Inhibitors of acyl-coA:cholesterol O-acyltransferase. 2. Identification and structure-activity relationships of a novel series of N-alkyl-N- (heteroaryl-substituted benzyl)-N'-arylureas

2390

J . Med. Chem. 1998, 41, 2390-2410

In h ibitor s of Acyl-CoA:Ch olester ol O-Acyltr a n sfer a se. 2. Id en tifica tion a n d

Str u ctu r e-Activity Rela tion sh ip s of a Novel Ser ies of

N-Alk yl-N-(h eter oa r yl-su bstitu ted ben zyl)-N′-a r ylu r ea s¹

Akira Tanaka,*^,†Takeshi Terasawa,^†Hiroyuki Hagihara,^‡Yuri Sakuma,^§Noriko Ishibe,^‡Masae Sawada,^‡

Hisashi Takasugi,^†and Hirokazu Tanaka^|

Medicinal Chemistry Research Laboratories, Medicinal Biology Research Laboratories, and New Drug Research Laboratories,

Fujisawa Pharmaceutical Co. Ltd., 2-1-6 Kashima, Yodogawa-ku, Osaka 532, J apan, and Exploratory Research Laboratories,

Fujisawa Pharmaceutical Co. Ltd., 5-2-3 Tokodai, Tsukuba, Ibaraki 300-26, J apan

Received February 6, 1998

A series of N-alkyl-N-(heteroaryl-substituted benzyl)-N′-arylurea and related derivatives

represented by 2 and 3 have been prepared and evaluated for their ability to inhibit acyl-CoA:

cholesterol O-acyltransferase in vitro and to lower plasma cholesterol levels in cholesterol-fed

rats in vivo. Among these novel compounds, the type 3 series was superior. A pyrazol-3-yl

group on the N-benzyl group of this trisubstituted urea (i.e. 3, Ar₁) pyrazol-3-yl) was identified

as a heteroaromatic ring providing a good profile of biological activity. As a result of

optimization of the combination with the N-alkyl group (R) and N-aryl group (Ar₃), compound

3a q (FR186054) was identified as a new, orally efficacious ACAT inhibitor, which exhibited

potent in vitro ACAT inhibitory activity (rabbit intestinal microsomes IC₅₀) 99 nM) and

excellent hypocholesterolemic effects in cholesterol-fed rats, irrespective of administration mode

(ED₅₀) 0.046 mg/kg dosed via the diet, ED₅₀) 0.44 mg/kg administered by gavage in PEG400

vehicle). Moreover, a toxicological study revealed compound 3a q to be nontoxic to the adrenal

glands of dogs when tested at a single dose of 10 mg/kg po.

In tr od u ction

effects in human trials, including CL 277,082, have

proved disappointing.^11c,12As part of our research

program directed at the development of potent ACAT

inhibitors that are particularly effective in in vivo

models of hypercholesterolemia, we have recently in-

vestigated and reported on a novel series of N-alkyl-N-

(biphenylylmethyl)-N′-arylurea derivatives represented

by 1 as a series related to CL 277,082.¹³From this

series, FR182980 was identified as a potent ACAT

inhibitor in vitro and an efficacious hypocholesterolemic

agent in vivo. Due to the encouraging biological results,

we have continued our efforts to develop novel ACAT

inhibitors and opted to design, prepare, and evaluate

the novel series of N-alkyl-N-(heteroaryl-substituted

benzyl)-N′-arylureas and related derivatives repre-

sented by 2 and 3, replacing one of the phenyl rings of

the biphenyl moiety of 1 by a heteroaromatic ring as

heterocyclic isosteres of 1, since heterocyclic replace-

ment might be expected to improve physicochemical

characteristics such as aqueous solubility and influence

biological activity as well as toxicity. In this paper, we

disclose the synthesis, biological properties, and full

details of the structure-activity relationships of this

novel series of ACAT inhibitors.

Since the pioneering results of the Framingham study

were disclosed in 1971,²hypercholesterolemia has be-

come well-known as one of the major risk factors for

the development of coronary heart disease (CHD).³

Considerable efforts have been directed toward the

development of therapeutic agents to control plasma

cholesterol levels.⁴Acyl-CoA:cholesterol O-acyltrans-

ferase (ACAT, EC 2.3.1.26)⁵is an intracellular enzyme

responsible for catalyzing the esterification of free

cholesterol with fatty acyl-CoA to produce cholesteryl

esters. This enzyme plays an important role in the

absorption of dietary cholesterol, the secretion of hepatic

very low density lipoprotein (VLDL), and the accumula-

tion of cholesteryl esters in arterial lesions. Inhibition

of ACAT would be expected to reduce the absorption of

cholesterol, lower serum lipid levels,⁶and arrest pro-

gression and promote regression of atherosclerotic

plaques.⁷Therefore, ACAT inhibitors are very attrac-

tive targets for development of new treatments for

hypercholesterolemia and atherosclerosis.⁸

In recent years, a number of classes of compounds

have been shown to inhibit ACAT-catalyzed cholesterol

esterification.⁹These include N-alkyl-N-benzyl-N′-phe-

nylurea derivatives¹⁰such as CL 277,082^10awhich has

been the subject of various animal and human studies

(Figure 1).¹¹However, despite intensive research at-

tention on ACAT inhibitors, their hypocholesterolemic

Ch em istr y

The basic synthetic route to the novel trisubstituted

urea compounds 2a -g and 3a -bg prepared in this

work is summarized in Scheme 1 and Table 1. Reduc-

tive amination of benzaldehydes 4a -a f or benzylamine

5 with various alkylamines or carbonyl compounds

(methods A and B) or monoalkylation of various amines

with benzyl bromides 6a -c (method C) provided the key

* To whom correspondence should be addressed. Phone: 06-390-

5497. Fax: 06-304-5435.

^†Medicinal Chemistry Research Laboratories.

^‡Medicinal Biology Research Laboratories.

^§Exploratory Research Laboratories.

^|New Drug Research Laboratories.

Published on Web 05/23/1998

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2391

F igu r e 1. ACAT inhibitors.

Sch em e 1. Preparation of Target Molecules^a

a

Reagents: Method A; (1) RNH₂; (2) NaBH₄, EtOH; Method B; (1) NaOH(aq), CH₂Cl₂; (2) carbonyl compound; (3) NaBH₄, EtOH;

Method C; RNH₂; Method D; 2,4,6-Me₃PhNCO, CH₂Cl₂; Method E, 2,4,6-F₃PhNH₂, triphosgene, Et₃N, CH₂Cl₂; Method F; phenyl

b

N-arylcarbamate, Et₃N, toluene. When necessary, followed by a deprotection step; TFA, anisole or concentrated HCl, MeOH.

intermediate secondary amines 7a -ba . Elaboration to

the final hypocholesterolemic agents 2a -g and 3a -bg

was performed by one of three methods: (1) treatment

with 2,4,6-trimethylphenyl isocyanate (method D), (2)

reaction with 2,4,6-trifluoroaniline utilizing triphosgene

activation (method E), or (3) treatment with a phenyl

N-arylcarbamate¹³(method F). For the syntheses of 3n ,

3o, and 3a e, deprotection of the N-trityl group was

carried out with TFA-anisole or concentrated HCl in

MeOH after urea formation.

The various benzaldehyde derivatives 4a -a f were

prepared by several different methods as shown in

Schemes 2-13. Phenylthiophenecarboxaldehydes 4a

and 4b were synthesized by palladium-catalyzed cross-

coupling reaction of the appropriate bromothiophen-

ecarboxaldehyde 8a or 8b with phenylboric acid under

modified Suzuki cross-coupling conditions.^14aPhenyl-

furancarboxaldehyde 4c was also prepared by a similar

coupling reaction of bromofurancarboxaldehyde 10,

readily obtained from carboxylic acid 9 by amidation and

LiAlH₄reduction. Phenylpyridinecarboxaldehyde 4d

was prepared by the coupling reaction of methyl 6-chlo-

ronicotinate (11) with phenylboric acid followed by

LiAlH₄reduction and MnO₂oxidation.

14 with NH₂OH‚HCl or H₂NNH₂‚H₂O, respectively.

Subsequently, the ester function was transformed to

aldehyde by reduction and oxidation (Scheme 3).

Thienylbenzaldehydes 4g,h were prepared by Stille

coupling reaction¹⁵of 4-bromobenzyl alcohol with the

appropriate stannylthiophene 16a ,b, followed by MnO₂

oxidation (Scheme 4). (1H-Pyrrol-1-yl)benzaldehydes

4i,j were obtained from the appropriate benzoic acid

derivatives 18a ,b¹⁶by formation of the Weinreb amide

and LiAlH₄reduction to the aldehyde (Scheme 5).

Benzaldehyde derivatives with various heterocyclic

substituents at the 4-position (4k -o,p ) were prepared

by the reaction of 4-fluorobenzaldehyde (19) with the

appropriate azoles or 1-methylpiperazine in the pres-

ence of K₂CO₃. In the case of the reaction with 1,2,3-

triazole, two regioisomers 4n ,o were obtained favoring

4n (Scheme 6).

The synthetic routes to various pyrazolylbenzalde-

hydes are summarized in Schemes 7-9. (Pyrazol-3-yl)-

benzaldehydes 4q,r were prepared from ethyl 4-acetyl-

benzoate (20a) or 3-acetylbenzonitrile (20b) by treatment

with N,N-dimethylformamide dimethyl acetal (simul-

taneous ester exchange occurred in the case of 20a ),

followed by construction of the pyrazole ring with H₂-

NNH₂‚H₂O and transformation of ester or nitrile func-

tions by the usual methods. For the syntheses of 4s-

v, N-methylpyrazole ring systems were assembled by

Isoxazole and pyrazole derivatives 4e,f were prepared

from acetophenone (13). Construction of the heteroaro-

matic ring was achieved by the reaction of diketo ester

2392 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Tanaka et al.

Ta ble 1. Structures and Synthetic Methods of Benzaldehydes (4), Benzylamines (5), Benzyl Bromides (6), and Secondary Amines (7)

a

b

In the case of 7w , Et₃N was used to convert 4-(dimethylamino)benzylamine dihydrochloride to the free form. Commercially available.

cyclization of 21a ,b with 1 equiv of MeNHNH₂in AcOH

to give chromatographically separable regioisomeric

mixtures 23a ,b or 24a ,b. In both cases a 2:1 ratio was

observed favoring 23a or 24a , respectively.¹⁷However,

when the reaction was carried out with 1 equiv of

MeNHNH₂and AcOH in MeOH, in both cases the ratio

was reversed to 1:4 favoring 23b or 24b. To obtain all

isomers in synthetically useful amounts, we selected the

former conditions. Transformation of ester or nitrile

function to aldehyde gave N-methylpyrazolylbenzalde-

hydes 4s-v (Scheme 7). 3-(1-Tritylpyrazol-4-yl)benzal-

dehyde (4w ) was synthesized by Suzuki coupling

reaction^14b,cof 4-bromo-1-tritylpyrazole (26) and

3-formylphenylboric acid (28) which was obtained from

bromobenzene derivative 27 (Scheme 8). (1-Meth-

ylpyrazol-4-yl)benzaldehydes 4x,y were prepared by

Stille coupling reaction of stannylpyrazole (30) which

was readily obtained from 4-bromo-1-methylpyrazole

(29)¹⁸and bromobenzaldehydes 31a ,b (Scheme 9).

Imidazolylbenzaldehyde 4z was assembled from

3-acetylbenzonitrile (20b) via bromination and subse-

quent cyclization with HCONH₂, followed by conversion

of the nitrile function to aldehyde (Scheme 10).

Oxazolylbenzaldehyde 4a a was synthesized from

methyl 4-formylbenzoate (33) by treatment with tosyl-

methyl isocyanide (TosMIC) to construct the oxazole

ring, followed by transformation of the ester function

to aldehyde (Scheme 11).

The synthetic route to (1,3,4-oxadiazol-2-yl)benzalde-

hyde 4a b and 1,2,4-triazole compound 7ba is depicted

in Scheme 12. Methyl 4-formylbenzoate (33) was con-

verted to hydrazide 35 in three steps and was then

treated with ethyl acetimidate hydrochloride followed

by thermal cyclization to provide 1,3,4-oxadiazole com-

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2393

Sch em e 2^a

a

Reagents: (a) PhB(OH)₂, Pd(PPh₃)₄, 2 M Na₂CO₃, DME; (b) Me(MeO)NH‚HCl, HOBt, WSC, CH₂Cl₂; (c) LiAlH₄, THF; (d) MnO₂,

CHCl₃.

Sch em e 3^a

heating with benzylamine¹⁹and was then converted to

benzaldehyde derivative 38. Reductive amination and

selective deprotection of the benzyl group on the triazole

ring provided benzylamine 7ba .

Tetrazolylbenzaldehydes 4a c-a e were synthesized as

shown in Scheme 13. 3-Cyanobenzoic acid 40 was

esterified and treated with NaN₃to provide methyl

3-(1H-tetrazol-5-yl)benzoate 41. Subsequent transfor-

mation of the ester function to aldehyde followed by

protection of the tetrazole moiety with a trityl group

yielded 4a c. Alkylation of 42 with MeI afforded a

mixture of regioisomeric N-methyltetrazole compounds

4a d ,a e which were separated by column chromatogra-

phy.²⁰

a

Reagents: (a) (CO₂Me)₂, NaH, DMF; (b) NH₂OH‚HCl, MeOH;

(c) H₂NNH₂‚H₂O, EtOH; (d) DIBAL, CH₂Cl₂; (e) (1) LiAlH₄, THF;

(2) MnO₂, acetone.

2-Phenylimidazole-4-carboxaldehyde (4a f) was com-

mercially available.

Sch em e 4^a

Thiazolylbenzylamine hydrochloride 5 was prepared

from benzonitrile derivative 43 via conversion to methyl

ketone 44, bromination, construction of the thiazole ring

with thioacetamide, and deacetylation (Scheme 14).

The syntheses of benzyl bromide derivatives bearing

a heterocyclic ring 6a -c were accomplished as shown

in Scheme 15. Pyridylbenzyl bromides 6a ,b were

obtained by bromination of the corresponding com-

mercially available or known tolylpyridines 46a ,b²¹with

NBS in the presence of a catalytic amount of benzoyl

peroxide. Pyrazolylbenzyl bromide 6c was prepared by

coupling reaction of 4-methylphenylboric acid (47) and

4-bromo-1-tritylpyrazole (26) and subsequent bromina-

tion with NBS.

a

Reagents: (a) 4-BrC₆H₄CH₂OH, Pd(PPh₃)₄, xylene; (b) MnO₂,

CHCl₃.

Sch em e 5^a

Resu lts a n d Discu ssion

The compounds prepared were evaluated for their

ability to inhibit intestinal ACAT in vitro by incubation

with [1-¹⁴C]oleoyl-CoA and the mucosal microsomes

from the small intestine of cholesterol-fed rabbits ac-

cording to the method of Heider et al.²²with minor

modifications.^13,23In vivo hypocholesterolemic activity

was assessed in cholesterol-fed rats by oral administra-

tion of the test compounds as a dietary admixture in a

cholesterol-enriched diet.¹³The in vitro activity is

expressed as the nanomolar concentration of a com-

pound required to inhibit 50% of the enzyme activity

(IC₅₀), the in vivo cholesterol-lowering activity is pre-

a

Reagents: (a) Me(MeO)NH‚HCl, WSC, CH₂Cl₂; (b) LiAlH₄,

THF; (c) Me(MeO)NH‚HCl, HOBt, WSC, CH₂Cl₂.

pound 36. Subsequent desilylation and MnO₂oxidation

yielded (1,3,4-oxadiazolyl)benzaldehyde 4a b. The 1,2,4-

triazole ring system in amine 7ba was prepared from a

preexisting heterocyclic ring. Thus, 1,3,4-oxadiazole 36

was transformed to 4-benzyl-4H-1,2,4-triazole 37 by

2394 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Tanaka et al.

Sch em e 6^a

a

Reagents: (a) azole, K₂CO₃, DMF; (b) 1-methylpiperazine, K₂CO₃, DMF.

Sch em e 7^a

Sch em e 8^a

a

Reagents: (a) TrCl, Et₃N, DMF; (b) (1) ⁿBuLi, B(OiPr)₃, THF;

(2) dil. HCl; (c) 26, Pd(PPh₃)₄, K₂CO₃, toluene.

Sch em e 9^a

a

Reagents: (a) Me₂NCH(OMe)₂; (b) H₂NNH₂‚H₂O, AcOH,

a

Reagents: (a) ⁿBuLi, ⁿBu₃SnCl; (b) 30, Pd(PPh₃)₄, xylene.

MeOH; (c) LiAlH₄, THF; (d) MnO₂, acetone; (e) Raney Ni, HCO₂H,

H₂O; (f) MeNHNH₂, AcOH; (g) DIBAL, CH₂Cl₂.

Sch em e 10^a

sented in terms of percent reduction at the dose or ED₅₀,

the effective dose to reduce plasma total cholesterol level

by 50%.

Biological data for the urea compounds represented

by 2, replacing the inner phenyl ring of the biphenyl

moiety of 1 by a heteroaromatic ring, are shown in Table

2. To simplify the comparison, the N-alkyl (R) and

N-aryl group (Ar₃) were kept constant to cycloheptyl and

2,4,6-trimethylphenyl groups, respectively, as these had

been shown to give a good biological profile in our

previous series 1. Compared to the standard compound

1a , which was one of our lead compounds,¹³no clearly

superior compounds could be identified. Thus, conver-

sion of phenyl to a nonpolar heteroaromatic ring, for

example thiophene (2a , 2b), furan (2c), and isoxazole

(2d ), reduced in vitro ACAT inhibitory activity by

several orders and could not produce any significant

improvement in cholesterol-lowering effects in vivo.

Introduction of basic heteroaromatics, i.e. pyrazole (2e),

imidazole (2f), and pyridine (2g), resulted in compounds

a

Reagents: (a) Br₂, Et₂O, 1,4-dioxane; (b) HCONH₂; (c) Raney

Ni, HCO₂H, H₂O.

about 100-fold less active in vitro. In addition, com-

pound 2f was inactive at a dose of 1 mg/kg in vivo. On

the basis of these results, it was considered that a

heteroaromatic ring at this position may cause an

unfavorable effect upon interaction with the enzyme and

did not give any advantage over the parent compound

1a .

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2395

Sch em e 11^a

a

Reagents: (a) TosMIC, K₂CO₃, MeOH; (b) LiAlH₄, THF; (c) Swern oxidation.

Sch em e 12^a

a

Reagents: (a) NaBH₄, EtOH; (b) TBSCl, imidazole, DMF; (c) H₂NNH₂‚H₂O, EtOH; (d) (1) MeC(dNH)OEt‚HCl, Et₃N, EtOH; (2) 200

°C; (e) 1 N HCl, MeOH; (f) MnO₂, acetone; (g) BnNH₂; (h) cycloheptylamine; (i) Pd Black, HCO₂H, MeOH.

Sch em e 13^a

Sch em e 15^a

a

Reagents: (a) NBS, Bz₂O₂, CCl₄; (b) 26, Pd(PPh₃)₄, K₂CO₃,

toluene.

