Heterocyclic amides: Inhibitors of acyl-CoA:cholesterol O-acyl transferase with hypocholesterolemic activity in several species and antiatherosclerotic activity in the rabbit

Article abstract of DOI:10.1021/jm9604033

A series of heterocyclic amides were synthesized and evaluated as inhibitors of acyl-CoA: cholesterol O-acyltransferase (ACAT) in vitro and for cholesterol lowering in cholesterol-fed rats. Compounds were evaluated for cell-based macrophage ACAT inhibitio

Full text of DOI:10.1021/jm9604033

3908
J . Med. Chem. 1996, 39, 3908-3919
Heter ocyclic Am id es: In h ibitor s of Acyl-CoA:Ch olester ol O-Acyl Tr a n sfer a se
w ith Hyp och olester olem ic Activity in Sever a l Sp ecies a n d An tia th er oscler otic
Activity in th e Ra bbit
Andrew D. White,* Claude F. Purchase, II, J oseph A. Picard, Maureen K. Anderson,† Sandra Bak Mueller,†
Thomas M. A. Bocan,† Richard F. Bousley,† Katherine L. Hamelehle,† Brian R. Krause,† Peter Lee,†
Richard L. Stanfield,† and J ames F. Reindel‡
Departments of Medicinal Chemistry, Atherosclerosis Therapeutics, and Pathology and Experimental Toxicology, Parke-Davis
Pharmaceutical Research, Division of Warner-Lambert Company, 2800 Plymouth Road, Ann Arbor, Michigan 48105
Received J une 6, 1996X
A series of heterocyclic amides were synthesized and evaluated as inhibitors of acyl-CoA:
cholesterol O-acyltransferase (ACAT) in vitro and for cholesterol lowering in cholesterol-fed
rats. Compounds were evaluated for cell-based macrophage ACAT inhibition, bioactivity, and
adrenal toxicity. Candidates were selected for evaluation in cholesterol-fed dogs and, ultimately,
the injured cholesterol-fed rabbit model of atherosclerosis. The heterocyclic amides potently
inhibited rabbit liver ACAT (IC50’s ) 0.014-0.11 µM), and the majority of compounds
significantly lowered plasma cholesterol (42-68%) in an acute cholesterol-fed rat model at 3
mg/kg. The most efficacious compounds in the rat were evaluated for bioactivity in vivo and
arterial ACAT inhibition in a cell-based macrophage ACAT assay. Two highly bioactive analogs,
(()-2-(3-dodecylisoxazol-5-yl)-2-phenyl-N-(2,4,6-trimethoxyphenyl)acetamide (13a ) and (()-2-
(5-dodecylisoxazol-3-yl)-2-phenyl-N-(2,4,6-trimethoxyphenyl)acetamide (16a ), were selected for
further study and were found to be nontoxic in a guinea pig model of adrenal toxicity.
Compounds 13a and 16a lowered total cholesterol in the cholesterol-fed rat, rabbit, and dog
models of pre-established hypercholesterolemia. Compound 13a in the injured cholesterol-fed
rabbit model of atherosclerosis was effective in slowing the development of cholesteryl ester-
rich thoracic aortic lesions, reducing lesion coverage by 53% at a dose of 1 mg/kg.
In tr od u ction
ester-rich cells are the precursors of the foam cells of
the early atherosclerotic lesion.8 The data suggesting
a direct role for ACAT in the formation of atherosclerotic
lesions has maintained this enzyme as a very attractive
target,2 despite the fact that clinical trials with several
ACAT inhibitors have proved disappointing.9-11
Hypercholesterolemia is an independent risk factor
definitively linked to coronary heart disease, which is
the leading cause of death in nations of the Western
hemisphere.1 Cholesterol in the body is derived from
two sources: endogenous biosynthesis and absorption
from the diet.2 Inhibition of either process represents
an attractive approach to lowering plasma cholesterol.
The HMG-CoA reductase inhibitors, which inhibit the
rate-limiting enzyme in cholesterol biosynthesis, have
proven clinically effective at lowering total and low-
density lipoprotein (LDL) cholesterol. Most recently
they have been shown to reduce mortality and morbidity
from coronary heart disease (CHD) in both patients with
diagnosed CHD3 and middle-aged men without diag-
nosed CHD,4 thus realizing the ultimate goal for a
cholesterol-lowering agent.
The enzyme acyl-CoA:cholesterol O-acyltransferase
(ACAT, EC 2.3.1.26) catalyzes the intracellular forma-
tion of cholesteryl esters. Evidence suggests that
inhibition of ACAT can prevent absorption of dietary
cholesterol and lower plasma total cholesterol (TC) in
cholesterol-fed (C-fed) animal models.5 Additional stud-
ies show hepatic cholesteryl ester content is directly
proportional to VLDL secretion rate.6 Recently, ACAT
inhibition has been shown to decrease both the secretion
rate of cholesteryl esters and apolipoprotein B from
perfused monkey livers.7 Inhibition of ACAT in the
arterial wall may reduce the accumulation of cholesteryl
esters in monocyte macrophages. These cholesteryl
Previous work in our laboratories12-17 identified
several series of potent ACAT inhibitors which lowered
plasma total cholesterol in cholesterol-fed animal mod-
els. The early work focused on primarily amide-based
inhibitors.12 This culminated in the discovery of CI-976,
which exerted its antiatherosclerotic effects by inhibi-
tion of arterial ACAT independent of cholesterol lower-
ing.2,18 In a related series of tetrazole amides,19 the
compound 2 provided a potent and efficacious lead.
Animal studies with enantiomers of 2 suggested that it
racemized in vivo.19 We report here the synthesis and
biological evaluation of racemic heterocyclic isosteres of
tetrazole 2. Subsequent to the initiation of our studies,
it was determined that 2 was inactive in a rabbit
bioassay. We set out to synthesize a variety of hetero-
cyclic isosteres of tetrazole 2. Our goal was to provide
a compound that inhibited both liver and arterial ACAT
and was efficacious in cholesterol-lowering animal
models, nonadrenotoxic, and bioactive. Such a com-
pound would then be evaluated in an injured cholesterol-
fed rabbit model of atherosclerosis.
Ch em istr y
The compounds examined in this study were prepared
by several different methods. The R-unsubstituted
3-alkylisoxazole 10 was synthesized from homologation
of the carboxylic acid 4 as shown in Scheme 1. Thus
† Department of Atherosclerosis Therapeutics.
‡ Department of Pathology and Experimental Toxicology.
X Abstract published in Advance ACS Abstracts, September 1, 1996.
S0022-2623(96)00403-7 CCC: $12.00 © 1996 American Chemical Society

Heterocyclic Amides: Inhibition of ACAT
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20 3909
Sch em e 1a
a
(a) NaOEt, EtOH, (CO2Et)2; (b) NH2OH‚HCl, AcOH, H2O; (c) (i) Et3N, THF, EtOCOCl; (ii) NaBH4; (d) PBr3, CH2Cl2; (e) NaBH4,
DMSO; (f) (i) BuLi, THF; (ii) CO2; (g) (i) CDI, THF; (ii) ArNH2.
Sch em e 2a
a
(a) NaNO2, DMF; (b) Et3N, 2PhNCO, benzene; (c) (i) n-BuLi, THF; (ii) 2,4,6-trimethoxyphenyl isocyanate; (d) (i) n-BuLi, THF; (ii)
CO2; (e) (i) CDI, THF; (ii) ArNH2; (f) ClRh(PPh3)3, H2, benzene.
represents the method of choice for generating the
desired regioselectivity. An alkyl halide was converted
to a nitroalkane by reaction with sodium nitrite in DMF.
