Imidazole substituted biphenyls: A new class of highly potent and in vivo active inhibitors of P450 17 as potential therapeutics for treatment of prostate cancer

Article abstract of DOI:10.1016/S0968-0896(99)00160-1

3- And 4-imidazol-1-yl-methyl substituted biphenyl compounds (named as meta- and para-substituted compounds) were synthesized bearing additional substituents in 3'-/4'-position as inhibitors of P450 17 (17α-hydroxylase-C17,20-lyase). P450 17 is the key enzyme of androgen biosynthesis. Its inhibition is a novel therapeutic strategy for treatment of prostate cancer (PC). Twenty-nine compounds were synthesized by Ar-Mg-Br, Negishi or Suzuki aryl-aryl cross coupling and tested toward human and rat enzyme. Most of the compounds showed moderate to excellent activity against one of the enzymes (0.087 μM ≤ IC₅₀ ≤ 7.7 μM (ketoconazole: 0.74 μM) for the human enzyme, 0.63 μM ≤ IC₅₀ ≤ 32 μM (ketoconazole: 67 μM) for the rat enzyme). Interestingly, strong species differences were observed. In addition compounds were tested for inhibition toward P450 arom. The 3-imidazol-1-yl-methyl substituted compounds showed good inhibitory activity of P450 arom, while for the 4-substituted compounds negligible inhibition was found. For the most active group of P450 17 inhibitors, (i.e. the 4-imidazol-1-yl-methyl substituted compounds) a QSAR study was performed for inhibition of the human enzyme leading to the result that a hydrophilic substituent in 3'-/4'-position is very important. The most promising compounds (with respect to activity toward both enzymes) were tested in vivo using SD-rats for reduction of plasma testosterone concentrations 2 and 6h after single ip application. The fluorine substituted compound 8c decreased the testosterone plasma concentration to castration level (after 2h; 5 mg/kg) showing a biological half live of about 6h.

Full text of DOI:10.1016/S0968-0896(99)00160-1

Bioorganic & Medicinal Chemistry 7 (1999) 1913±1924
Imidazole Substituted Biphenyls: A New Class of Highly Potent
and In Vivo Active Inhibitors of P450 17 as Potential
Therapeutics for Treatment of Prostate Cancer
Bertil G. Wachall, Markus Hector, Yan Zhuang and Rolf W. Hartmann*
University of the Saarland, FR 12.1 Pharmaceutical and Medicinal Chemistry, P.O. Box 151150, D-66041 Saarbrucken, Germany
È
Received 4 December 1998; accepted 25 March 1999
AbstractÐ3- And 4-imidazol-1-yl-methyl substituted biphenyl compounds (named as meta- and para-substituted compounds) were
synthesized bearing additional substituents in 30-/40-position as inhibitors of P450 17 (17a-hydroxylase-C17,20-lyase). P450 17 is the
key enzyme of androgen biosynthesis. Its inhibition is a novel therapeutic strategy for treatment of prostate cancer (PC). Twenty-
nine compounds were synthesized by Ar-Mg-Br, Negishi or Suzuki aryl±aryl cross coupling and tested toward human and rat
enzyme. Most of the compounds showed moderate to excellent activity against one of the enzymes (0.087 mMꢀIC50ꢀ7.7 mM
(ketoconazole: 0.74 mM) for the human enzyme, 0.63 mMꢀ IC50ꢀ32 mM (ketoconazole: 67 mM) for the rat enzyme). Interestingly,
strong species di€erences were observed. In addition compounds were tested for inhibition toward P450 arom. The 3-imidazol-1-yl-
methyl substituted compounds showed good inhibitory activity of P450 arom, while for the 4-substituted compounds negligible
inhibition was found. For the most active group of P450 17 inhibitors, (i.e. the 4-imidazol-1-yl-methyl substituted compounds) a
QSAR study was performed for inhibition of the human enzyme leading to the result that a hydrophilic substituent in 30-/40-posi-
tion is very important. The most promising compounds (with respect to activity toward both enzymes) were tested in vivo using SD-
rats for reduction of plasma testosterone concentrations 2 and 6 h after single ip application. The ¯uorine substituted compound 8c
decreased the testosterone plasma concentration to castration level (after 2 h; 5 mg/kg) showing a biological half live of about 6 h.
# 1999 Elsevier Science Ltd. All rights reserved.
Introduction
target and attempts were made to obtain speci®c ster-
oidal6±10 as well as nonsteroidal1±3,11±17 inhibitors.
17a-Hydroxylase-C17,20-lyase (P450 17), a cytochrome
P450 monooxygenase, is the key enzyme of the andro-
gen biosynthesis. It catalyzes the hydroxylation of
progesterone and pregnenolone into the corresponding
17a-products, as well as the cleavage of the C17±C20
bond to yield androstenedione and DHEA (dehydro-
epiandrosterone). These steroids are weak androgens
which subsequently are converted by other enzymes
(17bHSD, 3bHSD, 5a-reductase) to the most potent
androgens testosterone and DHT (dihydrotestosterone).
For the development of nonsteroidal inhibitors an
iron complexing group, mostly a nitrogen bearing
heterocycle, was combined with a lipophilic moi-
ety.4,5,11,13,16,17 In some cases an additional sub-
stituent1,12,14,15,18 was introduced to mimic the
hydrophilic C3 group of the substrate. As a substitute of
the steroidal nucleus di€erent strategies were used.
While other groups pursued A-ring12 or B-(D)-
ring11,13,18 mimetic approaches, our group developed
A-B-ring type1,2,14,16 inhibitors.
As androgens have been implicated in the development
and progression of prostatic cancer, a promising alter-
native to treatment with antiandrogens and GnRH
analogues might be the use of inhibitors of P450 17.1±5
For that reason P450 17 attracted attention as a therapeutic
Bifonazole (I, Chart 1), a long known antimycotic,
which had shown weak rat P450 17 inhibitory activity,19
is supposed to mimic the A- and C-ring of progester-
one.20 So far it has not received attention as a leading
structure for P450 17 inhibitors. However, the highly
potent steroidal inhibitor II (as well as its progesterone
analogue), recently published by Njar et al.,10 encouraged
us to perform a systematic structure±activity study in
the class of A-C-ring mimetics.
Key words: Imidazole-substituted biphenyls; 17a-hydroxylase-C17,20-
lyase (P450 17); enzyme inhibitors; QSAR; theoretical calculations;
antineoplastics.
* Corresponding author. Tel.: +49-681-302-3424; fax: +49-681-302-
4386; e-mail: rwh@rz.uni-sb.de
0968-0896/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved.
PII: S0968-0896(99)00160-1

1914
B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
to yield 10b. Since the direct synthesis of the carboxy
and amino biphenyls 8g, 9l and 12l with aryl-Mg-Br in
threefold excess with PdCl2(dppf)27 failed, 8g, 9l and
12l were synthesized by alternative routes. The amino
compound 9l was obtained by reduction of the nitro
analogue 9i under a 5 bar H2 atmosphere (method D,
Scheme 1). Because of the low yield of this reaction, for
the synthesis of 12l the acetylic group of 12k was
cleaved with H2SO4 (method E, Scheme 1). The carboxy
compound 8g was formed by hydrolyzing the nitrile 8f
(method K, Scheme 1).
Biological Results
The inhibitory activity towards P450 17 rat and human
testicular enzymes was tested using microsomal frac-
tions, progesterone as substrate and RP-HPLC with
UV-detection. The rat assay was recently described by
us.1 It results in the formation of 17a-hydroxy-
progesterone and androstenedione.
Chart 1. Selected inhibitors of P450 17.
We report here the synthesis and the inhibition studies
toward rat and human P450 17 (and P450 arom) of 29
imidazole substituted biphenyls (Chart 2). We present
the ®rst QSAR study for P450 17 inhibitors and
describe the in vivo potency of selected compounds.
