Synthesis and activity of a novel series of 3-biarylquinuclidine squalene synthase inhibitors

Article abstract of DOI:10.1021/jm950907l

Quinuclidines with a 3-biaryl substituent are a new class of potent, orally active squalene synthase (SQS) inhibitors. Variants around these rigid structures indicate key structural requirements for cationic SQS inhibitors. Thus the lower in vitro potency found for quinuclidines bearing 3- substituents, which did not overlay the biphenyl group of 3-(biphenyl-4-yl)- 3-hydroxyquinuclidine (2) (IC₅₀ = 16 nM, rat microsomal SQS), implied a directional requirement for the 3-substituent. Similarly, the lower potency of the 3-terphenyl analogue 6 (IC₅₀ = 370 nM) indicated size constraints for this substituent. In compounds with a linking group between the quinuclidine and biphenyl ring, linking groups of lower lipophilicity were less well tolerated (e.g., 17, CH₂CH₂, IC₅₀ = 5 nM vs 19, NHCO, IC₅₀ = 1.2 μM). Replacement of the distal phenyl ring of 2 with a more polar pyridine heterocycle caused a reduction in in vitro potency. In general, good in vivo activity in the rat was restricted to 3-hydroxy analogues, with the 3-[4-(pyrid-4-yl)phenyl] derivative 39 (IC₅₀ = 161 nM) showing the best inhibition (following oral dosing) of cholesterol biosynthesis from mevalonate (ED₅₀ = 2.7 mg/kg).

Full text of DOI:10.1021/jm950907l

J . Med. Chem. 1996, 39, 2971-2979
2971
Syn th esis a n d Activity of a Novel Ser ies of 3-Bia r ylqu in u clid in e Squ a len e
Syn th a se In h ibitor s1
George R. Brown,* David S. Clarke, Alan J . Foubister, Susan Freeman, Peter J . Harrison,† Michael C. J ohnson,
Keith B. Mallion, J ohn McCormick, Fergus McTaggart, Alan C. Reid, Graham J . Smith, and Melvyn J . Taylor
Cardiovascular and Muscoskeletal Department, Zeneca Pharmaceuticals, Alderley Park, Macclesfield,
Cheshire SK10 4TG, U.K.
Received December 11, 1995X
Quinuclidines with a 3-biaryl substituent are a new class of potent, orally active squalene
synthase (SQS) inhibitors. Variants around these rigid structures indicate key structural
requirements for cationic SQS inhibitors. Thus the lower in vitro potency found for quinu-
clidines bearing 3-substituents, which did not overlay the biphenyl group of 3-(biphenyl-4-yl)-
3-hydroxyquinuclidine (2) (IC50 ) 16 nM, rat microsomal SQS), implied a directional
requirement for the 3-substituent. Similarly, the lower potency of the 3-terphenyl analogue 6
(IC50 ) 370 nM) indicated size constraints for this substituent. In compounds with a linking
group between the quinuclidine and biphenyl ring, linking groups of lower lipophilicity were
less well tolerated (e.g., 17, CH2CH2, IC50 ) 5 nM vs 19, NHCO, IC50 ) 1.2 µM). Replacement
of the distal phenyl ring of 2 with a more polar pyridine heterocycle caused a reduction in in
vitro potency. In general, good in vivo activity in the rat was restricted to 3-hydroxy analogues,
with the 3-[4-(pyrid-4-yl)phenyl] derivative 39 (IC50 ) 161 nM) showing the best inhibition
(following oral dosing) of cholesterol biosynthesis from mevalonate (ED50 ) 2.7 mg/kg).
Ch a r t 1
Raised levels of plasma LDL cholesterol are widely
accepted2 to be a risk factor for human coronary heart
disease. Although patients have benefitted from cho-
lesterol-lowering regimes, clear evidence for a reduction
in patient mortality had been lacking. Recently, how-
ever, the Scandinavian 4S clinical study with the
HMGCoA reductase inhibitor simvastatin has reported3
an improvement in the survival of patients with existing
coronary disease. This study has thus added impetus
to the search for novel hypocholesterolemic agents which
would give a greater reduction in cholesterol levels than
is currently available from the HMGCoA reductase
inhibitor class of drugs and hence the prospect of more
effective treatment of coronary disease.
Plasma LDL cholesterol levels are lowered when there
is a temporary interruption of cholesterol biosynthesis,
which causes upregulation of hepatic LDL receptors and
a consequent removal of LDL cholesterol from the blood
plasma. Indirect clinical precedent supporting this
hypothesis is found for the HMGCoA reductase inhibitor
class of drugs,4 and as part of efforts to find new
hypocholesterolemic agents, the inhibition of other steps
of the biosynthesis pathway has been investigated.
Inhibition of squalene synthase (SQS) has been postu-
lated to be advantageous, and potent in vitro inhibitors
have been discovered.5 The most effective in vivo
inhibitors of SQS are, however, the polyanionic natural
products6 (termed squalestatins or zaragozic acids) and
the substituted bisphosphonates.7 Both of these inhibi-
tor series have been reported8 to have poor oral bio-
availability in animals and to display potentially toxic
actions. Our search for an alternative series of inhibi-
tors led to the discovery of weak in vitro inhibition (IC50
) 14 µM) in a rat liver microsomal SQS assay for the
â-adrenergic receptor-blocking drug metoprolol (1; Chart
1). Further directed screening of related compounds
from the Zeneca compound collection with either similar
chemical structure or similar â-receptor antagonist
properties afforded little inhibitory activity, indicating
the discriminating nature of the SQS enzyme. However,
a quinuclidine derivative, 2 (which was originally
designed as a rigid conformer of the “ethanolamine”
† Deceased.
X Abstract published in Advance ACS Abstracts, J uly 1, 1996.
S0022-2623(95)00907-1 CCC: $12.00 © 1996 American Chemical Society

2972 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 15
Ta ble 1. In Vitro Activities of Substituted 3-Hydroxyquinuclidines
Brown et al.
a
b
All new compounds analyzed correctly ((0.4%) for C,H,N and afforded 1H-NMR data consistent with the structures assigned. HCl
salt. c Squibb 32377 used as standard SQS inhibitor; lit.5b IC50 ) 9 µM.
Sch em e 1. General Procedure Aa
class9 of â-adrenergic receptor-blocking drugs), was
identified as a potent SQS inhibitor (IC50 ) 16 nM). A
program of work was instituted to give further insight
into the structure-activity relationship around 3-bi-
arylquinuclidines as SQS inhibitors, and the synthesis
and inhibitory properties are now described for this
novel10 series of cationic SQS inhibitors.
Ch em istr y
Compounds 2 and 6-11 (Table 1) were prepared by
a
s
(a) BuLi, THF, -70 °C; (b) p-TSA, PhMe; (c) H2, Pd/C.
reaction of quinuclidin-3-one and the appropriate bro-
s
moaryl compound in the presence of BuLi (general
was protected as a borane complex). In a similar
manner 3-hydroxyquinuclidine (N-B) borane12 13a was
allowed to react with farnesyl bromide in the presence
of NaH to give 12 (Chart 1) after deprotection with HCl.
Farnesol was treated with NaH before reaction with the
quinuclidine spiro-oxirane (N-B) borane13 13b (Chart 1)
to give 14 after deprotection with HCl. The E and Z
olefins 15 and 16 were separated by column chroma-
tography after Wittig reaction between 3-formylquinu-
clidine14 and [(4-biphenylyl)methyl]triphenylphosphonium
chloride in the presence of KOtBu. Catalytic transfer
hydrogenation of 15, with HCO2NH4 in the presence of
10% Pd/C, gave the ethyl derivative 17. 4-Phenylbenz-
procedure A, Scheme 1). The enantiomers 2a ,b were
obtained by chromatography of 2 on a chiral column.
Dehydration of 2 in refluxing PhMe in the presence of
4-toluenesulfonic acid afforded 3, which was hydroge-
nated over Pd/C catalyst to give 4. Reaction of the
known11 quinuclidin-3-one (N-B) borane 13 with the
Grignard reagent from 4-(4-bromophenyl)benzene fol-
lowed by methylation with MeI in the presence of NaH
and subsequent deprotection of the nitrogen atom with
HCl gave the methyl ether 5 (in general, alkylation
reactions of OH-substituted quinuclidines proceeded in
poor yield, unless the quinuclidine ring nitrogen atom

Novel 3-Biarylquinuclidine SQS Inhibitors
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 15 2973
Sch em e 2a
idine to afford respectively 35, 40, and 41 (Table 3).