3g). These compounds retained high in vitro activity,

and several compounds (3b, 3d , and 3g) exhibited

potent hypocholesterolemic activity in cholesterol-fed

rats comparable to that of the parent compound 1a . It

is interesting that in the case of pyrrole compounds, the

in vivo activity of 3g substituted at position 3 was more

potent than 4-substitution (3f), even though in vitro

activity was equivalent. However, we decided that a

breakthrough would not be expected by these very

simple modifications. Moreover, most of the early ACAT

inhibitors, designed to act in the intestine, preventing

absorption of dietary cholesterol, are highly lipophilic

and have poor bioavailability which translates into quite

poor in vivo activity. Therefore, a major thrust of more

recent approaches has been to functionalize lipophilic

inhibitors to alter their physicochemical properties since

this can be expected to dramatically affect not only

biological activity but also systemic bioavailability.^9cFor

instance, the recently reported CI-999, a relatively

water soluble ACAT inhibitor, is weakly potent in vitro,

but showed remarkable efficacy in vivo (Figure 1).²⁴

Therefore, we opted to examine introduction of more

polar basic aromatic rings, which had been disappoint-

ing in the case of previous series. With regard to in vitro

activity, pyridine (3h , 3i), pyrazole (3k -3m , 3o-3u ),

a

Reagents: (a) DMF, POCl₃, MeOH, EtOAc; (b) NaN₃, NH₄Cl,

DMF; (c) LiAlH₄, THF; (d) MnO₂, acetone; (e) TrCl, pyridine; (f)

MeI, NaH, DMF.

Sch em e 14^a

a

Reagents: (a) MeMgBr, THF, Et₂O; (b) (1) Br₂, DME; (2)

MeC(dS)NH₂, NaHCO₃, EtOH; (c) concentrated HCl, EtOH.

In contrast to the foregoing results, the structure-

activity relationships of the urea series represented by

3, replacing the terminal phenyl ring of the biphenyl

moiety of 1 by a heteroaromatic ring, were quite different

(Table 3). Our preliminary investigations involved

replacing the phenyl by a thiophene or pyrrole ring (3a -

2396 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Tanaka et al.

Ta ble 2. Biological Activities of

N-Alkyl-N-((phenyl-substituted heteroaryl)methyl)-N′-arylureas

Having identified pyrazole as a heteroaromatic ring

providing a good profile of biological activity, we next

concentrated our efforts on varying N-alkyl group (R)

and N-aryl group (Ar) (Tables 4 and 5). In the non-N-

methylpyrazole series, the best compound 3m was

selected for further modification (Table 4). Conversion

of 2,4,6-trimethylphenyl to 2,4,6-trifluorophenyl, which

is one of the standard aromatic rings for ACAT inhibi-

tors,²⁵increased both in vitro and in vivo activity (3a i).

However, introduction of 2,4-bis(methylthio)-6-meth-

ylpyridine, which afforded the best compound FR182980

in our previously reported series, significantly reduced

activity (3a j). Although replacement of the cycloheptyl

group of 3m by smaller ring cycloalkyl groups (3a k , 3a l)

retained in vitro activity, in vivo hypocholesterolemic

activity was reduced; similar trends in the structure-

activity relationships were observed for our previously

disclosed biphenyl series, represented by structure 1.¹³

In the case of a benzyl group, although (2,4,6-trimeth-

ylphenyl)urea (3a m ) was not attractive, (2,4,6-trifluo-

rophenyl)urea (3a n ) showed potent in vitro and in vivo

activity. Furthermore, incorporation of 2,4-bis(meth-

ylthio)-6-methylpyridine, which was disappointing in

the case of a cycloheptyl group, gave the compound with

the best cholesterol-lowering effect (3a q, FR186054,

ED₅₀) 0.046 mg/kg). These results suggest that the

combination of the N-alkyl group (R) and N-aryl group

(Ar) is very subtle and markedly influences biological

activity.

Introduction of a substituent to the 4-position of the

N-benzyl group of 3a q resulted in reduced in vitro

activity (3a r and 3a v) irrespective of electronic and/or

steric effects; however, cholesterol-lowering activity in

vivo was retained. Although methoxy compound 3a r

possessed about the same level of activity as the parent

compound 3a q, a change in the position of the methoxy

group markedly reduced the hypocholesterolemic activ-

ity (3a s, 3a t). Additionally, a 2-phenylethyl group

reduced in vivo activity (3a w ). The best in vitro activity

was obtained by introduction of a dimethylamino group

to the 4-position of the N-benzyl group in 3a n (com-

pound 3a o, IC₅₀) 12 nM); however, its in vivo choles-

terol-lowering effect was relatively reduced. As a

consequence these modifications could not produce any

significant improvement in the biological activity.

imidazole (3v), and oxadiazole rings (3a c) were superior

to oxazole (3a b) and thiazole (3a d ). Triazole derivatives

(3x-3a a ) showed variable in vitro ACAT inhibitory

activity but only weak in vivo activity. It is very

interesting that a nonaromatic, highly basic, N-meth-

ylpiperazine ring compound (3a h ) also possessed potent

inhibitory activity, although its in vivo activity was not

sufficient to justify further interest, possibly related to

metabolism. These results suggest that both lipophilic

and more polar basic components are acceptable at this

position. Among the aromatic rings examined, pyrazole

was attractive because of its moderate basicity. In the

non-N-methylpyrazole series (3k -3o), dependence of

the activity on the position of the pyrazole substituent

on the phenyl ring was observed. That is, in the case

of pyrazol-3-yl compounds, while in vitro activity was

similar, with respect to in vivo efficacy, attachment to

the 3-position on the phenyl ring was clearly superior

(3l vs 3m ). On the other hand, in the case of the

regioisomeric pyrazol-4-yl compounds, attachment to the

3-position was preferred for both in vitro and in vivo

activity (3n vs 3o). In the N-methylpyrazole series (3p -

3u ), a distinct tendency was not observed. Among these

pyrazole compounds, 3m in particular exhibited a very

potent hypocholesterolemic effect (ED₅₀) 0.097 mg/kg).

Although tetrazole compound 3a e was also prepared

and evaluated, it resulted in a complete loss of activity.

Since N-methylation of the tetrazole ring restores the

biological activity (3a f, 3a g), it can be concluded that

an acidic functional unit is not acceptable to the enzyme

site.

An attempt to apply the best combination, i.e. benzyl

group and substituted pyridine, to compound 3l, whose

pyrazole ring is connected at the 4-position of the phenyl

ring, improved in vivo activity (3a y), but it was inferior

to compound 3a q.

Similar modifications were performed on the N-

methylpyrazole series (Table 5); however, a compound

with potent in vivo biological activity was not identified.

As a result of these investigations, 3m , 3a i, 3a n , and

3a q, which all showed potent in vivo hypocholester-

olemic activity, were selected for further studies.

It has been shown previously that the bioavailability

of ACAT inhibitors can be markedly influenced by

modes of drug dosing.^13,26Therefore, we next evaluated

the hypocholesterolemic effects of the selected com-

pounds (3m , 3a i, 3a n , and 3a q) in a different admin-

istration model, i.e. dosing of the test compound by

gavage in poly(ethylene glycol) (PEG400) as a vehicle

(Table 6).¹³Utilizing this model, 3a n which showed

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2397

Ta ble 3. Biological Activities of N-Alkyl-N-(heteroaryl-substituted benzyl)-N′-arylureas

2398 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Ta ble 3. (Continued)

Tanaka et al.

Ta ble 4. Biological Activities of N-Alkyl-N-(pyrazolylbenzyl)-N′-arylureas

ACAT

inhibitory hypocholesterolemic

yield^b

activity^c

activity^d

no.

3m

3a i

3a j

3a k

3a l

R

Ar

position

formula^a

C₂₇H₃₄N₄O

C₂₄H₂₅F₃N₄O

mp (°C)

(method) IC₅₀(nM)

ED₅₀(mg/kg)

cycloheptyl

cyclohexyl

cyclopentyl

2,4,6-Me₃Ph

2,4,6-F₃Ph

Py-deriv

2,4,6-Me₃Ph

2,4,6-F₃Ph

3

4

180-181

158-159

65 (D)

52 (E)

62 (F)

18 (D)

25 (D)

86 (D)

26 (E)

98 (F)

83 (F)

78 (F)

68 (F)

74 (F)

82 (F)

76 (F)

61 (F)

87 (F)

61 (D)

67 (F)

86 (F)

65

22

260

39

22

21

0.097

0.062

>0.32 (24)

0.12

<1 (76)***

>1 (36)

0.096

<0.32 (68)*

<0.32 (64)*

0.046

e

C

₂₆H₃₃N₅OS₂

amorphous solid

193-194

C₂₆H₃₂N₄O‚0.2H₂O

C₂₅H₃₀N₄O‚0.5H₂O

C₂₇H₂₈N₄O

C₂₄H₁₉F₃N₄O

C₂₆H₂₄F₃N₅O

3a m benzyl

3a n

3a o

3a p

3a q

3a r

3a s

3a t

benzyl

14

12

4-Me₂N-benzyl 2,4,6-F₃Ph

4-F-benzyl

benzyl

4-MeO-benzyl Py-deriv

2-MeO-benzyl Py-deriv

3-MeO-benzyl Py-deriv

4-Me₂N-benzyl Py-deriv

amorphous solid

2,4,6-F₃Ph

Py-deriv

C₂₄H₁₈F₄N₄O‚0.25H₂O 204-206

ND

99

200

ND

72

250

ND

52

100

55

C

₂₆H₂₇N₅OS₂

₂₇H₂₉N₅O₂S₂

209-210

170-173

<0.1 (81)**

>0.1 (inactive)

>0.1 (13)

<0.1 (61)*

<0.1 (66)**

>0.1 (inactive)

>1 (17)

amorphous solid

165-166

3a u

3a v

C₂₈H₃₂N₆OS₂

185-188

166-168

4-F-benzyl

Py-deriv

2,4,6-Me₃Ph

Py-deriv

C

₂₆H₂₆FN₅OS₂

₂₇H₂₉N₅OS₂

3a w 2-phenylethyl

3l

3a x

3a y

amorphous solid

174-175

cycloheptyl

benzyl

C₂₇H₃₄N₄O‚0.1H₂O

C

₂₆H₃₃N₅OS₂

₂₆H₂₇N₅OS₂

<0.32 (77)*

<0.32 (58)

150-152

^a-d,*See corresponding footnotes of Table 2. ^eSatisfactory analytical data could not be obtained for this compound. Anal. N: calcd,

14.13; found, 13.25. Py-deriv denotes 2,4-bis(methylthio)-6-methylpyridin-3-yl. ND denotes not determined.

excellent activity when dosed as a dietary admixture,

was only modestly potent. However, it was gratifying

that the other three compounds were still efficacious

even when dosed by gavage in PEG400. Among these

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2399

Ta ble 5. Biological Activities of N-Alkyl-N-((methylpyrazolyl)benzyl)-N′-arylureas

Ta ble 6. Biological Activities of Selected Compounds and Effect of Administration Mode

hypocholesterolemic activity^c

ED₅₀(mg/kg)

ACAT inhibitory

activity^a

foam cell formation

inhibitory activity^b

IC₅₀(nM)

administration mode

no.

R

Ar

IC₅₀(nM)

diet^d

gavage^e

3m

cycloheptyl

benzyl

2,4,6-Me₃Ph

2,4,6-F₃Ph

Py-deriv

65

22

14

99

30

460

580

7400

350

48

ND

0.097

0.062

0.096

0.046

0.034

5.0

2.0

0.79

8.6

0.44

0.11

ND

3a i

3a n

3a q

FR182980

CL 277,082

CI-999

benzyl

33

4000

55000

0.61

a

b

See footnote c of Table 2. IC₅₀(nM) for acetylated LDL-induced accumulation of cholesteryl esters in mouse peritoneal macrophages.

^cED₅₀values are the effective dose to reduce plasma total cholesterol level by 50% of the control value. Compound was administered as

d

a dietary admixture. ^eCompound was administered by gavage in PEG400 as a vehicle. Py-deriv denotes 2,4-bis(methylthio)-6-methylpyridin-

3-yl.

compounds, 3a q in particular showed the most potent

cholesterol-lowering effect in both dosing models. Al-

though the precise reasons why 3a q exhibited such high

potency are still unclear at this point, it may in part be

presumably attributed to improved pharmacokinetics of

this inhibitor as a result of incorporation of the substi-

tuted pyridine part which provides a protonation site

to improve solubility and make the molecule more polar.

As previously stated, macrophage-derived foam cells

play an important role in lesion progression. ACAT

inhibition in arterial macrophages would be expected

to exert an antiartherosclerotic effect by inhibiting foam

cell formation in the arterial wall.^7,8Furthermore, the

possibility of the existence of isozymes of ACAT has been

suggested.²⁷Thus, selected compounds were further

assessed for their ability to inhibit acetylated LDL-

induced accumulation of cholesteryl esters in mouse

peritoneal macrophages (Table 6). Compound 3a q was

found to be relatively less active in the macrophage

assay than FR182980 but still retained a high level of

activity. On the other hand, 3a n was found to have

weak inhibitory activity, possibly related to its poor

ability to penetrate the macrophage cell wall and/or

essentially weak inhibitory activity of the macrophage

ACAT.

Recently various classes of ACAT inhibitors have been

2400 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Tanaka et al.

inner phenyl ring of the biphenyl moiety of series 1 by

basic heteroaromatic rings appears to be unfavorable

for interaction with the enzyme. (2) Although introduc-

tion of basic heteroaromatic rings as the terminal

aromatic ring of the biaryl moiety is acceptable, acidic

rings such as tetrazole are unfavorable. Pyrazole was

identified as the heteroaromatic ring providing the best

balance of biological activity. (3) The position connect-

ing the heteroaromatic ring and the inner phenyl ring

can influence biological activity. (4) Combination with

the N-alkyl group (R) and N-aryl group (Ar₃) is very

subtle and has an enormous effect on the activity. On

the basis of the main results described above, N-benzyl-

N-[3-(pyrazol-3-yl)benzyl]-N′-[2,4-bis(methylthio)-6-me-

thylpyridin-3-yl]urea (3a q, FR186054) was identified as

a potent, nonadrenotoxic, orally efficacious ACAT in-

hibitor irrespective of dosing method and was selected

for further development. The details of pharmacological

studies on this compound and the results of further

efforts to overcome the adrenal toxicity of FR182980,

the best compound in our previous biphenyl series 1,

will be the subject of further communications from these

laboratories.

F igu r e 2. Plasma concentrations in fed dog (dose ) 10 mg/

kg, n ) 1).

shown to induce toxicological effects on the adrenal

glands of certain species.^26a,28-31Therefore, 3a n , 3a q,

and FR182980 were assessed for adrenal toxicity in

rabbits (n ) 3-4) at a single dose of 5 mg/kg iv and/or

dog (n ) 1) at a single dose of 10 mg/kg po using PEG400

as a vehicle. Among these compounds, FR182980

showed a mild effect in rabbits, as indicated by slight

alterations consisting of mononuclear cell infiltration in

the adrenal cortex and, furthermore, significant adrenal

toxicity in dog, as indicated by necrosis of cortical cells

in the adrenal cortex. However drug-related histo-

pathologic alterations to the adrenal glands of dogs were

not observed for compounds 3a n and 3a q. Figure 2

shows a time course for plasma drug levels in fed dog

following oral administration of each compound at a

dose of 10 mg/kg in this toxicological study. It should

be noted that the plasma level of 3a q was similar to

that of FR182980, indicating that the intrinsic lack of

adrenotoxicity is not related to serum concentration. On

the other hand, poorly absorbed 3a n , predicted from

its modest hypocholesterolemic activity when dosed by

gavage, was essentially nontoxic in part due to the low

systemic exposure. However, setting aside these plasma

drug levels in dogs, 3a n was concluded to be nontoxic

on the basis of the result of the toxicological study in

rabbits after intravenous administration. It is unclear

whether the observed adrenotoxicity is mechanism- or

compound-related,^{28b-e,29e,f,30,31}and additionally why our

three compounds displayed such different effects on

adrenal tissue. However, researchers at Parke-Davis

have reported recently a tendency similar to that

displayed in our results that toxicity was reduced

significantly by making the molecule more polar and

basic in nature.^26aFurthermore, several reports includ-

ing nontoxic analogues have appeared.^29c,d,f,32

Exp er im en ta l Section

Ch em istr y. Gen er a l P r oced u r es. Melting points were

measured on a Bu¨chi 535 apparatus in open capillaries and

are uncorrected. IR spectra were recorded on

a Horiba

Spectradesk FT-210 spectrometer as KBr disks, neat, or films

as indicated. NMR spectra were measured on a Bruker

AC200P (¹H, 200 MHz). Chemical shifts are given in parts

per million, and tetramethylsilane was used as the internal

standard for spectra obtained in DMSO-d₆and CDCl₃. All J

values are given in hertz. Mass spectra were measured on a

Hitachi Model M-1000H mass spectrometer using APCI for

ionization. Elemental analyses were carried out on a Perkin-

Elmer 2400 CHN elemental analyzer. Reagents and solvents

were used as obtained from commercial suppliers without

further purification. Column chromatography was performed

using silica gel, and reaction progress was determined by TLC

analysis on silica gel coated glass plates. Visualization was

with UV light (254 nm) or iodine. The term “evaporated” or

“evaporation” refers to removal of solvent on a rotary evapora-

tor at reduced pressure.

5-P h en ylth iop h en e-2-ca r boxa ld eh yd e (4a ). To a solu-

tion of 5-bromothiophene-2-carboxaldehyde 8a (2.00 g, 10.5

mmol) and phenylboric acid (PhB(OH)₂) (1.66 g, 13.6 mmol)

in 1,2-dimethoxyethane (DME) (18 mL) were added a 2 M Na₂-

CO₃solution (13.6 mL) and Pd(PPh₃)₄(605 mg, 0.52 mmol),

and the mixture was heated at 80 °C for 5 h. The reaction

mixture was poured into a mixture of CH₂Cl₂and ice water.

The separated organic layer was washed with water and brine,

dried (MgSO₄), and evaporated, and the residue was purified

by silica gel column chromatography (hexane-EtOAc, 5:1

elution) to give 4a (1.80 g, 91%) as a solid: ¹H NMR (CDCl₃)

δ 7.33-7.50 (4H, m), 7.60-7.80 (3H, m), 9.90 (1H, s); IR (KBr)

1647, 1441, 1232, 754 cm^-1; MS m/z 189 (MH⁺).

On the basis of the results discussed above, compound

3a q (FR186054) bearing a novel pyrazole ring was

identified as a potent, nonadrenotoxic, orally efficacious

ACAT inhibitor, independent of the administration

mode, and selected for further development as a new

treatment for hypercholesterolemia and atherosclerosis.

The following compound was prepared in a similar manner

from 4-bromothiophene-2-carboxaldehyde 8b (10.5 mmol) and

PhB(OH)₂(13.6 mmol).

4-P h en ylth iop h en e-2-ca r boxa ld eh yd e (4b): yield 1.97 g

(100%); ¹H NMR (CDCl₃) δ 7.30-7.66 (5H, m), 7.82-7.90 (1H,

m), 8.00-8.08 (1H, m), 9.98 (1H, d, J ) 1.2 Hz); IR (KBr) 1676,

1539, 1429, 1173, 760 cm^-1; MS m/z 189 (MH⁺).

