
(1H, dt, J ¼ 2:6, 8.8 Hz), 7.03 (1H, s), 7.31 (1H, dd,

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2269
J ¼ 9:6, 2.6 Hz), 7.61 (1H, s), 7.64 (1H, dd, J ¼ 8:8,
4.8 Hz). Anal. Calcd for C15H13FN2S: C, 66.15; H, 4.81;
N, 10.29. Found: C, 66.16; H, 4.68; N, 10.27.
aqueous layer was extracted with AcOEt. The organic
layers were combined, dried, and concentrated, and the
residue was chromatographed on silica gel using
CH2Cl2–MeOH (40:1 to 10:1) to give 36 as an amor-
phous solid (7.51 g, 66%) and 37 as crystals (2.79 g, 25%).
5.28. 2-Acetyl-5-fluoro-3-methylbenzo[b]thiophene (34)
36: IR (KBr): 1671, 1514, 1296, 1167, 805, 660 cmꢀ1. 1H
NMR (CDCl3) d: 1.42 (3H, d, J ¼ 7:0 Hz), 2.71 (3H, s),
3.17 (1H, dd, J ¼ 17:0, 5.8 Hz), 3.34 (1H, dd, J ¼ 17:0,
7.4 Hz), 3.50–3.67 (1H, m), 6.85 (1H, s), 7.25 (1H, dt,
J ¼ 2:6, 8.8 Hz), 7.50 (1H, dd, J ¼ 9:4, 2.6 Hz), 7.57
(1H, s), 7.76 (1H, dd, J ¼ 8:8, 4.8 Hz).
To a mixture of 22v (9.97 g, 60.0 mmol) and acetyl
chloride (5.55 mL, 78.0 mmol) in carbon disulfide
(100 mL) was added AlCl3 (16.0 g, 120.0 mmol) with ice
cooling. The mixture was stirred at room temperature
for 2 h, poured onto crushed ice, diluted with 1 N HCl,
and extracted with AcOEt. The extract was washed with
water and aqueous NaHCO3, dried, and concentrated,
and the residue was suspended in EtOH and collected by
filtration to give 34 as crystals (7.43 g, 59%). mp 80 ꢂC
(EtOH). IR (KBr): 1649, 1522, 1441, 1377, 1360, 1294,
37: mp 169–172 ꢂC (AcOEt). IR (KBr): 3125, 1605,
1443, 1167, 1132, 1088, 970, 922, 853, 801, 656 cmꢀ1. 1H
NMR (CDCl3+CD3OD) d: 1.82 (3H, s), 2.32 (3H, s),
6.48 (1H, d, J ¼ 16:0 Hz), 6.51 (1H, d, J ¼ 16:0 Hz),
6.90 (1H, s), 7.03 (1H, dt, J ¼ 2:4, 8.8 Hz), 7.25 (1H, dd,
J ¼ 9:8, 2.4 Hz), 7.50 (1H, s), 7.66 (1H, dd, J ¼ 8:8,
5.0 Hz). Anal. Calcd for C16H15FN2OS: C, 63.56; H,
5.00; N, 9.26. Found: C, 63.28; H, 5.13; N, 9.00.
1
1238, 1184, 845, 826 cmꢀ1. H NMR (CDCl3) d: 2.64
(3H, s), 2.72 (3H, s), 7.26 (1H, dt, J ¼ 2:2, 8.8 Hz), 7.52
(1H, dd, J ¼ 9:4, 2.2 Hz), 7.78 (1H, dd, J ¼ 8:8, 4.6 Hz).
Anal. Calcd for C11H9FOS: C, 63.44; H, 4.36. Found: C,
63.40; H, 4.13.