Compounds 36-39 were prepared from the appropriate
biaryl bromide and quinuclidin-3-one using general
procedure A. When 2-phenylthiazole (instead of a
bromo derivative) was reacted with quinuclidin-3-one
using general procedure A, 42 resulted. Compounds 43
and 44 (Chart 1) were prepared by general procedure
A using respectively 4-bromo-4′-[(tert-butyldimethylsi-
lyl)oxy]biphenyl and 4-bromo-4′-fluorobiphenyl as start-
ing materials. Spectroscopic data are provided as
Supporting Information for compounds, which do not
appear in the Experimental Section in detail (i.e., those
prepared by the general procedures).
(a) CBr4, PPh3, Zn; (b) nBuLi, THF; (c) CH3CO2NH4, Pd/C.
a
Biologica l Resu lts a n d Discu ssion
Sch em e 3. General Procedure Ba
The structural requirements for inhibitory activity
were examined by variation of (a) the quinuclidine ring,
(b) the biaryl rings, (c) a linking group between the
3-biaryl substituent and the quinuclidine ring, and (d)
the biaryl ring with a selection of heteroaromatic rings.
Thus the inhibitory potency in vitro in the rat microso-
mal SQS assay was retained following modifications to
the quinuclidine ring of 2 (Table 1), as shown by the
dehydro and desoxy examples 3 and 4. The hydroxyl
group in 2 was not essential for potent in vitro enzyme
inhibition, however, as 2 and 4 were equipotent as SQS
inhibitors. The methyl ether 5 was a much less potent
inhibitor, and this result implied a steric impediment
to activity at the 3-position of the quinuclidine ring.
Both the enantiomers of 2 displayed inhibitory activity,
although the (+)-enantiomer 2a was found to be more
potent.
In anticipation that the biaryl group was binding to
a lipophilic region of the enzyme, an additional phenyl
ring was introduced onto 2, which led to a reduction in
potency (as in 6), but an even greater reduction in
potency was observed when the distal phenyl ring was
not present, as in 7. When the distal phenyl ring was
replaced by a saturated ring, e.g., cyclohexyl 8 or
dioxanyl 9, inhibitory potency was also reduced relative
to 2, and thus the best inhibitory activity was found in
compounds with planar biaryl substitution. The biaryl
quinuclidines 10 and 11, however, were also found to
be less active than 2, which implies that there is also a
directional requirement for the rigid biaryl side chain.
The more marked loss of inhibitory potency found for
11, against 10 (2.5 µM vs 60 nM), may reflect the
coplanarity of the thiophene rings in 11. These test
results for compounds 6-11 thus suggest that among
the ring variations examined, the 4-biphenyl group is
optimal for potent inhibitory activity, for both the size
and the planarity and in the directional requirement of
the substituent in relation to the rigid quinuclidine ring
system.
a
(a) THF; (b) sBuLi, THF, quinuclidin-3-one; (c) HetBr, NH4Cl,
Pd(PPh3)4, Na2CO3.
aldehyde was allowed to react with 3-aminoquinucli-
dine, and the resulting imine 18 was reduced with
NaBH4 to give 19. Acylation of 3-aminoquinuclidine
with 4-phenylbenzoyl chloride and 4-phenylbenzene-
sulfonyl chloride gave 20 and 21, respectively.
Reaction15 of 4-phenylbenzaldehyde (Scheme 2), CBr4,
PPh3, and zinc dust gave 1-(biphenyl-4-yl)-2,2-dibromo-
ethylene (22), which on treatment with nBuLi and
quinuclidin-3-one afforded the ethynyl derivative 23.
Reduction of 23 with HCO2NH4 in the presence of 10%
Pd/C gave the ethyl-linked derivative 24. Compounds
25 and 26 were prepared by reaction of quinuclidin-3-
one and trimethylsulfoxonium iodide with 4-phenylphe-
nol or 4-phenylthiophenol (respectively) in the presence
of NaOH and nBu4HSO4. Oxidation of 26 with NaIO4
gave the sulfoxide 27 and with potassium peroxymono-
sulfate the sulfone 28. Wadsworth-Emmons reaction
of quinuclidin-3-one with diethyl [(biphenyl-4-yl)methyl]-
phosphonate in the presence of KOtBu and reduction
of the product with HCO2NH4 in the presence of Pd/C
afforded 29. The thio-linked quinuclidine 30 was pre-
pared from 3-chloroquinuclidine and 4-phenylthiophenol
in the presence of NaH, and subsequent oxidation (as
for the preparation of 28) gave the sulfone 31. Reaction
of the Li derivative prepared from 4-bromobiphenyl with
3-formylquinuclidine gave a separable mixture of the
diastereoisomeric pairs 32 and 33. Reaction of thiophene-
2-boronic acid and 3-(4-bromophenyl)-3-hydroxyquinu-
clidine with (PPh3)4 Pd as catalyst gave 34.
When compounds were synthesized (Table 2) with a
link group inserted between the biaryl residue and the
quinuclidine ring, the 4-biphenyl group was chosen for
all analogues, so that the different link groups could be
compared. In the two-atom-linked compounds, a two-
carbon link (15 and 17) produced very potent SQS
inhibitors, but the cis olefin 16 was of lower potency
(supporting the above hypothesis that there is a direc-
tional requirement of the biaryl substituent for high
inhibitory potency). Quinuclidines 19-21 (CLOGP
range 3.5-4.2) contain less lipophilic linking groups
The known16 (4-bromophenyl)boronic acid N-methyl-
O,O-diethanolamine ester was prepared in situ and
allowed to react with quinuclidin-3-one (general proce-
dure B, Scheme 3) in the presence of BuLi, and the
product was reacted in the presence of (PPh3)4Pd with
2-bromothiazole, 3-bromoquinoline, and 2-bromopyrim-
s

2974 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 15
Ta ble 2. In Vitro Activities of Bridged Quinuclidines
Brown et al.
IC50 rat microsomal
SQS (n ) 2; nM)
compd
R
X
mp (°C)
>300b
formulaa
15
H
4
C21H23N‚HCl‚H2O
16
H
216-217b
580
C21H23N‚HCl‚0.25H2O
17
19
20
21
23
24
25
26
27
28
29
30
31
32
33
H
H
H
H
OH
OH
OH
OH
OH
OH
H
CH2CH2
NHCH2
NHCO
NHSO2
CtC
CH2CH2
CH2O
CH2S
CH2SO
CH2SO2
CH2
S
SO2
223-224b
180-181b
183-185
77-78
217-218
224-225b
132-133
145-147b
157-162
203-205
283-287b
72-77
5
140
1.2 µM
>2.5 µM
3
7
13
8
C21H25N‚HCl
C20H24N2‚2HCl‚H2O
C20H22N2O‚0.25H2O
C19H22N2O2S‚0.5EtOAc
C21H21NO
C21H25NO‚HCl‚0.3H2O
C20H23NO2‚0.2H2O
C20H23NOS‚HCl‚H2O
C20H23NO2S‚0.5H2O
C20H23NO3S‚0.25H2O
C20H23NO3S
>2.5 µM
>2.5 µM
27
H
H
H
H
21
C19H21NS
126-127
182-184
213-214
>2.5 µM
2.5 µM
2.5 µM
C19H21NO2S‚0.5H2O
CHOH
CHOH
C
C
20H23NO‚0.4H2O
20H23NO‚0.65H2O
a
b
All new compounds analyzed correctly ((0.4%) for C,H,N and afforded 1H-NMR data consistent with the structures assigned. HCl
salt.