Con clu sion

5-P h en ylfu r a n -2-ca r boxa ld eh yd e (4c). To a suspension

of 5-bromofuran-2-carboxylic acid 9 (10.0 g, 52.4 mmol), N,O-

dimethylhydroxylamine hydrochloride (5.10 g, 52.4 mmol), and

1-hydroxybenzotriazole (HOBt) (7.07 g, 52.4 mmol) in CH₂Cl₂

(300 mL) was added dropwise a solution of 1-(3-(dimethylami-

no)propyl)-3-ethylcarbodiimide (WSC) (6.37 g, 52.4 mmol) in

In summary, we have prepared a novel series of

N-alkyl-N-(heteroaryl-substituted benzyl)-N′-arylurea

and related derivatives and evaluated them as ACAT

inhibitors. The SAR study in this series of compounds

revealed the following main features: (1) Replacing the

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2401

CH₂Cl₂(60 mL) at room temperature, and the mixture was

stirred for 18 h. The reaction mixture was poured into water,

the separated organic layer was washed with water and brine,

dried (MgSO₄), and evaporated, and the residue was purified

by silica gel column chromatography (hexane-EtOAc, 1:1

elution) to give N-methoxy-N-methyl-5-bromofuran-2-carbox-

amide (7.60 g, 62%) as a solid: ¹H NMR (CDCl₃) δ 3.34 (3H,

s), 3.77 (3H, s), 6.45 (1H, d, J ) 3.5 Hz), 7.09 (1H, d, J ) 3.5

Hz); IR (KBr) 3107, 2981, 2937, 1637, 1564, 1466 cm^-1; MS

m/z 234, 236 (MH⁺).

dispersion, 8.0 g, 200 mmol) at 5 °C. The mixture was stirred

at room temperature for 1 h and then heated at 50 °C for 30

min. After cooling, the mixture was treated with 2.4 N HCl

(70 mL) and extracted with EtOAc. The organic layer was

washed with water and brine, dried (MgSO₄), evaporated, and

purified by silica gel column chromatography (hexane-

EtOAc, 4:1 to 1:1 elution) to give methyl 2,4-dioxo-4-phenyl-

butyrate 14 (20.3 g, 59%) as a semisolid: ¹H NMR (CDCl₃) δ

3.95 (3H, s), 7.10 (1H, s), 7.45-7.68 (3H, m), 7.95-8.06 (2H,

m), 15.0-15.5 (1H, br); IR (KBr) 1732, 1622, 1601, 1574, 1444,

1269 cm^-1; MS m/z 207 (MH⁺).

To a suspension of LiAlH₄(584 mg, 15.4 mmol) in THF (80

mL) was added dropwise a solution of the above amide (3.60

g, 15.4 mmol) in THF (35 mL) at 5 °C, and the mixture was

stirred at the same temperature for 15 min. To the mixture

were added anhydrous NaF (2.58 g, 61.5 mmol) and water

(0.83 mL), followed by stirring at room temperature for 30 min.

Insoluble materials were removed by filtration and washed

with THF. The filtrate was evaporated and purified by silica

gel column chromatography (hexane-EtOAc, 5:2 elution) to

give 5-bromofuran-2-carboxaldehyde 10 (2.11 g, 78%) as a

solid: ¹H NMR (CDCl₃) δ 6.57 (1H, d, J ) 3.6 Hz), 7.19 (1H,

d, J ) 3.6 Hz), 9.54 (1H, s); IR (KBr) 1670, 1464, 1377, 1271

A solution of 14 (6.0 g, 29.1 mmol) and NH₂OH‚HCl (6.07

g, 87.4 mmol) in MeOH (120 mL) was refluxed for 4 h. After

evaporation and dilution with CHCl₃, the solution was washed

with water and brine, dried (MgSO₄), evaporated, and purified

by silica gel column chromatography (hexane-EtOAc, 3:1

elution) to give methyl 5-phenylisoxazole-3-carboxylate 15a

(5.25 g, 89%) as a solid: ¹H NMR (CDCl₃) δ 4.01 (3H, s), 6.94

(1H, s), 7.45-7.55 (3H, m), 7.75-7.88 (2H, m); IR (KBr) 1728,

1570, 1448, 1250 cm^-1; MS m/z 204 (MH⁺).

To a solution of 15a (4.73 g, 23.3 mmol) in CH₂Cl₂(150 mL)

was added dropwise diisobutylaluminum hydride (DIBAL)

(1.02 M toluene solution, 45.7 mL, 46.6 mmol) at -60 °C, and

the mixture was stirred at the same temperature for 1 h. To

the mixture were added anhydrous NaF (7.83 g, 186.4 mmol)

and water (2.52 mL), and the mixture was stirred at room

temperature for 1 h. Insoluble materials were removed by

filtration and washed with EtOAc. The filtrate was evaporated

and purified by silica gel column chromatography (hexane-

EtOAc, 3:1 elution) to give 4e (1.94 g, 48%) as a solid: ¹H NMR

(CDCl₃) δ 6.90 (1H, s), 7.35-7.68 (3H, m), 7.75-7.92 (2H, m),

10.20 (1H, s); IR (KBr) 3126, 1713, 1568, 1456, 1184 cm^-1; MS

m/z 174 (MH⁺).

cm^-1

.

To a solution of 10 (2.09 g, 11.9 mmol) and PhB(OH)₂(1.89

g, 15.5 mmol) in DME (18 mL) were added a 2 M Na₂CO₃

solution (15.5 mL) and Pd(PPh₃)₄(690 mg, 0.60 mmol), and

the mixture was heated at 80 °C for 6 h. The reaction mixture

was poured into a mixture of CH₂Cl₂and ice water. The

separated organic layer was washed with water and brine,

dried (MgSO₄), evaporated, and purified by silica gel column

chromatography (hexane-EtOAc, 5:1 elution) to give 4c (1.88

g, 92%) as an oil: ¹H NMR (CDCl₃) δ 6.85 (1H, d, J ) 3.7 Hz),

7.33 (1H, d, J ) 3.7 Hz), 7.37-7.53 (3H, m), 7.80-7.92 (2H,

m), 9.66 (1H, s); IR (neat) 1674, 1522, 1475, 1257 cm^-1; MS

m/z 173 (MH⁺).

6-P h en ylp yr id in e-3-ca r boxa ld eh yd e (4d ). To a solution

of methyl 6-chloronicotinate 11 (6.86 g, 40.0 mmol) and PhB-

(OH)₂(5.85 g, 48.0 mmol) in DME (150 mL) were added a 2 M

Na₂CO₃solution (48 mL) and Pd(PPh₃)₄(2.31 g, 2.0 mmol),

and the mixture was refluxed for 16 h at 80 °C. The reaction

mixture was poured into a mixture of EtOAc and ice water.

The separated organic layer was washed with water and brine,

dried (MgSO₄), evaporated, and purified by silica gel column

chromatography (hexane-EtOAc, 2:1 elution) to give methyl

6-phenylnicotinate 12 (7.75 g, 91%) as a solid: ¹H NMR

(CDCl₃) δ 3.98 (3H, s), 7.40-7.57 (3H, m), 7.82 (1H, dd, J )

8.3, 0.9 Hz), 8.00-8.10 (2H, m), 8.35 (1H, dd, J ) 8.3, 2.2 Hz),

9.28 (1H, dd, J ) 2.2, 0.9 Hz); IR (KBr) 3070, 3032, 2993, 2945,

2843, 1724, 1595, 1435 cm^-1; MS m/z 214 (MH⁺).

To a suspension of LiAlH₄(1.68 g, 44.2 mmol) in THF (200

mL) was added dropwise a solution of 12 (9.42 g, 44.2 mmol)

in THF (120 mL) at 5 °C, and the mixture was stirred at room

temperature for 4 h. To the mixture were added anhydrous

NaF (7.42 g, 177 mmol) and water (2.39 mL) at 5 °C, and the

mixture was stirred at room temperature for 30 min. Insoluble

materials were removed by filtration and washed with THF.

The filtrate was evaporated and purified by silica gel column

chromatography (iPE-EtOAc, 1:1 elution) to give (6-phenylpy-

ridin-3-yl)methanol (7.24 g, 89%) as an oil: ¹H NMR (CDCl₃)

δ 4.74 (2H, s), 7.35-7.55 (3H, m), 7.67-7.85 (2H, m), 7.90-

8.05 (2H, m), 8.62 (1H, d, J ) 1.3 Hz); IR (neat) 3323 (br),

2866, 1601, 1564, 1477 cm^-1; MS m/z 186 (MH⁺).

To a solution of (6-phenylpyridin-3-yl)methanol (7.24 g, 39.1

mmol) in CHCl₃(100 mL) was added activated MnO₂(34.0 g,

391 mmol), and the mixture was refluxed for 3.5 h. The cooled

mixture was then filtered and evaporated to give 4d (5.96 g,

83%) as a solid: ¹H NMR (CDCl₃) δ 7.42-7.60 (3H, m), 7.92

(1H, d, J ) 8.3 Hz), 8.02-8.15 (2H, m), 8.24 (1H, dd, J ) 8.3,

2.2 Hz), 9.13 (1H, dd, J ) 2.2, 0.7 Hz), 10.14 (1H, s); IR (KBr)

3059, 2835, 2787, 2742, 1697, 1593, 1558 cm^-1; MS m/z 184

(MH⁺).

5-P h en ylp yr a zole-3-ca r boxa ld eh yd e (4f). A solution of

14 (6.0 g, 29.1 mmol) and H₂NNH₂‚H₂O (1.42 mL, 29.1 mmol)

in EtOH (48 mL) was refluxed for 5 h. After evaporation, the

resulting solid was collected and washed with iPE to give

methyl 5-phenylpyrazole-3-carboxylate 15b (3.0 g, 51%) as a

solid: ¹H NMR (DMSO-d₆) δ 3.83, 3.88 (total 3H, each s), 7.18-

7.53 (4H, m), 7.78-7.94 (2H, m), 13.98, 14.08 (total 1H, each

br s); IR (KBr) 3400-2500 (br), 1730, 1491, 1244 cm^-1; MS

m/z 203 (MH⁺).

To a suspension of LiAlH₄(960 mg, 25.3 mmol) in THF (100

mL) was added dropwise a solution of 15b (3.93 g, 19.5 mmol)

in THF (40 mL) at 5 °C, and the mixture was stirred at room

temperature for 3.5 h. To the mixture were added anhydrous

NaF (4.25 g, 101.2 mmol) and water (1.37 mL) at 5 °C, and

the mixture was stirred at room temperature for 2 h. Insoluble

materials were removed by filtration and washed with THF.

The filtrate was evaporated and the resulting precipitate

collected by filtration and washed with iPE to give (5-

phenylpyrazol-3-yl)methanol (1.30 g, 38%) as a solid: ¹H NMR

(DMSO-d₆) δ 4.38-4.58 (2H, m), 4.95-5.37 (1H, m), 6.52-6.66

(1H, m), 7.20-7.53 (3H, m), 7.68-7.90 (2H, m), 12.75, 13.02

(total 1H, each br s); IR (KBr) 3500-2500 (br), 1471, 1360,

1030, 1001, 766 cm^-1; MS m/z 175 (MH⁺).

To a solution of the above pyrazolylmethanol (1.30 g, 7.5

mmol) in acetone (130 mL) was added activated MnO₂(6.5 g,

75 mmol), and the mixture was refluxed for 1.5 h. The cooled

mixture was then filtered and the filtrate evaporated to give

4f (1.16 g, 90%) as a solid: ¹H NMR (DMSO-d₆) δ 7.20-7.56

(4H, m), 7.75-7.95 (2H, m), 9.93 (1H, s), 14.05-14.30 (1H, br);

IR (KBr) 3500-2400 (br), 1676, 1473, 1282, 1192 cm^-1; MS

m/z 173 (MH⁺).

4-(2-Th ien yl)ben za ld eh yd e (4g). A solution of 4-bro-

mobenzyl alcohol (4.85 g, 25.9 mmol) and 2-(tri-n-butylstan-

nyl)thiophene 16a (11.6 g, 31.1 mmol) in xylene (60 mL) was

treated with Pd(PPh₃)₄(0.9 g, 0.78 mmol), and the mixture

was heated at 140 °C for 1 h. After cooling, the resulting

precipitate was collected and washed with hexane to give 4-(2-

thienyl)benzyl alcohol 17a (2.96 g, 60%) as a solid: ¹H NMR

(CDCl₃) δ 1.70 (1H, t, J ) 5.9 Hz), 4.71 (2H, d, J ) 5.9 Hz),

7.08 (1H, dd, J ) 5.1, 3.6 Hz), 7.22-7.42 (4H, m), 7.61 (2H, d,

5-P h en ylisoxa zole-3-ca r boxa ld eh yd e (4e). To a solution

of acetophenone 13 (20.0 g, 167 mmol) and dimethyl oxalate

(23.6 g, 200 mmol) in DMF (160 mL) was added NaH (60% oil

2402 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Tanaka et al.

J ) 8.3 Hz); IR (KBr) 3334 (br), 1427, 1213, 1047, 806 cm^-1

MS m/z 173 (MH⁺- H₂O).

;

To a suspension of LiAlH₄(855 mg, 22.5 mmol) in THF (100

mL) was added dropwise a solution of the above benzamide

(5.19 g, 22.5 mmol) in THF (100 mL) at 5 °C, and the mixture

was stirred at the same temperature for 2 h. To the mixture

were added anhydrous NaF (3.78 g, 90.0 mmol) and water

(1.22 mL) at 5 °C, and the mixture was stirred at room

temperature for 30 min. Insoluble materials were removed

by filtration and washed with THF. The filtrate was evapo-

rated and purified by silica gel column chromatography

(hexane-EtOAc, 4:1 elution) to give 4j (2.93 g, 76%) as an

oil: ¹H NMR (CDCl₃) δ 6.40 (2H, dd, J ) 2.2, 2.2 Hz), 7.16

(2H, dd, J ) 2.2, 2.2 Hz), 7.55-7.80 (3H, m), 7.90-7.95 (1H,

To a solution of 17a (2.95 g, 15.5 mmol) in CHCl₃(180 mL)

was added activated MnO₂(13.5 g, 155 mmol), and the mixture

was refluxed for 1 h. The cooled mixture was then filtered,

and the filtrate was evaporated to give 4g (2.92 g, 100%) as a

solid: ¹H NMR (CDCl₃) δ 7.14 (1H, dd, J ) 5.1, 3.7 Hz), 7.40

(1H, dd, J ) 5.1, 1.1 Hz), 7.47 (1H, dd, J ) 3.7, 1.1 Hz), 7.77

(2H, d, J ) 8.5 Hz), 7.89 (2H, d, J ) 8.5 Hz), 10.00 (1H, s); IR

(KBr) 1699, 1601, 1213, 1170 cm^-1; MS m/z 189 (MH⁺).

4-(3-Th ien yl)ben za ld eh yd e (4h ). To a solution of 4-bro-

mobenzyl alcohol (4.85 g, 25.9 mmol) and 3-(tri-n-butylstan-

nyl)thiophene 16b (11.6 g, 31.1 mmol) in xylene (60 mL) was

added Pd(PPh₃)₄(0.9 g, 0.78 mmol), and the mixture was

heated at 140 °C for 1 h. After cooling, the resulting

precipitate was collected and washed with hexane to give 4-(3-

thienyl)benzyl alcohol 17b (2.67 g, 54%) as a solid: ¹H NMR

(CDCl₃) δ 1.72 (1H, t, J ) 5.9 Hz), 4.72 (2H, d, J ) 5.9 Hz),

7.30-7.50 (5H, m), 7.60 (2H, d, J ) 8.3 Hz); IR (KBr) 3310

m), 10.06 (1H, s); IR (neat) 3130, 1699, 1651, 1591, 1502 cm^-1

;

MS m/z 172 (MH⁺).

4-(1H-P yr a zol-1-yl)ben za ld eh yd e (4k ). To a solution of

4-fluorobenzaldehyde 19 (1.0 g, 8.06 mmol) and pyrazole (0.66

g, 9.67 mmol) in DMF (10 mL) was added powdered K₂CO₃

(1.34 g, 9.67 mmol), and the mixture was stirred at 120 °C for

5 h. After cooling, the reaction mixture was diluted with

EtOAc (60 mL), washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(hexane-EtOAc, 3:1 elution) to give 4k (1.09 g, 78%) as a

solid: ¹H NMR (CDCl₃) δ 6.54 (1H, dd, J ) 2.5, 1.8 Hz), 7.79

(1H, d, J ) 1.5 Hz), 7.85-8.10 (5H, m), 10.02 (1H, s); IR (KBr)

1695, 1605, 1390, 1200 cm^-1; MS m/z 173 (MH⁺).

The following compounds (4l-m ) were prepared in a similar

manner from 4-fluorobenzaldehyde 19 and the appropriate

azole compound.

4-(Im id a zol-1-yl)ben za ld eh yd e (4l): yield 758 mg (55%);

¹H NMR (CDCl₃) δ 7.27 (1H, s), 7.38 (1H, s), 7.59 (2H, d, J )

8.5 Hz), 8.00 (1H, s), 8.03 (2H, d, J ) 8.5 Hz), 10.05 (1H, s);

IR (KBr) 3109, 1686, 1605, 1524, 1483 cm^-1; MS m/z 173

(MH⁺).

(br), 1425, 1200, 1045, 1014, 777 cm^-1; MS m/z 173 (MH⁺

H₂O).

-

To a solution of 17b (2.55 g, 13.4 mmol) in CHCl₃(150 mL)

was added activated MnO₂(11.7 g, 134 mmol), and the mixture

was refluxed for 1 h. The cooled mixture was then filtered,

and the filtrate was evaporated to give 4h (2.35 g, 93%) as a

solid: ¹H NMR (CDCl₃) δ 7.41-7.47 (2H, m), 7.62 (1H, dd, J

) 2.1, 2.1 Hz), 7.76 (2H, d, J ) 8.3 Hz), 7.92 (2H, d, J ) 8.3

Hz), 10.02 (1H, s); IR (KBr) 1689, 1601, 1211, 1167 cm^-1; MS

m/z 189 (MH⁺).

4-(1H-P yr r ol-1-yl)ben za ld eh yd e (4i). To a suspension of

4-(1H-pyrrol-1-yl)benzoic acid 18a (3.74 g, 20.0 mmol) and N,O-

dimethylhydroxylamine hydrochloride (1.95 g, 20.0 mmol) in

CH₂Cl₂(100 mL) was added dropwise a solution of WSC (2.43

g, 20.0 mmol) in CH₂Cl₂(15 mL) at room temperature, and

the mixture was stirred for 18 h. The reaction mixture was

poured into water, and the separated organic layer was washed

with water and brine, dried (MgSO₄), evaporated, and purified

by silica gel column chromatography (hexane-EtOAc, 1:1

elution) to give 4-(1H-pyrrol-1-yl)-N-methoxy-N-methylbenza-

mide (2.12 g, 46%) as a solid: ¹H NMR (CDCl₃) δ 3.39 (3H, s),

3.58 (3H, s), 6.38 (2H, dd, J ) 2.2, 2.2 Hz), 7.15 (2H, dd, J )

2.2, 2.2 Hz), 7.42 (2H, d, J ) 8.8 Hz), 7.81 (2H, d, J ) 8.8 Hz);

IR (KBr) 3132, 2960, 2937, 1639, 1610, 1524 cm^-1; MS m/z

231 (MH⁺).