The nitroalkane was converted to the nitrile oxide in
situ using Mukaiyama conditions23 (Et3N/PhNCO) and
cyclized with 3-phenyl-1-propyne to afford the 3-alkyl-
5-benzylisoxazole 11 regiselectively. Deprotonation of
11 with n-BuLi occurred selectively at the benzyl
position R to oxygen,21 and subsequent quenching of the
the intermediate in situ with 2,4,6-trimethoxyphenyl
isocyanate gave the 3-alkylisoxazole amide 13a . The
reaction when repeated with 2,6-diisopropyl- or 2,4-
difluorophenyl isocyanate failed to give the desired
amides. Instead, the anion generated from 11 was
quenched with CO2 and the resultant acid was coupled
with (2,6-diisopropylphenyl)- or (2,4-difluorophenyl)-
aniline using CDI to give the 3-alkylisoxazole amides
(13b,c). The regioisomeric 5-alkylisoxazoles (16a -c)
were prepared in a similar fashion utilizing the ap-
propriate nitroalkane and alkyne in a [3 + 2] cycload-
dition. The desired 2-phenylnitroethane was obtained
by reduction of 2-phenylnitroethene using ClRh(PPh)3
as described by Birch.24 The [3 + 2] cycloaddition of
the nitrile oxide generated in situ from 2-phenylnitro-
ethane and Et3N/PhNCO with tetradecyne gave the
5-alkylisoxazole 14. Deprotonation of 14 with n-BuLi
occurred selectively at the benzyl position R to nitrogen,
and subsequent quenching in situ of the intermediate
with 2,4,6-trimethoxyphenyl isocyanate gave the 5-alky-
lisoxazole amide 16a . The 3-alkylisoxazole amides 16b
and 16c were obtained in a manner similar to that for
2-tetradecanone was condensed with diethyl oxalate and
sodium ethoxide to give the enolate 3. The isoxazole
ring was constructed via cyclization of the sodium
enolate 3 and hydroxylamine to give 4 using the method
of Seki.20 The acid 4 was homologated via reduction
with sodium borohydride, conversion of the subsequent
alcohol to the bromide, and reduction of the methylene
bromide to a methyl group using sodium borohydride
to give isoxazole 8. The methylisoxazole 8 was selec-
tively deprotonated at the position R to oxygen21 and
the anion quenched with CO2 to give the homologated
carboxylic acid 9. The acid 9 was activated with
carbonyldiimidazole (CDI), and the imidazolide was
coupled with 2,4,6-trimethoxyaniline in situ to yield the
R-unsubstituted amide 10.
The R-phenyl-substituted 3- and 5-alkylisoxazoles
(13a -c, 16a -c) were synthesized regioselectively as
shown in Scheme 2. The [3 + 2] nitrile oxide alkyne
cycloaddition has been described22 for isoxazoles and

3910 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20
White et al.
Sch em e 3a
a
(a) (i) Dihydropyran, heptane, Amberlyst-15; (ii) NaNO2, DMF; (b) Et3N, 2PhNCO, benzene; (c) TsOH, MeOH; (d) (i) J ones reagent,
acetone; (ii) MeOH, HCl(g); (e) NaH, DMF, RX; (f) KOH, MeOH; (g) CDI, THF, ArNCO.
Sch em e 4a
a
(a) (i) LDA, THF, -78 °C; (ii) ArNCO; (b) KOH, EtOH; (c) (i) CDI, THF; (ii) Me(CH2)11CONHNH2; (d) 3P2O5-4EtOH; (e) (i) CDI,
THF; (ii) Me(CH2)11C(NH2)NOH; (f) AcOH.
Sch em e 5a
a
(a) (i) NaH, DMF; (ii) ArNCO; (b) NH2OH‚HCl, Et3N, EtOH; (c) Me(CH2)11COCl, iPr2NEt, THF; (d) AcOH.
compounds 13b,c. The anion of 14 was quenched with
CO2, and the resultant acid was coupled with (2,6-
diisopropyl-phenyl)- or (2,4-difluorophenyl)aniline using
CDI to give the 5-alkylisoxazole amides (16b,c).
1,3,4-oxadiazole amides (26a ,b). The acid 23 was also
utilized to synthesize the 3-alkyl-1,2,4-oxadiazole (28)
as depicted in Scheme 4. The acid 23 was activated
with CDI, and the imidazolide was coupled with a
hydroxyamidine, made from a nitrile and hydroxy-
lamine, to give the O-acylamidoxime intermediate,
which was cyclized with acetic acid to give the 3-alkyl-
1,2,4-oxadiazole amide (28).
The R,R-dimethyl and spirocyclopentane-substituted
isoxazole derivatives (20, 21) were synthesized accord-
ing to Scheme 3. Thus, 2-bromoethanol was protected
as its tetrahydropyranyl ether and the bromide dis-
placed with nitrite to give 17a . The isoxazole 17b was
constructed via a [3 + 2] cycloaddition with alkyne and
the nitrile oxide formed in situ from 17a and Et3N/
PhNCO. It was necessary to use the alcohol oxidation
state since cycloaddition with the appropriate nitrile
ester did not proceed. Deprotection of 17b under acidic
conditions gave the alcohol, which was oxidized to the
carboxylic acid using J ones reagent. Esterification gave
19a , which was bis-alkylated R to the ester to give
compound 19b. Saponification and coupling of the
resultant acid with (2,4,6-trimethoxyphenyl)aniline us-
ing CDI gave the desired isoxazole amides (20, 21).
The 1,3,4-oxadiazole ring system (26a ,b) was synthe-
sized using the known cyclization of a diacyl hy-
drazide.25 The 3-alkyl-1,2,4-oxadiazole ring system (28)
was assembled by cyclization of an O-acylamidoxime26
as depicted in Scheme 4. Ethyl phenylacetate was
deprotonated with lithium diisopropylamide (LDA) and
then acylated with an isocyanate, and the resultant
ester was saponified to afford acid 23. The acid 23 was
coupled with an acylhydrazine to yield the diacyl
intermediate, which was cyclodehydrated with a mix-
ture of phosphorus pentoxide and ethanol27 to afford the
The 5-alkyl-1,2,4-oxadiazole ring system (30) was
synthesized by cyclization of an O-acylamidoxime26
according to Scheme 5. Benzyl cyanide was deproto-
nated with LDA and acylated with a 2,4,6-trimethox-
yphenyl isocyanate to give a â-keto nitrile, which was
reacted with hydroxylamine under standard conditions
to give the hydroxyamidine 29. Compound 29 was
O-acylated with tridecanoyl chloride to give an O-
acylamidoxime, which was cyclodehydrated with acetic
acid to give the 5-alkyl-1,2,4-oxadiazole amide (30).
The pyrazole amide 35 was synthesized from a pre-
existing heterocyclic ring as shown in Scheme 6. Pyra-
zole was deprotonated with sodium hydride and N-alky-
lated with ethyl R-bromophenylacetate. The N-sub-
stituted pyrazole was then formylated at the 4-position
using standard Vilsmeier-Haack conditions to give the
N-substituted 4-formylpyrazole 31. The aldehyde was
then elaborated via a Wittig reaction, and the ester
functionality was saponified to give the pyrazole acetic
acid 33. The acid 33 was coupled with (2,4,6-trimethox-
yphenyl)aniline using dicyclohexylcarbodiimide (DCC)
to give an unsaturated pyrazole amide. The alkene at

Heterocyclic Amides: Inhibition of ACAT
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20 3911
Sch em e 6a
a
(a) NaH, THF, PhCH(Br)CO2Et; (b) POCl3, DMF; (c) n-BuLi, Ph3P+C11H23‚Br-, THF, -78 °C; (d) NaOH, EtOH; (e) DCC, ArNH2; (f)
5% Pd/C, H2, 50 psi; (g) 20% Pd/C, AcOH, H2, 50 psi; (h) Et3N, DMF, PhCH(Br)CO2Et.
Sch em e 7a
a
(a) TMSN3, 150 °C, autoclave; (b) NaH, DMF, PhCH(Br)CO2Et; (c) chromatography; (d) NaOH, EtOH; (e) ArNH2, DCC, CH2Cl2.
propanesulfonic acid (MOPS), 1 mM EDTA (pH 7.4). This
suspension was sonicated to form vesicles, which were then
sterilized by filtration (0.45 µM filter). Following the prein-
cubation, the media with vesicles was replaced with serum-
free DMEM containing the test compound in DMSO and
incubated for 1 h, after which 14C-labeled sodium oleate was
added for an additional 4 h. The media was removed, and cells
were washed and extracted with hexane/2-propanol (3:2 v/v)
containing internal standard ([14C]cholesterol). Neutral lipids
were separated by TLC followed by isotopic scanning (Phos-
phorImager, Molecular Dynamics, Sunnyvale, CA). Cell pro-
tein concentration was determined by the method of Lowry et
al.31 Data are reported as the concentration (µM) required to
inhibit the enzyme activity by 50%.
ACAT Bioa ssa y. Bioactivity was assessed in male New
Zealand white rabbits. The animals were conditioned to meal
feeding for 1 week and then given a meal containing the drug
at 25 mg/kg in an oil vehicle (3% peanut oil/3% coconut oil).