Ta ble 3. In Vitro Activities of 3-Heteroarylquinuclidines
(e.g., NHCO), and here inhibitory potency was well
below that of 15 and 17 (CLOGP ) 5.2, 5.5) with the
sulfonamide group affording a compound, 21 (CLOGP
) 3.5), only showing inhibition at micromolar concen-
trations. When the two-atom-linked 3-biphenylylqui-
nuclidines also had a 3-hydroxy substituent, the overall
CLOGP values were lowered due to the presence of the
OH group, but comparisons of inhibitory potencies
within this less lipophilic series revealed the same trend
between IC50 values and CLOGP as found for the non-
hydroxy quinuclidines (24, IC50 ) 7 nM, CLOGP ) 4.3
vs 28, IC50 > 2.5 µM, CLOGP ) 2.7). The quinuclidines
with a single link atom also showed this trend between
the nature of the linking group and enzyme inhibitory
potency (29 and 30, CLOGP ) 5.0, 6.5 vs 31 and 32,
CLOGP ) 3.3). Thus within a series of quinuclidine
SQS inhibitors, the less lipophilic linking groups (Table
2) lowered the in vitro inhibitory potency. These results
may be explained by the hypothesis that the 3-biaryl
substituent in these quinuclidine SQS inhibitors was
acting as a mimic of a farnesyl chain subunit, where a
polar function would be expected to be less well tolerated
in a lipophilic region of the active site (see below).
Introduction of heteroaromatic rings in place of the
distal phenyl ring of 2 (Table 3) did not afford an in
vitro structure-activity relationship based on CLOGP
values. Greatest in vitro potency was found for the
thiophene 34 and the thiazole ring-containing 35, 36,
and 42, whereas the more polar nitrogen-substituted
ring systems present in 37-40 were apparently less well
accepted at the inhibitory site. Unexpectedly the py-
rimidine 41 was a potent SQS inhibitor.
Analysis of how these new SQS inhibitors might be
acting in vitro was based on consideration of the enzyme
mechanism.17 SQS assembles two molecules of farnesyl
pyrophosphate (FPP) into squalene in two distinct steps.
The first of these requires the transfer of a farnesyl
residue from one FPP onto the C(2)-C(3) double bond
of the other to give presqualene pyrophosphate (PSPP).
This in turn is converted into squalene by rearrange-
ments that are terminated by the transfer of hydride
a
All new compounds analysed correctly ((0.4%) for C,H,N and
afforded 1H-NMR data consistent with the structures assigned.
from the NADPH cofactor. Both steps have been
envisaged17 to involve a cyclopropyl carbocationic in-
termediate. Ammonium,18 amidinium,19 and sulfo-
nium20 inhibitors of SQS have been described which
potentially mimic such putative carbocationic interme-
diates, but with the exception of certain farnesylamine

Novel 3-Biarylquinuclidine SQS Inhibitors
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 15 2975
derivatives,21 SQS inhibitory activity has been low
(micromolar). The potent (nM) quinuclidine SQS in-
hibitors (pKa for 2 ) 9.1) described above may also
inhibit the enzyme by acting as carbocation mimics for
either the first or second step of the FPP to squalene
conversion. Thus in the phosphate buffer used in the
in vitro test, ion pair formation may occur between the
quinuclidine inhibitors and phosphate/pyrophosphate
ions. The biarylquinuclidines also conform to Biller’s
hypothesis22 (regarding phosphonate SQS inhibitors)
that aryl units may act as isosteres for isoprenyl
subunits in the farnesyl chain because the 4-biphenyl
group was an optimal 3-substituent. This hypothesis
may account for the poor inhibitory potency seen with
quinuclidines containing less lipophilic link groups
(Table 2) and of compounds with a distal phenyl ring
replaced by the more polar pyridine ring (37-39, IC50
range 161-240 nM). The farnesyl compounds 12 and
14 were prepared to examine the hypothesis further and
found to be good in vitro SQS inhibitors (IC50 ) 70 and
50 nM, respectively) but with a lower potency than 2.
In fully extended conformations, however, 12 and 14
would overlay more optimally with the biphenyl-3-yl
compound 10, which has a similar inhibitory potency.
information on the structural requirements for the
acceptance of cationic inhibitors at the enzyme active
site. Thus the lipophilic biaryl side chain in the most
potent in vitro inhibitors is rigidly held in relation to
the protonated quinuclidine nitrogen atom. The lower
in vitro potency found for compounds bearing 3-substit-
uents which do not overlay the biphenyl group of 2
implied a directional requirement for the lipophilic
biaryl group. In compounds with a linking group
between the quinuclidine and biaryl rings, the presence
of a less lipophilic linking group moderated the SQS
inhibitory potency and replacement of the distal phenyl
rings of 2 with a more polar pyridine heterocycle gave
a reduction in in vitro potency. Good in vivo activity
was restricted to 3-hydroxy analogues, with the pyridyl
derivative 39 showing the best inhibition of rat in vivo
cholesterol biosynthesis.
Exp er im en ta l Section
Melting points were determined with a Buchi apparatus and
1
are uncorrected. The H-NMR spectra were determined with
a Bruker AM (200 MHZ) spectrometer (with SiMe4 as an
internal standard), and mass spectra were measured on a
MS902 Kratos (AEI) instrument. Optical rotations were
measured on a Perkin Elmer 241 polarimeter and elemental
analyses determined on a Perkin Elmer series II-2400 ana-
lyzer. Reactions were carried out under an atmosphere of
argon, and column chromatography was on E. Merck silica gel
(Kieselgel 60, 230-400 mesh). Solvents were dried over
MgSO4 before evaporation. Sodium hydride was 60% disper-
sion in mineral oil.
Oral dosing of compound 2 to rats gave an ED50 for
inhibition of cholesterol biosynthesis (from mevalonate)
of 7 mg/kg (95% confidence limits, 3.6-13.6), but the
more potent enantiomer in vitro (2a ) had the same
potency in vivo as 2. This finding of in vivo activity for
the potentially cationic quinuclidine SQS inhibitors (e.g.,
2) contrasts with its lack in some earlier series of
inhibitors that are referenced above. Recently, however,
an oxypropylamine series of inhibitors23 and further
quinuclidines in the patent literature10 have been
claimed to afford significant activity following oral
dosing to rats. In anticipation that 2 and related
biphenyl derivatives might be hydroxylated in vivo, the
4-hydroxy derivative 43 (Chart 1) and the corresponding
4-fluoro derivative 44 were tested in rats by oral dosing.
Gen er a l P r oced u r e A: P r ep a r a t ion of 3-Bia r yl-3-
h yd r oxyqu in u clid in es 2 a n d 6-11. 3-(Bip h en yl-4-yl)-3-
h yd r oxyqu in u clid in e (2). sBuLi in cyclohexane (100 mL,
130 mmol) was added to a stirred solution of 4-bromobiphenyl
(25 g, 107 mmol) in dry THF (240 mL) at -78 °C. The mixture
was stirred for 5 min, and a solution of quinuclidin-3-one (12
g, 96 mmol) in dry THF (100 mL) was added during 20 min.
Stirring was continued at -78 °C for 30 min and the mixture
allowed to reach room temperature over 2 h; 2 M HCl (225
mL) was added below 10 °C and the aqueous layer washed
with Et2O (2 × 300 mL) before the addition of excess 10 M
NaOH to pH 14. The mixture was extracted with EtOAc which
had been heated to 50 °C and the extract allowed to cool, dried,
and evaporated to give a colorless solid, which crystallized from
EtOAc to give 2 (11.0 g, 41%): mp 165-166 °C; 1H-NMR
(CDCl3/CD3CO2D) δ 1.7-1.9 (m, 3H), 2.5 (m, 1H), 2.5-2.7 (m,
1H), 3.2-3.5 (m, 4H), 3.7 (d, 1H, J ) 13.6 Hz), 4.0 (d, 1H, J )
Although 43 exhibited a lower in vitro potency (IC50
)
132 nM) than 2, the putative metabolite possessed
similar activity in vivo (ED50 ) 12 mg/kg). In vitro
potency was restored (18 nM vs 16 nM for 2) in the
fluoro analogue 44, for which metabolism analogous to
that of 2 is blocked, and this compound showed an
identical oral ED50 in rats with that of 2. Thus while
the presence of an OH group in 43 clearly reduces in
vitro potency, in vivo activity is unaffected. Other
compounds in Table 1 (3-14) afforded ED50 values
which were >10 mg/kg, and this also applied to com-
pounds without a 3-OH group in Table 2, i.e., 15-20
and 29-33. The 3-hydroxy derivatives 23-26 were less
active having ED50 values in the range 35-50 mg/kg,
but good oral activity was discovered among the het-
erocyclic analogues of 2 (Table 3). The potent in vitro
inhibitors (such as 34-36 and 43; Table 3) had ED50
values which were >10 mg/kg, but despite their lower
in vitro inhibitory potency, the pyridyl ring-containing
analogues 37-41 had an ED50 range of 2-16 mg/kg. In
particular 39 was the most potent compound in vivo,
with an ED50 of 2.7 mg/kg (95% confidence limits, 1.4-
5.2).