4-(1H-1,2,4-Tr ia zol-1-yl)ben za ld eh yd e (4m ): yield 1.95

g (47%); ¹H NMR (CDCl₃) δ 7.92 (2H, d, J ) 8.6 Hz), 8.06 (2H,

d, J ) 8.6 Hz), 8.16 (1H, s), 8.70 (1H, s), 10.07 (1H, s); IR (KBr)

3130, 2856, 1709, 1603, 1518, 1441, 1275 cm^-1; MS m/z 174

(MH⁺).

4-(1H-1,2,3-Tr ia zol-1-yl)ben za ld eh yd e (4n ) a n d 4-(2H-

1,2,3-Tr ia zol-2-yl)ben za ld eh yd e (4o). To a solution of

4-fluorobenzaldehyde 19 (5.0 g, 40.3 mmol) and 1,2,3-triazole

(3.33 g, 48.3 mmol) in DMF (50 mL) was added powdered K₂-

CO₃(6.68 g, 48.3 mmol), and the mixture was stirred at 120

°C for 1 h. After cooling, the reaction mixture was diluted

with EtOAc (300 mL), washed with water and brine, dried

(MgSO₄), and evaporated to about 50 mL. The resulting

precipitate was collected and washed with hexane to give pure

4n (3.44 g, 49%) as a solid. The mother liquor was then

evaporated to about 10 mL and the resulting precipitate

collected by a similar procedure to give pure 4o (297 mg, 4%)

as a solid. 4n : ¹H NMR (CDCl₃) δ 7.91 (1H, s), 7.99 (2H, d, J

) 8.5 Hz), 8.08 (2H, d, J ) 8.5 Hz), 8.12 (1H, s), 10.09 (1H, s);

To a suspension of LiAlH₄(348 mg, 9.2 mmol) in THF (30

mL) was added dropwise a solution of the above benzamide

(2.11 g, 9.2 mmol) in THF (40 mL) at 5 °C, and the mixture

was stirred at the same temperature for 1.5 h. To the mixture

were added anhydrous NaF (1.54 g, 36.6 mmol) and water

(0.50 mL) at 5 °C, and the mixture was stirred at room

temperature for 30 min. Insoluble materials were removed

by filtration and washed with THF. The filtrate was evapo-

rated and purified by silica gel column chromatography

(hexane-EtOAc, 4:1 elution) to give 4i (1.57 g, 100%) as a

solid: ¹H NMR (CDCl₃) δ 6.41 (2H, dd, J ) 2.2, 2.2 Hz), 7.19

(2H, dd, J ) 2.2, 2.2 Hz), 7.54 (2H, d, J ) 8.6 Hz), 7.95 (2H,

d, J ) 8.6 Hz), 9.99 (1H, s); IR (KBr) 3130, 2805, 2745, 1689,

1605, 1520 cm^-1; MS m/z 172 (MH⁺).

IR (KBr) 3138, 3116, 2845, 1695, 1603, 1516, 1419, 1389 cm^-1

;

MS m/z 174 (MH⁺). 4o: ¹H NMR (CDCl₃) δ 7.89 (2H, s), 8.02

(2H, d, J ) 8.6 Hz), 8.29 (2H, d, J ) 8.6 Hz), 10.06 (1H, s); IR

(KBr) 3114, 3084, 2715, 1699, 1603, 1508, 1408, 1383 cm^-1

;

MS m/z 174 (MH⁺).

4-(4-Meth ylp ip er a zin -1-yl)ben za ld eh yd e (4p ). To a so-

lution of 4-fluorobenzaldehyde 19 (6.21 g, 50 mmol) and

1-methylpiperazine (6.01 g, 60 mmol) in DMF (100 mL) was

added powdered K₂CO₃(8.29 g, 60 mmol), and the mixture

was stirred at 150 °C for 4.5 h. After cooling, the reaction

mixture was poured into water and extracted with EtOAc. The

organic layer was washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(CH₂Cl₂-MeOH, 10:1 elution) to give 4p (5.31 g, 52%) as a

solid: ¹H NMR (DMSO-d₆) δ 2.22 (3H, s), 2.35-2.48 (4H, m),

3.30-3.42 (4H, m), 7.04 (2H, d, J ) 8.8 Hz), 7.70 (2H, d, J )

8.8 Hz), 9.71 (1H, s); IR (KBr) 2935, 2839, 2791, 2748, 1691,

1599, 1518, 1448 cm^-1; MS m/z 205 (MH⁺).

3-(1H-P yr r ol-1-yl)ben za ld eh yd e (4j). To a suspension of

3-(1H-pyrrol-1-yl)benzoic acid 18b (5.62 g, 30.0 mmol), N,O-

dimethylhydroxylamine hydrochloride (2.93 g, 30.0 mmol), and

HOBt (4.05 g, 30.0 mmol) in CH₂Cl₂(150 mL) was added

dropwise a solution of WSC (3.65 g, 30.0 mmol) in CH₂Cl₂(30

mL) at room temperature, and the mixture was stirred for 20

h. The reaction mixture was poured into water. The sepa-

rated organic layer was washed with water and brine, dried

(MgSO₄), evaporated, and purified by silica gel column chro-

matography (hexane-EtOAc, 1:1 elution) to give 3-(1H-pyrrol-

1-yl)-N-methoxy-N-methylbenzamide (5.19 g, 75%) as an oil:

¹H NMR (CDCl₃) δ 3.39 (3H, s), 3.57 (3H, s), 6.36 (2H, dd, J )

2.2, 2.2 Hz), 7.12 (2H, dd, J ) 2.2, 2.2 Hz), 7.40-7.62 (3H, m),

7.70-7.75 (1H, m); IR (neat) 3130, 2935, 1645, 1608, 1587,

1500 cm^-1; MS m/z 231 (MH⁺).

4-(P yr a zol-3-yl)ben za ld eh yd e (4q). A mixture of ethyl

4-acetylbenzoate 20a (10 g, 52.1 mmol) and N,N-dimethylfor-

mamide dimethyl acetal (41.8 mL, 312.6 mmol) was heated

at 85 °C for 18 h. After cooling, the resulting solid was

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2403

collected and washed with iPE to give methyl 4-(3-(dimethy-

lamino)-1-oxo-2(E)-propenyl)benzoate 21a (10.4 g, 86%) as a

solid: ¹H NMR (DMSO-d₆) δ 2.94 (3H, s), 3.17 (3H, s), 3.88

(3H, s), 5.85 (1H, d, J ) 12.2 Hz), 7.77 (1H, d, J ) 12.2 Hz),

7.90-8.05 (4H, m); IR (KBr) 1718, 1637, 1578, 1541, 1425

cm^-1; MS m/z 234 (MH⁺).

To a suspension of 21a (5.0 g, 21.5 mmol) in MeOH (150

mL) were added AcOH (1.84 mL, 32.2 mmol) and H₂NNH₂‚H₂O

(1.56 mL, 32.2 mmol). After 10 h of stirring at room temper-

ature, solvents were evaporated. The residue was dissolved

in EtOAc, washed with water and brine, dried (MgSO₄), and

evaporated to give methyl 4-(pyrazol-3-yl)benzoate 22a (4.21

g, 97%) as a solid: ¹H NMR (DMSO-d₆) δ 3.86 (3H, s), 6.85

(1H, d, J ) 2.2 Hz), 7.84 (1H, br s), 7.85-8.10 (4H, m), 13.10,

13.55 (total 1H, each br s); IR (KBr) 3500-2800 (br), 1709,

1610, 1537, 1439, 1414 cm^-1; MS m/z 203 (MH⁺).

To a suspension of LiAlH₄(1.02 g, 26.9 mmol) in THF (120

mL) was added dropwise a solution of 22a (4.18 g, 20.7 mmol)

in THF (60 mL) at 5 °C, and the mixture was stirred at 50 °C

for 4 h. After cooling, anhydrous NaF (4.52 g, 107.6 mmol)

and water (1.45 mL) were added at 5 °C, and the mixture was

stirred at room temperature for 1 h. Insoluble materials were

removed by filtration and washed with THF, and the filtrate

was evaporated to give 4-(pyrazol-3-yl)benzyl alcohol (3.33 g,

93%) as a solid: ¹H NMR (DMSO-d₆) δ 4.51 (2H, d, J ) 5.7

Hz), 5.07-5.27 (1H, m), 6.60-6.74 (1H, br s), 7.20-7.85 (5H,

m), 12.82, 13.24 (total 1H, each br s); IR (KBr) 3178 (br), 1522,

1456, 1419, 1032, 841, 762 cm^-1; MS m/z 175 (MH⁺).

To a solution of the above benzyl alcohol (3.23 g, 18.6 mmol)

in acetone (300 mL) was added activated MnO₂(32.3 g, 371

mmol), and the mixture was refluxed for 1 h. The cooled

mixture was then filtered and evaporated to give 4q (2.98 g,

93%) as an oil: ¹H NMR (DMSO-d₆) δ 6.90 (1H, d, J ) 2.3

Hz), 7.83 (1H, br s), 7.85-8.12 (4H, m), 10.00 (1H, s), 13.13

(1H, br); IR (neat) 3700-2400 (br), 1697, 1606, 1211, 1171,

837 cm^-1; MS m/z 173 (MH⁺).

3-(P yr azol-3-yl)ben zaldeh yde (4r ). A mixture of 3-acetyl-

benzonitrile 20b (90 g, 0.62 mol) and N,N-dimethylformamide

dimethyl acetal (164 mL, 1.24 mol) was heated at 90 °C for 2

h. After cooling, excess reagent was removed by evaporation,

and the resulting solid was collected and washed with iPE to

give 3-(3-(dimethylamino)-1-oxo-2(E)-propenyl)benzonitrile 21b

(98.4 g, 79%) as a solid: ¹H NMR (DMSO-d₆) δ 2.96 (3H, s),

3.17 (3H, s), 5.92 (1H, d, J ) 12.1 Hz), 7.65 (1H, dd, J ) 7.8,

7.8 Hz), 7.78 (1H, d, J ) 12.1 Hz), 7.88-8.00 (1H, m), 8.14-

8.26 (1H, m), 8.34 (1H, s); IR (KBr) 3070, 2910, 2800, 2226,

1643, 1599, 1551, 1417, 1360, 1111, 762 cm^-1; MS m/z 201

(MH⁺).

To a solution of 21b (108.7 g, 0.54 mol) in MeOH (1.0 L)

were added AcOH (46.6 mL, 0.81 mol) and H₂NNH₂‚H₂O (39.4

mL, 0.81 mol) at 5 °C. After 24 h of stirring at room

temperature, solvent was evaporated. The residue was dis-

solved in EtOAc (1 L), washed with saturated NaHCO₃

solution, water, and brine, dried (MgSO₄), and evaporated to

give 3-(pyrazol-3-yl)benzonitrile 22b (91.8 g, 100%) as a solid:

¹H NMR (DMSO-d₆) δ 6.89 (1H, dd, J ) 2.0, 2.0 Hz), 7.61 (1H,

dd, J ) 7.8, 7.8 Hz), 7.68-7.80 (1H, m), 7.84 (1H, dd, J ) 2.3,

1.5 Hz), 8.12-8.30 (3H, m), 13.08, 13.46 (total 1H, each br);

IR (KBr) 3470-2330 (br), 2227, 1558, 1466, 1356, 1055, 760

cm^-1; MS m/z 170 (MH⁺).

To a suspension of 22b (91.8 g, 0.54 mol) in HCO₂H (730

mL) was added a suspension of Raney nickel (NDT-90) (180

mL) in water (140 mL), and the mixture was refluxed for 3 h.

After the mixture was cooled to room temperature, Raney

nickel was filtered off and washed with HCO₂H (500 mL). The

filtrate was evaporated to 200 mL, and CH₂Cl₂(1.0 L) was

added thereto. The mixture was adjusted to pH 8-9 with 5

N NaOH solution under ice cooling. The resulting insoluble

materials were removed by filtration. The organic layer was

separated, and the aqueous layer was extracted with CH₂Cl₂.

The combined organic layer was washed with water and brine,

dried (MgSO₄), evaporated, and purified by silica gel column

chromatography (CH₂Cl₂-MeOH, 20:1 elution) to give 4r (80.4

g, 86%) as an oil: ¹H NMR (DMSO-d₆) δ 6.84 (1H, d, J ) 2.2

Hz), 7.64 (1H, dd, J ) 7.5, 7.5 Hz), 7.70-7.95 (2H, m), 8.15

(1H, d, J ) 7.5 Hz), 8.34 (1H, s), 10.07 (1H, s), 13.03 (1H, br

s); IR (neat) 3680-2460 (br), 1693, 1606, 1587, 1188, 768 cm^-1

;

MS m/z 173 (MH⁺).

4-(1-Meth yl-1H-pyr azol-3-yl)ben zaldeh yde (4s) an d 4-(2-

Meth yl-2H-p yr a zol-3-yl)ben za ld eh yd e (4t). To a solution

of 21a (5.23 g, 22.5 mmol) in AcOH (50 mL) was added

MeNHNH₂(1.31 mL, 24.7 mmol), and the mixture was stirred

at room temperature for 3 h. To the solution was added 5 N

NaOH solution (180 mL) under ice cooling, and the mixture

was extracted with EtOAc. The organic layer was washed with

saturated NaHCO₃solution, water, and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(CH₂Cl₂-MeOH, 120:1 elution) to give first methyl 4-(1-

methyl-1H-pyrazol-3-yl)benzoate 23a (3.14 g, 65%) as a solid

and then methyl 4-(2-methyl-2H-pyrazol-3-yl)benzoate 23b

(1.63 g, 34%) as a solid. 23a : ¹H NMR (CDCl₃) δ 3.92 (3H, s),

3.97 (3H, s), 6.61 (1H, d, J ) 2.2 Hz), 7.41 (1H, d, J ) 2.2 Hz),

7.86 (2H, d, J ) 8.3 Hz), 8.06 (2H, d, J ) 8.3 Hz); IR (KBr)

3134, 2949, 1705, 1612, 1439, 1344, 1281 cm^-1; MS m/z 217

(MH⁺). 23b: ¹H NMR (CDCl₃) δ 3.93 (3H, s), 3.96 (3H, s),

6.38 (1H, d, J ) 2.0 Hz), 7.51 (2H, d, J ) 8.3 Hz), 7.54 (1H, d,

J ) 2.0 Hz), 8.13 (2H, d, J ) 8.3 Hz); IR (KBr) 3135, 2960,

1718, 1614, 1464, 1425, 1286 cm^-1; MS m/z 217 (MH⁺).

To a solution of 23a (2.5 g, 11.6 mmol) in CH₂Cl₂(80 mL)

was added dropwise DIBAL (1.02 M toluene solution, 25.0 mL,

25.5 mmol) at -50 °C, and the mixture was stirred at the same

temperature for 30 min. To the mixture were added anhy-

drous NaF (4.28 g, 102.0 mmol) and water (1.38 mL), and the

mixture was stirred at room temperature for 1 h. Insoluble

materials were removed by filtration and washed with CH₂-

Cl₂, and the filtrate was evaporated to give 4-(1-methyl-1H-

pyrazol-3-yl)benzyl alcohol (1.74 g, 80%) as a solid: ¹H NMR

(CDCl₃) δ 1.90 (1H, t, J ) 5.7 Hz), 3.95 (3H, s), 4.70 (2H, d, J

) 5.7 Hz), 6.54 (1H, d, J ) 2.2 Hz), 7.33-7.43 (3H, m), 7.78

(2H, d, J ) 8.2 Hz); IR (KBr) 3250 (br), 1508, 1462, 1431, 1360,

1302 cm^-1; MS m/z 189 (MH⁺).

To a solution of the above benzyl alcohol (1.50 g, 8.0 mmol)

in acetone (150 mL) was added activated MnO₂(13.9 g, 160

mmol), and the mixture was refluxed for 1 h. The cooled

mixture was then filtered and evaporated to give 4s (1.45 g,

98%) as a solid: ¹H NMR (CDCl₃) δ 3.99 (3H, s), 6.64 (1H, d,

J ) 2.3 Hz), 7.43 (1H, d, J ) 2.3 Hz), 7.86-8.03 (4H, m), 10.01

(1H, s); IR (KBr) 1695, 1603, 1566, 1431, 1306 cm^-1; MS m/z

187 (MH⁺).

To a suspension of LiAlH₄(264 mg, 6.94 mmol) in THF (40

mL) was added dropwise a solution of 23b (1.50 g, 6.94 mmol)

in THF (25 mL) at 5 °C, and the mixture was stirred at the

same temperature for 30 min. To the mixture were added

anhydrous NaF (1.17 g, 27.8 mmol) and water (0.38 mL), and

the mixture was stirred at room temperature for 1.5 h.

Insoluble materials were removed by filtration and washed

with THF, and the filtrate was evaporated to give 4-(2-methyl-

2H-pyrazol-3-yl)benzyl alcohol (1.30 g, 99%) as a solid: ¹H

NMR (CDCl₃) δ 2.12 (1H, t, J ) 5.7 Hz), 3.88 (3H, s), 4.77

(2H, d, J ) 5.7 Hz), 6.30 (1H, d, J ) 1.9 Hz), 7.35-7.52 (4H,

m), 7.51 (1H, d, J ) 1.9 Hz); IR (KBr) 3298 (br), 1495, 1460,

1425, 1385, 1273 cm^-1; MS m/z 189 (MH⁺).

To a solution of the above benzyl alcohol (1.27 g, 6.8 mmol)

in acetone (130 mL) was added activated MnO₂(11.8 g, 135

mmol), and the mixture was refluxed for 1 h. The cooled

mixture was then filtered, and the filtrate was evaporated to

give 4t (1.17 g, 93%) as a solid: ¹H NMR (CDCl₃) δ 3.95 (3H,

s), 6.41 (1H, d, J ) 1.9 Hz), 7.56 (1H, d, J ) 1.9 Hz), 7.61 (2H,

d, J ) 8.2 Hz), 7.98 (2H, d, J ) 8.2 Hz), 10.08 (1H, s); IR (KBr)

1695, 1608, 1568, 1390, 1215, 1184 cm^-1; MS m/z 187 (MH⁺).