5.31. 1-(5-Fluoro-3-methylbenzo[b]thiophen-2-yl)-3-(1H-
imidazol-4-yl)-4-methyl-1-pentanone (38) and (E)-3-(5-
Fluoro-3-methylbenzo[b]thiophen-2-yl)-1-(1H-imidazol-
4-yl)-4-methyl-1-penten-3-ol (39)
5.29. (E)-1-(5-Fluoro-3-methylbenzo[b]thiophen-2-yl)-3-
(1H-imidazol-4-yl)-2-propen-1-one (35)
To a mixture of 34 (7.13 g, 34.2 mmol) and 29 (12.18 g,
36.0 mmol) in THF–MeOH (1:1, 240 mL) was added 6 N
NaOH (15 mL) with ice cooling, and the mixture was
stirred at room temperature for 4 h and diluted with
water. The precipitate was collected by filtration and
washed with EtOH to give (E)-1-(5-fluoro-3-meth-
ylbenzo[b]thiophen-2-yl)-3-(1-triphenylmethyl-1H-imi-
dazol-4-yl)-2-propen-1-one as colorless crystals (18.35 g,
quantitative yield). This compound (5.10 g, 9.7 mmol)
was suspended in 1,2-dimethoxyethane (150 mL) and p-
toluenesulfonic acid monohydrate (5.71 g, 30.0 mmol)
was added, and the mixture was refluxed for 2 h and
cooled. The precipitate was collected by filtration and
dissolved in AcOEt–THF, and the solution was washed
with aqueous NaHCO3, dried, and concentrated. The
residue was suspended in ether and collected by filtration
to give 35 as crystals (2.37 g, 86%). mp 223–226 ꢂC
decomp. (MeOH). IR (KBr): 1661, 1607, 1518, 1292,
To a suspension of 35 (500 mg, 1.75 mmol) in THF
(40 mL) was added isopropylmagnesium chloride (2.0 M
solution in THF, 2.8 mL, 5.6 mmol) with ice cooling,
and the mixture was stirred for 1 h and quenched with
20% NH4Cl. The organic layer was separated and the
aqueous layer was extracted with AcOEt. The organic
layers were combined, dried, and concentrated, and the
residue was chromatographed on silica gel using
CH2Cl2–MeOH (40:1 to 10:1) to give 38 as an amor-
phous solid (222 mg, 38%) and 39 as an amorphous solid
(135 mg, 23%).
38: IR (KBr): 2961, 1672, 1514, 1165, 806, 662 cmꢀ1. 1H
NMR (CDCl3) d: 0.90 (3H, d, J ¼ 7:0 Hz), 0.99 (3H, d,
J ¼ 7:0 Hz), 2.07–2.22 (1H, m), 2.67 (3H, s), 3.18–3.26
(2H, m), 3.43 (1H, dd, J ¼ 17:4, 9.6 Hz), 6.82 (1H, s),
7.24 (1H, dt, J ¼ 2:6, 8.8 Hz), 7.48 (1H, dd, J ¼ 9:8,
2.6 Hz), 7.54 (1H, s), 7.76 (1H, dd, J ¼ 8:8, 4.8 Hz).
1
1181, 860, 804, 652 cmꢀ1. H NMR (DMSO-d6) d: 2.73
(3H, s), 7.40 (1H, d, J ¼ 15:0 Hz), 7.46 (1H, dt, J ¼ 2:4,
8.8 Hz), 7.71 (1H, d, J ¼ 15:0 Hz), 7.71 (1H, s), 7.85 (1H,
dd, J ¼ 10:2, 2.4 Hz), 7.87 (1H, s), 8.12 (1H, dd, J ¼ 8:8,
4.8 Hz). Anal. Calcd for C15H11FN2OS: C, 62.92; H,
3.87; N, 9.78. Found: C, 62.91; H, 3.70; N, 9.71.
39: IR (KBr): 2969, 1605, 1443, 1132, 1111, 972, 922,
801, 660 cmꢀ1
.
1H NMR (CDCl3) d: 0.92 (3H, d,
J ¼ 6:6 Hz), 1.03 (3H, d, J ¼ 6:6 Hz), 2.37 (3H, s), 2.48
(1H, sept, J ¼ 6:6 Hz), 6.60 (1H, d, J ¼ 15:8 Hz), 6.76
(1H, d, J ¼ 15:8 Hz), 6.93 (1H, s), 7.01 (1H, dt, J ¼ 2:6,
8.8 Hz), 7.24 (1H, dd, J ¼ 9:8, 2.6 Hz), 7.55 (1H, s), 7.65
(1H, dd, J ¼ 8:8, 4.8 Hz).
5.30. 1-(5-Fluoro-3-methylbenzo[b]thiophen-2-yl)-3-(1H-
imidazol-4-yl)-1-butanone (36) and (E)-2-(5-Fluoro-3-
methylbenzo[b]thiophen-2-yl)-4-(1H-imidazol-4-yl)-3-
buten-2-ol (37)
5.32. 4-[(E)-4-(5-Fluoro-3-methylbenzo[b]thiophen-2-yl)-
3-buten-2-yl]-1H-imidazole (9i)
To a suspension of 35 (10.74 g, 37.5 mmol) in THF
(900 mL) was added methylmagnesium bromide (3.0 M
solution in ether, 41.5 mL, 124.5 mmol) with ice cooling,
and the mixture was stirred for 0.5 h and quenched with
20% NH4Cl. The organic layer was separated and the
To a solution of 36 (7.51 g, 24.8 mmol) in THF–MeOH
(5:1, 150 mL) was added NaBH4 (0.95 g, 25.0 mmol)
with ice cooling. The mixture was stirred for 1 h, poured
into 20% NH4Cl, and extracted with AcOEt. The extract

2270
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
was dried and concentrated to give 1-(5-fluoro-3-meth-
ylbenzo[b]thiophen-2-yl)-3-(1H-imidazol-4-yl)-1-butan-
1-ol as colorless crystals. This alcohol was heated at
reflux for 1 h with p-toluenesulfonic acid monohydrate
(14.27 g, 75.0 mmol) in 1,2-dimethoxyethane (150 mL).