13.6 Hz), 7.3-7.7 (m, 9H); EI-MS m/z 279 (M+). Anal. (C19H21
NO‚0.1H2O) C, H, N.
-
(+)- a n d (-)-3-(Bip h en yl-4-yl)-3-h yd r oxyqu in u clid in e
(2a ,b). The racemate 2 (18 mg, 0.06 mmol) was resolved by
chromatography on a chiral cell OD (250 × 4.6 mm i.d. column)
using a 70:30:0.2 mixture (by volume) of n-hexane-iPrOH-
Et2NH as eluant at a flow rate of 1 mL/min, to give the
separate enantiomers which were crystallized from butan-2-
one to give as crystalline solids: 2a (8 mg, 88%, retention time
8.81 min) mp 158-159 °C, [R]22 ) +32.0° (c ) 3.4 mg/mL in
D
MeOH), and 2b (7.8 mg, 86%, 9.86 min) mp 159-160 °C, [R]22
) -31.2° (c ) 3.3 mg/mL in MeOH).
D
3-(Bip h en yl-4-yl)-2,3-d eh yd r oqu in u clid in e Hyd r och lo-
r id e (3). 4-Toluenesulfonic acid (9.76 g, 54 mmol) and 2 (4.7
g, 16.8 mmol) were heated under reflux in PhMe (300 mL) for
2 h using a Dean-Stark water separator. The PhMe was
evaporated and the residue dissolved in 1 M NaOH (125 mL).
The aqueous mixture was extracted with EtOAc and the
EtOAc layer washed with brine, dried, and concentrated to
60 mL. Excess of saturated ethereal HCl was added, and the
precipitated solid crystallized from MeOH-EtOAc to give, as
a colorless solid, 3 (3.7 g, 74%): mp 263-265 °C; 1H-NMR
(DMSO-d6) δ 1.6-1.8 (m, 2H), 1.95-2.15 (m, 2H), 2.9-3.1 (m,
2H), 3.5-3.7 (m, 3H), 7.1 (d, 1H, J ) 2.0 Hz), 7.3-7.5 (m, 3H),
In conclusion 3-biarylquinuclidines are potent inhibi-
tors of rat microsomal SQS and may (compared to other
more flexible cationic SQS inhibitors) provide useful

2976 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 15
Brown et al.
7.6-7.8 (m, 6H); EI-MS m/z 262 (M + H). Anal. (C19H19N‚
MeOH-CH2Cl2 followed by MeOH-CH2Cl2-0.880 ammonia
(10:90:0.1) to give 16 as free base (Rf ) 0.72), which was
dissolved in EtOH and an excess of ethereal HCl. Et2O was
added until crystallization began to give, as a colorless solid,
HCl) C, H, N.
3-(Bip h en yl-4-yl)qu in u clid in e Hyd r och lor id e (4).
3
(260 mg, 0.87 mmol) in EtOH (25 mL) was hydrogenated at
atmospheric pressure for 4 h over 10% Pd/C catalyst (30 mg).
The catalyst was filtered and the EtOH evaporated. The
residue was crystallized from MeOH-EtOAc to give, as a
colorless solid, 4 (175 mg, 58%): mp 248-249 °C; 1H-NMR
(DMSO-d6) δ 1.6-1.8 (m, 1H), 1.9-2.2 (m, 3H), 3.1-3.8 (m,
8H), 7.3-7.7 (m, 9H); EI-MS m/z 264 (M + H). Anal.
(C19H21N‚HCl‚1.5H2O) C, H, N.
1
16 (90 mg, 7%): mp 216-217 °C; H-NMR (D2O) δ 1.8-2.15
(m, 5H), 2.15-2.4 (m, 1H), 3.02-3.6 (m, 6H), 5.89-6.0 (m, 1H),
6.3-6.7 (d, 1H, J ) 12 Hz), 7.3-7.4 (d, 2H, J ) 7.0 Hz), 7.4-
7.6 (m, 3H), 7.6-7.8 (t, 4H); EI-MS m/z 290 (M + H). Anal.
(C21H23N‚HCl‚0.25H2O) C, H, N.
Further elution with the above eluant gave 15 as free base
(Rf ) 0.6), which was converted to the hydrochloride salt as
1
above to give 15 (65 mg, 5%): mp >300 °C; H-NMR (D2O) δ
3-(Bip h en yl-4-yl)-3-m eth oxyqu in u clid in e Hyd r och lo-
r id e (5). 4-Bromobiphenyl (1.68 g, 7.2 mmol) was added to
stirred Mg turnings (with a crystal of I2) in Et2O (8 mL) and
the mixture heated to reflux for 1.5 h. 1311 (1.0 g, 7.2 mmol)
in THF (10 mL) was added at room temperature and the
mixture heated under reflux for 1 h. After cooling, H2O (15
mL) was added and the mixture extracted with EtOAc. The
EtOAc layer was washed with H2O, dried, and evaporated to
a solid which was triturated with CH2Cl2 (10 mL), and the
borane complex of 2 (0.4 g, 19%) was collected. The complex
(382 mg, 1.3 mmol) in DMF (3 mL) was added to NaH (31.2
mg, 1.3 mmol) in DMF (0.5 mL) followed by MeI (369 mg, 2.6
mmol) and stirring continued for 3 h. H2O (30 mL) was added
and the mixture extracted with EtOAc. The EtOAc layer was
washed with H2O, dried, and evaporated and the residue
triturated in CH2Cl2-hexane (1:1) and filtered; the filtrate was
evaporated to give the borane complex of 5 (133 mg, 33%). This
complex (133 mg) in acetone (5 mL) was treated with EtOH/
HCl to pH 1, and after 30 min the mixture was concentrated
to 2 mL and Et2O (4 mL) added. The resulting precipitate
was collected to give, as a colorless solid, 5 (97 mg, 68%): mp
227-229 °C; 1H-NMR (DMSO-d6) δ 1.40-1.62 (m, 1H), 1.72-
2.0 (m, 2H), 2.10-2.29 (m, 1H), 2.80 (m, 1H), 2.88 (s, 3H), 3.1-
3.36 (m, 4H), 3.52-3.8 (m, 2H), 7.3-7.63 (m, 5H), 7.72 (t, 4H,
J ) 8.4 Hz); EI-MS m/z 294 (M + H). Anal. (C20H23NO‚
HCl‚0.4H2O) C, H, N.
1.8-2.2 (m, 5H), 2.8-3.0 (m, 1H), 3.1-3.22 (m, 1H), 3.3-3.7
(m, 5H), 6.25-6.4 (m, 1H), 6.5-6.6 (d, 1H, J ) 14.4 Hz), 7.43-
7.6 (m, 5H), 7.6-7.78 (m, 4H); EI-MS m/z 290 (M + H). Anal.
(C21H23N‚HCl‚H2O) C, H, N.
3-[(Bip h en yl-4-yl)eth -2-yl]qu in u clid in e Hyd r och lor id e
(17). Pd/C (10%, 40 mg) was added to a stirred solution of
HCO2NH4 (250 mg, 4 mmol) and 15 (243 mg, 0.75 mmol) in
MeOH (10 mL) and the mixture heated at 60 °C with stirring
for 1 h. A further quantity of HCO2NH4 (500 mg, 8 mmol)
was added and the mixture heated at 60 °C for a further 1 h.