3-(1-Meth yl-1H-pyr azol-3-yl)ben zaldeh yde (4u ) an d 3-(2-

Meth yl-2H-p yr a zol-3-yl)ben za ld eh yd e (4v). To a solution

of 21b (8.0 g, 40.0 mmol) in AcOH (80 mL) was added

MeNHNH₂(2.23 mL, 42.0 mmol), and the mixture was stirred

at room temperature for 3.5 h. A 5 N NaOH solution was

added under ice cooling, and the mixture was extracted with

EtOAc. The organic layer was washed with saturated NaH-

CO₃solution, water, and brine, dried (MgSO₄), and evaporated,

2404 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Tanaka et al.

and the residue was purified by silica gel column chromatog-

raphy (CH₂Cl₂-MeOH, 120:1 to 60:1 elution) to give first 3-(1-

methyl-1H-pyrazol-3-yl)benzonitrile 24a (4.45 g, 61%) as a

solid and then 3-(2-methyl-2H-pyrazol-3-yl)benzonitrile 24b

(2.09 g, 29%) as a solid. 24a : ¹H NMR (CDCl₃) δ 3.97 (3H, s),

6.56 (1H, d, J ) 2.3 Hz), 7.38-7.60 (3H, m), 7.95-8.10 (2H,

To a suspension of 26 (19.0 g, 48.7 mmol) and 28 (14.6 g,

97.4 mmol) in toluene (400 mL) were added powdered K₂CO₃

(10.1 g, 73.1 mmol) and Pd(PPh₃)₄(2.8 g, 2.4 mmol), and the

mixture was refluxed for 6 h. The reaction mixture was poured

into a mixture of EtOAc and ice water. The separated organic

layer was washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(hexane-EtOAc, 5:1 elution) to give 4w (2.65 g, 13%) as a

solid: ¹H NMR (DMSO-d₆) δ 7.00-7.15 (6H, m), 7.30-7.45

(9H, m), 7.52 (1H, s), 7.76 (1H, s), 7.76 (1H, dd, J ) 7.7, 7.7

Hz), 7.97 (1H, d, J ) 7.7 Hz), 8.13 (1H, d, J ) 7.7 Hz), 8.31

(1H, s), 10.13 (1H, s); IR (KBr) 3057, 3024, 1699, 1603, 1585,

1491, 1444 cm^-1; MS m/z 243 (Ph₃C⁺).

m); IR (KBr) 3115, 2935, 2220, 1602, 1471, 1352, 1246 cm^-1

;

MS m/z 184 (MH⁺). 24b: ¹H NMR (CDCl₃) δ 3.92 (3H, s), 6.37

(1H, d, J ) 1.5 Hz), 7.50-7.75 (5H, m); IR (KBr) 3066, 2951,

2231, 1475, 1416, 1335, 1236 cm^-1; MS m/z 184 (MH⁺).

To a solution of 24a (3.81 g, 20.8 mmol) in CH₂Cl₂(120 mL)

was added dropwise DIBAL (1.01 M toluene solution, 41.2 mL,

41.6 mmol) at -60 °C, and the mixture was stirred at the same

temperature for 30 min. To the mixture were added anhy-

drous NaF (7.0 g, 166.6 mmol) and water (2.25 mL), and the

mixture was stirred at room temperature for 3 h. Insoluble

materials were removed by filtration and washed with CH₂-

Cl₂. The filtrate was evaporated, and the residue was dis-

solved in THF (20 mL). Then 1 N HCl (40 mL) was added

and the solution stirred at room temperature for 3 h. A 5 N

NaOH solution (8 mL) was then added and the mixture was

extracted with CH₂Cl₂. The organic layer was washed with

water and brine, dried (MgSO₄), evaporated, and purified by

silica gel column chromatography (hexane-EtOAc, 1:2 elution)

to give 4u (3.24 g, 84%) as an oil: ¹H NMR (CDCl₃) δ 3.98

(3H, s), 6.62 (1H, d, J ) 2.2 Hz), 7.42 (1H, d, J ) 2.2 Hz),

7.51-7.62 (1H, m), 7.77-7.86 (1H, m), 8.05-8.13 (1H, m),

8.25-8.32 (1H, m), 10.07 (1H, s); IR (neat) 2941, 2829, 2730,

1695, 1606, 1585, 1439, 1242 cm^-1; MS m/z 187 (MH⁺).

4-(1-Meth yl-1H-p yr a zol-4-yl)ben za ld eh yd e (4x). To a

solution of 4-bromo-1-methyl-1H-pyrazole 29 (1.0 g, 6.2 mmol)

in ether (15 mL) was added dropwise n-BuLi (1.63 M hexane

solution, 4.2 mL, 6.83 mmol), keeping the temperature below

-60 °C, and the mixture was stirred at the same temperature

for 30 min. To the anion solution was added tri-n-butyltin

chloride (1.85 mL, 6.83 mmol) in ether (1.85 mL) dropwise,

followed by stirring for 1 h. The mixture was then warmed to

room temperature over 30 min and stirred for an additional 1

h. The reaction mixture was diluted with ether, washed with

water and brine, dried (MgSO₄), and evaporated to give crude

1-methyl-4-(tri-n-butylstannyl)-1H-pyrazole 30 (2.3 g, 100%)

as an oil that was used directly in the next reaction: ¹H NMR

(CDCl₃) δ 0.75-1.70 (27H, m), 3.93 (3H, s), 7.23 (1H, s), 7.42

(1H, s); IR (neat) 2930, 1504, 1460, 1120 cm^-1

.

To a solution of 4-bromobenzaldehyde 31a (462 mg, 2.5

mmol) and 30 (1.1 g, 3.0 mmol) in xylene (6 mL) was added

Pd(PPh₃)₄(87 mg, 0.075 mmol), and the mixture was heated

at 140 °C for 3 h. After cooling, the reaction mixture was

diluted with toluene (6 mL), and an aqueous solution (5 mL)

of KF (1.74 g, 30 mmol) was added thereto. After 1 h of

stirring at room temperature, insoluble materials were filtered

off. The filtrate was washed with water and brine, dried

(MgSO₄), evaporated, and purified by silica gel column chro-

matography (hexane-EtOAc, 1:2 elution) to give 4x (427 mg,

92%) as a solid: ¹H NMR (CDCl₃) δ 3.98 (3H, s), 7.62 (2H, d,

J ) 8.3 Hz), 7.73 (1H, s), 7.85 (1H, s), 7.87 (2H, d, J ) 8.3

Hz), 9.98 (1H, s); IR (KBr) 1693, 1605, 1169, 831 cm^-1; MS

m/z 187 (MH⁺).

To a solution of 24b (1.99 g, 10.9 mmol) in CH₂Cl₂(60 mL)

was added dropwise DIBAL (1.01 M toluene solution, 21.5 mL,

21.8 mmol) at -60 °C, and the mixture was stirred at the same

temperature for 30 min. To the mixture were added anhy-

drous NaF (3.65 g, 87.0 mmol) and water (1.17 mL), and the

mixture was stirred at room temperature for 2 h. Insoluble

materials were removed by filtration and washed with CH₂-

Cl₂. The filtrate was evaporated, and the residue was dis-

solved in THF (10 mL). Then 1 N HCl (20 mL) was added

and the solution stirred at room temperature for 2 h. A 5 N

NaOH solution (4 mL) was then added, and the mixture was

extracted with CH₂Cl₂. The organic layer was washed with

water and brine, dried (MgSO₄), evaporated, and purified by

silica gel column chromatography (hexane-EtOAc, 1:2 elution)

to give 4v (1.47 g, 73%) as a solid: ¹H NMR (CDCl₃) δ 3.94

(3H, s), 6.39 (1H, d, J ) 1.4 Hz), 7.56 (1H, d, J ) 1.4 Hz),

7.58-7.74 (2H, m), 7.89-7.97 (2H, m), 10.09 (1H, s); IR (KBr)

3041, 2831, 2733, 1697, 1579, 1462, 1377 cm^-1; MS m/z 187

(MH⁺).

The following compound was prepared in a similar manner

from 3-bromobenzaldehyde 31b (6.74 mmol) and 30 (8.09

mmol).

3-(1-Meth yl-1H-p yr a zol-4-yl)ben za ld eh yd e (4y): yield

978 mg (78%); ¹H NMR (CDCl₃) δ 3.98 (3H, s), 7.47-7.58 (1H,

m), 7.65-7.78 (3H, m), 7.83 (1H, s), 7.93-7.98 (1H, m), 10.04

(1H, s); IR (neat) 2943, 2818, 1686, 1608, 1230, 1174 cm^-1

;

3-(1-Tr ityl-1H-p yr a zol-4-yl)ben za ld eh yd e (4w ). To a

solution of 4-bromopyrazole 25 (5.00 g, 34.0 mmol) and Et₃N

(4.52 mL, 32.4 mmol) in DMF (45 mL) was added trityl chloride

(9.03 g, 32.4 mmol) at 5 °C, and the mixture was stirred at

room temperature for 3 h. The reaction mixture was diluted

with CHCl₃, washed with water and brine, dried (MgSO₄), and

evaporated. The resulting solid was collected and washed with

iPE to give 4-bromo-1-trityl-1H-pyrazole 26 (9.00 g, 71%) as a

solid: ¹H NMR (CDCl₃) δ 7.07-7.23 (6H, m), 7.23-7.42 (9H,

m), 7.38 (1H, d, J ) 0.6 Hz), 7.62 (1H, d, J ) 0.6 Hz); MS m/z

243 (Ph₃C⁺).

MS m/z 187 (MH⁺).

3-(Im id a zol-4-yl)ben za ld eh yd e (4z). A suspension of

3-acetylbenzonitrile 20b (25.4 g, 0.175 mol) in ether-1,4-

dioxane (10:1, 275 mL) was treated dropwise with bromine (9.0

mL, 0.175 mol) at room temperature and then stirred for 40

min. The mixture was then treated with an aqueous solution

(200 mL) of NaHCO₃(15 g, 0.18 mol) under ice cooling and

extracted with EtOAc. The organic layer was washed with

saturated NaHCO₃solution, water, and brine, dried (MgSO₄),

and evaporated to give crude 3-(bromoacetyl)benzonitrile (39.2

g, 100%) as a solid: ¹H NMR (CDCl₃) δ 4.42 (2H, s), 7.66 (1H,

dd, J ) 8.1, 8.1 Hz), 7.85-7.95 (1H, m), 8.18-8.32 (2H, m);

IR (KBr) 3103, 3068, 2941, 2229, 1707, 1599, 1429, 1279, 1223,

To a solution of 2-(3-bromophenyl)-1,3-dioxolane 27 (4.58

g, 20.0 mmol) and triisopropyl borate (5.27 g, 28.0 mmol) in

THF (100 mL) was added dropwise n-BuLi (1.70 M hexane

solution, 16.5 mL, 28.0 mmol) at -70 °C over 50 min. The

mixture was warmed to room temperature and stirred for 1

h. The reaction mixture was poured into 2 N HCl (40 mL),

stirred for 40 min, and extracted with EtOAc. The organic

layer was washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(EtOAc elution) to give 3-formylphenylboric acid 28 (620 mg,

21%) as a solid: ¹H NMR (DMSO-d₆) δ 7.58 (1H, dd, J ) 7.5,

7.5 Hz), 7.94 (1H, d, J ) 7.5 Hz), 8.11 (1H, d, J ) 7.5 Hz),

8.33 (3H, br s), 10.03 (1H, s); IR (KBr) 3363, 1678, 1603, 1581

cm^-1; MS m/z 151 (MH⁺).

1149 cm^-1

.

A mixture of 3-(bromoacetyl)benzonitrile (38.2 g, 0.17 mol)

and HCONH₂(190 mL) was heated at 185 °C for 30 min. After

being cooled to room temperature, the reaction mixture was

poured into saturated NaHCO₃solution (400 mL) and ex-

tracted with EtOAc (1.8 L). The organic layer was washed

with water and brine, dried (MgSO₄), and evaporated. The

resulting precipitate was collected and washed with EtOAc-

iPE (2:1) to give 3-(imidazol-4-yl)benzonitrile 32 (14.8 g, 51%)

as a solid: ¹H NMR (DMSO-d₆) δ 7.50-7.68 (2H, m), 7.70-

7.87 (2H, m), 8.12 (1H, d, J ) 7.4 Hz), 8.18 (1H, s), 12.32 (1H,

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2405

br s); IR (KBr) 3240-2250 (br), 2224, 1606, 1477, 1333, 1070,

970, 824, 789 cm^-1; MS m/z 170 (MH⁺).

the mixture was stirred at ambient temperature for 1.5 h. The

mixture was poured into 0.1 N HCl (100 mL) and extracted

with EtOAc. The organic layer was washed with water and

brine, dried (MgSO₄), and evaporated to give methyl 4-(((tert-

butyldimethylsilyl)oxy)methyl)benzoate (8.43 g, 100%) as an

oil: ¹H NMR (CDCl₃) δ 0.11 (6H, s), 0.95 (9H, s), 3.91 (3H, s),

4.79 (2H, s), 7.39 (2H, d, J ) 8.2 Hz), 8.01 (2H, d, J ) 8.2 Hz);

IR (neat) 2954, 2859, 1724, 1464, 1281, 1107, 841 cm^-1; MS

m/z 281 (MH⁺).

A mixture of the above ester (1.0 g, 3.57 mmol) and

H₂NNH₂‚H₂O (0.87 mL, 17.9 mmol) in EtOH (0.8 mL) was

refluxed for 1 h. After cooling, the reaction mixture was

poured into water and extracted with EtOAc. The organic

layer was washed with water and brine, dried (MgSO₄), and

evaporated to give 4-(((tert-butyldimethylsilyl)oxy)methyl)-

benzoic acid hydrazide 35 (1.0 g, 100%) as a solid: ¹H NMR

(DMSO-d₆) δ 0.08 (6H, s), 0.91 (9H, s), 4.47 (2H, s), 4.75 (2H,

s), 7.36 (2H, d, J ) 8.2 Hz), 7.79 (2H, d, J ) 8.2 Hz), 9.72 (1H,

s); IR (KBr) 3273 (br), 2954, 2858, 1662, 1599, 1539, 1335,

1254, 1093, 841 cm^-1; MS m/z 281 (MH⁺).

To a mixture of 35 (8.0 g, 28.6 mmol) and ethyl acetimidate

hydrochloride (4.24 g, 34.3 mmol) in EtOH (160 mL) was added

Et₃N (4.8 mL, 34.3 mmol) at room temperature, and the

mixture was stirred for 30 min. After evaporation, the residue

was dissolved in EtOAc (120 mL), washed with water and

brine, dried (MgSO₄), and evaporated. The resulting residue

was then heated neat at 200 °C for 10 min, cooled to room

temperature, and purified by silica gel column chromatography

(hexane-EtOAc, 2:1 elution) to give 2-[4-(((tert-butyldimeth-

ylsilyl)oxy)methyl)phenyl]-5-methyl-1,3,4-oxadiazole 36 (6.35

g, 73%) as a solid: ¹H NMR (DMSO-d₆) δ 0.10 (6H, s), 0.92

(9H, s), 2.58 (3H, s), 4.80 (2H, s), 7.52 (2H, d, J ) 8.2 Hz),

7.95 (2H, d, J ) 8.2 Hz); IR (KBr) 2956, 2933, 2897, 2860,

1576, 1502, 1257, 1086, 843 cm^-1; MS m/z 305 (MH⁺).

A solution of 36 (2.0 g, 6.6 mmol) in MeOH (20 mL) was

treated dropwise with 1 N HCl (13 mL, 13.0 mmol) at 5 °C,

and the mixture was then stirred at room temperature for 1

h. The reaction mixture was then recooled to 5 °C, NaHCO₃

(1.15 g, 13.7 mmol) was added carefully, and the mixture was

extracted with CH₂Cl₂. The organic layer was washed with

water and brine, dried (MgSO₄), and evaporated. The result-

ing solid was collected and washed with hexane to give 4-(5-

methyl-1,3,4-oxadiazol-2-yl)benzyl alcohol (0.75 g, 60%) as a

solid: ¹H NMR (DMSO-d₆) δ 2.58 (3H, s), 4.59 (2H, d, J ) 5.4

Hz), 5.39 (1H, t, J ) 5.4 Hz), 7.53 (2H, d, J ) 8.1 Hz), 7.93

(2H, d, J ) 8.1 Hz); IR (KBr) 3323 (br), 2877, 2819, 1614, 1576,

1416, 1257, 1053, 833, 729 cm^-1; MS m/z 191 (MH⁺).

To a solution of the above benzyl alcohol (723 mg, 3.81

mmol) in acetone (75 mL) was added activated MnO₂(6.62 g,

76.1 mmol), and the mixture was refluxed for 1 h. The cooled

mixture was then filtered, and the filtrate was evaporated to

give 4a b (645 mg, 90%) as a solid: ¹H NMR (CDCl₃) δ 2.66

(3H, s), 8.02 (2H, d, J ) 8.3 Hz), 8.22 (2H, d, J ) 8.3 Hz),

10.10 (1H, s); IR (KBr) 2829, 1701, 1610, 1590, 1550, 1421

cm^-1; MS m/z 189 (MH⁺).

N-Cycloh ep t yl-4-(5-m et h yl-1,2,4-t r ia zol-3-yl)b en zyl-

a m in e (7ba ). A mixture of 36 (5.05 g, 16.6 mmol) and

benzylamine (18 mL, 166 mmol) was heated at 150 °C for 2

days. After cooling, the mixture was purified by silica gel

column chromatography (CH₂Cl₂-MeOH, 20:1 elution) to give

4-benzyl-3-[4-(((tert-butyldimethylsilyl)oxy)methyl)phenyl]-5-

methyl-4H-1,2,4-triazole 37 (5.04 g, 77%) as a solid: ¹H NMR

(CDCl₃) δ 0.08 (6H, s), 0.94 (9H, s), 2.37 (3H, s), 4.77 (2H, s),

5.16 (2H, s), 6.90-7.03 (2H, m), 7.27-7.40 (5H, m), 7.50 (2H,

d, J ) 8.2 Hz); IR (KBr) 2953, 2929, 2885, 2854, 1524, 1460,

1431, 1255, 1101, 1003, 835 cm^-1; MS m/z 394 (MH⁺).

A solution of 37 (3.50 g, 8.9 mmol) in MeOH (35 mL) was

treated dropwise with 1 N HCl (17.8 mL, 17.8 mmol) at 5 °C,

and the mixture was then stirred at room temperature for 1

h. The reaction mixture was then recooled to 5 °C, NaHCO₃

(1.57 g, 18.7 mmol) was added carefully, and the mixture was

extracted with CH₂Cl₂. The organic layer was washed with

water and brine, dried (MgSO₄), and evaporated. The result-

ing solid was collected and washed with hexane to give 4-(4-

To a suspension of 32 (7.0 g, 41.4 mmol) in HCO₂H (56 mL)

was added a suspension of Raney nickel (NDT-90) (14 mL) in

water (11 mL), and the mixture was refluxed for 3 h. After

cooling, Raney nickel was filtered off and washed with HCO₂H,

and the filtrate was evaporated. The residue was dissolved

in THF-water, and the mixture was adjusted to pH 8-9 with

5 N NaOH solution under ice cooling. The resulting insoluble

materials were removed by filtration. The organic layer was

separated, and the aqueous layer was extracted with THF. The

combined organic layer was washed with water and brine,

dried (MgSO₄), and evaporated. The resulting solid was

collected and washed with THF-EtOAc to give 4z (5.27 g, 74%)

as a solid: ¹H NMR (DMSO-d₆) δ 7.59 (1H, dd, J ) 7.6, 7.6

Hz), 7.67-7.80 (3H, m), 8.05-8.15 (1H, m), 8.31 (1H, s), 10.04

(1H, s), 12.30 (1H, br); IR (KBr) 3390-2080 (br), 1691, 1606,

1479, 1327, 1186, 1066, 978, 781 cm^-1; MS m/z 173 (MH⁺).