The mixture was concentrated, diluted with aqueous
NaHCO3, and extracted with AcOEt–THF. The extract
was dried and concentrated, and the residue was
chromatographed on silica gel using AcOEt–EtOH
(10:1) as an eluent, followed by recrystallization to give
9i as colorless prisms (5.49 g, 77%). mp 158–159 ꢂC. IR
(KBr): 1601, 1443, 1169, 941, 847, 826, 800, 658,
5.36. Ethyl 2-methyl-2-(1-triphenylmethyl-1H-imidazol-
4-yl)propanoate (43)
To a mixture of 42 (4.00 g, 22.0 mmol) and triethylamine
(3.66 mL, 26.3 mmol) in DMF (50 mL) was added
chlorotriphenylmethane (6.22 g, 22.3 mmol) with ice
cooling. The mixture was stirred at room temperature
for 2 h, diluted with water, and extracted with AcOEt.
The extract was washed with water, dried, and concen-
trated, and the residue was suspended in diisopropyl-
ether and collected by filtration to give 43 as colorless
crystals (8.20 g, 88%). mp 118–119 ꢂC (AcOEt–hexane).
IR (KBr): 1726, 1493, 1447, 1252, 1142, 758, 745,
702 cmꢀ1. 1H NMR (CDCl3) d: 1.16 (3H, t, J ¼ 7:0 Hz),
1.52 (6H, s), 4.10 (2H, q, J ¼ 7:0 Hz), 6.65 (1H, d,
J ¼ 1:0 Hz), 7.10–7.15 (6H, m), 7.31–7.34 (10H, m).
Anal. Calcd for C28H28N2O2: C, 79.22; H, 6.65; N, 6.60.
Found: C, 79.30; H, 6.46; N, 6.81.
631 cmꢀ1
.
1H NMR (CDCl3) d: 1.50 (3H, d,
J ¼ 7:0 Hz), 2.32 (3H, s), 3.73 (1H, quint, J ¼ 7:0 Hz),
6.25 (1H, dd, J ¼ 15:6, 7.0 Hz), 6.77 (1H, d,
J ¼ 15:6 Hz), 6.86 (1H, s), 7.03 (1H, dt, J ¼ 2:6,
8.8 Hz), 7.25 (1H, dd, J ¼ 9:8, 2.6 Hz), 7.62 (1H, dd,
J ¼ 8:8, 4.8 Hz), 7.63 (1H, s). Anal. Calcd for
C16H15FN2S: C, 67.11; H, 5.28; N, 9.78. Found: C,
67.01; H, 5.15; N, 10.03.
5.37. 2-Methyl-2-(1-triphenylmethyl-1H-imidazol-4-
yl)propanal (44)
5.33. 4-[(E)-1-(5-Fluoro-3-methylbenzo[b]thiophen-2-yl)-
4-methyl-1-penten-3-yl]-1H-imidazole (9j)
Prepared from 43 by the method described for 32 in 67%
yield. Mp 114–115.5 ꢂC (AcOEt–hexane). IR (KBr):
1721, 1493, 1447, 1184, 748, 698 cmꢀ1. 1H NMR (CDCl3)
d: 1.39 (6H, s), 6.66 (1H, d, J ¼ 1:2 Hz), 7.09–7.16 (6H,
m), 7.30–7.35 (9H, m), 7.41 (1H, d, J ¼ 1:2 Hz), 9.60
(1H, s). Anal. Calcd for C26H24N2O: C, 82.07; H, 6.36;
N, 7.36. Found: C, 82.04; H, 6.06; N, 7.53.
Prepared from 38 by the method described for 9i in 80%
yield. An amorphous solid. IR (KBr): 2961, 1601, 1445,
.