For the human enzyme assay we have applied the same
procedure, as it gets along without radiolabelled sub-
strate (tritiated pregnenolone is commonly used29). In
contrast to the rat enzyme 16a- and 17a-hydroxy-
progesterone are formed in a ratio of 3:10 as it is
described by others.30
Table 2 shows the IC50 values and the inhibitory
potencies of the compounds relative to the long known
P450 17 inhibitor ketoconazole (KTZ; rp values). KTZ,
an antimycotic (inhibitor of fungal lanosterol-14a-
demethylase), had shown bene®t in the treatment of
prostate cancer in men, but because of its short biolo-
gical half life, its poor selectivity (i.e. its considerable
ability to inhibit other steroidogenic P450 enzymes as
well) and its gastro-intestinal e€ects, it is not commonly
accepted for wide use in patients.31
Chemistry
Formation of 121 and 221 was carried out by SN reac-
tion with imidazole, 18K6 and K2CO3 starting from the
corresponding bromobenzylbromides according to
Baggaley et al.22 The synthesis of the biphenyls was
performed by Suzuki reaction23 (method A, Scheme 1)
in case of available boronic acids. Otherwise
a
Pd(PPh3)4 catalyzed coupling of Grignard reagents was
used24 (method B, Scheme 1), starting from substituted
bromobenzenes to give the biphenylic compounds 9a,
9d, 9e and 12a (Table 1). For the synthesis of 8f an
alternative synthetic route was used because of the labi-
lity of the nitrile group. The biphenyl structure was
synthesized by Negishi reaction25 (method G, Scheme
1). After NBS bromation (method H, Scheme 1), 8f
was obtained by reaction with imidazole (method I,
Scheme 1).
In general no correlation between the inhibition data of
the two species could be observed (rhuman,rat=0.24).
While KTZ is only a moderate inhibitor against the rat
enzyme, its potency increases more than 90-fold to be a
strong inhibitor toward the human enzyme. On the
other hand, some compounds showed a decreased inhi-
bition of the human enzyme compared to the rat data
(e.g. 8d, by a factor of four).
The phenolic compounds were synthesized from the
corresponding methoxy biphenyls by ether cleavage
with BBr3 (method C, Scheme 1).
The compounds showed moderate to excellent activity
against the rat enzyme, the potency of the p-sub-
stituted biphenyls being clearly enhanced compared to
the m-substituted. In case of the latter compounds inhi-
bitory activity of the unsubstituted substance was only
increased by one substituent, the 40-OH group (com-
pound 11b).
To avoid polymerization acetal cleavage of 10a was
performed in HCl with resorcin26 (method F, Scheme 1)
In the group of the p-substituted biphenyls compounds
bearing their substituent in 40-position (compounds
8±8h) were, with the exception of 9b, superior to the
30-substituted compounds. Lipophilic substituents in
40-position enhanced activity leading to rp values of
more than 50. Contrarily substitution in 30-position by
Chart 2. Structure of the title compounds.

B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
1915
Scheme 1. Preparation of compounds. Reagents: Method A: Pd(PPh3)4, Na2CO3, toluene; Method B: Mg, Pd(PPh3)4, THF; Method C: BBr3,
CH2Cl2 MeOH; Method D: Pd/C, H2, p; Method E: H2SO4, r¯x; Method F: HCl, resorcin; Method G: BuLi, ZnCl2, Pd(PPh3)4; Method H: NBS,
CCl4; Method I: imidazole, 18-K-6, K2CO3, acetone; Method K: H2SO4, HOAc.
lipophilic substituents led to a loss of activity. The 30-
OH compound 9b was the most potent inhibitor of the
rat enzyme in this study (rp=106). Neither the same
substitutent in 40-position (8b) nor other hydrophilic
substituents in 30- or 30- and 40-position (9k, 9l and 10b)
could enhance activity.
A further increase in activity could be achieved by
introducing two OH groups in 30- and 40-position.
Compound 10b is the most active compound of this
study against the human enzyme with an rp of 8.5. The
thiophene bearing inhibitor 13 showed, in contrast to
the rat enzyme, a very good inhibition of the human
enzyme.
Looking at the human enzyme data di€erent structure
activity relationships were observed. With few excep-
tions the compounds showed a moderately to strongly
enhanced inhibitory activity (up to 36 times for 10b)
compared to the rat enzyme. As seen for the rat enzyme,
m-substituted biphenyls (compounds 11±12) were less
active than the para-substituted analogues (compound
8±10). An increase in activity could only be obtained by
a hydroxy substituent (compounds 11b and 12b). In
contrast to the rat enzyme lipophilic substituents in the
40-position of the para-substituted biphenyls decreased
inhibitory activity, whereas the hydroxy group
enhanced activity (8b, rp=2.4). The 30-substituted com-
pounds (9a±9l) turned out to be superior to 40-sub-
stituted derivatives (8±8h), the hydrophilic compounds
9b, 9k and 9l showing maximum activity (OH com-
pound 9b, rp=5.7).
In addition, selected compounds were tested for inhibi-
tion of P450 arom (Table 3). While the m-substituted
compounds showed a good inhibition potency for P450
arom, the most active P450 17 inhibitors, that is, the p-
group compounds showed poor inhibitory activity for
this enzyme. Furthermore compounds 8a and 11d were
tested for inhibition of P450 TxA2. With IC50 values of
17 mM (8a) and 12 mM (11d), respectively, they showed
only weak activity compared to the reference compound
dazoxiben (IC50=1.1 mM).
QSAR
The good correlation between the human IC50s of the
p-substituted compounds and physicochemical parameters

1916
B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
Table 1. Structures, synthetic methods, and analytic data
Compound
Y
Formula
mp (ꢁC)
Methoda
Recrystallization
Yieldb
8
8a
8b
8c
8d
8e
8f
8g
8h
9a
9b
9c
9d
9e
9i
9k
9l
10a
10b
11
11a
11b
11c
11d
12a
12b
12k
12l
13
H
40-OMe
40-OH
C16N14N2
C17H16N2O
C16H14N2O
C16H13N2F
C16H13N2Cl
C17H16N2
141±143c
170±171
260±262
139±141
94±96
138±140
49±51
308±310
248±250
90±91
194±196
oil
88±89
65±66
97±98
171±173
159±160
134±135
201±203
oil
146±148
192±194
200e
A
A
C
A
A
A
I
Ðf
i-propanol/MeOH
i-propanol/MeOH
i-propanol
73
90
67
87
58
65
92
50
44
89
40
45
65
56
78
34
35
68
27
47
71
90
62
70
72
99
71
95
79
40-F
40-Cl
Ðf
40-Me
n-hexane/ethyl acetate
n-hexane-acetone
Ðf
40-CN
C17H13N3
40-COOH
40-SMe
30-OME
30-OH
C17H14N2O2
C17H16N2Sd
C17H16N2O
C16H14N2O
C16H13N2F
C16H13N2Cl
C17H16N2
C16H13N3O2
C18H17N3O
C16H15N3
K
A
B
C
A
B
B
A
A
D
A
F
A
A
C
A
A
B
C
A
E
A
i-propanol/MeOH
n-hexane/ethyl acetate
i-propanol
30-F
Ðg
30-Cl
Ðh
30-Me
Ðh
30-NO2
30-NHCOCH3
30-NH2
30,40-OCH2O-
30,40-diOH
H
n-hexane/ethyl acetate
n-hexane i-propanol
n-hexane/MeOH
i-propanol
ethy acetate/MeOH
Ðh
C17H14N2O2
C16H14N2O2
C16H14N2
40-OMe
40-OH
C17H16N2Od
C16H14N2O
C16H13N2F
C16H13N2Cl
C17H16N2O
C16H14N2O
C18H17N3O
C16H15N3
i-propanol/MeOH
i-propanol
40-F
Ðf
i-propanol
40-Cl
59±60
oil
194±195
160±161
68±69
30-OME
30-OH
Ði
MeOH
30-NHCOCH3
30-NH2
Ðf
n-hexane/ethyl acetate
i-propanol/MeOH
C14H12N2S
144±145
a
Capital letters refer to synthetic methods A±K in Experimental.