4-(Oxa zol-5-yl)ben za ld eh yd e (4a a ). To a solution of

methyl 4-formylbenzoate 33 (4.0 g, 24.4 mmol) and tosylmethyl

isocyanide (TosMIC) (5.0 g, 25.6 mmol) in MeOH (40 mL) was

added powdered K₂CO₃(3.54 g, 25.6 mmol), and the mixture

was refluxed for 3.5 h. After cooling, the reaction mixture was

diluted with EtOAc (300 mL), washed with water and brine,

dried (MgSO₄), evaporated, and purified by silica gel column

chromatography (hexane-EtOAc, 2:1 to 1:1 elution) to give

methyl 4-(oxazol-5-yl)benzoate 34 (4.04 g, 82%) as a solid: ¹H

NMR (CDCl₃) δ 3.94 (3H, s), 7.48 (1H, s), 7.73 (2H, d, J ) 8.7

Hz), 7.97 (1H, s), 8.10 (2H, d, J ) 8.7 Hz); IR (KBr) 3118, 1726,

1614, 1275, 1109 cm^-1; MS m/z 204 (MH⁺).

To a suspension of LiAlH₄(826 mg, 21.8 mmol) in THF (100

mL) was added dropwise a solution of 34 (4.42 g, 21.8 mmol)

in THF (40 mL) at 5 °C, and the mixture was stirred at the

same temperature for 30 min. To the mixture were added

anhydrous NaF (3.66 g, 87.1 mmol) and water (1.18 mL), and

the mixture was stirred at room temperature for 30 min.

Insoluble materials were removed by filtration and washed

with THF. The filtrate was evaporated to give 4-(oxazol-5-

yl)benzyl alcohol (3.32 g, 87%) as a solid: ¹H NMR (CDCl₃) δ

4.74 (2H, s), 7.34 (1H, s), 7.43 (2H, d, J ) 8.1 Hz), 7.65 (2H, d,

J ) 8.1 Hz), 7.91 (1H, s); IR (KBr) 3330 (br), 1510, 1491, 1041,

818 cm^-1; MS m/z 176 (MH⁺).

To a solution of oxalyl chloride (1.5 mL, 17.2 mmol) in CH₂-

Cl₂(30 mL) was added a solution of DMSO (1.83 mL, 25.7

mmol) in CH₂Cl₂(4 mL), keeping the temperature below -60

°C, and the mixture was stirred for 20 min. To the mixture

was added a solution of 4-(oxazol-5-yl)benzyl alcohol (2.5 g,

14.3 mmol) in CH₂Cl₂(25 mL) and DMSO (2 mL) at the same

temperature, and the mixture was then stirred for 1 h. To

the reaction mixture was added Et₃N (8 mL, 57.2 mmol), and

the mixture was then stirred for 30 min and warmed to room

temperature over 30 min. After 1 h of stirring, the mixture

was diluted with EtOAc, washed with water and brine, dried

(MgSO₄), evaporated, and purified by silica gel column chro-

matography (hexane-EtOAc, 1:1 elution) to give 4a a (2.20

g, 89%) as a solid: ¹H NMR (CDCl₃) δ 7.54 (1H, s), 7.83 (2H,

d, J ) 8.5 Hz), 7.96 (2H, d, J ) 8.5 Hz), 8.00 (1H, s), 10.03

(1H, s); IR (KBr) 3124, 1693, 1610, 1211, 1111, 829 cm^-1; MS

m/z 174 (MH⁺).

4-(5-Meth yl-1,3,4-oxa d ia zol-2-yl)ben za ld eh yd e (4a b).

To a solution of methyl 4-formylbenzoate 33 (5.0 g, 30.5 mmol)

in EtOH (50 mL) was added carefully NaBH₄(576 mg, 15.3

mmol) at 5 °C, followed by stirring at the same temperature

for 30 min. The mixture was poured into water and extracted

with CH₂Cl₂. The organic layer was washed with water and

brine, dried (MgSO₄), and evaporated to give methyl 4-hy-

droxymethylbenzoate (5.06 g, 100%) as a solid: ¹H NMR

(CDCl₃) δ 1.89 (1H, t, J ) 5.9 Hz), 3.92 (3H, s), 4.77 (2H, d, J

) 5.9 Hz), 7.44 (2H, d, J ) 8.2 Hz), 8.03 (2H, d, J ) 8.2 Hz);

IR (KBr) 3304 (br), 1722, 1614, 1437, 1286, 1111, 1047, 1016,

756 cm^-1; MS m/z 167 (MH⁺).

A solution of methyl 4-hydroxymethylbenzoate (5.0 g, 30.1

mmol) and imidazole (4.1 g, 60.2 mmol) in DMF (25 mL) was

treated with TBDMSCl (4.77 g, 31.6 mmol) at 5 °C, and then

2406 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Tanaka et al.

benzyl-5-methyl-4H-1,2,4-triazol-3-yl)benzyl alcohol (2.35 g,

95%) as a solid: ¹H NMR (CDCl₃) δ 2.36 (3H, s), 3.10-3.25

(1H, m), 4.65-4.77 (2H, m), 5.14 (2H, s), 6.90-7.03 (2H, m),

7.25-7.50 (7H, m); IR (KBr) 3188 (br), 1535, 1487, 1425, 1363,

1039, 854, 739 cm^-1; MS m/z 280 (MH⁺).

To a solution of the above benzyl alcohol (1.18 g, 4.23 mmol)

in acetone (120 mL) was added activated MnO₂(7.35 g, 84.6

mmol), and the mixture was refluxed for 2 h. The cooled

mixture was then filtered, and the filtrate was evaporated to

give 4-(4-benzyl-5-methyl-4H-1,2,4-triazol-3-yl)benzaldehyde

38 (1.14 g, 97%) as a solid: ¹H NMR (CDCl₃) δ 2.44 (3H, s),

5.22 (2H, s), 6.93-7.07 (2H, m), 7.30-7.47 (3H, m), 7.73 (2H,

d, J ) 8.3 Hz), 7.94 (2H, d, J ) 8.3 Hz), 10.05 (1H, s); IR (KBr)

3450 (br), 1689, 1608, 1572, 1531, 1207 cm^-1; MS m/z 278

(MH⁺).

) 7.9, 7.9 Hz), 8.10-8.20 (1H, m), 8.25-8.38 (1H, m), 8.60-

8.70 (1H, m); IR (KBr) 3151 (br), 1705, 1684, 1618, 1562 cm^-1

;

MS m/z 205 (MH⁺).

To a suspension of LiAlH₄(3.71 g, 98.0 mmol) in THF (280

mL) was added dropwise a solution of 41 (10.0 g, 49.0 mmol)

in THF (150 mL) at 5 °C, and the mixture was stirred at 50

°C for 4 h. After cooling, 6 N HCl was added at 5 °C and the

mixture extracted with EtOAc. The organic layer was washed

with water and brine, dried (MgSO₄), and evaporated to give

3-(1H-tetrazol-5-yl)benzyl alcohol (6.88 g, 80%) as a solid: ¹H

NMR (DMSO-d₆) δ 4.61 (2H, s), 5.20-5.60 (1H, br), 7.48-7.65

(2H, m), 7.85-7.98 (1H, m), 8.05 (1H, s); IR (KBr) 3600-2100

(br), 1562, 1485, 1419, 1219 cm^-1; MS m/z 177 (MH⁺).

To a solution of the above benzyl alcohol (6.75 g, 38.4 mmol)

in acetone (680 mL) was added activated MnO₂(66.7 g, 767

mmol), and the mixture was refluxed for 8 h. The cooled

mixture was filtered, and the filtrate was evaporated to give

3-(1H-tetrazol-5-yl)benzaldehyde 42 (5.22 g, 78%) as a solid:

¹H NMR (DMSO-d₆) δ 7.86 (1H, dd, J ) 7.7, 7.7 Hz), 8.08-

8.20 (1H, m), 8.30-8.42 (1H, m), 8.57 (1H, dd, J ) 1.5, 1.5

Hz), 10.13 (1H, s); IR (KBr) 3500-2400 (br), 1674, 1612, 1560,

1373, 1207 cm^-1; MS m/z 175 (MH⁺).

To a solution of 42 (1.0 g, 5.75 mmol) in pyridine (15 mL)

was added trityl chloride (1.76 g, 6.32 mmol) at 5 °C, and the

mixture was stirred at room temperature for 4 h. The reaction

mixture was poured into water and extracted with EtOAc. The

organic layer was washed with 1 N HCl, water, and brine,

dried (MgSO₄), and then evaporated to give crude 4a c (2.51

g, 100%) as a solid: ¹H NMR (DMSO-d₆) δ 7.05-7.20 and

7.38-7.53 (15H, m), 7.80 (1H, dd, J ) 7.7, 7.7 Hz), 8.05-8.14

(1H, m), 8.30-8.40 (1H, m), 8.50-8.55 (1H, m), 10.12 (1H, s);

IR (KBr) 1699, 1516, 1491, 1446, 1201 cm^-1; MS m/z 243

(Ph₃C⁺).

3-(2-Meth yl-2H-tetr a zol-5-yl)ben za ld eh yd e (4a d ) a n d

3-(1-Meth yl-1H-tetr a zol-5-yl)ben za ld eh yd e (4a e). To a

solution of 42 (600 mg, 3.45 mmol) in DMF (6 mL) was added

NaH (60% oil dispersion, 138 mg, 3.45 mmol) at 5 °C. After

15 min of stirring at the same temperature, MeI (0.43 mL,

6.9 mmol) was added to the mixture, followed by stirring at

room temperature for 3 h and at 40 °C for 30 min. The

reaction mixture was poured into water and extracted with

EtOAc. The organic layer was washed with water and brine,

dried (MgSO₄), evaporated, and purified by silica gel column

chromatography (hexane-EtOAc, 1:1 elution) to give first 4a d

(511 mg, 79%) as a solid and then 4a e (82 mg, 13%) as a solid.

4a d : ¹H NMR (DMSO-d₆) δ 4.47 (3H, s), 7.81 (1H, dd, J )

7.7, 7.7 Hz), 8.05-8.10 (1H, m), 8.33-8.40 (1H, m), 8.55-8.58

(1H, m), 10.14 (1H, s); IR (KBr) 3072, 2839, 1691, 1587, 1520,

1443 cm^-1; MS m/z 189 (MH⁺). 4a e: ¹H NMR (DMSO-d₆) δ

4.22 (3H, s), 7.87 (1H, dd, J ) 7.7, 7.7 Hz), 8.13-8.25 (2H, m),

8.38-8.40 (1H, m), 10.14 (1H, s); IR (KBr) 1699, 1608, 1535,

1450, 1394 cm^-1; MS m/z 189 (MH⁺).

3-(2-Meth ylth iazol-4-yl)ben zylam in e Hydr och lor ide (5).

To a solution of methylmagnesium bromide (3 M in Et₂O, 200

mL, 0.6 mol) in THF (400 mL) was added dropwise a solution

of N-(3-cyanobenzyl)acetamide 43 (34.8 g, 0.2 mol) in THF (400

mL) at room temperature, and the mixture was then stirred

at 60 °C for 5 h. After cooling, water (400 mL) was added to

the reaction mixture at 5 °C, the pH was adjusted to 7 with 6

N HCl, and the mixture was then extracted with EtOAc. The

organic layer was washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(EtOAc-MeOH, 20:1 elution) to give N-(3-acetylbenzyl)aceta-

mide 44 (36.1 g, 95%) as an oil: ¹H NMR (DMSO-d₆) δ 1.89

(3H, s), 2.57 (3H, s), 4.31 (2H, d, J ) 6.0 Hz), 7.40-7.90 (4H,

m), 8.30-8.50 (1H, m); IR (neat) 3292, 3072, 2927, 1684, 1541,

1431 cm^-1; MS m/z 192 (MH⁺).

To a solution of 44 (9.56 g, 50.0 mmol) in DME (150 mL)

was added dropwise at room temperature bromine (2.56 mL,

50.0 mmol), and the mixture was stirred at the same temper-

ature for 1.5 h. The resulting precipitate was dissolved by

addition of EtOH (150 mL), thioacetamide (4.51 g, 60.0 mmol)

and NaHCO₃(8.40 g, 100 mmol) were added thereto, and the

solution was refluxed for 2.5 h. The reaction mixture was

A mixture of 38 (1.16 g, 4.19 mmol) and cycloheptylamine

(0.64 mL, 5.03 mmol) in toluene (20 mL) was heated at 120

°C for 3 h and then cooled to room temperature and evapo-

rated. The residue was dissolved in EtOH (25 mL). To the

solution was added carefully NaBH₄(159 mg, 4.19 mmol), and

the mixture was stirred at ambient temperature for 2 h. The

mixture was poured into water and extracted with CH₂Cl₂.

The organic layer was washed with water and brine, dried

(MgSO₄), evaporated, and purified by silica gel column chro-

matography (CH₂Cl₂-MeOH, 8:1 elution) to give N-cyclohep-

tyl-4-(4-benzyl-5-methyl-4H-1,2,4-triazol-3-yl)benzylamine 39

(1.37 g, 87%) as an oil: ¹H NMR (CDCl₃) δ 1.30-1.93 (12H,

m), 2.38 (3H, s), 2.60-2.77 (1H, m), 3.81 (2H, s), 5.16 (2H, s),

6.90-7.05 (2H, m), 7.27-7.44 (5H, m), 7.49 (2H, d, J ) 8.2

Hz); IR (neat) 3298, 2924, 2852, 1612, 1527, 1458, 1358 cm^-1

;

MS m/z 375 (MH⁺).

A solution of 39 (500 mg, 1.34 mmol) in MeOH (25 mL) was

treated with palladium black (500 mg) and HCO₂H (1.25 mL)

and stirred at room temperature for 4.5 h, monitoring by TLC

carefully. The catalyst was then filtered off, and the filtrate

was basified with 1 N NaOH solution under ice cooling and

evaporated to dryness. The residue was dissolved in CH₂Cl₂-

MeOH (5:1), dried (MgSO₄), evaporated, and purified by silica

gel column chromatography (CH₂Cl₂-MeOH, 4:1 elution) to

give 7ba (220 mg, 58%) as an amorphous solid: ¹H NMR

(CDCl₃) δ 1.30-2.00 (12H, m), 2.48 (3H, s), 2.65-2.80 (1H,

m), 3.83 (2H, s), 4.60-5.15 (2H, br), 7.36 (2H, d, J ) 8.2 Hz),

7.94 (2H, d, J ) 8.2 Hz); IR (KBr) 3172 (br), 2926, 2854, 1564,

1458, 1099 cm^-1; MS m/z 285 (MH⁺).

3-(2-Tr ityl-2H-tetr a zol-5-yl)ben za ld eh yd e (4a c). To a

solution of DMF (17.1 mL, 0.22 mol) in EtOAc (50 mL) was

added POCl₃(20.3 mL, 0.22 mol) at 5 °C, and the mixture was

stirred at room temperature for 1 h. The mixture was diluted

with EtOAc (200 mL) and 3-cyanobenzoic acid 40 (25.0 g, 0.17

mol) added thereto at 5 °C. After 30 min of stirring at the

same temperature, the mixture was added dropwise to MeOH

(100 mL) at 5 °C and stirred at room temperature for 18 h.

The reaction mixture was quenched with water (200 mL),

adjusted to pH 7 with powdered K₂CO₃, and then extracted

with EtOAc. The organic layer was washed with water and

brine, dried (MgSO₄), evaporated, and purified by silica gel

column chromatography (hexane-EtOAc, 5:1 elution) to give

methyl 3-cyanobenzoate (18.0 g, 66%) as a solid: ¹H NMR

(DMSO-d₆) δ 3.90 (3H, s), 7.76 (1H, dd, J ) 7.8, 7.8 Hz), 8.15

(1H, ddd, J ) 7.8, 1.5, 1.5 Hz), 8.26 (1H, ddd, J ) 7.8, 1.5, 1.5

Hz), 8.33 (1H, dd, J ) 1.5, 1.5 Hz); IR (neat) 2953, 2229, 1720,

1600, 1444, 1294 cm^-1; MS m/z 162 (MH⁺).

A mixture of methyl 3-cyanobenzoate (8.0 g, 49.7 mmol),

NaN₃(19.4 g, 298 mmol), and NH₄Cl (16.0 g, 298 mmol) in

DMF (32 mL) was heated at 120 °C for 2.5 h. After cooling,

the mixture was poured into a mixture of ice water (300 mL)

and EtOAc (100 mL). To the mixture was added NaNO₂(20.5

g, 298 mmol) (to decompose excess NaN₃), followed by 6 N HCl

until the pH was adjusted to 1-2 under ice cooling. After 30

min of stirring at room temperature, the mixture was extracted

with a mixture of EtOAc and THF. The organic layer was

washed with water and brine, dried (MgSO₄), and evaporated

to give methyl 3-(1H-tetrazol-5-yl)benzoate 41 (10.0 g, 99%)

as a solid: ¹H NMR (DMSO-d₆) δ 3.93 (3H, s), 7.78 (1H, dd, J

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2407

poured into water and extracted with EtOAc. The organic

layer was washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(EtOAc elution) to give N-[3-(2-methylthiazol-4-yl)benzyl]-

acetamide 45 (8.24 g, 67%) as a solid: ¹H NMR (DMSO-d₆) δ

1.88 (3H, s), 2.72 (3H, s), 4.29 (2H, d, J ) 5.9 Hz), 7.21 (1H, d,

J ) 7.6 Hz), 7.37 (1H, dd, J ) 7.6, 7.6 Hz), 7.75-7.88 (2H, m),

7.90 (1H, s), 8.35-8.50 (1H, m); IR (KBr) 3296, 3109, 3068,

2929, 1643, 1551, 1431 cm^-1; MS m/z 247 (MH⁺).

To a solution of 45 (8.23 g, 33.4 mmol) in EtOH (100 mL)

was added concentrated HCl (13.9 mL), and the mixture was

refluxed for 12 h. The mixture was ice cooled, and acetone

(100 mL) was added slowly. The resulting precipitate was

collected, washed with acetone, and dried to give 5 (5.14 g,

64%) as a solid: ¹H NMR (DMSO-d₆) δ 2.73 (3H, s), 4.00-

4.15 (2H, m), 7.42-7.52 (2H, m), 7.90-8.00 (1H, m), 7.97 (1H,

s), 8.14 (1H, s), 8.57 (3H, br s); IR (KBr) 2840 (br), 2636, 1605,

1576, 1508 cm^-1; MS m/z 205 (MH⁺- HCl).

4-(P yr id -2-yl)ben zyl Br om id e (6a ). To a mixture of 2-(4-

tolyl)pyridine 46a (3.39 g, 20.0 mmol) and N-bromosuccinimide

(NBS) (4.27 g, 24.0 mmol) in CCl₄(100 mL) was added benzoyl

peroxide (48 mg, 0.2 mmol), and the mixture was refluxed for

2 h. After the mixture was cooled to room temperature,

insoluble materials were filtered off. The filtrate was evapo-

rated and purified by silica gel column chromatography

(hexane-EtOAc, 4:1 elution) to give impure 6a (4.52 g, 91%)

as an oil: ¹H NMR (CDCl₃) δ inter alia 4.55 (2H, s), 7.20-

7.33 (1H, m), 7.50 (2H, d, J ) 8.4 Hz), 7.65-7.85 (2H, m), 7.98

(2H, d, J ) 8.4 Hz), 8.65-8.75 (1H, m); IR (neat) 3051, 3008,

1735, 1585, 1565 cm^-1; MS m/z 248, 250 (MH⁺).