Blood samples were obtained at time zero (before drug) and
1, 2, and 4 h postdrug meal. The plasma samples (0.2 mL)
were extracted into hexane, dried, dissolved in chloroform/
methanol (2:1 v/v), and assayed for microsomal liver ACAT
inhibition.30 Standards were prepared for each drug by adding
compound directly to rabbit plasma in DMSO.
the 4-position of the pyrazole was hydrogenated over
Pd/carbon to afford the pyrazole amide 35.
The imidazole amide 40 was synthesized from a pre-
existing heterocyclic ring as shown in Scheme 6. Thus,
4-(hydroxymethyl)imidazole was oxidized with MnO2,
and the resulting imidazole aldehyde was N-protected
with a trityl group according to the procedure described
by Kelly et al.28 Wittig reaction of the N-protected
4-formyl imidazole with n-undecyltriphenylphospho-
rane, followed by hydrogenation, which removed the
trityl group and saturated the side chain, gave 37
(Scheme 6). The alkylimidazole was then deprotonated
with sodium hydride and N-alkylated with ethyl R-bro-
mophenylacetate to give 38. The ester 38 was saponi-
fied, and the resultant acid was coupled with (2,4,6-
trimethoxyphenyl)aniline using DCC to yield the
imidazole amide 40.
The 1,2,3-triazole amide 44 was synthesized as shown
in Scheme 7. Cycloaddition of tetradecyne with trim-
ethylsilyl azide according to the general method de-
scribed by Birkofer29 yielded the 4-dodecyl-1,2,3-triazole
41. Deprotonation of 41 with sodium hydride and
N-alkylation with ethyl R-bromophenylacetate gave a
mixture of regioisomers, purified by column chroma-
tography. The major isomer 42 had a proton NMR and
MS (loss of N2 evident) consistent with a 1,4 substitution
pattern. The ester 42 was saponified, and the resultant
acid was coupled with (2,4,6-trimethoxyphenyl)aniline
using DCC to give the triazole amide 44.
In Vivo Ra t Assa ys. In vivo efficacy in rats was examined
in an acute assay (APCC) as described by Krause et al.30 The
compounds were administered by gavage in carboxymethyl-
cellulose (1.5%) and Tween-20 (0.2%) in water at either 30 or
3 mg/kg (3-4 pm). The animals were then allowed to consume
overnight a diet supplemented with 5.5% peanut oil, 1.5%
cholesterol, and 0.5% cholic acid. The data were expressed
as percent decrease of total cholesterol (TC) relative to controls.
This model measures the ability of the compound to prevent
the overnight rise in plasma TC induced by a high-fat, high-
cholesterol meal. In
a
2 week chronic model (CPCC),30
Biologica l Meth od s
hypercholesterolemia was first established with a 1 week diet
of 5.5% peanut oil/1.5% cholesterol/0.5% cholic acid, followed
by administration of the compounds with continued diet for 1
week. In this model changes in TC, HDL cholesterol (HDL-
C), and non HDL cholesterol (non HDL-C) were monitored.
In Vivo Dog Assa y. In vivo efficacy in cholesterol-fed
female Beagle dogs was examined according to the method
described by Krause et al.30 The dogs were dosed with bulk
drug in capsules daily before meals for 1 week. Efficacy was
expressed as the percent change in plasma TC before and after
treatment.
In Vitr o Liver a n d Ma cr op h a ge Assa ys. ACAT inhibi-
tion in vitro was determined by incubating the compounds with
[1-14C]oleoyl-CoA, and microsomes were isolated from the
livers of cholesterol-fed rats.30 The cell culture assay (MAI)
used murine IC-21 macrophages as a model for cells of the
arterial wall. The IC-21 mouse macrophages (American Type
Culture Collection, Rockville, MD) were preincubated for 16
h in serum-free medium (Dulbecco’s modified Eagle medium,
DMEM) containing albumin (20 µM) and phosphatidylserine/
cholesterol vesicles. The latter were prepared by combining
phosphatidylserine (27.4 µmol) and cholesterol (26 µmol) in
chloroform and then evaporating in order to disperse the dried
lipids into 5 mL of 150 mM NaCl, 5 mM 3-(N-morpholino)-
Ad r en a l Toxicity Assa y. Compounds were evaluated for
adrenal toxicity in chow-fed guinea pigs. The test compounds
were dosed (100 mg/kg) by gavage in an oleic acid vehicle over

3912 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20
White et al.
Ta ble 1. ACAT Inhibition in Vitro and Hypocholesterolemic
2 weeks. Drug-related pathological alterations of the adrenal
cortical cells were evaluated as compared with untreated
controls.32
Activity in Vivo
In Vivo Ra bbit Assa ys. Efficacy in cholesterol-fed rabbits
was also evaluated in order to attempt to determine a dose
which did not lower plasma total cholesterol for the antiath-
erosclerotic rabbit model. Any subsequent antiatherosclerotic
activity at this dose could then be directly attributed to arterial
ACAT inhibition and not cholesterol lowering. New Zealand
White rabbits were meal-fed a 0.5% cholesterol, 3% peanut
oil, 3% coconut oil diet for 1 week prior to administration of
the compounds for 2 weeks in the same diet. Blood was
obtained from the heart of fasted animals after nitrogen
asphyxiation for determining plasma TC concentrations. An-
tiatherosclerotic activity was evaluated in the injured choles-
terol-fed rabbit.18 Diet-induced (thoracic aorta) and injury-
induced (iliac-femoral) atherosclerotic lesions were produced
after 9 weeks on a 0.5% cholesterol, 3% peanut oil, 3% coconut
oil diet (1 week prior to, and 8 weeks after surgery). The
compounds were then dosed for 8 weeks, and lesion area was
evaluated.
Resu lts a n d Discu ssion
Previous studies from these laboratories demon-
strated ACAT inhibition to be optimal in amides with
2,6-diisopropyl-, 2,4,6-trimethoxy-, or 2,4-difluorophe-
nylamide substitution in the aniline ring.12-14 Thus
these were the the substitution patterns employed in
this study. The activities in vitro and in vivo of the
isoxazole amides, the first analogs prepared, were
shown to be optimal in the 2,6-diisopropyl and 2,4,6-
trimethoxyphenyl-substituted analogs (13a -b, 16a -b)
depicted in Table 1. However at the 3 mg/kg dose in
the APCC rat, the 2,4,6-trimethoxyphenyl 13a was more
effective than 2,6-diisopropylphenyl derivative 13b.
Therefore the 2,4,6-trimethoxyphenyl group was utilized
in subsequent analogs. The chain length of the side
chain has been previously optimized33 in related series
and was kept constant at 12 carbons. The introduction
of R-substitution next to the amide was neccessary
because in the related tetrazole amide series, the
desphenyl compounds were toxic to the adrenal glands
of guinea pigs while the R-phenyl-substituted com-
pounds exemplified by 2 were nontoxic, even when
certain analogs in the series were demonstrated to be
bioactive.34 In this series, the one desphenyl analog
prepared (10) was less potent in vitro and in vivo at 3
mg/kg in the rat than the corresponding R-phenyl-
substituted compound (13a ). However, the bis-alkyl-
substituted analogs (20, 21) were significantly less
potent in vitro and less efficacious for total cholesterol
lowering in the rat than the R-phenyl-substituted
compound (13a ). We set out to examine a variety of
heterocyclic replacements for the tetrazole moiety in 2,
keeping the 2,4,6-trimethoxyphenyl, R-phenyl, and C12
substituents constant. We concentrated our efforts on
oxygen- and nitrogen-containing heterocycles as these
had been shown to be more effective than sulfur-
containing heterocycles in a series of related heterocyclic
ureas.35 Both the 3- and 5-dodecylisoxazoles (13a , 16a )
were excellent compounds in vitro and vivo in the rat
with the 3-dodecylisoxazole 13a being more efficacious
at lowering total cholesterol at 3 mg/kg in the rat (Table
1). When the various oxadiazole isosteres (26-30) were
examined, the 1,3,4-oxadiazole 26a with a 2,4,6-tri-
methoxyphenylamide moiety was found to be compa-
rable to the isoxazoles 13a and 13b. The 2,6-diisopropyl
analog 26b was comparable in vitro, but in vivo in the
rat at 3 mg/kg, efficacy fell off sharply. The 1,2,4-
oxadiazole regioisomers (28, 30) were equivalent to each
other in vitro and vivo in the acute rat model. When
compared with the optimal isoxazoles 13a and 16a , the
1,2,4-oxadiazole regioisomers (28, 30) were marginally
less potent in vitro, but their efficacy was essentially
equivalent at 3 mg/kg in the in vivo APCC rat model.