The mixture was cooled and filtered through diatomaceous
earth, and the residues were washed with MeOH. The MeOH
filtrates were evaporated, and the residue was partitioned
between 4 M NaOH and CH2Cl2. The CH2Cl2 layer was
separated, dried, and evaporated to give an oil, which was
purified by flash column chromatography on silica gel, eluting
with MeOH-CH2Cl2-0.880 ammonia (10:90:0.1). The product
was dissolved in acetone and an excess of ethereal HCl added
followed by sufficient Et2O to cause crystallization, as a
colorless solid, of 17 (115 mg, 47%): mp 223-224 °C; 1H-NMR
(D2O) δ 1.6-2.1 (m, 8H), 2.5-2.65 (t, 2H, J ) 8.3 Hz), 2.75-
2.9 (m, 1H), 3.1-3.5 (m, 5H), 7.22-7.32 (d, 2H, J ) 7.0 Hz),
7.32-7.52 (m, 3H), 7.55-7.65 (d, 2H, J ) 8.3 Hz), 7.65-7.75
(d, 2H, J ) 8.3 Hz); EI-MS m/z 292 (M + H). Anal. (C21H25N‚
HCl) C, H, N.
3-[[(Bip h en yl-4-yl)m eth yl]a m in o]qu in u clid in e Hyd r o-
ch lor id e (19). 4-Phenylbenzaldehyde (160 mg, 0.88 mmol)
and 3-aminoquinuclidine (110 mg, 0.87 mmol) were heated
under reflux in PhMe (50 mL) for 2 h using a Dean-Stark
water separator, and the PhMe was evaporated. The residue
was purified by medium pressure column chromatography on
alumina (ICN Alumina N 32-63), eluting with EtOAc to give
3-[[(biphenyl-4-yl)methylene]amino]quinuclidine, as a colorless
solid (18; 150 mg, 60%): mp 82-84 °C; 1H-NMR (CDCl3) δ
1.35-1.5 (m, 1H), 1.6-1.8 (m, 3H), 2.2-2.3 (m, 1H), 2.8-3.0
(m, 4H), 3.0-3.2 (m, 2H), 3.4-3.5 (m, 1H), 7.3-7.5 (m, 3H),
7.55-7.65 (m, 4H), 7.8 (d, 2H, J ) 8.3 Hz), 8.3 (s, 1H); EI-MS
m/z 291 (M + H).
NaBH4 (260 mg, 7 mmol) was added to a stirred solution of
18 (990 mg, 3.4 mmol) in MeOH (50 mL) and the mixture
stirred for 2 h. The MeOH was evaporated and the residue
dissolved in 1 M HCl (12 mL). The aqueous solution was
washed with Et2O (3 × 25 mL) before the addition of excess
10 M NaOH to pH 14. The mixture was extracted with Et2O
and the extract dried and evaporated. An excess of saturated
ethereal HCl was added to precipitate a solid which was
crystallized from MeOH-EtOAc to give, as a colorless solid,
19 (820 mg, 74%): mp 180-181 °C; 1H-NMR (DMSO-d6) δ 1.7-
2.0 (m, 3H), 2.2-2.4 (m, 1H), 2.6 (s, 1H), 3.1-3.8 (m, 8H), 4.2
(s, 2H), 7.3-7.5 (m, 3H), 7.6-7.8 (m, 6H); EI-MS m/z 293 (M
+ H). Anal. (C20H24N2‚2HCl‚H2O) C, H, N.
3-[(Bip h en yl-4-yl)ca r ba m oyl]qu in u clid in e (20). Et3N
(2.44 mL, 17.5 mmol) was added dropwise to 4-biphenylcar-
bonyl chloride (1.0 g, 4.6 mmol) and 3-aminoquinuclidine
dihydrochloride (1.0 g, 5.0 mmol) in CH2Cl2 (10 mL). After
18 h the precipitate was collected and dissolved in H2O; 2 M
NaOH was added to pH 9 and the mixture extracted with
EtOAc. The extracts were dried and evaporated and the
residue crystallized from EtOAc-hexane to give 20 (450 mg,
32%): mp 183-185 o C; 1H-NMR (CDCl3) δ 1.53 (m, 1H), 1.76
(m, 3H), 2.08 (m, 1H), 2.69 (d, 1H, J ) 12.6 Hz), 2.9 (m, 4H),
3.45 (m, 1H), 4.2 (m, 1H), 6.35 (d, 1H, J ) 6.3 Hz), 7.4 (m,
3H), 7.6 (m, 4H), 7.85 (d, 2H, J ) 6.3 Hz). Anal. (C20H22N2-
O‚0.25H2O) C, H, N.
3-(F a r n esyloxy)qu in u clid in e (12). 13a 12 (1.4 g, 10 mmol)
was added to NaH (414 mg, 11 mmol) in DMF (10 mL),
farnesyl bromide (2.7 mL, 10 mmol) in DMF (3 mL) added at
5 °C, and the mixture stirred for 3 h at ambient temperature.
The mixture was poured onto H2O (130 mL) and extracted with
EtOAc. The EtOAc layer was washed with H2O, dried, and
evaporated to a residue, which was purified by chromatogra-
phy on silica gel eluting with pentane-EtOAc (19:1) to give
an oil (2.65 g, 77%). The oil (2.0 g) in acetone (35 mL) was
treated with EtOH/HCl to pH 1 and stirred for 20 h. The
acetone was evaporated and the residue partitioned between
Et2O and H2O. The aqueous phase was made alkaline to pH
11 with 10 M NaOH and extracted with Et2O. The Et2O layer
was washed with H2O, dried, and evaporated to give, as an
1
oil, 12 (1.55 g, 80%); H-NMR (CDCl3) δ 1.22-1.48 (m, 2H),
1.55-1.78 (m, 12H), 1.85 (m, 1H), 1.9-2.2 (m, 9H), 2.60-3.0
(m, 5H), 3.03-3.18 (m, 1H), 3.48 (m, 1H), 3.85-4.07 (m, 2H),
5.08 (m, 2H), 5.35 (m, 1H); EI-MS m/z 362 (M + H). Anal.
(C22H37NO) C, H, N.
3-[(F a r n esyloxy)m eth yl]-3-h yd r oxyqu in u clid in e (14).
Compound 14 was prepared in a similar manner to 25, by
opening the known13 intermediate borane-protected epoxide
13b in situ with farnesol sodium salt and deprotection to give,
as an oil, 14 (50%); 1H-NMR (CDCl3) δ 1.15-1.37 (m, 1H), 1.50
(m, 1H), 1.57 (s, 6H), 1.65 (s, 6H), 1.82-2.2 (m, 11H), 2.45-
3.0 (m, 7H), 3.21 (d, 1H, J ) 8.3 Hz), 3.37 (d, 1H, J ) 8.3 Hz),
4.0 (d, 2H, J ) 6.3 Hz), 5.07 (m, 2H), 5.31 (m, 1H); EI-MS m/z
362 (M + H). Anal. (C23H39NO2) C, H, N.
(E)- a n d (Z)-3-[(4-P h en yl)styr -2-yl]qu in u clid in e Hy-
d r och lor id e (15 a n d 16). KOtBu (1.12 g, 10 mmol) was
added to a stirred suspension of [(4-biphenylyl)methyl]triphen-
ylphosphonium chloride (4.4 g, 9.4 mmol) in THF (60 mL). The
mixture was stirred for 30 min and cooled to -40 °C before a
solution of 3-formylquinuclidine14 (570 mg, 4.1 mmol) in THF
(5.0 mL) was added over 10 min. The mixture was stirred at
ambient temperature for 16 h before the THF was evaporated
and the residue dissolved in CH2Cl2. The solution was washed
with H2O, dried, and evaporated and the residue purified by
flash column chromatography on silica gel eluting with 10%

Novel 3-Biarylquinuclidine SQS Inhibitors
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 15 2977
3-(Bip h en ylsu lfon a m id o)qu in u clid in e (21). 4-Biphen-
ylsulfonic acid (0.6 g, 2.56 mmol) and SOCl2 (1.53 g, 12.8 mmol)
were heated under reflux for 18 h, and the mixture was
evaporated. The residue in CH2Cl2 (6 mL) was added to a
mixture of 3-aminoquinuclidine dihydrochloride (0.56 g, 2.81
mmol) and Et3N (2.0 mL, 14.3 mmol) in CH2Cl2 (30 mL) at 0
25 except that 4-phenylthiophenol was used as starting
material. The EtOAc extract was washed with saturated brine
(50 mL) and extracted with 2 M HCl (8 × 25 mL). The
hydrochloride salt crystallized from the aqueous solution to
give, as a colorless solid, 26 (9%): mp 170-175 °C; EI-MS m/z
326 (M + H).
o
C. The mixture was stirred for 3 h and evaporated. The
The aqueous filtrate was cooled in ice, basified with 10 M
NaOH (50 mL), and extracted with EtOAc (3 × 130 mL). The
EtOAc extract was dried and evaporated to give, as a colorless
solid, 26 as free base (4%): mp 145-147 °C; 1H-NMR (CDCl3)
δ 1.2-1.4 (m, 1H), 1.5-1.6 (m, 2H), 1.9-2.0 (m, 1H), 2.0-2.2
(m, 1H), 2.5-3.0 (m, 7H), 3.1-3.5 (m, 2H), 7.2-7.6 (m, 9H);
EI-MS m/z 326 (M + H). Anal. (C20H23NOS) C, H, N.