1169, 953, 920, 851, 799, 656, 631 cmꢀ1 1H NMR
(CDCl3) d: 0.95 (3H, d, J ¼ 7:2 Hz), 0.99 (3H, d,
J ¼ 7:2 Hz), 2.14–2.30 (1H, m), 2.32 (3H, s), 3.33 (1H,
dd, J ¼ 9:0, 7.2 Hz), 6.28 (1H, dd, J ¼ 15:6, 9.0 Hz),
6.76 (1H, d, J ¼ 15:6 Hz), 6.86 (1H, s), 7.03 (1H, dt,
J ¼ 2:6, 8.8 Hz), 7.24 (1H, dd, J ¼ 9:6, 2.6 Hz), 7.63
(1H, dd, J ¼ 8:8, 4.8 Hz), 7.63 (1H, s).
5.38. Diethyl (5-fluorobenzo[b]thiophen-2-yl)methyl-
phosphonate (40)
To a suspension of LiAlH4 (1.69 g, 44.6 mmol) in THF
(100 mL) was added a solution of 24ii (10.00 g,
44.6 mmol) in THF (80 mL) with ice cooling. The mix-
ture was stirred at room temperature for 1 h, quenched
by the addition of water, and diluted with 1 N HCl.
After separation of the layers, the aqueous layer was
further extracted with AcOEt. The organic layers were
combined, washed with aqueous NaHCO3, dried, and
concentrated to give (5-fluorobenzo[b]thiophen-2-
yl)methanol as colorless crystals (7.80 g, 96%). mp 94 ꢂC
(diisopropylether–hexane). IR (KBr): 3277, 1605, 1449,
5.34. Optical resolution of 9i
Separation of 9i into its enantiomers (S)-9i and (R)-9i
was carried out by HPLC using Chiralcelꢁ OD (4.6 mm
i.d. · 250 mm) with detection at 254 nm. Elution with a
mixture of 2-propanol–hexane (8:92) at a flow rate of
0.7 mL/min at room temperature gave (S)-9i and (R)-9i.
20
D
(S)-9i: retention time ¼ 23.0 min. ½aꢁ )5.1 (c 0.498,
20
MeOH). (R)-9i: retention time ¼ 29.1 min. ½aꢁ +5.0 (c
D
0.503, MeOH).
1
1013, 874, 814 cmꢀ1. H NMR (CDCl3) d: 4.93 (2H, s),
5.35. Ethyl 2-methyl-2-(1H-imidazol-4-yl)propanoate (42)
7.07 (1H, dt, J ¼ 2:6, 8.8 Hz), 7.18 (1H, s), 7.39 (1H, dd,
J ¼ 9:6, 2.6 Hz), 7.74 (1H, dd, J ¼ 8:8, 4.8 Hz). Anal.
Calcd for C9H7FOS: C, 59.32; H, 3.87. Found: C, 59.18;
H, 3.90. This alcohol (2.98 g, 16.4 mmol) was dissolved
in THF (15 mL) and the solution was cooled with an ice
bath. Thionyl chloride (3.50 mL, 48.0 mmol) was added,
and the mixture was stirred at room temperature for 2 h
and at reflux for 1 h, concentrated, diluted with aqueous
NaHCO3, and extracted with AcOEt. The extract was
dried and concentrated, and the residue was chromato-
graphed on silica gel using hexane as an eluent to give 2-
chloromethyl-5-fluorobenzo[b]thiophene as colorless
crystals (2.26 g, 69%). This compound (2.00 g,
9.97 mmol) was heated at 160 ꢂC for 3 h with tri-
ethylphosphite (3.46 g, 20.8 mmol), and then excess tri-
ethylphosphite was removed under reduced pressure.
A mixture of 4148 (54.5 g, 230 mmol) and formamide
(220 g, 4.88 mol) was heated at 120 ꢂC for 2 h and at
160 ꢂC for 18 h. The mixture was cooled to room tem-
perature, diluted with aqueous NaHCO3, and extracted
with AcOEt. The extract was concentrated and then
excess formamide was removed by distillation under
reduced pressure. The residue was crystallized from
ether to give 42 as colorless crystals (8.40 g, 20%). mp
91.5–93.0 ꢂC (AcOEt–hexane). IR (KBr): 2988, 1719,
1264, 1161, 1140, 982, 853, 631 cmꢀ1. 1H NMR (CDCl3)
d: 1.24 (3H, t, J ¼ 7:2 Hz), 1.58 (6H, s), 4.16 (2H, q,
J ¼ 7:2 Hz), 6.90 (1H, s), 7.60 (1H, s). Anal. Calcd for
C9H14N2O2: C, 59.32; H, 7.74; N, 15.37. Found: C,
59.11; H, 7.62; N, 15.30.