The N-alkylated heterocycles (35, 40, and 44) were
chosen as we have previously shown that a free ring
NH is detrimental to activity.35 The 1,2,3-triazole amide
derivative 44 was essentially equivalent to the isoxazole
13a in vitro and in vivo in the rat. The pyrazole amide
derivative 35 was less potent in vitro and essentially
as efficacious in the rat as the isoxazole 13a , while the
imidazole amide derivative 40 was significantly less
potent in vitro and less efficacious in vivo at 3 mg/kg in
the rat than the isoxazole 13a .
Four of the more optimal compounds (13a , 16a , 26a ,
a n d 44) were compared in vitro in a cell-based mac-
rophage ACAT assay to assess their ability to penetrate
into cells and inhibit ACAT in the target (arterial)
tissue. The compounds were also evaluated in a bioas-
say measuring rat liver microsomal ACAT inhibition in
plasma extracts from drug treated rabbits to determine
if the compounds were bioactive in plasma. This
represents a crude assessment of whether the compound
is being absorbed (Table 2). Activity in macrophage
ACAT assay and bioassay screens is essential for a
compound expected to affect arterial ACAT. All of the
compounds (13a , 16a , 26a , and 44) inhibited macroph-

Heterocyclic Amides: Inhibition of ACAT
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20 3913
Ta ble 2. ACAT Inhibition in Cell Culture, Bioassay, and
Ta ble 3. Effect of ACAT Inhibitors in a Rabbit Model of
Hypocholesterolemic Activity in Vivo
Atherosclerosis
% ∆TC
thoeracic
dose
bioassay % aortic lesion
%
plasma
MAI
ABIO %
CDOG
at 10
compound (mg/kg) inhibitiona coverage (%)b ∆TCc TGd % ∆
IC50 inhibitionb
CFR (mg/kg)e
compound (µM)a at 25 mg/kg CPCCc mg/kgd
% ∆TC
CI-976
13a
13a
13a
16a
25
1
5
25
1
5
46
0
46
94
0
-41*
-53*
-46*
-32*
-20
-24* -7
-26* +1
-32* +111*
-26* +168*
-17* +24
-27* +66*
-27* +157*
13a
16a
26a
44
0.17
0.31
0.048
0.054
94
92
21
12
-65*
-61*
-39
-44* -76* (25), -64* (5)
-44* -63* (25), -66* (5)
ND
ND
ND
ND
ND
16a
16a
68
92
-29
a
MAI is ACAT inhibition in cell culture measured in murine
25
-36*
b
IC-21 macrophages. ABIO denotes the rabbit bioassay. Data
represents percent inhibition for rat liver microsomal ACAT
inhibition from rabbit plasma. c CPCC represents percent change
a
Bioassay in chow fed rabbits, data represents percent inhibi-
tion of rat liver microsomal ACAT in the plasma drawn from
d
b
in TC in the chronic rat model. CDOG represents the C-fed
rabbits. Data expressed as percent change in lesion coverage
relative to control in the thoracic aorta. c Denotes percent change
female beagle dog model, data is expressed as percent change in
TC relative to untreated controls. An asterisk (*) denotes values
significantly different from controls, p < 0.05.
d
in plasma total cholesterol. Denotes percent change in plasma
triglyceride levels. An asterisk (*) denotes value significantly
different from control, p < 0.05 using a Student’s t-test.
age ACAT with IC50’s of <1 µM (Table 2). In the
bioassay, the isoxazoles (13a , 16a ) both gave essentially
complete ACAT inhibition when dosed at 25 mg/kg in
the rabbit. However, compounds 26a and 44 were not
significantly bioactive, with only 21 and 12% inhibition
when dosed at 25 mg/kg. The isoxazoles (13a , 16a ) were
evaluated in several more challenging cholesterol-lower-
ing models. The compounds 13a and 16a lowered total
cholesterol 65 and 61%, respectively, in the 2 week
chronic rat model of pre-established hypercholester-
olemia. Compounds 13a and 16a could not be distin-
guished in the cholesterol-fed rabbit model of pre-
established hypercholesterolemia, each lowering total
cholesterol >60% at a dose of 5 mg/kg. In the cholesterol-
fed dog model, which mirrors the clinical situation in
that drug is dosed by bulk capsule daily to animals with
pre-established hypercholesterolemia, 13a and 16a were
equivalent, both lowering TC 44%. As a result of the
excellent hypocholesterolemic profile, macrophage ACAT
inhibition, and bioactivity, 13a and 16a were tested in
a model to assess adrenal toxicity in guinea pigs in vivo.
This toxicity problem has been observed previously with
potent lipophilic urea type ACAT inhibitors but was
thought not to be related to ACAT inhibition.32 No
adrenal cortical atrophy of the zona fasciculata, necrosis
of adrenal cortical cells in the adrenal cortex, or
cytoplasmic course vacuolation was observed in the
guinea pig with 13a or 16a dosed orally at 100 mg/kg
for 2 weeks in oleic acid.
The goal of finding potent, bioactive, nontoxic, effica-
cious cholesterol-lowering ACAT inhibitors having been
achieved, the two isoxazoles were evaluated in a long-
term rabbit model of atherosclerosis. The compounds
(13a , 16a ) were compared against CI-976, our proto-
typical ACAT inhibitor which is antiatherosclerotic at
5 mg/kg, a dose at which there is generally no effect on
plasma cholesterol in this rabbit model of atheroscle-
rosis.18 The 3-alkylisoxazole (13a ) was effective in
slowing the development of cholesteryl ester-rich tho-
racic aortic lesions, showing a significant effect at all
doses (Table 3). The 5-alkylisoxazole 16a only produced
a statistical effect on lesion area at the high dose of 25
mg/kg. Interestingly, the 3-alkylisoxazole 13a blocks
lesion progression at a dose (1 mg/kg) at which it is
inactive in the bioassay, suggesting that total cholesterol
lowering of 26% may be responsible for the lesion effects.
The isoxazole 13a was equivalent to CI-976, our proto-
typical ACAT inhibitor in this model.18 Unfortunately,
however, significant hypertriglyceridemia was observed
at 5 and 25 mg/kg, which complicates the intepretation
of the data at these doses. The hypertriglyceridemia
may be a consequence of potent liver ACAT inhibition
by 13a , as with no cholesteryl ester, the liver has only
triglyceride to package into lipoproteins. Presumably,
at the 1 mg/kg dose, where no hypertriglyceridemia is
observed, 13a and 16a are not bioactive and not
inhibiting liver ACAT. Neither compound affected the
more complex cholesteryl ester (CE)-poor injury-induced
iliac femoral lesions. This observation is not suprising
given the nature of the iliac femoral lesion, which
consists primarily of smooth muscle cells and matrix
with a low CE-rich macrophage content.
Con clu sion
The majority of heterocyclic amides synthesized here
inhibited liver ACAT in vitro (IC50’s ) 0.014-0.11 µM),
suggesting that ACAT is insensitive to changes in this
part of the molecule which do not introduce a free
heterocyclic ring NH.35 The heterocyclic amides were
all efficacious in lowering plasma cholesterol (40-68%)
in an acute cholesterol-fed rat model at 30 mg/kg.
Several compounds were efficacious at 3 mg/kg in this
model. Two optimal isoxazoles (13a , 16a ) inhibited
macrophage ACAT in a cell-based assay, were bioactive
in a rabbit bioassay and were nontoxic to the adrenal
glands of guinea pigs in vivo. Both compounds signifi-
cantly lowered cholesterol in models with pre-estab-
lished hypercholesterolemia in cholesterol-fed rats,
cholesterol-fed rabbits, and cholesterol-fed dogs. These
two compounds were selected for evaluation in a long-
term model of atherosclerosis. Compound 13a was
effective in the injured cholesterol-fed rabbit model of
atherosclerosis in slowing the development of cholesteryl
ester (CE)-rich thoracic aortic lesions, reducing lesion
coverage 53% at 1 mg/kg and was equivalent to CI-976,
our prototypical ACAT inhibitor, in this model.18 The
hypertriglyceridemia observed at 5 and 25 mg/kg in this
model may be a consequence of potent liver ACAT
inhibition, thus with no CE the liver has only TG to
package into lipoproteins. The significance of hyper-
triglyceridemia in the rabbit model of atherosclerosis
is unknown. Further studies of 13a and related com-
pounds in models of atherosclerosis designed to avoid
the hypertriglyceridemia observed in this study will be
the subject of future communications from these labo-
ratories.

3914 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20
White et al.