3-[[(Bip h en yl-4-yl)su lfin yl]m eth yl]-3-h yd r oxyqu in u cli-
d in e (27). NaIO4 (2.5 g, 11.6 mmol) was added to a solution
of 26 (1.1 g, 3.3 mmol) in MeOH (10 mL). The mixture was
stirred for 5 h and the solvent evaporated. H2O (15 mL) was
added and the ice-cooled mixture made basic with 10 M NaOH.
The mixture was extracted with EtOAc (3 × 50 mL), and the
extracts were dried and evaporated. The residue was purified
by flash column chromatography on silica gel, eluting with
EtOAc-MeOH-0.880 ammonia (95:5:3) to give, as a colorless
solid, a 2:1 mixture of diastereomers of 27 (0.3 g, 27%): mp
157-162 °C; 1H-NMR (CDCl3) δ 1.3-1.9 (m, 3H), 2.0 (m, <1H,
minor diastereomer), 2.1-2.4 (m, 1H), 2.5 (m, <1H, major
diastereomer), 2.6-3.1 (m, 7H), 3.0-3.2 (m, 2H), 3.1-3.2 (m,
1H), 4.1-4.6 (m, 1H), 7.35-7.55 (m, 3H), 7.55-7.65 (m, 2H),
residue was shaken with 1 M NaOH (25 mL) and EtOAc (75
mL) and the EtOAc layer washed with brine, dried, and
evaporated. The residue was chromatographed on alumina
(ICN Alumina N 32-63), eluting with EtOAc to give 21 (320
mg, 37%): mp 77-78 °C; 1H-NMR (CDCl3) δ 1.3-1.85 (m, 5H),
2.40-2.85 (m, 5H), 3.1 (m, 1H), 3.38 (m, 1H), 4.8-5.25 (m,
1H), 7.45 (m, 3H), 7.6 (m, 2H), 7.7 (m, 2H), 7.92 (m, 2H). Anal.
(C19H22N2O2S‚0.5EtOAc) C, H, N.
3-[(Bip h en yl-4-yl)eth yn yl]-3-h yd r oxyqu in u clid in e (23).
CBr4 (25.2 g, 76 mmol)20 was added to PhP3 (26.2 g, 100 mmol)
in dry CH2Cl2 (600 mL) and the mixture stirred for 15 min.
Zn dust (6.5 g, 100 mmol) was added in one portion and the
mixture stirred for 19 h. 4-Phenylbenzaldehyde15 (9.1 g, 50
mmol) was added and stirring continued for 3 h. PhP3 (5.2 g,
20 mmol) and CBr4 (5.0 g, 15 mmol) were added, and the
mixture was stirred for 3 h. The CH2Cl2 was evaporated and
the residue extracted with boiling hexane (4 × 200 mL) and
filtered while hot. The filtrates were concentrated to 400 mL
when colorless crystals formed of 22 (9.6 g, 56%); mp 105-
106 °C; EI-MS m/z 340 (M + H).
nBuLi in n-hexane (6.4 mL, 1.6 M, 10 mmol) was added
dropwise to 22 (1.2 g, 6.7 mmol) in THF (15 mL) at -60 °C
and the mixture stirred at ambient temperature for 1 h. The
mixture was cooled to -60 °C and quinuclidin-3-one (787 mg,
6.3 mmol) in THF (5.0 mL) added dropwise during 10 min.
The mixture was stirred for 1 h, and the reaction was quenched
by the slow addition of H2O (1.0 mL). The THF was evapo-
rated to give a residue, which crystallized from MeOH to give,
7.65-7.8 (m, 4H); EI-MS m/z 342 (M + H). Anal. (C20H23-
NO2S) C, H, N.
3-[[(Bip h en yl-4-yl)su lfon yl]m et h yl]-3-h yd r oxyq u in u -
clid in e (28). Oxone (1.85 g, 3 mmol) was added to 26 (1.1 g,
3.3 mmol) in MeOH (20 mL). The mixture was stirred for 4 h
and filtered. The residue was washed with MeOH and the
filtrate evaporated. The residue was treated with ice-cooled
8 M NaOH (35 mL) and extracted with EtOAc (3 × 50 mL).
The extracts were concentrated to 60 mL and the crystals
which separated recrystallized twice from MeOH to give, as a
colorless solid, 28 (0.3 g, 25%): mp 203-205 °C; 1H-NMR
(DMSO-d6) δ 1.1-1.2 (m, 1H), 1.3-1.7 (m, 2H), 1.8-2.0 (m,
2H), 2.5-2.8 (m, 5H), 3.0 (d, 1H, J ) 13.3 Hz), 3.5-3.8 (m,
2H), 4.7 (s, 1H), 7.4-7.6 (s, 3H), 7.6-7.8 (m, 2H), 7.8-8.0 (m,
4H); EI-MS m/z 358 (M + H). Anal. (C20H23NO3S) C, H, N.
3-[(Bip h en yl-4-yl)m eth yl]qu in u clid in e Hyd r och lor id e
(29). A solution of diethyl [(4-biphenylyl)methyl]phosphonate
(2.14 g, 7 mmol) in THF (40 mL) was added to a stirred
solution of KOtBu (790 mg, 7.05 mmol) in THF (40 mL) and
the mixture stirred for 10 min. The mixture was cooled to 0
°C and a solution of quinuclidin-3-one (800 mg, 6.4 mmol) in
THF (30 mL) added during 10 min while maintaining the
reaction temperature at 0 °C. The mixture was stirred for 16
h, during which period the reaction mixture was allowed to
warm to ambient temperature. H2O was added, and the
aqueous phases were separated and extracted with Et2O and
CH2Cl2. The CH2Cl2 and Et2O extracts were dried and
evaporated. The residue (350 mg) was dissolved in MeOH (16
mL), and HCO2NH4 (401 mg, 6.36 mmol) was added followed
by 10% Pd/C (60 mg). The resulting mixture was stirred at
50-60 °C for 30 min and the catalyst filtered off. The filtrate
was evaporated and the residue purified by flash chromatog-
raphy on silica gel, eluting with EtOAc-MeOH-0.880 am-
monia (85:10:5) to give a gum. The gum was dissolved in a
solution of HCl in EtOH and the EtOH evaporated to a residue
which was crystallized from EtOAc to give, as a colorless solid,
29 (290 mg, 82%): mp 283-287 °C; 1H-NMR (DMSO-d6) δ 1.6-
1.9 (m, 4H), 2.0-2.2 (m, 1H), 2.2-2.4 (m, 1H), 2.7-2.9 (m, 3H),
3.0-3.4 (m, 5H), 7.3-7.5 (m, 5H), 7.5-7.7 (m, 4H), 10.2-10.4
(s, 1H); EI-MS m/z 278 (M + H). Anal. (C20H23N‚HCl‚0.2H2O)
C, H, N.
1
as a colorless solid, 23 (300 mg, 15%): mp 217-218 °C; H-
NMR (DMSO-d6) δ 1.2-1.4 (m, 1H), 1.5-1.7 (m, 1H), 1.8-
2.02 (m, 3H), 2.6-2.78 (t, 4H, J ) 8.3 Hz), 2.8-2.92 (d, 1H, J
) 13.3 Hz), 3.02-3.14 (d, 1H, J ) 13.3 Hz), 5.61 (s, 1H), 7.32-
7.54 (m, 5H), 7.62-7.73 (m, 4H); EI-MS m/z 304 (M + H). Anal.