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2271
The residue was chromatographed on silica gel using
hexane–AcOEt (1:1) as an eluent to give 40 (2.69 g, 89%)
force field (ver. 98.0, Molecular Simulations Inc., San
Diego, CA). The superimposition between 9k and 17a-
hydroxypregnenolone was created as follows. It was
hypothesized that one of the imidazole nitrogen of 9k
and the pyridine nitrogen of CB-7630 exist at similar
positions because both atoms probably make the coor-
dinate bonds with the heme iron in the enzyme.
According to this hypothesis, 9k and CB-7630 were
superimposed using the overlap function of Insight II
(ver. 2000, Molecular Simulations Inc., San Diego, CA)
under the condition that the two nitrogen atoms existed
close in space. After some trials, an overlap was chosen
on the basis of the intersection volume between two
molecules. Conformational stability of 9k was also
considered by comparing with the most stable confor-
mation, which was generated in the previous search. The
adopted conformation of 9k differed only by 9 kcal/mol
from the most stable conformation. Then, the steroidal
scaffold with the most stable conformation of 17a-
hydroxypregnenolone was overlaid on that of CB-7630
using the overlap selected above.
1
as a colorless oil. IR (neat): 1445, 1051, 1026 cmꢀ1. H
NMR (CDCl3) d: 1.30 (6H, t, J ¼ 7:2 Hz), 3.43 (2H, d,
J ¼ 21:4 Hz), 4.09 (2H, q, J ¼ 7:2 Hz), 4.13 (2H, q,
J ¼ 7:2 Hz), 7.05 (1H, ddt, J ¼ 2:4, 1.0, 8.8 Hz), 7.17
(1H, dd, J ¼ 2:4, 1.0 Hz), 7.36 (1H, dd, J ¼ 9:6, 2.4 Hz),
7.68 (1H, dd, J ¼ 8:8, 4.8 Hz).
5.39. 4-(E)-4-(5-Fluorobenzo[b]thiophen-2-yl)-2-methyl-
3-buten-2-yl]-1H-imidazole (9k)
To a suspension of sodium hydride (60% dispersion in
oil, 370 mg, 9.2 mmol) in THF (8 mL) was added a
solution of 40 (2.54 g, 8.4 mmol) in THF (10 mL) with ice
cooling, and the mixture was stirred for 1 h. A solution of
44 (3.20 g, 8.4 mmol) in THF (20 mL) was added, and the
mixture was stirred at room temperature for 18 h, diluted
with water, and extracted with AcOEt. The extract was
dried and concentrated, and the residue was suspended
in diisopropylether and collected by filtration to give 4-
[(E)-4-(5-fluorobenzo[b]thiophen-2-yl)-2-methyl-3-bu-
ten-2-yl]-1-triphenylmethyl-1H-imidazole (4.08 g, 92%).
This compound (3.94 g, 7.45 mmol) was heated with
pyridinium chloride (1.04 g, 9.0 mmol) in MeOH (60 mL)
at 60 ꢂC for 4.5 h. The mixture was concentrated, diluted
with aqueous NaHCO3, and extracted with AcOEt–
THF. The extract was dried and concentrated, and the
residue was chromatographed on silica gel using AcOEt–
EtOH (20:1) as an eluent to give 9k as colorless crystals
(2.22 g, 98%). mp 160–163 ꢂC (AcOEt–hexane). IR
5.42. Assay of inhibitory activity on rat C17;20-lyase
Inhibitory activity against rat C17;20-lyase was deter-
mined by the method described previously with some
modifications.27 Testes excised from 13-week old, male
SD rats were homogenized, and testicular microsomes
were prepared by a series of centrifugations. The reac-
tion mixture contains 75 mM phosphate buffer (pH 7.4),
7 lg of the microsome protein, 10 nM [1,2-3H]-17a-
hydroxyprogesterone (NEN), 5 mM NADPH (Oriental
Yeast), and test compounds in a total volume of 20 lL.
The test compounds were serially diluted with dimeth-
ylformamide, and then fivefold diluted with distilled
water. Test compound solution, 5 lL, was added to the
reaction mixture. The reaction was terminated by
addition of 40 lL of ethyl acetate after 15 min incuba-
tion at 37 ꢂC, then vortexed for 30 s and briefly centri-
fuged. The organic phase, 30 lL, was applied to silica gel
thin layer chromatography plates (Whatman, LHPK).
The substrate and the products (androstenedione and
testosterone) were separated in the toluene–acetone (7:2)
solvent system. Detection of the spots and measurement
of the radioactivity as PSL were performed with a
BAS2000 Bio-image analyzer (FUJIX). The concentra-
tion of the test compounds necessary to reduce the
concentration of the products by 50% (the concentration
in the control group in which no test compound is added
is set to 100%) was calculated.