4-(P yr id -3-yl)ben zyl Br om id e (6b). To a mixture of 3-(4-

tolyl)pyridine 46b (1.79 g, 10.6 mmol) and NBS (1.88 g, 10.6

mmol) in CCl₄(50 mL) was added benzoyl peroxide (52 mg,

0.2 mmol), and the mixture was refluxed for 6 h. After the

mixture was cooled to room temperature, insoluble materials

were filtered off. The filtrate was washed with water and

brine, dried (MgSO₄), and evaporated to give impure 6b (2.11

g, 80%) as an oil: MS m/z 248, 250 (MH⁺).

4-(1-Tr ityl-1H-p yr a zol-4-yl)ben zyl Br om id e (6c). To a

suspension of 26 (11.7 g, 30.0 mmol) and 4-methylphenylboric

acid 47 (9.23 g, 45.0 mmol) in toluene (250 mL) were added

powdered K₂CO₃(6.22 g, 45.0 mmol) and Pd(PPh₃)₄(1.73 g,

1.5 mmol), and the mixture was refluxed for 8 h. The reaction

mixture was poured into a mixture of EtOAc and ice water.

The separated organic layer was washed with water and brine,

dried (MgSO₄), evaporated, and purified by silica gel column

chromatography (hexane-EtOAc, 7:1 elution) to give 4-(4-

tolyl)-1-trityl-1H-pyrazole 48 (3.75 g, 31%) as a solid: ¹H NMR

(DMSO-d₆) δ 2.27 (3H, s), 7.00-7.45 (19H, m), 7.73 (1H, s),

8.04 (1H, s); MS m/z 243 (Ph₃C⁺).

To a mixture of 48 (3.74 g, 9.34 mmol) and NBS (1.66 g,

9.34 mmol) in CCl₄(100 mL) was added benzoyl peroxide (45

mg, 0.19 mmol), and the mixture was refluxed for 6 h. After

being cooled to room temperature, the reaction mixture was

poured into water and extracted with CH₂Cl₂. The organic

layer was washed with water and brine, dried (MgSO₄), and

evaporated to give impure 6c (3.36 g, 75%) as a solid: ¹H NMR

(DMSO-d₆) δ inter alia 4.77 (2H, s), 7.00-8.10 (21H, m).

Typ ica l P r oced u r e for Meth od A. N-Ben zyl-3-(p yr a -

zol-3-yl)ben zyla m in e (7v). A mixture of 3-(pyrazol-3-yl)-

benzaldehyde 4r (56.0 g, 0.33 mol) and benzylamine (42.6 mL,

0.39 mol) in toluene (560 mL) was refluxed for 5 h. The

mixture was cooled to room temperature and evaporated. The

residue was suspended in EtOH (840 mL), and NaBH₄(12.3

g, 0.33 mol) was added carefully with ice cooling. The mixture

was then stirred at 50 °C for 1 h. After additional stirring at

room temperature for 2 h, the reaction mixture was evapo-

rated. To the residue was added water (300 mL), and the

mixture was extracted with CH₂Cl₂. The organic layer was

washed with water and brine, dried (MgSO₄), evaporated, and

purified by silica gel column chromatography (CH₂Cl₂-MeOH,

10:1 elution) to give 7v (71.8 g, 84%) as a solid: ¹H NMR

(DMSO-d₆) δ 3.71 (2H, s), 3.72 (2H, s), 6.68 (1H, d, J ) 2.1

Hz), 7.15-7.42 (7H, m), 7.50-7.90 (3H, m), 12.85, 13.22 (total

1H, each br); IR (KBr) 3310-2290 (br), 1606, 1543, 1441, 1354

cm^-1; MS m/z 264 (MH⁺).

N-[4-(Dim et h yla m in o)b en zyl]-3-(p yr a zol-3-yl)b en zyl-

a m in e (7w ). A mixture of 3-(pyrazol-3-yl)benzaldehyde 4r

(1.20 g, 6.98 mmol), 4-(dimethylamino)benzylamine dihydro-

chloride (1.87 g, 8.37 mmol), and Et₃N (11.7 mL, 83.7 mmol)

in toluene (30 mL) was refluxed for 5 h. Insoluble materials

were removed by filtration, and the filtrate was evaporated.

The residue was dissolved in EtOH (18 mL), NaBH₄(264 mg,

6.98 mmol) was added carefully, and the mixture was stirred

at ambient temperature for 2 h. The reaction mixture was

poured into water and extracted with CH₂Cl₂. The organic

layer was washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(CH₂Cl₂-MeOH, 8:1 elution) to give 7w (1.68 g, 79%) as an

oil: ¹H NMR (CDCl₃) δ 2.93 (6H, s), 3.75 (2H, s), 3.84 (2H, s),

6.59 (1H, d, J ) 2.2 Hz), 6.65-6.75 (2H, m), 7.15-7.40 (4H,

m), 7.55-7.66 (2H, m), 7.76 (1H, s); IR (neat) 3700-2330 (br),

1614, 1524, 1446, 1350, 804, 766 cm^-1; MS m/z 440 (M + Me₂-

NC₆H₄CH₂⁺).

Gen er a l P r oced u r e for Meth od B. N-Cycloh ep tyl-3-

(2-m eth ylth ia zol-4-yl)ben zyla m in e (7a w ). To a solution

of 3-(2-methylthiazol-4-yl)benzylamine hydrochloride 5 (2.41

g, 10.0 mmol) in CH₂Cl₂-water (3:1, 40 mL) was added 5 N

NaOH solution to adjust the pH to 9-10. The separated

organic layer was washed with water and brine, dried (MgSO₄),

and evaporated. To the residue was added cycloheptanone

(1.77 mL, 15.0 mmol), and the mixture was stirred at 120 °C

for 5 h. After being cooled to room temperature, the mixture

was dissolved in EtOH (30 mL). To the solution was added

carefully NaBH₄(378 mg, 10.0 mmol), and the mixture was

stirred at ambient temperature for 2.5 h. The mixture was

poured into water and extracted with CH₂Cl₂. The organic

layer was washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(CH₂Cl₂-MeOH, 20:1 elution) to give 7a w (2.07 g, 69%) as an

oil: ¹H NMR (CDCl₃) δ 1.25-2.00 (12H, m), 2.62-2.82 (1H,

m), 2.78 (3H, s), 3.82 (2H, s), 7.32 (1H, s), 7.25-7.42 (2H, m),

7.70-7.88 (2H, m); IR (neat) 3381, 2916, 2854, 1497, 1458

cm^-1; MS m/z 301 (MH⁺).

Gen er a l P r oced u r e for Meth od C. N-Cycloh ep tyl-4-

(p yr id in -2-yl)ben zyla m in e (7a x). A mixture of impure

4-(pyrid-2-yl)benzyl bromide 6a (2.56 g, 10.3 mmol) and

cycloheptylamine (3.94 mL, 30.9 mmol) was stirred at 120 °C

for 3 h. After the mixture was cooled to room temperature, a

mixture of CH₂Cl₂and water was added, and the separated

organic layer was washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(CH₂Cl₂-MeOH, 10:1 elution) to give 7a x (1.33 g, 46%) as an

oil: ¹H NMR (DMSO-d₆) δ 1.15-2.15 (12H, m), 2.50-2.70 (1H,

m), 3.74 (2H, s), 7.25-7.35 (1H, m), 7.44 (2H, d, J ) 8.2 Hz),

7.80-8.00 (2H, m), 8.02 (2H, d, J ) 8.2 Hz), 8.58-8.72 (1H,

m); IR (neat) 2920, 2852, 1587, 1560, 1466, 1435 cm^-1; MS

m/z 281 (MH⁺).

Gen er a l P r oced u r e for Meth od D. N-Cycloh ep tyl-N-

[3-(p yr a zol-3-yl)b en zyl]-N′-(2,4,6-t r im et h ylp h en yl)u r ea

(3m ). To a solution of N-cycloheptyl-3-(pyrazol-3-yl)benzy-

lamine 7s (730 mg, 2.71 mmol) in CH₂Cl₂(15 mL) was added

2,4,6-trimethylphenyl isocyanate (437 mg, 2.71 mmol), and the

mixture was stirred at room temperature for 2 h. After

evaporation, the residue was purified by silica gel column

chromatography (iPE-EtOAc, 1:1 elution) to give 3m (755 mg,

65%) as a solid: mp 180-181 °C; ¹H NMR (DMSO-d₆) δ 1.30-

1.90 (12H, m), 2.08 (6H, s), 2.20 (3H, s), 4.10-4.25 (1H, m),

4.54 (2H, s), 6.62 (1H, br s), 6.82 (2H, s), 7.18-7.82 (6H, m),

12.86, 13.30 (total 1H, each br s); IR (KBr) 3406, 3209, 2924,

2856, 1639, 1498, 1242, 1209 cm^-1; MS m/z 431 (MH⁺). Anal.

(C₂₇H₃₄N₄O) C, H, N.

Gen er a l P r oced u r e for Meth od E. N-Cycloh ep tyl-N-

[4-(2-th ien yl)ben zyl]-N′-(2,4,6-tr iflu or op h en yl)u r ea (3a ).

To a solution of 2,4,6-trifluoroaniline (441 mg, 3.0 mmol) and

triphosgene (297 mg, 1.0 mmol) in CH₂Cl₂(15 mL) was added

Et₃N (0.42 mL, 3.0 mmol) at 5 °C, and the mixture was

refluxed for 1.5 h. The mixture was cooled to room temper-

2408 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Tanaka et al.

ature and a solution of N-cycloheptyl-4-(2-thienyl)benzylamine

7g (570 mg, 2.0 mmol) in CH₂Cl₂(6 mL) added thereto. After

2 h of stirring, the reaction mixture was poured into water.

The separated organic layer was washed with water and brine,

dried (MgSO₄), evaporated, and purified by silica gel column

chromatography (hexane-EtOAc, 4:1 elution) to give 3a (736

mg, 80%) as a solid: mp 136-137 °C; ¹H NMR (CDCl₃) δ 1.38-

2.08 (12H, m), 4.25-4.45 (1H, m), 4.55 (2H, s), 5.57 (1H, s),

6.55-6.72 (2H, m), 7.09 (1H, dd, J ) 5.1, 3.6 Hz), 7.22-7.42

(4H, m), 7.64 (2H, d, J ) 8.3 Hz); IR (KBr) 3300, 2927, 1635,

1520, 1444, 1120, 1041 cm^-1; MS m/z 459 (MH⁺). Anal.

(C₂₅H₂₅F₃N₂OS) C, H, N.

Typ ica l P r oced u r e for Met h od F . N-Ben zyl-N-[3-

(p yr a zol-3-yl)ben zyl]-N′-[2,4-bis(m eth ylth io)-6-m eth ylp y-

r id in -3-yl]u r ea (3a q, F R186054). To a solution of N-benzyl-

3-(pyrazol-3-yl)benzylamine 7v (54.0 g, 0.21 mol) and Et₃N

(143 mL, 1.03 mol) in toluene (1.35 L) was added phenyl

N-[2,4-bis(methylthio)-6-methylpyridin-3-yl]carbamate¹³(62.4

g, 0.20 mmol) at room temperature, and the mixture was

stirred for 24 h. The resulting precipitate was collected and

recrystallized from CH₂Cl₂-MeOH-hexane to give 3a q (74.4

g, 78%) as a solid: mp 209-210 °C; ¹H NMR (DMSO-d₆) δ

2.42 (6H, s), 2.46 (3H, s), 4.49 (4H, s), 6.67 (1H, br s), 6.90

(1H, s), 7.18-7.90 (10H, m), 8.29 (1H, s), 12.88, 13.30 (total

1H, each br s); IR (KBr) 3390, 3246, 2920, 1651, 1562, 1489,

1228 cm^-1; MS m/z 490 (MH⁺). Anal. (C₂₆H₂₇N₅OS₂) C, H,

N.

in DMEM supplemented with 10% (v/v) fetal bovine serum

(FBS), 100 units/mL penicillin, and 100 µg/mL streptomycin

(10% FBS-DMEM) at a final concentration of 2 × 10⁶cells/

mL. Each plastic dish (16 mm diameter) was seeded with 0.5

mL of the cell suspension and incubated for 2 h at 37 °C in

humidified air containing 5% CO₂. The monolayers formed

were washed with DMEM to remove nonadherent cells, then

incubated in 10% FBS-DMEM for a further 18 h at 37 °C

and used for the experiment.

The macrophages were incubated in 0.5 mL of 10% FBS-

DMEM containing 0.2 mmol/L [1-¹⁴C]oleate-fatty acid free

bovine serum albumin (BSA) complex, 30 µg/mL acetylated

human LDL, and test compound dissolved in DMSO for 4 h

at 37 °C in humidified air containing 5% CO₂. The concentra-

tion of DMSO was adjusted to 0.1%. Control was incubated

without test compound, and blank was incubated without

acetylated LDL and test compound. After incubation, the cells

were washed with PBS, and cellular lipids were then extracted

with 0.25 mL of hexane-isopropyl alcohol (3:2, v/v) for 30 min

at room temperature. The extracts were dried under nitrogen,

dissolved in 50 µL of chloroform-methanol (2:1, v/v), and

spotted on TLC plates which were then developed with

hexane-ether-acetic acid (73:25:2, v/v/v) as a solvent system.

The radioactivity of the fraction containing cholesteryl [1-¹⁴C]-

oleate was measured as the cellular cholesteryl ester ac-

cumulation. The cells, remaining after the lipid extraction,

were dissolved in 0.5 N NaOH solution (0.2 mL) for 30 min at

room temperature and then neutralized with 1 N HCl (0.1 mL).

A 150-µL aliquot was assayed for protein utilizing a Bio-Rad

protein assay system (Bio-Rad).

P r oced u r es for Dep r otection of P r otected Tr isu bsti-

tu ted Ur ea s. N-Cycloh ep tyl-N-[3-(1H-tetr a zol-5-yl)ben -

zyl]-N′-(2,4,6-tr im eth ylp h en yl)u r ea (3a e). To a suspension

of N-cycloheptyl-N-[3-(2-trityl-2H-tetrazol-5-yl)benzyl]-N′-(2,4,6-

trimethylphenyl)urea (1.46 g, 2.17 mmol) in MeOH (14 mL)

was added concentrated HCl (0.72 mL, 8.7 mmol), and the

mixture was stirred at room temperature for 1 h. The

insoluble white solid was collected and washed with MeOH

and water to give 3a e (0.79 g, 84%) as a solid: mp 204-206

Ack n ow led gm en t. We would like to thank Dr.

Masaharu Hashimoto, Toxicology Research Laborato-

ries, and Dr. Fumio Shimojo, Technological Develop-

ment Laboratories, for the toxicological study. We also

especially wish to thank Dr. David Barrett, Medicinal

Chemistry Research Laboratories, for his help in pre-

paring the manuscript.

1

°C; H NMR (DMSO-d₆) δ 1.35-1.90 (12H, m), 2.06 (6H, s),

2.20 (3H, s), 4.14-4.34 (1H, m), 4.59 (2H, s), 6.82 (2H, s), 7.46-

7.66 (2H, m), 7.80-7.90 (1H, m), 8.04 (1H, s); IR (KBr) 3359,

3300-2400 (br), 1595, 1512, 1456, 1257 cm^-1; MS m/z 433

(MH⁺). Anal. (C₂₅H₃₂N₆O) C, H, N.

Refer en ces

N-Cycloh ep tyl-N-[4-(p yr a zol-4-yl)ben zyl]-N′-(2,4,6-tr i-

m eth ylp h en yl)u r ea (3n ). A mixture of N-cycloheptyl-N-[4-

(1-trityl-1H-pyrazol-4-yl)benzyl]-N′-(2,4,6-trimethylphenyl)-

urea (1.05 g, 1.56 mmol), anisole (2 mL), and TFA (6 mL) was

stirred at 80 °C for 3 h. The reaction mixture was evaporated

and the residue poured into water, adjusted to pH 9 with 1 N

NaOH solution, and extracted with EtOAc. The separated

organic layer was washed with water and brine, dried (MgSO₄),

evaporated, and purified by silica gel column chromatography

(iPE-EtOAc, 1:1 elution) to give 3n (210 mg, 31%) as an

amorphous solid: ¹H NMR (DMSO-d₆) δ 1.30-1.85 (12H, m),

2.09 (6H, s), 2.21 (3H, s), 4.05-4.25 (1H, m), 4.48 (2H, s), 6.83

(2H, s), 7.28 (2H, d, J ) 8.2 Hz), 7.50 (1H, br s), 7.56 (2H, d,

J ) 8.2 Hz), 7.87 (2H, s); IR (KBr) 3195, 2926, 2856, 1630,

1605, 1510 cm^-1; MS m/z 431 (MH⁺). Anal. (C₂₇H₃₄N₄O‚0.25-

H₂O) C, H, N.

(1) A portion of this work was communicated in a preliminary

form: Tanaka, A.; Terasawa, T.; Hagihara, H.; Kinoshita, T.;

Sakuma, Y.; Ishibe, N.; Sawada, M.; Takasugi, H.; Tanaka, H.

Synthesis, X-ray Crystal Structure, and Biological Activity of

FR186054, a Novel, Potent, Orally Active Inhibitor of Acyl-CoA:

Cholesterol O-Acyltransferase (ACAT) Bearing a Pyrazole Ring.

Bioorg. Med. Chem. Lett. 1998, 8, 81-86.

(2) Kannel, W. B.; Castelli, W. P.; Gordon, T.; McNamara, P. M.

Serum Cholesterol, Lipoproteins, and the Risk of Coronary Heart

Disease. The Framingham Study. Ann. Intern. Med. 1971, 74,

1-12.

(3) (a) Martin, M. J .; Hulley, S. B.; Browner, W. S.; Kuller, L. H.;

Wentworth, D. Serum Cholesterol, Blood Pressure, and Mortal-

ity: Implications from a Cohort of 361 662 Men. Lancet 1986,

2, 933-936. (b) Badimon, J . J .; Fuster, V.; Chesebro, J . H.;

Badimon, L. Coronary Atherosclerosis: A Multifactorial Disease.

Circulation 1993, 87 (suppl. II), 3-16.

(4) McCarthy, P. A. New Approaches to Atherosclerosis: An Over-

view. Med. Res. Rev. 1993, 13, 139-159.

The following compound was prepared in a similar manner

from N-cycloheptyl-N-[3-(1-trityl-1H-pyrazol-4-yl)benzyl]-N′-

(2,4,6-trimethylphenyl)urea (800 mg).

(5) For the role of ACAT, see: (a) Spector, A. A.; Mathur, S. N.;

Kaduce, T. L. Role of Acylcoenzyme A:Cholesterol O-Acyltrans-

ferase in Cholesterol Metabolism. Prog. Lipid Res. 1979, 18, 31-

53. (b) Suckling, K. E.; Stange, E. F. Role of Acyl-CoA:Cholesterol

Acyltransferase in Cellular Cholesterol Metabolism. J . Lipid Res.

1985, 26, 647-671.