(C21H21NO) C, H, N.
3-[(Bip h en yl-4-yl)et h yl]-3-h yd r oxyq u in u clid in e H y-
d r och lor id e (24). A mixture of 23 (303 mg, 1 mmol), HCO2-
NH4 (800 mg, 12.7 mmol), and 5% Pd/C (50 mg) in MeOH (20
mL) was stirred at 60 °C for 30 min, and further portions of
HCO2NH4 (100 mg, 1.6 mmol) were added at 20 min intervals
over 1 h while maintaining the reaction temperature at 60 °C.
The mixture was cooled, filtered through diatomaceous earth,
and washed with MeOH. The filtrate was evaporated and the
residue dissolved in H2O, basified with 4 M NaOH, and
extracted with CH2Cl2 (3 × 10 mL). The extracts were dried,
and an excess of ethereal HCl was added. Et2O (30 mL) was
added to precipitate, as a solid, 24 (280 mg, 90%): mp 224-
225 °C; 1H-NMR (DMSO-d6) δ 1.58-2.1 (m, 5H), 2.15-2.32
(m, 1H), 2.56-2.86 (m, 2H), 2.92-3.3 (m, 7H), 5.16 (s, 1H),
7.28-7.7 (m, 9H); EI-MS m/z 308 (M + H). Anal. (C21H25
NO‚HCl‚0.3H2O) C, H, N.
-
3-[[(Bip h e n yl-4-yl)oxy]m e t h yl]-3-h yd r oxyq u in u cli-
d in e (25). A solution11 of NaOH (9.1 g, 227 mmol) in H2O
(91 mL) was added to a stirred mixture of quinuclidin-3-one
(9.5 g, 76 mmol), 4-phenylphenol (13.7 g, 80 mmol), trimeth-
ylsulfoxonium iodide (33.4 g, 151 mmol), and tetrabutylam-
monium hydrogen sulfate (1.2 g, 3.5 mmol) in PhMe (150 mL).
The mixture was stirred for 2 days. Saturated brine (220 mL)
was added and the mixture extracted with EtOAc (4 × 140
mL). The EtOAc extract was dried and evaporated to give a
residue, which was purified by flash column chromatography
on silica gel, eluting with EtOAc-MeOH-0.880 ammonia (90:
10:3). Recrystallization from EtOAc gave, as a colorless solid,
3-[(Bip h en yl-4-yl)th io]qu in u clid in e (30). NaH (0.2 g, 5
mmol) was added to a stirred solution of 4-phenylthiophenol
(0.5 g, 2.66 mmol) in dry DMF (5 mL) and the mixture stirred
for 30 min. 3-Chloroquinuclidine hydrochloride (554 mg, 3.05
mmol) was added and the mixture heated under reflux for 16
h. The mixture was evaporated and the residue dissolved in
H2O and extracted with EtOAc. The extract was washed with
1 M NaHCO3 solution, dried, and evaporated. The residue was
1
25 (0.8 g, 4%): mp 132-133 °C; H-NMR (CDCl3) δ 1.3-1.5
(m, 1H), 1.5-1.7 (m, 2H), 2.0-2.2 (m, 2H), 2.3-2.7 (m, 1H),
2.6-3.1 (m, 6H), 3.9 (d, 1H, J ) 8.3 Hz), 4.1 (d, 1H, J ) 8.3
Hz), 7.0 (d, 2H, J ) 8.3 Hz), 7.2-7.6 (m, 7H); EI-MS m/z 310
(M + H). Anal. (C20H23NO2‚0.2H2O) C, H, N.
3-[[(Bip h e n yl-4-yl)t h io]m e t h yl]-3-h yd r oxyq u in u cli-
d in e (26). The preparation of 26 was identical with that of

2978 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 15
Brown et al.
purified by flash chromatography on silica gel, eluting with
EtOAc-MeOH-0.880 ammonia (90:8:2) to give, as a colorless
solid, 30 (305 mg, 38%): mp 72-77 °C; 1H-NMR (CDCl3) δ
1.4-1.85 (m, 3H), 1.9-2.0 (m, 1H), 2.0-2.2 (m, 1H), 2.7-3.1
(m, 5H), 7.3-7.6 (m, 9H); EI-MS m/z 296 (M + H). Anal.
(C19H21NS) C, H, N.
3-[(Bip h en yl-4-yl)su lfon yl]q u in u clid in e (31). Oxone
(2.41 g, 3.9 mmol) in H2O (5 mL) was added to 30 (386 mg,
1.3 mmol) in MeOH (5 mL) at 0 °C and the mixture stirred
for 2 h. Stirring was continued at ambient temperature and
the mixture partitioned between H2O (10 mL) and EtOAc (50
mL). The EtOAc layer was separated, dried, and evaporated
to give an oil which was purified by flash chromatography on
silica gel, eluting with EtOAc-MeOH-0.880 ammonia (90:8:
2) to give, as a colorless solid, 31 (50 mg, 9%): mp 126-127
°C; 1H-NMR for HCL salt (D2O) δ 2.16 (m, 2H), 2.29 (m, 1H),
2.71 (m, 1H), 2.83 (m, 1H), 3.62 (m, 4H), 3.84 (m, 1H), 4.03
(m, 1H), 4.32 (m, 1H), 7.77 (m, 3H), 7.97 (m, 2H), 8.2 (m, 4H);
EI-MS m/z 328 (M + H). Anal. (C19H21NO2S‚0.5H2O) C, H,
N.
2 M HCl were added, and the mixture was washed with
EtOAc. The aqueous phase was basified with 10 M NaOH and
extracted with CH2Cl2. The CH2Cl2 extract was washed with
saturated brine solution, dried, and evaporated. The residue
was triturated with EtOAc to give, as a solid, 35 (120 mg,
8%): mp 218-219 °C; 1H-NMR (DMSO-d6) δ 1.20-1.52 (m,
3H), 1.93 (m, 1H), 2.02-2.22 (m, 1H), 2.53-2.9 (m, 3H), 2.93
(d, 1H, J ) 13.6 Hz), 3.40 (d, 1H, J ) 13.6 Hz), 5.22 (s, 1H),
7.62 (d, 2H, J ) 8.4 Hz), 7.75 (d, 1H, J ) 3 Hz), 7.90 (m, 3H);
EI-MS m/z 289 (M + H). Anal. (C16H18NO2S‚0.5H2O) C, H,
N.
Biologica l Assa ys. SQS inhibition in vitro and in vivo
inhibition of cholesterol biosynthesis were determined as
previously reported.23
Su p p or tin g In for m a tion Ava ila ble: Table of 1H-NMR
and mass spectral data for 15 compounds made by the general
procedures (2 pages). Ordering information is given on any
current masthead page.
3-[[(Bip h en yl-4-yl)h yd r oxy]m eth yl]qu in u clid in es (32
a n d 33). sBuLi in cyclohexane (14.87 mL, 1.3 M, 19.3 mmol)
was added to 4-bromobiphenyl (4.29 g, 18.4 mmol) in THF (35
mL) at -78 °C and the mixture stirred at -70 °C for 30 min.
A solution of freshly prepared 3-formylquinuclidine (2.56 g,
18.5 mmol) in THF (40 mL) was added while maintaining the
temperature at -70 °C. The mixture was allowed to warm to
ambient temperature and stirred for 16 h. The mixture was
evaporated and the residue purified by flash column chroma-
tography on silica gel, eluting with EtOAc-MeOH-0.880
ammonia (90:8:2) to give, after crystallization from EtOAc, the
less polar diastereomeric pair as a colorless solid. 32 (184 mg,
2%): mp 182-184 °C; 1H-NMR (DMSO-d6) δ 1.2-1.7 (m, 3H),
1.75-1.95 (m, 2H), 2.1-2.2 (m, 2H), 2.25-2.45 (m, 1H), 2.55-
2.8 (m, 4H), 4.3-4.45 (m, 1H), 5.1-5.2 (m, 1H), 7.3-7.5 (m,
Refer en ces
(1) These results were reported in part at the XIIIth International
Symposium on Medicinal Chemistry, Paris, France, Sept.19-
23, 1994, Abstract P79, and the Xth International Symposium
on Atherosclerosis, Montreal, Canada, Oct. 9-14, 1994. Ab-
stracts published in Atherosclerosis 1994, 109, 252.