No e€orts were made to optimize yields.
Cuberes et al.28: 137 139ꢁC.
b
c
d
e
f
Â0.5 H2SO4.
Sublimation.
No further puri®cation was neceaasry.
HPLC, RP18, H2O/MeOH (6/4).
g
h
i
Column chromatography, ammonia saturated ethyl acetate:MeOH (5:1).
Column chromatography, ammonia saturated CH2Cl2:EtOH (9:1).
from a qualitative point of view, led to a QSAR study.
Chosen for QSAR were all p-substituted compounds (8±
10 and 13) with exception of the totally inactive COOH
compound 8g.
(for all compounds; Table 4) in a MeOH-bu€er system
(r(fR; RMW)=0.91, s=0.26, F=96.5; r(fR; RMW)=0.96*,
s=0.26, F=147.0) and regressed against pK(IC50)s to
give an improved correlation (r=0.88, s=0.22,
F=19.7). It was found, that the addition of a second
variable (Table 5) increased correlation signi®cantly.
For some parameters no data were available for com-
pounds 10 and 13. Hence these compounds were not
implemented in these cases (not implemented: 10, 13:*).
Stepwise multiple regression of pIC50s against various
hydrophobic, steric and electronic parameters was per-
formed for the 30- and 40-substituted groups individually.
Beside combination of RMW with an electronic para-
meter, that is, s (pIC50= 0.36 (‹0.07) RMW 0.53
(‹0.25) s+1.18 (‹0.17), n=8, r=0.94, s=0.17,
F=18.2) best results (eq. 1) were obtained by combina-
tion with the steric parameter B3:
The 30-substituted compounds (9a±9k) had no correla-
tions with electronic parameters (s (Hammett)33:
r=0.53) and only weak to moderate correlations with
steric or lipophilic parameters (B3 (Sterimol33): r=0.60;
fR(revised Rekker substituent lipophilicity32): r=0.76).
To get a better correlation, RMW values were determined
pIC50
ˆ
0:37ꢀÆ0:05†RMW 0:51ꢀÆ0:13†B3
‡ 2:02ꢀÆ0:26†
ꢀ1†
n ˆ 8; r ˆ 0:97; s ˆ 0:12; F ˆ 39:8

B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
1917
Table 2. P450 17 inhibition data
Compound
Y
Imidazolyl-methyl
IC50 rat (mM)
rp rata
IC50c human (mM)
rp humana
8
8a
8b
8c
8d
8e
8f
8g
8h
9a
9b
9c
9d
9e
9i
9k
9l
10a
10b
11
11a
11b
11c
11d
12a
12b
12k
12l
13
H
40-OMe
40-OH
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
p
2.0
7.9
2.6
0.98
1.4
1.3
1.2
n.i.
8.5
6.5
0.63
4.9
11
7.6
4.6
3.0
6.0
20
3.1
5.3
32
2.9
6.1
5.0
16
5.1
13
27
2.2
67
34
9
0.98
3.7
0.31
0.96
5.8
4.2
2.5
n.i.b
7.7
0.59
0.13
0.66
1.3
1.3
1.8
0.23
0.21
3.1
0.087
2.2
4.5
0.86
2.9
13
3.7
1.2
2.1
4.2
0.76
0.21
2.4
0.77
0.13
0.18
0.30
Ð
0.10
1.3
5.7
1.1
0.57
0.57
0.41
3.2
3.5
0.24
8.5
0.34
0.16
0.86
0.26
0.07
0.20
0.62
0.35
0.18
2.2
26
68
48
52
56
Ð
9
10
106
14
6
40-F
40-Cl
40-Me
40-CN
40-COOH
40-SMe
30-OME
30-OH
30-F
30-Cl
30-Me
9
30-NO2
30-NHCOCH3
30-NH2
30,40-OCH2O-
30,40-diOH
H
15
22
11
3
22
13
2
23
11
13
4
13
5
p
p
m
m
m
m
m
m
m
m
m
p
40-OMe
40-OH
40-F
40-Cl
30-OME
30-OH
30-NHCOCH3
30-NH2
2
30
1
0.33
0.74
KTZ
1.0
a
rp: Relative potency (against ketoconazole (KTZ), rp ketoconazole=1).
n.i.=No inhibition (at 125 mM for the rat and 2.5 mM for the human enzyme, respectively).
IC50 of pregnenolone=23 mM.
b
c
The 40-substituted compounds (8±8h) showed better
correlation against electronic (Pol (polarizability):
r=0.79, s=0.32, F=9.9), steric (against B3: r=0.81,
s=0.30, F=11.8) and mixed parameters (MR (molar
refractivity33): r=0.78, s=0.32, F=9.2). Although an
enhanced correlation factor was also achieved for fR
(r=0.78, s=0.33, F=3.9), only a minor improvement
could be found for replacing fR by RMW (r=0.78,
s=0.32, F=9.1). Again increasing correlations were
obtained by adding a further variable (Table 6).
pIC50
ˆ
0:26ꢀÆ0:08†RMW 0:06ꢀÆ0:02†MR
‡ 0:74ꢀÆ0:21†
ꢀ2†
n ˆ 8; r ˆ 0:94; s ˆ 0:20; F ˆ 18:2
For the 30- and 40-substituted compounds 8±10b (+13)
a correlation could only be found with lipophilicity;
again with RMW superior to fR(r(fR)=0.70, s=0.42,
F=16.5; (RMW)=0.82, s=0.34, F=33.9). Although an
improvement was observed for group 8 as well as for 9,
adding of B3* as second variable (Table 7) gave no sig-
ni®cantly enhanced correlation.
Combination of lipophilic and electronic as well as
steric parameters gave improved correlations:
pIC50= 0.53 (‹0.22) fR 0.17 (‹0.06) Pol+4.90
(‹1.87), n=8, r=0.91, s=0.23, F=12.0; pIC50= 0.23
(‹0.10) RMW 0.80 (‹0.30) B3+1.16 (‹0.42), n=8,
r=0.91, s=0.23, F=12.7. However, the following
equation (eq. 2) describes the variables which were best
correlated to the inhibition data:
To solve this problem an indicator variable34 m* was
introduced: m was set 0 for 40-substituted and 1 for
30-substituted compounds. This structure information
describing parameter led to the ®nal QSAR description
(eq. 3) of the human P450 17 inhibitor activity for the

1918
B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
Table 5. Correlation matrix for group 8
Table 3. P450 arom inhibition data
Compound
Imidazolyl-methyl
IC50 P450 arom [mM]
Parameter
B3
RMW
ꢀ
8
8b
8e
9a
9b
9d
9i
p
p
p
p
p
p
p
p
m
m
m
m
m
m
m
m
m
66%a
31%a
51%a
55%a
57%a
65%a
70%a
48%a
0.60
0.56
0.57
0.37
0.20
B3
RMW
ꢀ
1
0.13
1
0.47
0.23
1
Table 6. Correlation matrix for group 9
10a
11
Parameter
B3
fR
MR
Pol
RMW
11a
11b
11c
11d
12a
12b
12k
12l
B3
fR
MR
Pol
RMW
1
0.54
1
0.79
0.43
1
0.80
0.46
0.99
1
0.52
0.99
0.37
0.23
1
0.25
0.49
2.5
1.9
a
% Inhibition at 25 mM (aminogluethimide: IC50=18.5 mM).
KTZ slightly reduced the testosterone plasma level after
2 h. After 6 h, however, a stimulation of the testosterone
concentration above control (threefold), was observed.