(KBr): 1599, 1443, 1175, 1127, 957, 870, 801, 629 cmꢀ1
.
1H NMR (CDCl3) d: 1.52 (6H, s), 6.37 (1H, d,
J ¼ 16:0 Hz), 6.55 (1H, d, J ¼ 16:0 Hz), 6.85 (1H, s), 7.01
(1H, dt, J ¼ 2:4, 8.8 Hz), 7.02 (1H, s), 7.30 (1H, dd,
J ¼ 9:4, 2.4 Hz), 7.63 (1H, dd, J ¼ 8:8, 4.8 Hz), 7.64 (1H,
s). Anal. Calcd for C16H15FN2S: C, 67.11; H, 5.28; N,
9.78. Found: C, 67.31; H, 5.28; N, 9.82.
5.40. Single-crystal X-ray analysis of (R)-9i
An analytical sample of (R)-9i as the fumarate for X-ray
analysis was obtained by recrystallization from MeOH.
X-ray measurement was performed on a Rigaku
AFC5R diffractometer with Cu-Ka radiation. Crystal
data for (R)-9i fumarate: [C16H16FN2S]þ[C4H3O4]ꢀ,
M ¼ 402.4, orthorhombic, space group P212121
ꢀ
ꢀ
ꢀ
(#19), a ¼ 15:567(1) A, b ¼ 15:700(1) A, c ¼ 7:977ð1Þ A,
V ¼ 1949:7ð4Þ A , Dcalcd ¼ 1:371 g/cm3, Z ¼ 4; Final R
3
ꢀ
values were R1 ¼ 0:047 for 2080 reflections with Fo > 4r
(Fo), wR2 ¼ 0:123 for all the 3375 reflections. The
absolute configuration was determined by the Flack
parameter52 of 0.03(4). Further details of the X-ray
structure data are available on request from the Cam-
bridge Crystallographic Data Centre (deposition num-
ber CCDC 228638).
5.43. Assay of inhibitory activity on human C17;20-lyase
Human C17;20-lyase was expressed in E. Coli with
N-terminal sequence modification (MALLLAVF) as
51
described previously.
The vector pCWoriþ was
5.41. Molecular modeling studies
obtained as a generous gift from Dr. F. W. Dahlquist
(University of Oregon). The membrane fraction pre-
pared from E. Coli expressing human C17;20-lyase was
used for the following assay.
The conformations of 9k, 17a-hydroxypregnenolone,
and CB-7630 were generated using the Discover cvff

2272
N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
Pretlow, T. G.; Harris, S. E.; Wilson, E. M.; Mohler, J. L.;
French, F. S. Mol. Endocrinol. 1997, 11, 450.
7. Akhtar, M.; Corina, D. L.; Miller, S. L.; Shyadehi, A. Z.;
Wright, J. N. J. Chem. Soc., Perkin Trans. 1 1994, 263.
8. Swinney, D. C.; Mak, A. Y. Biochemistry 1994, 33, 2185.
9. Akhtar, M.; Corina, D.; Miller, S.; Shyadehi, A. Z.;
Wright, J. N. Biochemistry 1994, 33, 4410.
10. Wauwe, J. P. V.; Janssen, P. A. J. J. Med. Chem. 1989, 32,
2231.
11. Jarman, M.; Smith, H. J.; Nicholls, P. J.; Simons, C. Nat.
Prod. Rep. 1998, 495.
12. Rajfer, J.; Sikka, S. C.; Rivera, F.; Handelsman, D. J.
J. Clin. Endocrinol. Metab. 1986, 63, 1193.
13. Trachtenberg, J. J. Urol. 1984, 132, 61.
14. Williams, G.; Kerle, D. J.; Doble, A.; Dunlop, H.; Smith,
C.; Allen, J.; Yeo, T.; Blooms, S. R. Br. J. Urol. 1986, 58,
45.
The reaction mixture contains 75 mM phosphate buffer
(pH 7.4), 1 mM magnesium chloride, 0.5 pmol of
recombinant C17;20-lyase, 0.5 pmol of recombinant
cytochrome b5 (Pan Vera), 20.8 ng of recombinant
NADPH-cytochrome P450 reductase (Pan Vera), 10 nM
[1,2-3H]-17a-hydroxypregnenolone (Amersham), 5 mM
NADPH (Oriental Yeast), and test compounds in a
total volume of 20 lL. The reaction was terminated by
addition of 40 lL of ethyl acetate after 15 min incuba-
tion at 37 ꢂC, then vortexed for 30 s and briefly centri-
fuged. The organic phase, 30 lL, was applied to silica gel
thin layer chromatography plates (Whatman, LHPK).