(2) The Lipid Research Clinics Coronary Primary Prevention Trial
Results. J . Am. Med. Assoc. 1984, 251, 351-374.
(3) Pedersen, T. R.; Kjekshus, J .; Berg, K.; Haghfelt, T.; Fargeman,
O.; Thorgeirsson, G.; Pyorala, K.; Mertinen, T.; Olsson, A. G.;
Wedel, H.; Wilhelmsmen, L. Randomised trial of cholesterol
lowering in 4444 patients with coronary heart disease: the
Scandinavian Simvastatin Survival Study (4S). Lancet 1994,
344, 1383-1389.
(4) Adams, J . L.; Metcalf, B. Therapeutic Consequences of the
Inhibition of Sterol Metabolism. In Comprehensive Medicinal
Chemistry; Sammes, P. G., Taylor, J . B., Eds.; Pergamon Press:
Oxford, 1990; Vol. 2, pp 333-364.
(5) (a) Biller, S. A.; Forster, C.; Gordon, E. M.; Harrity, T.; Scott,
W. A.; Ciosek, C. P., J r. Isoprenoid (Phosphinylmethyl)phospho-
nates as Inhibitors of Squalene Synthase. J . Med. Chem. 1988,
31, 1869-1871. (b) Biller, S. A.; Forster, C.; Gordon, E. M.;
Harrity, T.; Rich, L. C.; Marreta, J .; Ciosek, C. P., J r. Isoprenyl
Phosphinylformates: New Inhibitors of Squalene Synthase. J .
Med. Chem. 1991, 34, 1912-1914.
(6) (a) Baxter, A.; Fitzgerald, B. J .; Hutson, J . L.; McCarthy, A. D.;
Motteram, J . M.; Ross, B.; Sapra, M.; Snowden, M. A.; Watson,
N. S.; Williams, R. J .; Wright, C. Squalestatin I, a Potent
Inhibitor of Squalene Synthase, Which Lowers Serum Choles-
terol in Vivo. J . Biol. Chem. 1992, 267, 11705-11708. (b)
Bergstrom, J . D.; Kurtz, M. M.; Amend, A. M.; Karras, J . D.;
Bostedor, R. G.; Bansal, V. S.; Dufresne, C.; VanMiddlesworth,
F. L.; Hensens, O. D.; Liesch, J . M.; Zink, D. L.; Wilson, K. E.;
Onish, J .; Milligan, J . A.; Bills, G.; Kaplan, L.; Natlin Omstead,
M.; J enkins, R. G.; Huang, L.; Meinz, M. S.; Quinn, L.; Burg, R.
W.; Kong, Y. L.; Mochales, S.; Mojena, M.; Martin, L.; Plaez, F.;
Diez, M. T.; Alberts, A. W. Zaragozic Acids: A Family of Fungal
Metabolites that are Picomolar Inhibitors of Squalene Synthase.
Proc. Natl. Acd. Sci. U.S.A. 1993, 90, 80-84.
(7) Biller, S. A.; Ciosek, C. P., J r.; Dickson, J . K.; Gordon, E. M.;
Harrity, T.; Hamilton, K. A.; J olibois, K. G.; Kunselman, A. K.;
Lawrence, M.; Mookhtiar, K. A.; Rich, L. C.; Slusarchyk, D. A.;
Sulsky, R. B. Lipophilic 1,1-Bisphosphonates Are Potent Squalene
Synthase Inhibitors and Orally Active Cholesterol Lowering
Agents in Vivo. J . Biol. Chem. 1993, 268, 24832-24837.
(8) (a) 206th National ACS Meeting, Chicago, IL, 1993; Division of
Medicinal Chemistry Abstracts, pp 16-20. (b) Meeting report
in Current Drugs, Anti-atherosclerotic Agents Handbook; Harper,
G. D., Ed.; September 1993; A1.
(9) Main, B. G.; Tucker, H. Recent â-Adrenergic Blocking Agents.
In Progress in Medicinal Chemistry; Ellis, G. P., J r.; West, G.
B., Eds.; Elsevier Science Publishers: New York, 1985; Vol. 22,
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5H), 7.55-7.7 (m, 4H); EI-MS m/z 294 (M + H). Anal. (C20H23
NO‚0.4H20) C, H, N.
-
Further elution and crystallization from EtOAc gave, as a
colorless solid, the more polar diastereomeric pair 33 (170 mg,
2%): mp 213-214 °C; 1H-NMR (DMSO-d6) δ 1.1-1.5 (m, 4H),
1.65-1.9 (m, 2H), 2.6-2.9 (m, 5H), 2.9-3.1 (m, 1H), 4.4-4.5
(m, 1H), 5.1-5.2 (m, 1H), 7.3-7.5 (m, 5H), 7.55-7.7 (m, 4H);
EI-MS m/z 294 (M + H). Anal. (C20H23NO‚0.65H2O) C, H, N.
3-[4-(Th ien -2-yl)p h en yl]-3-h yd r oxyq u in u clid in e (34).
Saturated NaHCO3 solution (10 mL) was added to 3-(4-
bromophenyl)-3-hydroxyquinuclidine (490 mg, 1.73 mmol),
thiophene-2-boronic acid (320 mg, 2.5 mmol), and (PPh3)4Pd
(20 mg) in dimethoxyethane (25 mL) and the mixture heated
under reflux for 1.5 h. H2O (100 mL) was added to the cooled
mixture and the mixture extracted with EtOAc. The EtOAc
layer was extracted with 2 M HCl and the acid extract basified
to pH 12 with 8 M NaOH, before extraction with EtOAc. The
EtOAc was washed with saturated brine, dried, and evapo-
rated. The residue was recrystallized from EtOAc to give, as
a gray solid, 34 (301 mg, 60%): mp 165-168 °C; 1H-NMR
(DMSO-d6) δ 1.20-1.50 (m, 3H), 1.92 (m, 1H), 2.05-2.23 (m,
1H), 2.60-2.97 (m, 5H), 3.32 (d, 1H, J ) 13.2 Hz), 5.22 (s,
1H), 7.08-7.15 (m, 1H), 7.42-7.65 (m, 6H); EI-MS m/z 286
(M + H). Anal. (C17H19NOS‚0.5H2O) C, H, N.
Gen er a l P r oced u r e B. 3-[4-(Th ia zoyl-2-yl)p h en yl]-3-
h yd r oxyqu in u clid in e (35). A solution of sBuLi in cyclohex-
ane (7.5 mL, 1.3 M, 9.75 mmol) was added dropwise during
10 min to (4-bromophenyl)boronic acid N-methyl-O,O-dietha-
nolamine ester16 (1.42 g, 5 mmol) in THF (25 mL) at -100 °C.
The mixture was stirred for 30 min and a solution of quinu-
clidin-3-one (0.625 g, 5 mmol) in THF (10 mL) added during
10 min while maintaining the temperature at -100 °C. The
mixture was stirred for 1 h at -100 °C, allowed to warm to
ambient temperature, and stirred for a further 2 h. An
aqueous solution of NH4Cl (0.55g, 10 mmol) in H2O (5 mL)
was added and the mixture stirred for 30 min. The THF was
evaporated, and PhMe (20 mL) and saturated Na2CO3 solution
(10 mL) were added to the residue. A solution of 2-bromothia-
zole (870 mg, 5.3 mmol) in absolute EtOH (10 mL) was added
to the mixture at 25 °C. (PPh3)4Pd (100 mg) was added and
the mixture heated under reflux for 4 h. After cooling, ice and
(10) Subsequently patent applications and a communication have
been published, claiming quinuclidines as SQS inhibitors. (a)
Alberts, A. W.; Berger, G. D.; Meade, B.; Bergstrom, J . D.
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Preparation of Biphenylquinuclidines as Squalene Synthase
Inhibitors. PCT Int. Appl. WO 9309115 AI 920513; Chem. Abstr.
1993, 119, 117132. (d) Zhao, M.; Kumar, N.; Neuenschwander,

Novel 3-Biarylquinuclidine SQS Inhibitors
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