In contrast 9b showed enhanced (but not signi®cant)
inhibitory activity after 2 h, combined with a moderate
increase after 6 h. The most active ¯uoro compound 8c
totally blocked androgen biosynthesis 2 h after applica-
tion, and showed a 50% inhibition of the testosterone
concentraton after 6 h.
p-substituted compounds with an strongly improved
correlation:
pIC50
ˆ
0:31ꢀÆ0:05†RMW 0:60ꢀÆ0:15†B3
‡ 0:58ꢀÆ0:10†m ‡ 1:47ꢀÆ0:25†
ꢀ3†
n ˆ 16Ã; r ˆ 0:95; s ˆ 0:18; F ˆ 39:1
In vivo
Discussion and Conclusion
Some of the most potent inhibitors of the human
enzyme showed too poor rat activity to be tested in vivo
(e.g. compounds 10b and 13). Compounds 8c and 9b
were evaluated for reduction of plasma testosterone
concentration in male Sprague±Dawley rats (Table 8).
Compounds were applied intraperitoneally equimolar to
10 mg/kg body weight KTZ. Testosterone concentra-
tions were determined from blood samples, taken by
cardiac puncture after 2 and 6 h.
The synthesized imidazole substituted biphenyls demon-
strate that an A-C-ring mimetic approach is a reasonable
strategy for developing potent inhibitors of P450 17.
Compared to KTZ or bifonazole (similar activity as
KTZ toward rat enzyme20) the best compounds showed
excellent inhibitory activity against rat (9b: rp 106) and
human enzyme (10b: rp 8.5). They almost reached the
activity of the powerful steroidal inhibitor II10 (IC50 rat:
0.18 mM; IC50 human: 0.04 mM in our test system).
Table 4. RMW values
Table 7. Correlation matrix for group 8 and 9
Compound
RMw
fR subst.a
fR tot.b
Parameter
B3
m
RMW
8
2.48
2.55
1.04
4.20
2.90
3.54
1.78
3.50
2.52
1.14
3.38
2.73
3.40
2.34
1.22
1.20
2.38
0.64
2.00
0.204
0.274
0.353
0.933
0.444
0.823
0.155
0.724
0.274
0.353
0.933
0.444
0.724
0.039
0.902
0.616
0.585
0.910
0.603
4.29
4.36
3.73
5.02
4.53
4.91
3.93
4.81
4.36
3.73
5.02
4.53
4.81
4.05
3.18
3.47
3.50
3.18
3.48
B3
m
RMW
1
0.32
1
0.21
0.26
1
8a
8b
8c
8d
8e
8f
8h
9a
9b
9c
9d
9e
9i
Table 8. Reduction of the plasma testosterone concentrations in SD-
rats
Compounda
Plasma testosterone level [ng/mL]b
2 h
6 h
Control
KTZ
Control
8c
3.31‹2.07
1.66‹0.74***
2.15‹2.01
0.06‹0.06*
0.83‹0.28ns
0.52‹0.26
1.43‹0.61*
0.29‹0.08
0.15‹0.11**
0.37‹0.07**
9k
9l
10a
10b
13
9b
a
All compounds were applied equimolar to 10 mg/kg KTZ.
Signi®cance (Wilcoxon): * p<0.01; ** p<0.025; *** p<0.05; ns: not
signi®cant: p>0.05.
a
subst.: Substituent, revised Rekker lipophilicity.32
tot.: Molecule, revised Rekker lipophilicity.32
b
b

B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
1919
1
In both species the para substituted compounds were
superior to the meta substituted. Nevertheless large
species discrepancies were observed (rhuman,rat=0.24), as
found by others.9,10 For the rat enzyme best results were
obtained with lipophilic substituent in 40-position (10c±
f) or an OH substituent in 30-position (9b).
as indicated. H NMR spectra were recorded on a Bru-
ker AM-400 instrument (400 MHz). Chemical shifts are
given in parts per million, and TMS was used as internal
standard for spectra obtained in DMSO-d6 and CDCl3.
All J values are given in Hz. Purity was checked by GC-
MS on a HP G1800A GCD-system. Reagents and sol-
vents were used as obtained from commercial suppliers
without further puri®cation. Column chromatography
was performed using silica-gel 60 (50±200 mm), and
reaction progress was determined by TLC analysis on
ALUGRAM1 SIL G/UV254 (Macherey-Nagel). Boro-
nic acids and bromoaryls used as starting materials were
commercially obtained (Lancaster, Fluka, Acros).
For the human enzyme di€erent correlations were
found: The ®rst QSAR study for P450 17 human led to
eq. 3, which demonstrates the superiority of the 30-sub-
stituted compounds (positive coecient of m), and the
similar binding mode of the 30- and 40-substituted inhi-
bitors (correlation with m) as well as the steric hin-
drance for substituents with too big width (negative
coecient of B3). In addition a strong correlation with
substituent hydrophilicity was found (negative coe-
cient of RMW). This correlation is the ®rst QSAR proof
for the hydrophilic residues at the ends of the substrate
binding loops, predicted for P450 17 in di€erent mole-
cular modeling studies.35±37
Method A
4-(Imidazol-1-yl-methyl)biphenyl (8). A 50 mL-¯ask was
charged with Pd(PPh3)4 (0.076 g, 0.066 mmol), toluene
(10 mL), N-(4-bromobenzyl)imidazole (1) (0.37 g,
1.6 mmol), and an aqueous solution of Na2CO3 (5 mL
of a 2 M solution) under nitrogen atmosphere, and then
phenyl boronic acid (0.38 g, 3.1 mmol) in ethanol was
added. The mixture was re¯uxed for 2.5 h under vigor-
ous stirring. After the reaction was complete, the resi-
dual boronic acid was oxidized with 30% H2O2 (0.5 mL)
at room temperature for 1 h. The product was extracted
with CH2Cl2/ethanol (9=1), and washed with saturated
NaCl solution. The organic layer was extracted with 0.1
N HCl. The aqueous layer was washed with ethyl ace-
tate and alkalized with saturated Na2CO3 until the pro-
duct precipitated. The crude product was washed with
water and diethyl ether to give 8 (0.135 g, 73%) as a
white solid: mp 141±143ꢁC (Cuberes et al.29: 137±
139ꢁC); IR 3100, 3030, 1510, 1485, 1440, 1235, 1065,
Looking at inhibition potency against other P450
enzymes, P450 arom plays an important role. Since tes-
tosterone is accumulated by blocking of P450 arom,
more testosterone (already a potent androgen) will be
converted into the most potent androgen DHT. To
avoid androgen stimulation, inhibitory activity against
P450 arom has to be estimated as an unwanted side
e€ect. Hence the good selectivity toward P450 arom of
the most active, para substituted compounds, is of great
importance in the development of P450 17 inhibitors for
the treatment of PC. On the other hand the meta sub-
stituted compounds might be a starting point for devel-
oping speci®c P450 arom inhibitors as potential
therapeutics for breast cancer.
825, 665 cm 1; H NMR (CDCl3) 5.16 (s, 2H, -CH2-),
1
6.94 (s, 1H, Im H40), 7.11 (s, 1H, Im H50), 7.22 (d,
J=8.0 Hz, 2H, Ar H3,H5), 7.34±7.38 (m, 1H, Ar H40),
7.42±7.46 (m, 2H, Ar H30,H50), 7.56±7.58 (m, 5H, Ar
H2,H6,H20,H60, Im H20); GC±MS m/z (M+): 234.1
(calcd 234.1).
For the in vivo study only compounds with a high
potency toward human and rat enzyme could be taken
in consideration. Compounds with high activity toward
the human enzyme and low activity against the rat
enzyme could not be tested. They might of course be
promising drug candidates (e.g. 9k,l or the most active
compound 10b, as well as the F-compound 9c, and the
thiophene compound 13, with a possibly enhanced
metabolic stability).
40-Methoxy-4-(imidazol-1-yl-methyl)-biphenyl (8a). Col-
orless needles: mp 170±171ꢁC; IR 3100, 2960, 1610,
1
1500, 1255, 1035, 815 cm 1; H NMR (CDCl3) 3.84 (s,
3H, -OCH3), 5.14 (s, 2H, -CH2-), 6.93 (s, 1H, Im H40),
6.98 (d, J=8.8 Hz, 2H, Ar H30,H50), 7.10 (s, 1H, Im
H50), 7.20 (d, J=8.0 Hz, 2H, Ar H3,H5), 7.50 (d,
J=8.8 Hz, 2H, Ar H20,H60)0, 7.53 (d, J=8.0 Hz, 2H, Ar
H2,H6), 7.57 (s, 1H, Im H2 ); GC±MS m/z (M+): 264.1
(calcd 264.1).