1H), 4.43 (s, 2H), 2.64 (t, 2H), 1.65 (m, 2H), 1.26 (m, 18H),
0.88 (t, 3H) ppm; EIMS m/ z 330 (M+). Anal. (C16H28BrNO)
C, H, N.
Exp er im en ta l Section
Unless otherwise noted, all reagents were obtained from
commercial suppliers and were used without further purifica-
tion. Column chromatography was performed on Merck silica
gel 60 (230-400 mesh). Melting points were determined on a
Thomas-Hoover melting point apparatus and are uncorrected.
3-Dod ecyl-5-m eth ylisoxa zole (8). A suspension of 7 (9.99
g, 0.030 mol) in DMSO (100 mL) was warmed to give a cloudy
solution and allowed to cool to room temperature. Sodium
borohydride (1.2 g, 0.032 mol) was added in one portion, and
the mixture was stirred for 3 days under nitrogen. The
mixture was poured into 0.1 M HCl (900 mL) and extracted
with ethyl ether. The organic layer was washed with brine,
dried (MgSO4), and concentrated in vacuo. The residue was
purified by column chromatography on silica gel, eluting with
3% acetone in petroleum ether. The product was concentrated
and dried in vacuo to give 8 (3.96 g, 52%) as a white solid:
NMR spectra were determined on
a Brucker 250 MHz,
VarianXL 300 MHz, or Varian Unity 400 MHz. Chemical
shifts (δ) are expressed in ppm, relative to internal tetram-
ethylsilane. Mass spectra were obtained on a VG Masslab
Trio-2A, VG Analytical 7070E/HF, or Finnigan 4500 mass
spectrometer. Elemental analyses were determined on a
Perkin-Elmer 240C elemental analyzer and were within 0.4%.
1
2,4-Dioxoh exa d eca n oic Acid , Eth yl Ester , Mon oso-
d iu m Sa lt (3). To a stirred volume of absolute ethanol (260
mL) at 5 °C under nitrogen was added portionwise sodium
metal (4.3 g, 0.19 mol) over 45 min, and the mixture was
allowed to warm to room temperature. To the resulting
solution was added a suspension of 2-tetradecanone (39.1 g,
0.184 mol) in diethyloxalate (25 mL, 0.184 mol). The mixture
was heated at 60 °C for 5 h and allowed to cool. The resulting
suspension was chilled (3 °C), filtered off, and washed with
ethanol. The solids were recrystallized from ethanol to give
3 (25.9 g, 39%) as a pale yellow solid: 200 MHz 1H NMR
(DMSO-d6) δ 5.4 (br s, 1H), 4.0 (q, 2H), 2.2 (m, 2H), 1.4 (m,
2H), 1.2 (m, 21H), 0.85 (t, 3H) ppm; EIMS m/ z 313 (M - 23
+ 2+). Anal. (C18H31NaO4) C, H.
3-Dod ecylisoxa zole-5-ca r boxylic Acid (4). To a stirred
solution of 3 (15.5 g, 0.046 mol) in glacial acetic acid (125 mL)
at 55 °C was added dropwise a solution of hydroxylamine
hydrochloride (6.45 g, 0.093 mol) in water (32 mL) over 10 min,
and the mixture was stirred at 60 °C for 25 h. The mixture
was allowed to cool and partitioned between water (250 mL)
and chloroform (400 mL). The organic layer was washed with
brine, dried (MgSO4), and concentrated in vacuo. The residue
was dissolved in toluene and concentrated in vacuo and the
residue recrystallized from chloroform and then toluene to give
4 (5.62 g, 43%) as a white solid: mp 119-122 °C; 200 MHz 1H
NMR (DMSO-d6) δ 14.2 (br s, 1H), 7.1 (s, 1H), 2.66 (t, 2H),
1.64 (m, 2H), 1.3 (m, 18H), 0.84 (t, 3H) ppm; EIMS m/ z 282
(MH+). Anal. (C16H27NO3) C, H, N.
mp 35-38 °C; 200 MHz H NMR (CDCl3) δ 5.80 (s, 1H), 2.60
(t, 2H), 2.37 (s, 3H), 1.63 (m, 2H), 1.25 (m, 18H), 0.87 (t, 3H)
ppm; EIMS m/ z 252 (MH+). Anal. (C16H29NO) C, H, N.
2-(3-Dod ecylisoxa zol-5-yl)a cetic Acid (9). To a stirred
suspension of 8 (3.40 g, 0.0135 mol) in dry THF (900 mL) at
-78 °C was added in one portion a 1.6 M solution of n-
butyllithium in hexanes (8.5 mL, 0.014 mol), and the mixture
was stirred for 1.5 h. The mixture was poured onto freshly
crushed dry ice and allowed to warm overnight. The mixture
was concentrated, and the residue was partitioned between
petroleum ether and 0.5 M NaOH. The aqueous layer was
washed with petroleum ether, acidified with concentrated HCl
to pH ∼1-2, and extracted with CHCl3. The extract was dried
(MgSO4) and concentrated to give a waxy solid which was
recrystallized from toluene to give 9 (0.65 g, 16%) as a white
1
solid: mp 79-80 °C; 200 MHz H NMR (DMSO-d6) δ 12.8 (br
s, 1H), 6.29 (s, 1H), 3.85 (s, 2H), 2.58 (t, 2H),1.59 (m, 2H), 1.25
(m, 18H), 0.87 (t, 3H) ppm; EIMS m/ z 296 (MH+). Anal.
(C17H29NO3) C, H, N.
2-(3-Dod ecylisoxa zol-5-yl)-N-(2,4,6-tr im eth oxyp h en yl)-
a ceta m id e (10). To a stirred solution of 9 (0.64 g, 0.0022 mol)
in dry THF (20 mL) at room temperature under nitrogen was
added in one portion 1,1′-carbonyldiimidazole (CDI) (0.38 g,
0.0024 mol), and the mixture was stirred for 2 h. To this
solution were added 2,4,6-trimethoxyaniline hydrochloride
(0.48 g, 0.0022 mol) and triethylamine (0.33 mL, 0.0024 mol)
in THF (30 mL). The mixture was stirred for 2 days. The
solution was concentrated, and the residue was dissolved in
dichloromethane. The solid was filtered through silica gel,
eluting with 25% acetone in petroleum ether. The filtrate was
concentrated in vacuo to give an oil which crystallized on
standing to give 10 (0.96 g, 96%) as a pale yellow solid: mp
3-Dod ecyl-5-(h yd r oxym eth yl)isoxa zole (6). To a stirred
solution of 4 (24.3 g, 0.0863 mol) and triethylamine (12.0 mL,
0.0861 mol) in THF (600 mL) at 3 °C under nitrogen was added
in one portion a chilled (3 °C) solution of ethyl chloroformate
(8.25 mL, 0.0863 mol) in THF (30 mL). A white precipitate
formed immediately. The suspension was stirred for 1.25 h
before sodium borohydride (6.54 g, 0.173 mol) was added in
portions over 10 min. The mixture was stirred for 1.5 h while
warming to room temperature. The mixture was chilled and
carefully quenched with water (350 mL). The organic layer
was diluted with dichloromethane. The aqueous layer was
extracted with THF-dichloromethane and then dichlo-
romethane. The organic solutions were combined, dried (Na2-
SO4), and concentrated in vacuo. The residue was purified
by column chromatography on silica gel, eluting with 10%
acetone in petroleum ether. Fractions containing product were
concentrated, and the residue was dissolved in dichlo-
romethane, concentrated and dried in vacuo to give 6 (11.1 g,
48%) as a white solid: mp 57-59 °C; 250 MHz 1H NMR
(CDCl3) δ 6.10 (s, 1H), 4.73 (d, 2H), 2.64 (t, 2H), 2.48 (t, 1H),
1.64 (m, 2H), 1.25 (m, 18H), 0.88 (t, 3H) ppm. EIMS m/ z 268
(MH+). Anal. (C16H29NO2) C, H, N.
1
107-109 °C; 250 MHz H NMR (CDCl3) δ 6.71 (br s, 0.67 H),
6.42 (br s, 0.33H), 6.22 (0.67 H), 6.14 (s, 2.33H), 3.79-3.87
(m, 11H), 2.65 (m, 2H), 1.67 (m, 2H), 1.25 (m, 18H), 0.88 (t,
3H) ppm; EIMS m/ z 460 (M+). Anal. (C26H40N2O5) C, H, N.