The substrate and the product (DHEA) were separated
in the cyclohexane–ethyl acetate (3:2) solvent system.
The following procedures were the same as the assay of
rat enzyme inhibitory activity described above, and IC50
value was determined.
15. Coster, R. D.; Wouters, W.; Bruynseels, J. J. Steroid
Biochem. Mol. Biol. 1996, 56, 133.
16. Potter, G. A.; Barrie, S. E.; Jarman, M.; Rowlands, M. G.
J. Med. Chem. 1995, 38, 2463.
5.44. Assay of inhibitory effects on testosterone biosyn-
thesis in rats
17. Barrie, S. E.; Potter, G. A.; Goddard, P. M.; Haynes, B.
P.; Dowsett, M.; Jarman, M. J. Steroid Biochem. Mol.
Biol. 1994, 50, 267.
18. Cherry, P. C.; Cocker, J. D.; Searle, A. D. WO 94/27989;
Chem. Abstr. 1995, 123, 83368.
19. Ideyama, Y.; Kudoh, M.; Tanimoto, K.; Susaki, Y.;
Nanya, T.; Nakahara, T.; Ishikawa, H.; Yoden, T.;
Okada, M.; Fujikura, T.; Akaza, H.; Shikama, H. Prostate
1998, 37, 10.
20. L-39 (University of Maryland): Long, B. J.; Grigoryev,
D. N.; Nnane, I. P.; Liu, Y.; Ling, Y.-z.; Brodie, A. M.
Cancer Res. 2000, 60, 6630.
Test compounds were suspended in 0.5% methylcellu-
lose and orally administered to 9 or 10-week old, male
SD (Sprague-Dawley) rats at a dose of 25 mg/kg. The
rats in the control group received 0.5% methylcellulose.
Blood samples were obtained 2 and 5 h after the
administration. The serum testosterone concentrations
were determined by a specific radioimmunoassay kit
(Dia Sorin s.r.l, Italy). The percentage of the testoster-
one concentration of the group of rats, which received
test compounds to that of the control group was cal-
culated (T/C, %), and regarded as the inhibitory activity.
21. BW 19 (University of the Saarland): Hartmann, R. W.;
€
Wachter, G.; Hector, M.; Wachall, B. 93rd Annual
Meeting of the American Association for Cancer
Research, San Francisco, CA, Apr. 6–10, 2002, #1020.
22. Nnane, I. P.; Long, B. J.; Ling, Y.-z.; Grigoryev, D. N.;
Brodie, A. M. Br. J. Cancer 2000, 83, 74.
23. Njar, V. C. O.; Brodie, A. M. H. Curr. Pharm. Des. 1999,
5, 163.
Acknowledgements
24. Njar, V. C. O.; Kato, K.; Nnane, I. P.; Grigoryev, D. N.;
Long, B. J.; Brodie, A. M. H. J. Med. Chem. 1998, 41, 902.
25. Ling, Y.-z.; Li, J.-s.; Liu, Y.; Kato, K.; Klus, G. T.;
Brodie, A. J. Med. Chem. 1997, 40, 3297.
26. Li, J.-s.; Li, Y.; Son, C.; Brodie, A. M. H. J. Med. Chem.
1996, 39, 4335.
We thank Drs. A. Miyake and T. Naka for helpful
discussions throughout this work, and Mr. A. Fujishima
and Ms. K. Higashikawa for measuring a single-crystal
X-ray Analysis, and Dr. F. W. Dahlquist (University of
Oregon) for providing pCWoriþ.
27. Li, J.-s.; Li, Y.; Son, C.; Brodie, A. M. H. Prostate 1995,
26, 140.
28. Njar, V. C. O.; Klus, G. T.; Johnson, H. H.; Brodie, A. M.
H. Steroids 1997, 62, 468.
References and notes
29. Recanatini, M.; Bisi, A.; Cavalli, A.; Belluti, F.; Gobbi, S.;
Rampa, A.; Valenti, P.; Palzer, M.; Palusczak, A.;
Hartmann, R. W. J. Med. Chem. 2001, 44, 672.
30. Hartmann, R. W.; Hector, M.; Wachall, B. G.; Palusczak,
A.; Palzer, M.; Huch, V.; Veith, M. J. Med. Chem. 2000,
43, 4437.