The moderate activity of the OH compound 9b is prob-
ably due to fast phase 2 metabolism (e.g. glucuronida-
tion or sulfatation). The possibly metabolically more
stable, ¯uorine substituted compound 8c has decreased
the testosterone plasma concentration to castration level
(after 2 h; 5 mg/kg) and might be a promising candidate
for treatment of hormone sensitive PC.
40-Fluoro-4-(imidazol-1-yl-methyl)-biphenyl (8c). White
crystals: mp 139±141ꢁC; IR 3100, 1605, 1500, 1230,
1
1080, 825 cm 1; H NMR (CDCl3) 5.17 (s, 2H, -CH2-),
6.96 (s, 1H, Im H40), 7.10±7.14 (m, 3H, Ar H30,H50, Im
H50), 7.23 (d, J=8.0 Hz, 2H, Ar H3,H5), 7.50±7.54 (m,
4H, Ar H2,H6,H20,H60), 7.65 (s, 1H, Im H20); GC±MS
m/z (M+): 252.1 (calcd 252.1).
Experimental
Chemistry
General procedures. Melting points were measured on a
Ko¯er melting point Thermopan apparatus and are
uncorrected. IR spectra were recorded on a Perkin±
Elmer 398 infrared spectrometer as KBr disks or ®lms
40-Chloro-4-(imidazol-1-yl-methyl)-biphenyl (8d). White
crystals: mp 94±96ꢁC; IR 3090, 1500, 1485, 1390, 1235,
1
1070, 815 cm 1; H NMR (CDCl3) 5.17 (s, 2H, -CH2-),
6.95 (s, 1H, Im H40), 7.13 (s, 1H, Im H40), 7.23 (d,

1920
B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
J=8.0 Hz, 2H, Ar H3,H5), 7.41 (d, J=8.4 Hz, 2H, Ar
H30,H50), 7.49 (d, J=8.4 Hz, 2H, Ar H20,H60), 7.54 (d,
J=8.0 Hz, 2H, Ar H2,H6), 7.64 (s, 1H, Im H20); GC±
MS m/z (M+): 268.1 (calcd 268.1).
(CDCl3) 5.19 (s, 2H, -CH2-), 6.95 (s, 1H, Im H40), 7.13
(m, 2H, Ar H4, Im H50), 7.34±7.45, 7.51±7.56 (m, 8H,
Ar H2,H5,H6,H20,H30, H40,H50,H60), 7.64 (s, 1H, Im
H20); GC±MS m/z (M+): 234.1 (calcd 234.1).
40-Methyl-4-(imidazol-1-yl-methyl)-biphenyl (8e). White
needles: mp 138±140ꢁC; IR 3110, 3015, 1500, 1235,
1115, 1075, 820 cm 1; 1H NMR (DMSO-d6) 2.33 (s, 3H,
-CH3), 5.22 (s, 2H, -CH2-), 6.92 (s, 1H, Im H40), 7.21 (s,
1H, Im H50), 7.23 (d, J=8.0 Hz, 2H, Ar H30,H50), 7.32
(d, J=8.0 Hz, 2H, Ar H3,H5), 7.54 (d, J=8.0 Hz, 2H,
Ar H20,H60), 7.62 (d, J=8.4 Hz, 2H, Ar H2,H6), 7.78
(d, J=8.0 Hz, Ar H2,H6), 7.64 (s, 1H, Im H20); GC±MS
m/z (M+): 248.2 (calcd 248.1).
40-Methoxy-3-(imidazol-1-yl-methyl)-biphenyl (11a)Â0.5
H2SO4. White solid: mp 146±148ꢁC; IR 3120, 3020,
1
2810, 1610, 1565, 1445, 1250, 1185, 1025, 845 cm 1; H
NMR (DMSO-d6) 3.80 (s, 3H, -OCH3), 5.42 (s, 2H,
-CH2-), 6.93 (s, 1H, Im H40), 7.02±7.05 (m, 2H, Ar
H30,H50), 7.31 (d, J=6.6 Hz, 1H, Ar H4), 7.42±7.50 (m,
2H, Ar H5, Im H40), 7.58±7.63 (m, 3H, Ar H2,H6, Im
H50), 7.69 (d, J=10.6 Hz, 2H, Ar H20,H60), 8.92 (s, 1H,
Im H20); GC±MS m/z (M+): 264.1 (calcd 264.1).
40-Thiomethyl-4-(imidazol-1-yl-methyl)-biphenyl (8h)Â0.5
40-Fluoro-3-(imidazol-1-yl-methyl)-biphenyl (11c). White
powder: mp 200ꢁC (sublimation); IR 3120, 1610, 1515,
1485, 1250, 1185, 1025, 845 cm 1; 1H NMR (DMSO-d6)
5.26 (s, 2H, -CH2-), 6.91 (s, 1H, Im H40), 7.22±7.31,
7.42±7.46, 7.55±7.70 (m, 9H, Ar H2,H4,H5,H6,H20,
H30,H50,H60, Im H40), 7.81 (s, 1H, Im H20); GC±MS
m/z (M+): 252.1 (calcd 252.1).
H2SO4. Yellow crystals: mp 248±250ꢁC; IR 3125, 3040,
1
1570, 1485, 1190, 1115, 1000, 805 cm
;
1H NMR
(DMSO-d6) 2.51 (s, 3H, -CH3), 5.40 (s, 2H, -CH2-), 7.35
(d, J=8.4 Hz, 2H, Ar H30,H50), 7.44±7.46 (m, 3H, Ar
H3,H5, Im H40), 7.62 (d, J=8.4 Hz, 2H, Ar H20,H60), 7.64
(s, 1H, Im H50), 7.69 (d, J=8.4 Hz, 2H, Ar H2,H6), 8.83
(s, 1H, Im H20); GC±MS m/z (M+): 280.1 (calcd 280.1).
40-Chloro-3-(imidazol-1-yl-methyl)-biphenyl (11d). Col-
30-Fluoro-4-(imidazol-1-yl-methyl)-biphenyl (9c). Slightly-
yellow oil: IR 3105, 3070, 2930, 1620, 1590, 1480, 1240,
orless crystals: mp 59±60ꢁC; IR 3110, 3040, 1610, 1590,
1
1480, 1090, 1010, 810 cm
;
1H NMR (DMSO-d6,
1185, 795 cm 1; H NMR (CDCl3) 5.18 (s, 2H, -CH2-),
TFA) 5.38 (s, 2H, -CH2-), 7.30 (s, 1H, Im H40), 7.36 (d,
J=7.5 Hz, 1H, Ar H4), 7.46±7.51 (m, 1H, Ar H5), 7.52±
7.57 (m, 3H, Ar H30,H50, Im H50), 7.65 (d, J=8.0 Hz,
1H, Ar H6), 7.68±7.71 (m, 3H, Ar H2,H20,H60), 8.59 (s,
1H, Im H20); GC±MS m/z (M+): 268.1 (calcd 268.1).
1
6.94 (s, 1H, Im H40), 7.06±7.08 (m, 1H, Ar H40), 7.14 (s,
1H, Im H50), 7.23±7.27 (m, 3H, Ar H20,H3,H5), 7.34 (d,
J=8.0 Hz, 1H, Ar H60), 7.38±7.42 (m, 1H, Ar H50), 7.56
(d, J=8.4 Hz, 2H, Ar H2,H6), 7.73 (s, 1H, Im H20);
GC±MS m/z (M+): 252.1 (calcd 252.1).
30-Acetamido-3-(imidazol-1-yl-methyl)-biphenyl
(12k).