3-Dod ecyl-5-(p h en ylm eth yl)isoxa zole (11). To a stirred
suspension of sodium nitrite (227 g, 3.29 mol) in DMF (3.8 L)
was added 1-bromotridecane (514.5 g, 1.95 mol), and the
mixture was stirred for 6 h at room temperature. The mixture
was poured into cold water (8 L) and extracted with petroleum
ether (2 × 2 L). The organic layer was washed with water (2
L) and brine, dried (MgSO4), and concentrated. The residue
was distilled in vacuo (bp 101-120 °C, 0.2 mmHg) to give 171.9
g of an oil which was purified by column chromatography on
silica gel, eluting with 1% ethyl acetate in petroleum ether to
give 1-nitrotridecane (109.8 g, 24.5%) as a clear colorless oil
which was not further purified. To a stirred solution of
3-phenyl-l-propyne (54.9 g, 0.472 mol) and phenyl isocyanate
(104 mL, 0.957 mol) in benzene (800 mL) at room temperature
under nitrogen was added dropwise over 30 min a solution of
the l-nitrotridecane (109.1 g, 0.476 mol) and triethylamine (6.7
mL, 0.048 mol) in benzene (400 mL). The mixture was stirred
for 1 h, refluxed for 6 h, allowed to cool, and chilled. The solid
that precipitated was filtered, and the filtrate was concen-
trated to an oil which was purified by column chromatography
on silica gel, eluting with 4% ether in petroleum ether to give
11 (57.8 g, 37%) as an off-white solid: mp 45-47 °C; 250 MHz
1H NMR (CDCl3) δ 7.27 (m, 5H), 5.74 (s, 1H), 4.04 (s, 2H),
2.59 (t, 2H), 1.58 (m, 2H), 1.25 (m, 18H), 0.88 (t, 3H) ppm;
EIMS m/ z 328 (MH+). Anal. (C22H33NO) C, H, N.
5-(Br om om eth yl)-3-d od ecylisoxa zole (7). To a stirred
solution of 6 (1.0 g, 0.0037 mol) in dichloromethane (20 mL)
at 3 °C was added in one portion phosphorus tribromide (0.13
mL, 0.0014 mol), and the solution was stirred for 1.5 h and
then at room temperature for 3 days. The mixture was washed
carefully with saturated sodium bisulfite, saturated sodium
bicarbonate, and brine. The organic layer was dried (MgSO4)
and concentrated in vacuo to a yellow oil. The oil was purified
by column chromatography on silica gel, eluting with 3%
acetone in hexanes to give 7 (0.47 g, 39%) as an off-white
1
solid: mp 35.5-37.5 °C; 300 MHz H NMR (CDCl3) δ 6.16 (s,

Heterocyclic Amides: Inhibition of ACAT
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20 3915
(()-2-(3-Dod e cylisoxa zol-5-yl)-2-p h e n yl-N-(2,4,6-t r i-
m eth oxyp h en yl)a ceta m id e (13a ). A stirred solution of 11
(38.3 g, 0.117 mol) in THF (600 mL) was cooled to -78 °C
under nitrogen. To the resulting suspension was added
dropwise a 2.01 M solution of n-butyllithium in hexanes (58
mL, 0.12 mol) over 10 min. The mixture was stirred for 1.25
h before a solution of 2,4,6-trimethoxyphenyl isocyanate13 (24.4
g, 0.117 mol) in THF (350 mL) was added dropwise over 30
min. The mixture was stirred for 45 min and then quenched
with the dropwise addition of 1 M HCl (235 mL, 0.235 mol)
followed by ethyl ether (500 mL). The mixture was allowed
to warm to room temperature. The organic layer was washed
with 0.2 M HCl, water, saturated aqueous sodium bicarbonate,
and brine, dried (MgSO4), and concentrated to a solid which
was recrystallized from diisopropyl ether and chromato-
graphed on silica gel eluting with 30% ethyl acetate in
petroleum ether to give 13a (40.7 g, 65%) as a white solid:
mp 106-107 °C; 250 MHz 1H NMR (CDCl3) δ 7.1-7.5 (m, 5H),
6.68 (s, 1H), 6.27 (s, 1H), 6.11 (s, 2H), 5.19 (s, 1H), 3.6-3.8
(m, 9H), 2.63 (t, 2H), 1.64 (m, 2H), 1.25 (m, 18H), 0.88 (t, 3H)
ppm; EIMS m/ z 536 (M+). Anal. (C32H44N2O5) C, H, N.
(()-2-(3-Dodecylisoxazol-5-yl)-2-ph en ylacetic Acid (12).
A stirred solution of 11 (6.03 g, 0.0184 mol) in THF (120 mL)
was cooled to -78 °C under nitrogen, and to the resulting
suspension was added dropwise a 2.1 M solution of n-
butyllithium in hexanes (8.8 mL, 0.018 mol) over 5 min. The
mixture was stirred for 1 h, then transferred via canula onto
freshly crushed dry ice, and allowed to warm overnight. The
mixture was partitioned between 0.2 M HCl and ethyl ether.
The organic layer was washed with water and brine, dried
(MgSO4), and concentrated to give a solid which was crystal-
lized from hexanes-ethyl ether to give 12 (5.16 g, 76%) as a
(()-2-(5-Dod e cylisoxa zol-3-yl)-2-p h e n yl-N-(2,4,6-t r i-
m eth oxyp h en yl)a ceta m id e (16a ). According to the proce-
dure described for 13a , compound 16a (59%) was synthesized
1
as a white solid: mp 90-91.5 °C; 400 MHz H NMR (CDCl3)
δ 7.50 (d, 2H), 7.36 (m, 2H), 7.29 (m, 1H), 7.02 (br s, 1H), 6.17
(s, 1H), 6.11 (s, 2H), 5.17 (s, 1H), 3.78 (s, 3H), 3.74 (s, 6H),
2.69 (t, 2H), 1.66 (m, 2H), 1.25 (m, 18H), 0.88 (t, 3H) ppm;
EIMS m/ z 536 (M+). Anal. (C32H44N2O5) C, H, N.
(()-2-(5-Dodecylisoxazol-3-yl)-2-ph en ylacetic Acid (15).
According to the procedure described for compound 12, com-
pound 15 (86%) was synthesized as a white solid: mp 84-85
°C; 400 MHz 1H NMR (CDCl3) δ 7.37 (m, 5H), 6.05 (s, 1H),
5.16 (s, 1H), 2.69 (t, 2H), 1.66 (m, 2H), 1.25 (m, 18H), 0.88 (t,
3H) ppm; CIMS m/ z 372 (MH+). Anal. (C23H33NO3) C, H, N.
(()-N-(2,6-Diisop r op ylp h en yl)-2-(5-d od ecylisoxa zol-3-
yl)-2-p h en yla ceta m id e (16b). According to the procedure
described for 13b, compound 16b (56%) was synthesized as a
white solid: mp 107-108 °C; 250 MHz 1H NMR (CDCl3) δ 7.72
(br s, 1H), 7.53 (d, 2H), 7.38 (m, 3H), 7.24 (d, 1H), 7.12 (d,
2H), 6.07 (s, 1H), 5.18 (s, 1H), 2.85 (m, 2H), 2.74 (t, 2H), 1.67
(m, 2H), 1.25 (m, 18H), 1.06 (m, 12H), 0.88 (t, 3H) ppm; EIMS
m/ z 531 (MH
+). Anal. (C35H50N2O2) C, H, N.
(()-N-(2,4-Diflu or op h en yl)-2-(5-d od ecylisoxa zol-3-yl)-
2-p h en yla ceta m id e (16c). According to the procedure de-
scribed for 13b, compound 16c (81%) was synthesized as a
1
yellow solid: mp 54-57 °C; 250 MHz H NMR (CDCl3) δ 8.47
(br s, 1H), 8.21 (m 1H), 7.41 (m, 5H), 6.84 (t, 2H), 6.01 (s, 1H),
5.11 (s, 1H), 2.72 (t, 2H), 1.67 (m 2H), 1.25 (m, 18H), 0.87 (t,
3H) ppm; EIMS m/ z 483 (MH+). Anal. (C29H36F2N2O2) C, H,
N.