1. Crawford, E. D.; Eisenberger, M. A.; McLeod, D. G.;
Spaulding, J. T.; Benson, R.; Dorr, F. A.; Blumenstein, B.
A.; Davis, M. A.; Goodman, P. J. New Engl. J. Med. 1989,
321, 419.
2. Labrie, F.; Belanger, A.; Simard, J.; Labrie, C.; Dupont,
A. Cancer Suppl. 1993, 71, 1059.
31. Hartmann, R. W.; Hector, M.; Haidar, S.; Ehmer, P. B.;
Reichert, W.; Jose, J. J. Med. Chem. 2000, 43, 4266.
32. Zhuang, Y.; Wachall, B. G.; Hartmann, R. W. Bioorg.
Med. Chem. 2000, 8, 1245.
33. Wachall, B. G.; Hector, M.; Zhuang, Y.; Hartmann, R.
W. Bioorg. Med. Chem. 1999, 7, 1913.
3. Hara, T.; Miyazaki, J.; Araki, H.; Yamaoka, M.; Kanzaki,
N.; Kusaka, M.; Miyamoto, M. Cancer Res. 2003, 63, 149.
4. Taplin, M.-E.; Bubley, G. J.; Ko, Y.-J.; Small, E. J.;
Upton, M.; Rajeshkumar, B.; Balk, S. P. Cancer Res.
1999, 59, 2511.
5. Culig, Z.; Hobisch, A.; Cronauer, M. V.; Cato, A. C.;
Hittmair, A.; Radmayr, C.; Eberle, J.; Bartsch, G.;
Klocker, H. Mol. Endocrinol. 1993, 7, 1541.
34. Njar, V. C. O.; Hector, M.; Hartmann, R. W. Bioorg.
Med. Chem. 1996, 4, 1447.
€
€
35. Wachter, G. A.; Hartmann, R. W.; Sergejew, T.; Grun,
G. L.; Ledergerber, D. J. Med. Chem. 1996, 39, 834.
36. McCague, R.; Rowlands, M. G.; Barrie, S. E.; Houghton,
J. J. Med. Chem. 1990, 33, 3050.
6. Tan, J.; Sharief, Y.; Hamil, K. G.; Gregory, C. W.; Zang,
D.-Y.; Sar, M.; Gumerlock, P. H.; deVere White, R. W.;

N. Matsunaga et al. / Bioorg. Med. Chem. 12 (2004) 2251–2273
2273
37. Barrie, S. E.; Jarman, M. Endocrine-Relat. Cancer 1996, 3,
25.
44. Chapman, N. B.; Clarke, K.; Saraf, S. D. J. Chem. Soc.
(C) 1967, 731.
38. Burkhart, J. P.; Gates, C. A.; Laughlin, M. E.; Resvick,
R. J.; Peet, N. P. Bioorg. Med. Chem. 1996, 4, 1411.
39. Guarna, A.; Occhiato, E. G.; Machetti, F.; Giacomelli, V.
J. Org. Chem. 1999, 64, 4985.
40. Arth, G. E.; Patchett, A. A.; Jefopoulus, T.; Bugianesi, R.
L.; Peterson, L. H. J. Med. Chem. 1971, 14, 675.
41. Ayub, M.; Levell, M. J. J. Steroid Biochem. 1987, 28,
521.
45. Beck, J. B. J. Org. Chem. 1972, 37, 3224.
46. Browne, L. J.; Gude, C.; Rodriguez, H.; Steele, R. E.;
Bhatnager, A. J. Med. Chem. 1991, 34, 725.
47. Burger, A.; Bernabe, M. J. Med. Chem. 1971, 14, 883.
48. Julia, P. M.; Igolen, J.; Igolen, H. Bull. Soc. Chim. Fr.
1962, 1060.
49. Compound 4 was unknown when we were developing this
study, but was reported by Hartmann recently.33
50. Machinist, J. M.; Mayer, M. D.; Shet, M. S.; Ferrero, J. L.;
Rodrigues, A. D. Drug Metab. Dispos. 1995, 23, 1163.
51. Imai, T.; Globerman, H.; Gertner, J. M.; Kagawa, N.;
Waterman, M. R. J. Biol. Chem. 1993, 268, 19681.
52. Flack, H. D. Acta Crystallogr. 1983, A39, 876.
42. Angelastro, M. R.; Laughlin, M. E.; Schatzman, G. L.;
Bey, P.; Blohm, T. R. Biochem. Biophys. Res. Commun.
1989, 162, 1571.
ꢁ
43. Ple, P. A.; Marnett, L. J. J. Heterocycl. Chem. 1988, 25,
1271.