30-Nitro-4-(imidazol-1-yl-methyl)-biphenyl (9i). Yellow
White needles: mp 160±161ꢁC; IR 3120, 3040, 2970,
needles: mp 97±98ꢁC; IR 3090, 3020, 1510, 1350, 1230,
2960, 1680, 1560, 1410, 1290, 1090, 835, 780 cm 1; H
1
1
1070, 850, 800, 740 cm 1; H NMR (CDCl3) 5.21 (s,
NMR (CDCl3) 2.19 (s, 3H, -CH3), 5.15 (s, 2H, -CH2-),
6.95 (s, 1H, Im H40), 7.09±7.12 (m, 2H, Ar H40, Im H50),
7.23±7.27 (m, 1H, Ar H4), 7.31±7.41 (m, 3H, Ar
H2,H5,H50), 7.48±7.53 (m, 2H, Ar H6,H60), 7.59 (s, 1H,
Im H20), 7.75 (s, 1H, Ar H20), 8.06 (s, 1H, NH); GC±
MS m/z (M+): 291.2 (calcd 291.1).
2H, -CH2-), 6.95 (s, 1H, Im H40), 7.14 (s, 1H, Im H50),
7.29 (d, J=8.0 Hz, 2H, Ar H3,H5), 7.60±7.66 (m, 4H,
Ar H2,H6,H50, Im H20), 7.89 (d, 8.0 Hz, 1H, Ar H60),
8.22 (dd, J=2.2, 7.5 Hz, 1H, Ar H40), 8.44 (d, J=2.2,
1H, Ar H20); GC±MS m/z (M+): 279.1 (calcd 279.1).
30-Acetamido-4-(imidazol-1-yl-methyl)-biphenyl (9k). White
3-(4-(Imidazol-1-yl-methyl)phenyl)-thiophene (13). Slightly-
yellow small leafs: mp 144±145ꢁC; IR 3100, 1510, 1440,
needles: mp 171±173ꢁC; IR 3140, 3120, 3020, 2920,
1
1
1680, 1620, 1555, 1480, 1320, 920, 830 cm 1; H NMR
1235, 1110, 1070, 745 cm 1; H NMR (CDCl3) 5.13 (s,
(DMSO-d6) 2.06 (s, 3H, -CH3), 5.24 (s, 2H, -CH2-), 6.92
(s, 1H, Im H40), 7.22 (s, 1H, Im H50), 7.29±7.40 (m, 4H,
Ar H3,H5,H40,H50), 7.53±7.56 (m, 3H, Ar H2,H6,H60),
7.78 (s, 1H, Im H20), 7.87 (s, 1H, Ar H20), 10.02 (s, 1H,
NH); GC±MS m/z (M+): 291.2 (calcd 291.1).
2H, -CH2-), 6.92 (s, 1H, Im H40), 7.10 (s, 1H, Im H50),
7.18 (d, J=8.0 Hz, 2H, Ar H3,H5), 7.36±7.41, 7.44±7.46
(m, 3H, Thiophene H20,H40,H50); 7.55±7.59 (m, 3H, Ar
H2, H6, Im H20); GC±MS m/z (M+): 240.1 (calcd
240.1).
30,40-Methylene dioxy-4-(imidazol-1-yl-methyl)biphenyl
Method B
(10a). White powder: mp 134±135ꢁC; IR 3100, 2905,
1480, 1450, 1240, 1040, 920, 810, 750 cm 1; H NMR
30-Methoxy-4-(imidazol-1-yl-methyl)-biphenyl (9a). To a
solution of 3-methoxy phenyl magnesium bromide
under nitrogen (prepared with Mg turnings (0.31 g,
12.6 mmol) in dry ether (10 mL) and 3-bromomethoxy-
benzene (1.4 g, 7.6 mmol) in dry THF (15 mL)) was
added Pd(PPh3)4 (0.25 g, 0.22 mmol), and N-(4-bromo-
benzyl)imidazole (1) (1.2 g, 5.1 mmol) in dry THF
(12 mL). The mixture was re¯uxed for 1 h, and the
resulting suspension was quenched with water (10 mL)
and 1 N HCl (8 mL). The aqueous layer was washed
1
(CDCl3) 5.15 (s, 2H, -CH2-), 6.00 (s, 2H, -O-CH2-O-),
6.87 (d, J=8.8 Hz, 1H, Ar H50), 6.94 (s, 1H, Im H40),
7.01±7.05 (m, 2H, Ar H20,H60), 7.12 (s, 1H, Im H50),
7.19 (d, J=8.4 Hz, 2H, Ar H3,H5), 7.49 (d, J=8.4 Hz,
2H, Ar H2,H6), 7.61 (s, 1H, Im H20); GC±MS m/z
(M+): 278.1 (calcd 278.1).
3-(Imidazol-1-yl-methyl)biphenyl (11). Colorless oil: IR
3100, 3030, 1600, 1505, 1230, 1080, 910 cm 1; 1H NMR

B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
1921
with ethyl acetate, alkalized with a saturated Na2CO3
solution, and extracted with ethyl acetate-MeOH (5:1).
The combined extracts were washed with water and
dried over Na2SO4. After evaporation of the solvent,
the obtained yellow oil was puri®ed by column chro-
matography (ammonia saturated CH2Cl2/EtOH, 9=1),
and the resulting solid was recrystallized from n-hexane-
ethyl acetate to give 9a (1.2 g, 89%) as white needles: mp
90±91ꢁC; IR 3100, 2960, 1610, 1590, 1480, 1300, 1230,
product was ®ltered and puri®ed by recrystallisation from
i-propanol-MeOH to give 8b (0.27 g, 67%) as
colorless needles: mp 260±262ꢁC; IR 3120, 3020, 2940,
2550, 1600, 1500, 1435, 1390, 1280, 1110, 930, 820, 665
cm 1; 1H NMR (DMSO-d6) 5.20 (s, 2H, -CH2-), 6.83 (d,
J=8.4Hz, 2H, Ar H30,H50), 6.91 (s, 1H, Im H40), 7.20 (s,
1H, Im H50), 7.28 (d, J=8.0 Hz, 2H, Ar H30,H50), 7.45
(d, J=8.4 Hz, 2H, Ar H20,H60), 7.55 (d, J=8.0Hz, 2H,
Ar H2,H6), 7.77 (s, 1H, Im H20), 9.74 (s, 1H, -OH); GC±
MS m/z (M+): 250.1 (calcd 250.1).
1
845, 760 cm 1; H NMR (CDCl3) 3.86 (s, 3H, -OCH3),
5.16 (s, 2H, -CH2-), 6.91 (dd, J=2.2, 8.4 Hz, 1H, Ar
H40), 6.94 (s, 1H, Im H40), 7.09 (t, J=2.2 Hz, 1H, Ar
H20), 7.12 (s, 1H, Im H50), 7.15 (d, J=7.5 Hz, 1H, Ar
H60), 7.22 (d, J=8.4 Hz, 2H, Ar H3,H5), 7.36 (t,
J=8.0 Hz, 01H, Ar H50), 7.57 (d, 2H, Ar H2,H6), 7.62 (s,
1H, Im H2 ); GC±MS m/z (M+): 264.1 (calcd 264.1).
30-Hydroxy-4-(imidazol-1-yl-methyl)-biphenyl (9b). White
needles: mp 194±196ꢁC; IR 3110, 3020, 2930, 2800,
2660, 1620, 1575, 1480, 1310, 1080, 790 cm 1; 1H NMR
(DMSO-d6) 5.22 (s, 2H, -CH2-), 6.84 (d, J=8.4 Hz, 2H,
Ar H3,H5), 6.90 (s, 1H, Im H40), 7.15 (d, J=7.5 Hz, 1H,
Ar H40), 7.23 (s, 1H, Im H50), 7.38 (t, J=7.5 Hz, 1H, Ar
H50), 7.43±7.50 (m, 4H, Ar H2,H6,H20,H60), 7.79 (s, 1H,
Im H20), 9.56 (s, 1H, -OH); GC±MS m/z (M+): 250.0
(calcd 250.1).