5-Dod ecyl-3-[2-(t et r a h yd r op yr a n -2-yloxy)et h yl]isox-
a zole (17b). Dihydropyran (78.5 mL, 0.86 mol) was added
dropwise to a mechanically stirred, ice-cooled mixture of
3-bromopropanol (100 g, 0.72 mol), Amberlyst-15 (5 g) and
heptane (1 L). The mixture was stirred for 18 h at room
temperature, filtered, and concentrated to afford a crude oil
which was diluted with DMF (500 mL), stirred for 18 h with
sodium nitrite (84.5 g, 1.22 mol), poured into water, and
extracted with ethyl acetate (2 × 500 mL). The combined
organic extracts were washed with water, dried over Na2SO4,
and chromatographed on silica gel, eluting with 20% ethyl
acetate in hexanes to afford an oil 17a (36.7 g) which was not
further purified but diluted with benzene (400 mL), tetrade-
cyne (53.5 g, 0.28 mol), and phenyl isocyanate (65.7 g, 0.55
mol). Triethylamine (3.9 mL, 0.028 mol) was added to the
mixture, which was refluxed for 3 h and stirred at room
temperature for a further 12 h. The mixture was filtered and
washed with benzene (100 mL) and the filtrate chromato-
graphed on silica gel, eluting with 15% ethyl acetate in hexane
to give the title compound as an oil (35.7 g, 13%): 400 MHz
1H NMR (CDCl3) δ 5.91 (s, 1H), 4.63 (m, 1H), 4.01 (m, 1H),
3.81 (m, 1H), 3.68 (m, 1H), 3.52-3.47 (m, 1H), 2.94 (t, J ) 6.8
Hz, 2H), 2.70 (t, J ) 7.8 Hz, 2H), 1.85-1.48 (m, 6H), 1.26 (s,
20H), 0.88 (t, J ) 6.8 Hz, 3H) ppm; CIMS m/ z 366 (MH+).
Anal. (C22H39NO3‚0.08H2O) C, H, N.
1
white solid: mp 110-111.5 °C; 400 MHz H NMR (CDCl3) δ
7.37 (m, 5H), 6.11 (s, 1H), 5.10 (s, 1H), 2.62 (dd, 2H), 1.62 (m,
2H), 1.21-1.34 (m, 18H), 0.88 (t, 3H) ppm; CIMS m/ z 372
(MH+). Anal. (C23H33NO3) C, H, N.
(()-N-(2,6-Diisop r op ylp h en yl)-2-(3-d od ecylisoxa zol-5-
yl)-2-p h en yla ceta m id e (13b). To a stirred solution of 12
(0.30 g, 0.000 81 mol) in THF (15 mL) at room temperature
under nitrogen was added CDI (0.14 g, 0.000 85 mol), and the
mixture was stirred for 2 h. To the solution was added 2,6-
diisopropylaniline (0.18 mL, 0.000 96 mol), and the mixture
was stirred at room temperature for 1 day and at reflux for 6
days. The reaction mixture was partitioned between ethyl
ether and 1 M HCl. The organic layer was washed with brine,
dried (Na2SO4), and concentrated in vacuo. The residue was
chromatographed on silica gel, eluting with 6% acetone in
petroleum ether. The product was dissolved in CH2Cl2,
concentrated, and dried in vacuo to give 13b (0.245 g, 57%) as
1
a white solid: mp 115-117 °C; 250 MHz H NMR (CDCl3) δ
7.46 (m, 5H), 7.26 (d, 1H), 7.13 (d, 2H), 6.91 (br s, 1H), 6.23
(s, 1H), 5.24 (s, 1H), 2.85 (m, 2H), 2.66 (t, 2H), 1.66 (m, 2H),
1.25 (m, 18H), 1.09 (m, 12H), 0.88 (t, 3H) ppm; EIMS m/ z 531
(MH+). Anal. (C35H50N2O2‚0.25H2O) C, H, N.
(()-N-(2,4-Diflu or op h en yl)-2-(3-d od ecylisoxa zol-5-yl)-
2-p h en yla ceta m id e (13c). According to the procedure de-
scribed for 13b, compound 13c (91%) was synthesized as a
2-(5-Dod ecylisoxa zol-3-yl)eth a n ol (18). Compound 17b
(20.2 g, 0.055 mol) was diluted with methanol (300 mL) and
p-toluenesulfonic acid (0.2 g) added. The mixture was stirred
for 18 h at room temperature, concentrated in vacuo, and
partitioned between ethyl acetate and dilute aqueous NaHCO3,
and the organic layer was washed with brine and chromato-
graphed on silica gel, eluting with 10% ethyl acetate in hexane,
to give the title compound as a white solid (15.4 g, 99%): 400
1
yellow solid: mp 68-70 °C; 250 MHz H NMR (CDCl3) δ 8.20
(m, 1H), 7.55 (br s, 1H), 7.41 (m, 5H), 6.83 (m, 2H), 6.15 (s,
1H), 5.16 (s, 1H), 2.64 (t, 2H), 1.64 (m, 2H), 1.25 (m, 18H),
0.85 (t, 3H) ppm; EIMS m/ z 483 (MH+). Anal. (C29H36F2N2O2)
C, H, N.
5-Dod ecyl-3-(p h en ylm eth yl)isoxa zole (14). To a stirred
solution of l-tetradecyne (29.9 g, 0.154 mol) and phenyl
isocyanate (33.4 mL, 0.307 mol) in benzene (450 mL) at room
temperature was added dropwise a solution of 2-phenylnitro-
ethane24 (35.2 g,0.154 mol) and triethylamine (2.15 mL, 0.0154
mol) in benzene (150 mL) over 10 min under nitrogen. The
mixture was stirred for 1 h, then refluxed for 10 h, cooled, and
filtered. The filtrate was concentrated, and the residue was
chromatographed on silica gel, eluting with 2% ethyl acetate
in petroleum ether to give 14 (20.6 g, 41%) as a yellow
1
MHz H NMR (CDCl3) δ 5.88 (s, 1H), 3.95 (m, 2H), 2.89 (t, J
) 5.8 Hz, 2H), 2.71 (t, J ) 7.6 Hz, 2H), 2.20 (t, J ) 5.8 Hz,
1H), 1.68 (m, 2H), 1.26 (s, 18H), 0.88 (t, J ) 6.8 Hz, 3H) ppm;
EIMS m/ z 282 (MH+). Anal. (C17H31NO2) C, H, N.
2-(5-Dod ecylisoxa zol-3-yl)-2-m et h ylp r op ion ic Acid
Meth yl Ester (19b). A solution of J ones reagent (112 mL,
1.25 M) was added dropwise over 1 h to 18 (15.1 g, 0.054 mol)
in acetone at 0 °C. The mixture was stirred for a further 4 h
and allowed to warm to room temperature, and the reaction
was quenched with 2-propanol (10 mL). The mixture was
poured into water (500 mL), concentrated in vacuo to remove
acetone and extracted with ethyl acetate (2 × 600 mL). The
organics were washed with brine, dried over MgSO4, and
1
crystalline solid: mp 41-45 °C; 250 MHz H NMR (CDCl3) δ
7.29 (m, 5H), 5.72 (s, 1H), 3.97 (s, 2H), 2.66 (t, 2H), 1.64 (m,
2H), 1.25 (m, 18H), 0.88 (t, 3H) ppm; EIMS m/ z 327 (M+).
Anal. (C22H33NO) C, H, N.

3916 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20
White et al.
concentrated to afford a white solid (14.8 g) which was
dissolved in methanol (600 mL). Gaseous HCl was bubbled
into the solution for 30 s, and the solution was stirred for 12
h, concentrated in vacuo, and partitioned between ethyl acetate
and water. The organic layer was washed with brine and
chromatographed on silica gel, eluting with 10, 20, and 30%
ethyl acetate in hexane to afford 19a , 10.8 g as an oil, 2.8 g of
which was diluted with DMF and methyl iodide (5.7 g, 0.0405
moL) under N2. NaH (0.97 g, 60% dispersion in mineral oil)
was added to the ice-cooled solution and the mixture stirred
for 12 h at room temperature. The mixture was poured into
ethyl acetate/brine and the organic layer dried over MgSO4
and chromatographed on silica gel, eluting with 5% ethyl
acetate in hexane to afford the title compound as an oil (2.5 g,
acetate and acidified with the dropwise addition of 1 M HCl
(265 mL). The resulting precipitate was filtered, washed with
water, and dried in vacuo to give 23a (48.4 g, 100%) as an
1
off-white solid: mp 111-113 °C (gas evolution); 250 MHz H
NMR (DMSO-d6) δ 12.6 (br s, 1H), 8.99 (s, 1H), 7.20-7.66 (m,
5H), 6.22 (s, 2H), 4.77 (s, 1H), 3.76 (s, 3H), 3.65 (s, 6H) ppm;
CIMS m/ z 346 (MH+). Anal. (C18H19NO6‚0.2H2O) C, H, N.