N-Cycloh ep tyl-N-[3-(p yr a zol-4-yl)ben zyl]-N′-(2,4,6-tr i-

m eth ylp h en yl)u r ea (3o): yield 102 mg (20%); ¹H NMR

(DMSO-d₆) δ 1.30-1.90 (12H, m), 2.08 (6H, s), 2.20 (3H, s),

4.10-4.30 (1H, m), 4.51 (2H, s), 6.83 (2H, s), 7.13 (1H, d, J )

7.5 Hz), 7.30 (1H, dd, J ) 7.5, 7.5 Hz), 7.44 (1H, d, J ) 7.5

Hz), 7.51 (2H, br s), 7.84 (1H, br s), 8.11 (1H, br s), 12.95 (1H,

(6) (a) Krause, B. R.; Anderson, M.; Bisgaier, C. L.; Bocan, T.;

Bousley, R.; DeHart, P.; Essenburg, A.; Hamelehle, K.; Homan,

R.; Kieft, K.; McNally, W.; Stanfield, R.; Newton, R. S. In Vivo

Evidence that the Lipid-regulating Activity of the ACAT Inhibi-

tor CI-976 in Rats is Due to Inhibition of Both Intestinal and

Liver ACAT. J . Lipid Res. 1993, 34, 279-294. (b) Largis, E. E.;

Wang, C. H.; DeVries, V. G.; Schaffer, S. A. CL 277,082: A Novel

Inhibitor of ACAT-Catalyzed Cholesterol Esterification and

Cholesterol Absorption. J . Lipid Res. 1989, 30, 681-690. (c)

Carr, T. P.; Rudel, L. L. Partial Inhibition of ACAT Decreases

ApoB Secretion by the Liver of African Green Monkeys. Arte-

riosclerosis 1990, 10, 823a. (d) Carr, T. P.; Parks, J . S.; Rudel,

L. L. Hepatic ACAT Activity in African Green Monkeys is Highly

Correlated to Plasma LDL Cholesteryl Ester Enrichment and

br s); IR (KBr) 3400, 3207, 2926, 2856, 1635, 1608, 1510 cm^-1

;

MS m/z 431 (MH⁺). Anal. (C₂₇H₃₄N₄O‚0.3H₂O) C, H, N.

Biologica l Meth od s. Effect on Ch olester yl Ester Ac-

cu m u la tion in Ma cr op h a ges. Peritoneal macrophages were

harvested from nonstimulated mice by peritoneal lavage with

phosphate-buffered saline (PBS) and pooled. They were

centrifuged at 400g for 10 min and washed with Dulbecco’s

modified Eagle medium (DMEM). The cells were resuspended

Inhibitors of Acyl-CoA:Cholesterol O-Acyltransferase

J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13 2409

Coronary Atherosclerosis. Arterioscler. Thromb. 1992, 12, 1274-

1283. (e) Burrier, R. E.; Deren, S.; McGregor, D. G.; Hoos, L.

M.; Smith, A. A.; Davis, H. R., J r. Demonstration of a Direct

Effect on Hepatic Acyl CoA:Cholesterol Acyl Transferase (ACAT)

Activity by an Orally Administered Enzyme Inhibitor in the

Hamster. Biochem. Pharmacol. 1994, 47, 1545-1551.

(7) (a) Brown, M. S.; Goldstein, J . L. Lipoprotein Metabolism in the

Macrophage: Implications for Cholesterol Deposition in Ath-

erosclerosis. Annu. Rev. Biochem. 1983, 52, 223-261. (b) Gillies,

P. J .; Robinson, C. S.; Rathgeb, K. A. Regulation of ACAT

Activity by a Cholesterol Substrate Pool During the Progression

and Regression Phases of Atherosclerosis: Implications for Drug

Discovery. Atherosclerosis 1990, 83, 177-185.

(8) Sliskovic, D. R.; White, A. D. Therapeutic Potential of ACAT

Inhibitors as Lipid Lowering and Anti-Atherosclerotic Agents.

Trends Pharmacol. Sci. 1991, 12, 194-199.

(9) For recent reviews of ACAT inhibitors, see: (a) Picard, J . A.

Patent Update: ACAT Inhibitors. Curr. Opin. Ther. Pat. 1993,

3, 151-160. (b) Matsuda, K. ACAT Inhibitors as Antiathero-

sclerotic Agents: Compounds and Mechanisms. Med. Res. Rev.

1994, 14, 271-305. (c) Sliskovic, D. R.; Trivedi, B. K. ACAT

Inhibitors: Potential Anti-atherosclerotic Agents. Curr. Med.

Chem. 1994, 1, 204-225.

(10) (a) DeVries, V. G.; Schaffer, S. A.; Largis, E. E.; Dutia, M. D.;

Wang, C.-H.; Bloom, J . D.; Katocs, A. S., J r. Potential Antiath-

erosclerotic Agents. 5. An Acyl-CoA:Cholesterol O-Acyltrans-

ferase Inhibitor with Hypocholesterolemic Activity. J . Med.

Chem. 1986, 29, 1131-1133. (b) DeVries, V. G.; Bloom, J . D.;

Dutia, M. D.; Katocs, A. S., J r.; Largis, E. E. Potential Antiath-

erosclerotic Agents. 6. Hypocholesterolemic Trisubstituted Urea

Analogues. J . Med. Chem. 1989, 32, 2318-2325.

(11) (a) Largis, E. E.; Wang, C. H.; DeVries, V. G.; Schaffer, S. A. CL

277,082: A Novel Inhibitor of ACAT-Catalyzed Cholesterol

Esterification and Cholesterol Absorption. J . Lipid Res. 1989,

30, 681-690. (b) Burrier, R. E.; Deren, S.; McGregor, D. G.; Hoos,

L. M.; Smith, A. A.; Davis, H. R., J r. Demonstration of a Direct

Effect on Hepatic Acyl CoA:Cholesterol Acyl Transferase (ACAT)

Activity by an Orally Administered Enzyme Inhibitor in the

Hamster. Biochem. Pharmacol. 1994, 47, 1545-1551. (c) Harris,

W. S.; Dujovne, C. A.; von Bergmann, K.; Neal, J .; Akester, J .;

Windsor, S. L.; Greene, D.; Look, Z. Effects of the ACAT Inhibitor

CL 277,082 on Cholesterol Metabolism in Humans. Clin. Phar-

macol. Ther. 1990, 48, 189-194.

(12) For recent results of clinical trials, see: (a) Roark, W. H.; Roth,

B. D. ACAT Inhibitors: Preclinical Profiles of Clinical Candi-

dates. Exp. Opin. Invest. Drugs 1994, 3, 1143-1152. (b) Lee, H.

T.; Picard, J . A. Recent Developments in Hypocholesterolemic

Agents. Exp. Opin. Ther. Pat. 1995, 5, 397-416 and references

therein.

(13) Tanaka, A.; Terasawa, T.; Hagihara, H.; Sakuma, Y.; Ishibe, N.;

Sawada, M.; Takasugi, H.; Tanaka, H. Inhibitors of Acyl-CoA:

Cholesterol O-Acyltransferase (ACAT). Part 1: Identification

and Structure-Activity Relationships of a Novel Series of

Substituted N-Alkyl-N-biphenylylmethyl-N′-arylureas. Bioorg.

Med. Chem. 1998, 6, 15-30.

(14) (a) Siddiqui, M. A.; Snieckus, V. The Directed Metalation

Connection to Aryl-Aryl Cross Coupling. Regiospecific Synthesis

of Phenanthridines, Phenanthridinones and the Biphenyl Al-

kaloid Ismine. Tetrahedron Lett. 1988, 29, 5463-5466 and

references therein. (b) Shieh, W.-C.; Carlson, J . A. A Simple

Asymmetric Synthesis of 4-Arylphenylalanines via Palladium-

Catalyzed Cross-Coupling Reaction of Arylboronic Acids with

Tyrosine Triflate. J . Org. Chem. 1992, 57, 379-381. (c) Koch,

K.-H.; Mu¨llen, K. Synthesis of Tetraalkyl-Substituted Oligo(1,4-

naphthylene)s and Cyclization to Soluble Oligo(peri-naphthyl-

ene)s. Chem. Ber. 1991, 124, 2091-2100.

(15) Stille, J . K. The Palladium-Catalyzed Cross-Coupling Reactions

of Organotin Reagents with Organic Electrophiles. Angew.

Chem., Int. Ed. Engl. 1986, 25, 508-524.

(16) Hansch, C.; Rockwell, S. D.; J ow, P. Y. C.; Leo, A.; Steller, E. E.

Substituent Constants for Correlation Analysis. J . Med. Chem.

1977, 20, 304-306.

(17) The structures of 23a and 24a were confirmed by X-ray

crystallographic analyses (data not shown).

(18) Hu¨ttel, R.; Wagner, H.; J ochum, P. Die Bromierung der Pyrazole.

(Bromination of Pyrazole.) Liebigs Ann. Chem. 1955, 593, 179-

200.

(19) Carlsen, P. H. J .; J ørgensen, K. B. Synthesis of Unsymmetrically

Substituted 4H-1,2,4-Triazoles. J . Heterocycl. Chem. 1994, 31,

805-807.

(20) The assignment of the regioisomers 4a d and 4a e was based on

their NMR chemical shifts compared with the known N-methyl-

5-phenyltetrazoles.³³The N-methyl protons of 2-isomer are

downfield from the 1-isomer.

(21) Ishikura, M.; Kamada, M.; Terashima, M. A Convenient Syn-

thesis of 3-Arylpyridines by the Palladium Catalyzed Coupling

Reaction of Diethyl(3-Pyridyl)Borane with Aryl Halides. Het-

erocycles 1984, 22, 265-268.

(22) Heider, J . G.; Pickens, C. E.; Kelly, L. A. Role of Acyl CoA:

Cholesterol Acyltransferase in Cholesterol Absorption and Its

Inhibition by 57-118 in the Rabbit. J . Lipid Res. 1983, 24, 1127-

1134.

(23) Sakuma, Y.; Hagihara, H.; Ohne, K.; Nagayoshi, A.; Mutoh, S.;

Ito, Y.; Notsu, Y.; Okuhara, M. Plasma Cholesterol Reducing

Effect of FR129169, A Novel Acyl-CoA:Cholesterol Acyltrans-

ferase Inhibitor, in the Rat. J pn. J . Pharmacol. 1996, 70, 35-

41.

(24) Sliskovic, D. R.; Krause, B. R.; Picard, J . A.; Anderson, M.;

Bousley, R. F.; Hamelehle, K. L.; Homan, R.; J ulian, T. N.;

Rashidbaigi, Z. A.; Stanfield, R. L. Inhibitors of Acyl-CoA:

cholesterol O-Acyl Transferase (ACAT) as Hypocholesterolemic

Agents. 6. The First Water-Soluble ACAT Inhibitor with Lipid-

Regulating Activity. J . Med. Chem. 1994, 37, 560-562.

(25) (a) Largis, E. E.; Katocs, A. S., J r. Abstracts of Papers, 10th

International Symposium on Drugs Affecting Lipid Metabolism,

Houston, 1989, p 33. (b) Wrenn, S. M., J r.; Parks, J . S.;

Immermann, F. W.; Rudel, L. L. ACAT Inhibitors CL 283,546

and CL 283,796 Reduce LDL Cholesterol without Affecting

Cholesterol Absorption in African Green Monkeys. J . Lipid Res.

1995, 36, 1199-1210.

(26) (a) Trivedi, B. K.; Purchase, T. S.; Holmes, A.; Augelli-Szafran,

C. E.; Essenburg, A. D.; Hamelehle, K. L.; Stanfield, R. L.;

Bousley, R. F.; Krause, B. R. Inhibitors of Acyl-CoA:Cholesterol

Acyltransferase (ACAT). 7. Development of a Series of Substi-

tuted N-Phenyl-N′-[(1-phenylcyclopentyl)methyl]ureas with En-

hanced Hypocholesterolemic Activity. J . Med. Chem. 1994, 37,

1652-1659. (b) Inskeep, P. B.; Davis, K. M.; Reed, A. E.

Pharmacokinetics of the Acyl Coenzyme A:Cholesterol Acyl

Transferase Inhibitor CP-105,191 in Dogs-The Effect of Food and

Sesame Oil on Systemic Exposure following Oral Dosing. J .

Pharm. Sci. 1995, 84, 131-133.

(27) (a) Chang, T. Y.; Chang, C. C. Y.; Cheng, D. Acyl-Coenzyme

A:Cholesterol Acyltransferase. Annu. Rev. Biochem. 1997, 66,

613-638. (b) Sturley, S. L. Molecular Aspects of Intracellular

Sterol Esterification: the Acyl Coenzyme A:Cholesterol Acyl-

transferase Reaction. Curr. Opin. Lipidol. 1997, 8, 167-173 and

references therein.

(28) (a) Dominick, M. A.; Bobrowski, W. A.; MacDonald, J . R.; Gough,

A. W. Morphogenesis of a Zone-Specific Adrenocortical Cytotox-

icity in Guinea Pigs Administered PD 132301-2, an Inhibitor of

Acyl-CoA:Cholesterol Acyltransferase. Toxicol. Pathol. 1993, 21,

54-62. (b) Vernetti, L. A.; MacDonald, J . R.; Wolfgang, G. H. I.;

Dominick, M. A.; Pegg, D. G. ATP Depletion is Associated with

Cytotoxicity of a Novel Lipid Regulator in Guinea Pig Adreno-

cortical Cells. Toxicol. Appl. Pharmacol. 1993, 118, 30-38. (c)

Dominick, M. A.; McGuire, E. J .; Reindel, J . F.; Bobrowski, W.

F.; Bocan, T. M. A.; Gough, A. W. Subacute Toxicity of a Novel

Inhibitor of Acyl-CoA:Cholesterol Acyltransferase in Beagle

Dogs. Fundam. Appl. Toxicol. 1993, 20, 217-224. (d) Reindel,

J . F.; Dominick, M. A.; Bocan, T. M. A.; Gough, A. W.; McGuire,

E. J . Toxicologic Effects of a Novel Acyl-CoA:Cholesterol Acyl-

transferase Inhibitor in Cynomolgus Monkeys. Toxicol. Pathol.

1994, 22, 510-518. (e) Wolfgang, G. H. I.; MacDonald, J . R.;

Vernetti, L. A.; Pegg, D. G.; Robertson, D. G. Biochemical

Alterations in Guinea Pig Adrenal Cortex Following Administra-

tion of PD 132301-2, an Inhibitor of Acyl-CoA:Cholesterol

Acyltransferase. Life Sci. 1995, 13, 1089-1093.

(29) (a) Smith, C.; Ashton, M. J .; Bush, R. C.; Facchini, V.; Harris,

N. V.; Hart, T. W.; J ordan, R.; McKenzie, R.; Riddell, D. RP

73163: A Bioavailable Alkylsulphinyl-Diphenylimidazole ACAT

Inhibitor. Bioorg. Med. Chem. Lett. 1996, 6, 47-50. (b) Sliskovic,

D. R.; Picard, J . A.; Roark, W. H.; Essenburg, A. D.; Krause, B.

R.; Minton, L. L.; Reindel, J . F.; Stanfield, R. L. Inhibitors of

Acyl-CoA:Cholesterol O-Acyl Transferase (ACAT) as Hypocho-

lesterolemic Agents. The Synthesis and Biological Activity of a

Series of Malonester Amides. Bioorg. Med. Chem. Lett. 1996, 6,

713-718. (c) O’Brien, P. M.; Sliskovic, D. R.; Picard, J . A.; Lee,

H. T.; Purchase, C. F., II; Roth, B. D.; White, A. D.; Anderson,

M.; Mueller, S. B.; Bocan, T.; Bousley, R.; Hamelehle, K. L.;

Homan, R.; Lee, P.; Krause, B. R.; Reindel, J . F.; Stanfield, R.

L.; Turluck, D. Inhibitors of Acyl-CoA:Cholesterol O-Acyltrans-

ferase. Synthesis and Pharmacological Activity of (()-2-Dodecyl-

R-phenyl-N-(2,4,6-trimethoxyphenyl)-2H-tetrazole-5-aceta-

mide and Structurally Related Tetrazole Amide Derivatives. J .

Med. Chem. 1996, 39, 2354-2366. (d) Purchase, C. F., II; White,

A. D.; Anderson, M. K.; Bocan, T. M. A.; Bousley, R. F.;

Hamelehle, K. L.; Homan, R.; Krause, B. R.; Lee, P.; Mueller,

S. B.; Speyer, C.; Stanfield, R. L.; Reindel, J . F. Tetrazole-

substituted Ureas as Inhibitors of Acyl-CoA:Cholesterol O-

Acyltransferase (ACAT). A Novel Preparation of Ureas from

Weakly Nucleophilic Amines. Bioorg. Med. Chem. Lett. 1996, 6,

1753-1758. (e) White, A. D.; Creswell, M. W.; Chucholowski,

A. W.; Blankley, C. J .; Wilson, M. W.; Bousley, R. F.; Essenburg,

A. D.; Hamelehle, K. L.; Krause, B. R.; Stanfield, R. L.; Dominick,

M. A.; Neub, M. Heterocyclic Ureas: Inhibitors of Acyl-CoA:

Cholesterol O-Acyltransferase as Hypocholesterolemic Agents.

2410 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 13

Tanaka et al.

J . Med. Chem. 1996, 39, 4382-4395. (f) Wilde, R. G.; Billheimer,

J . T.; Germain, S. J .; Hausner, E. A.; Meunier, P. C.; Munzer,

D. A.; Stoltenborg, J . K.; Gillies, P. J .; Burcham, D. L.; Huang,

S.-M.; Klaczkiewicz, J . D.; Ko, S. S.; Wexler, R. R. ACAT

Inhibitors Derived from Hetero-Diels-Alder Cycloadducts of

Thioaldehydes. Bioorg. Med. Chem. 1996, 4, 1493-1513.

Cholesterol Acyltransferase Inhibitor, FR145237. Toxicol. Appl.

Pharmacol. 1996, 140, 387-392.

(32) White, A. D.; Purchase, C. F., II; Picard, J . A.; Anderson, M. K.;

Mueller, S. B.; Bocan, T. M. A.; Bousley, R. F.; Hamelehle, K.

L.; Krause, B. R.; Lee, P.; Stanfield, R. L.; Reindel, J . F.

Heterocyclic Amides: Inhibitors of Acyl-CoA:Cholesterol O-Acyl

Transferase with Hypocholesterolemic Activity in Several Spe-

cies and Antiatherosclerotic Activity in the Rabbit. J . Med.

Chem. 1996, 39, 3908-3919.

(30) Warner, G. J .; Stoudt, G.; Bamberger, M.; J ohnson, W. J .;

Rothblat, G. H. Cell Toxicity Induced by Inhibition of Acyl

Coenzyme A:Cholesterol Acyltransferase and Accumulation of

Unesterified Cholesterol. J . Biol. Chem. 1995, 270, 5772-5778.

(31) Matsuo, M.; Hashimoto, M.; Suzuki, J .; Iwanami, K.; Tomoi, M.;

Shimomura, K. Difference between Normal and WHHL Rabbits

in Susceptibility to the Adrenal Toxicity of an Acyl-CoA:

(33) Butler, R. N. A Study of the Proton Nuclear Magnetic Resonance

Spectra of Aryl and Mono- and Disubstituted N-Methylazoles.

Can. J . Chem. 1973, 51, 2315-2322.

J M9800853

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Inhibitors of acyl-coA:cholesterol O-acyltransferase. 2. Identification and structure-activity relationships of a novel series of N-alkyl-N- (heteroaryl-substituted benzyl)-N'-arylureas

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