30-Chloro-4-(imidazol-1-yl-methyl)-biphenyl (9d). Color-
less crystals: mp 88±89ꢁC; IR 3140, 3100, 1620, 1530,
1
1470, 1420, 1260, 1090, 820, 795, 755 cm 1; H NMR
(CDCl3) 5.20 (s, 2H, -CH2-), 6.96 (s, 1H, Im H40), 7.15
(s, 1H, Im H50), 7.25 (d, J=8.0 Hz, 2H, Ar H3,H5),
7.32±7.45 (m, 3H, Ar H40,H50,H60), 7.53±7.57 (m, 3H,
Ar H2,H6,H20), 7.75 (s, 1H, Im H20); GC±MS m/z
(M+): 268.1 (calcd 268.1).
40-Hydroxy-3-(imidazol-1-yl-methyl)-biphenyl (11b). Col-
orless needles: mp 192±194ꢁC; IR 3120, 3020, 3040,
1
2910, 2580, 1610, 1520, 1485, 1280, 1110, 790 cm 1; H
NMR (DMSO-d6) 5.22 (s, 2H, -CH2-), 6.75 (d,
J=8.0 Hz, 1H, Ar H4), 6.91 (s, 1H, Im H40), 6.99 (s,
1H, Ar H2), 7.04 (d, J=7.5 Hz, 1H, Ar H6), 7.19±7.25
(m, 2H, Ar H5, Im H50), 7.31 (d, J=8.0 Hz, 2H, Ar
H30,H50), 7.57 (d, J=8.0 Hz, 2H, Ar H20,H60), 7.77 (s,
1H, Im H20); 9.48 (s, 1H, -OH); GC±MS m/z (M+):
250.0 (calcd 250.1).
30-Methyl-4-(imidazol-1-yl-methyl)-biphenyl (9e). Slightly-
yellow solid: mp 65±66ꢁC; IR 3100, 2930, 1605, 1500,
1
1230, 1025, 790, 765 cm 1; H NMR (CDCl3) 2.42 (s,
3H, -CH3), 5.16 (s, 2H, -CH2-), 6.94 (s, 1H, Im H40),
7.13 (s, 1H, Im H50), 7.16±7.24 (m, 3H, Ar H3,H5,H40),
7.31±7.38 (m, 3H, Ar H20,H50,H60), 7.57 (d, J=8.4 Hz,
3H, Ar H2,H6), 7.71 (s, 1H, Im H20); GC±MS m/z
(M+): 248.2 (calcd 248.1).
30-Hydroxy-3-(imidazol-1-yl-methyl)-biphenyl (12b). Col-
orless needles: mp 194±195ꢁC; IR 3160, 3100, 2940,
2680, 2560(l), 1600, 1515, 1450, 1310, 1090, 785, 750
30-Methoxy-3-(imidazol-1-yl-methyl)-biphenyl (12a). Col-
orless oil: IR 3100, 2940, 2840, 1605, 1580, 1480, 1230,
1040, 740 cm 1; 1H NMR (CDCl3) 3.86 (s, 3H, -OCH3),
5.18 (s, 2H, -CH2-), 6.91 (dd, J=1.8, 8.0 Hz, 1H, Ar
H40), 6.94 (s, 1H, Im H40), 7.06 (t, J=1.8 Hz, 1H, Ar
H20), 7.10±7.15 (m, 3H, Ar H4,H50, Im H50), 7.33±7.36
(m, 2H, Ar H2,H60), 7.42 (t, J=7.5 Hz, 1H, Ar H5),
7.54 (d, J=8.0 Hz, 1H, Ar H6), 7.62 (s, 1H, Im H20);
GC±MS m/z (M+): 264.1 (calcd 264.1).
cm 1; H NMR (DMSO-d6) 5.26 (s, 2H, -CH2-), 6.77
1
(dd, J=1.8, 8.4 Hz, 1H, Ar H40), 6.92 (s, 1H, Im H40),
6.97 (s, 1H, Ar H20), 7.03 (d, J=8.0 Hz, 1H, Ar H4),
7.22±7.26 (m, 3H, Ar H50,H60, Im H50), 7.42 (t,
J=8.0 Hz, 1H, Ar H5), 7.49 (s, 1H, Ar H2), 7.52 (d,
J=7.5 Hz, 1H, Ar H6), 7.81 (s, 1H, Im H20), 9.57 (s,
1H, -OH); GC±MS m/z (M+): 250.0 (calcd 250.1).
Method D
30-Amino-4-(imidazol-1-yl-methyl)-biphenyl (9l). To a
solution of 30-nitro-4-(imidazol-1-yl-methyl)biphenyl
(9i) (0.1 g, 0.4 mmol) was added Pd on charcoal (10%,
0.01 g). The ¯ask was evaporated and the solution was
stirred under an atmosphere of 5 bar hydrogen for 3 days.
Method C
40-Hydroxy-4-(imidazol-1-yl-methyl)-biphenyl (8b).
A
solution of 40-hydroxy-4-(imidazol-1-yl-methyl)biphenyl
(8a) (0.5 g, 1.9 mmol) in dry CH2Cl2 (54 mL) was cooled
at 78ꢁC. Under an atmosphere of nitrogen, BBr3
(0.43 mL, 4.2 mmol) was added slowly. After further
stirring 30 min at 78ꢁC and 3 h at room temperature,
2.3 mL methanol was added dropwise.
After removing the catalyst by ®ltration and drying
(Na2SO4), the solvent was evaporated. The crude pro-
duct was puri®ed by column chromatography (ammo-
nia saturated CH2Cl2/EtOH, 9=1), and the resulting
solid was recrystallized from n-hexane-MeOH to give 9l
(0.035 g, 35%) as slightly-yellow small leafs: mp 159±
160ꢁC; IR 3410, 3340, 3220, 3120, 3100, 1645, 1605,
1230, 1080, 740 cm 1; 1H NMR (DMSO-d6) 5.14 (s, 2H,
-NH2), 5.22 (s, 2H, -CH2-), 6.55 (d, J=8.0 Hz, 1H, Ar
H40), 6.75 (d, J=7.5 Hz, 1H, Ar H60), 6.81 (s, 1H, Ar
H20), 6.91 (s, 1H, Im H50), 7.08 (t, J=7.5, 8.0 Hz, 1H,
Ar H50), 7.21 (s, 1H, Im H50), 7.29 (d, J=8.0 Hz, 2H, Ar
The hydrobromide precipitated out of solution after the
volume was reduced to 1=4. The solid was ®ltered o€ and
after dissolving the precipitate in 1 M H2SO4, it was neu-
tralized with saturated NaHCO3. (If no hydrobromide
precipitated, the solution was evaporated to dryness and
the resulting residue was suspended several times with 1 M
sulfuric acid. The collected aqueous layers were neu-
tralized with saturated NaHCO3). The precipitating crude

1922
B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
1
H3,H5), 7.53 (d, J=8.4 Hz, 2H, Ar H2,H6), 7.77 (s, 1H,
Im H20); GC±MS m/z (M+): 249.1 (calcd 249.1).
820 cm 1; H NMR (CDCl3) 2.41 (s, 3H, -CH3), 7.29
(d, J=8.0 Hz, 2H, Ar H3,H5), 7.49 (d, J=8.0 Hz, 2H,
Ar H2,H6), 7.65±7.71 (m, 4H, Ar H20, H30,H50,H60).
Method E
Method H
30-Amino-3-(imidazol-1-yl-methyl)-biphenyl (12l). A solu-
tion of 30-acetamido-3-(imidazol-1-yl-methyl)-biphenyl
(12k) (0.45 g, 1.5 mmol) in 50% H2SO4 (45 mL) was
re¯uxed for 18 h and slowly neutralized with saturated
NaHCO3. The mixture was extracted with ethyl acetate/
MeOH (5/1). After drying (Na2SO4) and evaporating
the solvent, the crude product was recrystallized from
n-hexane-ethyl acetate to give 12l (0.35 g, 95%) as
slightly-brown crystals: mp 68±69ꢁC; IR 3450, 3420,
40-Cyano-4-bromomethylbiphenyl. To a solution of 40-
cyano-4-methylbiphenyl (7) (0.75 g, 3.9 mmol) in dry
CCl4 (4 mL) was added N-bromo succinimide (NBS;
0.69 g, 3.9 mmol) and dibenzoyl peroxide (DBPO;
0.034 g, 0.14 mmol). The mixture was stirred and slowly
heated to 60ꢁC. After the exogenous reaction had
begun, the mixture was re¯uxed for 2.5 h. After cooling,
it was ®ltered and washed with CCl4. The organic layer
was concentrated to half of the volume the crude pro-
duct precipitated out of solution and was recrystallized
from CCl4 to give the title compound (0.45 g, 52%) as
slightly ocherous crystals: mp 97±98ꢁC (Patent San-
doz:39 106±107ꢁC); IR 3060, 3040, 2240, 1610, 1500,
1010, 825 cm
-CH2Br), 7.51 (d, J=8.4 Hz, 2H, Ar H3,H5), 7.57 (d,
J=8.4 Hz, 2H, Ar H2,H6), 7.69 (d, J=8.4 Hz, 2H, Ar
H30,H50), 7.73 (d, J=8.4 Hz, 2H, Ar H20,H60).
1
3370, 3180, 1645, 1620, 1480, 1235, 1110, 785 cm 1; H
NMR (DMSO-d6) 5.18 (s, 2H, -NH2), 5.25 (s, 2H,
-CH2-), 6.56 (d, J=7.9 Hz, 1H, Ar H40), 6.72 (d,
J=7.4 Hz, 1H, Ar H60), 6.79 (s, 1H, Ar H20), 6.92 (s,
1H, Im H40), 7.09 (t, J=7.9 Hz, 1H, Ar H50), 7.20 (d,
J=8.0 Hz, 1H, Ar H4), 7.23 (s, 1H, Im H50), 7.38±7.48
(m, 3H, Ar H2,H5,H6), 7.80 (s, 1H, Im H20); GC±MS
m/z (M+): 249.1 (calcd 249.1).
1
;
1H NMR (CDCl3) 4.54 (s, 2H,
Method F
Method I
3040-Dihydroxy-4-(imidazol-1-yl-methyl)biphenyl (10b). A
solution of 30,40-methylendioxy-4-(imidazol-1-yl-meth-
yl)-biphenyl (10a) (0.15 g, 0.56 mmol) in concentrated
HCl (3 mL) was re¯uxed with 1,3-benzenediol (0.15 g,
1.4 mmol) for 1.5 h. The mixture was slowly cooled to
room temperature, diluted with water (20 mL), and
extracted with 1 N HCl. The combined aqueous layers
were neutralized with saturated NaHCO3, extracted
with ethyl acetate/MeOH (5/1). After drying (Na2SO4)
and evaporating the solvent, the crude product was
washed with diethyl ether, recrystallized from ethyl ace-
tate/MeOH to give 10b (0.04 g, 27%) as slightly-pink
40-Cyano-4-(imidazol-1-yl-methyl)-biphenyl (8f). Imida-
zole (0.4 g, 5.9 mmol), 40-cyano-4-bromomethylbiphenyl
(7f) (0.4 g, 1.5 mmol), 18-K-6 (0.01 g, 0.04 mmol) and
anhydrous K2CO3 (1.7 g, 11.8 mmol) in dry acetone
(10 mL) were re¯uxed for 2 h. The mixture was cooled,
extracted with ethyl acetate/MeOH (5/1), washed with
water, acidi®ed, and extracted with 0.1 N HCl. The
combined aqueous layers were alkalized with saturated
Na2CO3 and again extracted with ethyl acetate/MeOH
(5:1). After drying (Na2SO4) and evaporating the
solvent, the crude product was puri®ed by column
chromatography (ammonia saturated ethyl acetate/
MeOH, 9/1), and the resulting solid was recrystallized
from n-hexane/acetone to give 8 (0.35 g, 92%) as color-
less needles: mp 49±51ꢁC; IR 3390, 3300, 3120, 2240,
solid: mp 260±262ꢁC; IR 3120, 3020, 2940, 2560(l),
1
1605, 1510, 1415, 1290, 1080, 820 cm
;
1H NMR
(DMSO-d6) 5.21 (s, 2H, -CH2-), 6.79 (d, J=8.4 Hz, 1H,
Ar H50), 6.91 (d, J=8.0 Hz, 1H, Ar H60), 6.94 (s, 1H, Im
H40), 7.00 (s, 1H, Ar H20), 7.23 (s, 1H, Im H50), 7.27 (d,
J=8.4 Hz, 2H, Ar H3,H5), 7.49 (d, J=8.0 Hz, 2H, Ar
H2,H6), 7.83 (s, 1H, Im H20), 9.02, 9.07 (s, 2H, -OH);
GC±MS m/z (M+): 266.1 (calcd 266.1).
1610, 1510, 1500, 1080, 820 cm 1; H NMR (CDCl3)
1
5.20 (s, 2H, -CH2-), 6.94 (s, 1H, Im H40), 7.14 (s, 1H, Im
H50), 7.27 (d, J=8.0 Hz, 2H, Ar H3,H5), 7.58 (d,
J=8.0 Hz, 2H, Ar H2,H6), 7.65±7.67 (m, 3H, Ar
H30,H50, Im H20), 7.74 (d, J=8.4 Hz, 2H, Ar H20,H60);
GC±MS m/z (M+): 259.1 (calcd 259.1).
Method G
40-Cyano-4-methylbiphenyl (7). To a solution of 4-bro-
motoluene (4.3 g, 25 mmol) in dry THF (350 mL) under
nitrogen atmosphere at 78ꢁC was added slowly t-BuLi
(33 mL of a 1.5 M solution in n-pentane, 50 mmol).
After the addition of anhydrous ZnCl2 (3.4 g,
25.5 mmol), the cooling bath was removed. Pd(PPh3)4
(0.5 g, 0.43 mmol) and 4-bromobenzonitrile (1.8 g,
10.0 mmol) were added and the mixture was re¯uxed for
2.5 h and cooled to 0ꢁC. The mixture was quenched with
water (250 mL) and 0.1 N HCl (250 mL) and extracted
with ethyl acetate. After drying (Na2SO4) and evapor-
ating the solvent the crude product was recrystallized
from i-propanol to give 7 (1.6 g, 83%) as slightly-
ocherous needles: mp 104±107ꢁC (Gray and Mosley:38
109ꢁC); IR 3040, 2960, 2930, 2240, 1610, 1500, 1010,
Method K
40-Carboxy-4-(imidazol-1-yl-methyl)-biphenyl (8g).
A
solution of 40-cyano-4-(imidazol-1-yl-methyl)biphenyl
(8f) (0.15 g, 0.58 mmol) in 50% H2SO4 (2 mL) and acetic
acid (1 mL) was re¯uxed for 3.5 h, diluted with water
(7 mL), washed with ethyl acetate, alkalized with satu-
rated Na2CO3, and extracted with ethyl acetate/MeOH
(5=1). 0.1 N HCl was added slowly until 8g started to
precipitate as colorless crystals (0.80 g, 50%): mp 308±
310ꢁC; IR 3140, 3040, 2440(l), 1700, 1610, 1400, 1290(l),
1110, 1010, 740 cm 1; H NMR (CDCl3) 5.26 (s, 2H,
1
-CH2-), 6.94 (s, 1H, Im H40), 7.25 (s, 1H, Im H50), 7.37
(d, J=8.0 Hz, 2H, Ar H3,H5), 7.73 (d, J=8.0 Hz, 2H,
Ar H2,H6), 7.77±7.80 (m, 3H, Ar H30,H50, Im H20), 8.01

B. G. Wachall et al. / Bioorg. Med. Chem. 7 (1999) 1913±1924
1923
(d, J=8.0 Hz, 2H, Ar H20,H60); GC±MS m/z
(Mmethylester): 292.1 (calcd 292.1).
References
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