Tr id eca n oic Acid Hyd r a zid e (24). A solution of tride-
canoic acid methyl ester (24.6 g, 0.108 mol) and anhydrous
hydrazine (3.40 mL, 0.108 mol) in absolute ethanol (150 mL)
was stirred at room temperature for 24 h and then refluxed
for 2 days. The solution was allowed to cool, and the solid
that crystallized was filtered, washed, and dried in vacuo to
give 24 (18.6 g, 75%) as a white solid: mp 101-104 °C; 250
1
1
64%): 400 MHz H NMR (CDCl3) δ 5.92 (s, 1H), 3.70 (s, 3H),
MHz H NMR (DMSO-d6) δ 8.90 (br s, 1H), 4.14 (s, 2H), 1.98
2.70 (t, J ) 7.6 Hz, 2H), 1.66 (m, 2H), 1.60 (s, 6H), 1.26 (s,
18H), 0.88 (t, J ) 6.8 Hz, 3H) ppm; EIMS m/ z 388 (MH+).
Anal. (C20H35NO3) C, H, N.
(t, 2H), 1.47 (m, 2H), 1.23 (m, 18H), 0.85 (t, 3H) ppm; EIMS
m/ z 229 (MH+). Anal. (C13H28N2O) C, H, N.
(()-2-P h en yl-N-(tr id eca n oyla m in o)-N′-(2,4,6-tr im eth -
oxyp h en yl)m a lon a m id e (25a ). A solution of 23a (46.7 g,
0.135 mol) and CDI (24.7 g, 0.152 mol) in anhydrous THF (1.0
L) was stirred at room temperature under nitrogen for 2 h.
To the resulting suspension was added 24 (30.9 g, 0.135 mol),
and the mixture was stirred at room temperature for 17 h and
then at 40 °C for 21 h. The mixture was chilled to 5 °C and
filtered, and the residue was washed with THF, ethyl ether,
and then water and air-dried to give 25a (54.4 g, 72%) as a
2-(5-Dod ecylisoxa zol-3-yl)-N-(2,4,6-tr im eth oxyp h en yl)-
isobu tyr a m id e (20). Compound 19 (1.36 g, 0.0039 mol) was
refluxed with KOH (0.34 g, 0.006 mol) in methanol (100 mL)
for 24 h, acidified with 1 M HCl, and extracted with ethyl
acetate. The organic layer was washed with water, dried over
MgSO4, and concentrated to afford a white solid (2.27 g), which
was dissolved in a solution of THF (200 mL) and CDI (1.30 g,
0.008 mol). The mixture was refluxed under N2 for 2 h to give
the imidazolide in situ. Trimethoxyaniline hydrochloride (1.77
g, 0.008 mol) and Et3N (1.12 mL, 0.008 mol) were stirred in
THF (50 mL) for 30 min, and the slurry was added to the
imidazolide. The mixture was refluxed for 2 weeks, quenched
with water, concentrated to remove THF, extracted with CHCl3
(200 mL), dried over MgSO4, and chromatographed on silica
gel, eluting with 30% ethyl acetate in hexane to afford the title
compound as a white solid (2.42 g, 68%): mp 58-60 °C; 400
white solid: mp 175-180 °C; 250 MHz
1H NMR (DMSO) δ
10.2 (m, 2H), 9.1 (s, 1H), 7.55 (d, 2H), 7.37 (m, 3H), 6.26 (s,
2H), 4.64 (s, 1H), 3.79 (s, 3H), 3.72 (s, 6H), 2.13 (t, 2H), 1.51
(m, 2H), 1.25 (m, 18H), 0.87 (t, 3H) ppm; CIMS m/ z 556 (MH
+).
Anal. (C31H45N3O6) C, H, N.
(()-2-(5-Dodecyl[1,3,4]oxadiazol-2-yl)-2-ph en yl-N-(2,4,6-
tr im eth oxyp h en yl)a ceta m id e (26a ). To a flask charged
with granular phosphorus pentoxide (470 g, 3.31 mol) was
added dropwise over 30 min absolute ethanol (260 mL, 4.43
mol) under nitrogen. The mixture was heated on a steam bath
with periodic stirring for 3 h and allowed to cool. To the
mixture were added 25a (53.6 g, 0.0964 mol) and DMF (700
mL), and the mixture was stirred at 95 °C for 12 h. The
resulting solution was allowed to cool, poured into water (5
L), and extracted twice with CH2Cl2. The organics were
washed with water and brine, dried (MgSO4), and chromato-
graphed on silica gel, eluting with 20% acetone in petroleum
ether. The product was concentrated and crystallized from
ethanol-water to give 26a (7.37 g, 14%) as a white solid: mp
120-121 °C; 200 MHz 1H NMR (CDCl3) δ 7.85 (br s, 1H), 7.58
(d, 2H), 7.38 (m, 3H), 6.11 (s, 2H), 5.31 (s, 1H), 3.79 (s, 3H),
3.74 (s, 6H), 2.82 (t, 2H), 1.76 (m, 2H), 1.25 (m, 18H), 0.88 (t,
3H) ppm; EIMS m/ z 538 (MH+). Anal. (C31H43N3O5) C, H,
N.
1
MHz H NMR (CDCl3) δ 6.84 (s br, 2H), 6.11 (s, 2H), 6.05 (s,
1H), 3.78 (s, 3H), 3.74 (s, 6H), 2.74 (t, J ) 7.6 Hz, 2H), 1.76-
1.70 (m, 2H), 1.68 (s, 6H), 1.39-1.28 (m, 2H), 1.25 (s, 16H),
0.88 (t, J ) 7.0 Hz, 3H) ppm; CIMS m/ z 489 (MH+). Anal.
(C28H44N2O5) C, H, N.
1-(5-Dodecylisoxazol-3-yl)cyclopen tan ecar boxylic Acid
(2,4,6-Tr im eth oxyp h en yl)a m id e (21). The title compound
was prepared by a method analogous to the method for 20,
replacing methyl iodide with 1,4-dibromobutane to give the
1
title compound: 400 MHz H NMR (CDCl3) δ 6.74 (s br, 1H),
6.10 (s, 2H), 6.01 (s, 1H), 3.78 (s, 3H), 3.73 (s, 6H), 2.73 (t, J
) 7.8 Hz, 2H), 2.52-2.47 (m, 2H), 2.28-2.24 (m, 2H), 1.86-
1.67 (m, 6H), 1.39-1.28 (m, 2H), 1.25 (s, 16H), 0.88 (t, J ) 6.8
Hz, 3H); CIMS m/ z 515 (MH+). Anal. (C30H46N2O5) C, H, N.
(()-2-P h en yl-N-(2,4,6-t r im et h oxyp h en yl)m a lon a m ic
Acid Eth yl Ester (22). To a stirred solution of diisopropy-
lamine (43.4 mL, 0.310 mol) in dry THF (1.2 L) at room
temperature was added a 2.5 M solution of n-butyllithium in
hexanes (124 mL, 0.31 mol) in one portion, and the mixture
was cooled to -78 °C. To the solution was added a solution of
phenylacetic acid ethyl ester (50.8 g, 0.309 mol) in THF (500
mL) over 15 min under N2, and the mixture was stirred for 2
min. A solution of 2,4,6-trimethoxyphenyl isocyanate13 (64.9
g, 0.310 mol) in THF (500 mL) was added over 10 min. After
1.5 h, the reaction was quenched with 1 M HCl (310 mL, 0.310
mol), and the mixture was allowed to warm to room tempera-
ture.The mixture was concentrated to remove THF and
partitioned between water and CHCl3. The organic layer was
washed with 1 M HCl and brine, dried (Na2SO4), and chro-
matographed on silica gel, eluting with 50% ethyl acetate in
petroleum ether, and the product was crystallized from etha-
nol-ethyl ether to give 22 (46.9 g, 41%) as a white solid: mp
109-111 °C; 250 MHz 1H NMR (CDCl3) δ 7.94 (br s, 1H), 7.58
(d, 2H), 7.36 (m, 3H), 6.12 (s, 2H), 4.68 (s, 1H), 4.24 (m, 2H),
3.79 (s, 3H), 3.75 (s, 6H), 1.28 (t, 3H) ppm; EIMS m/ z 373
(M+). Anal. (C20H23NO6) C, H, N.
(()-N-(2,6-Diisopr opylph en yl)-2-ph en ylm alon am ic Acid
(23b). According to the procedures described for 22 and 23a ,
compound 23b was synthesized as a white solid: mp 198-
199 °C; 250 MHz
1H NMR (DMSO-d6) δ 12.8 (br s, 1H), 9.56
(s, 1H), 7.47 (d, 2H), 7.34 (m, 3H), 7.23 (m, 1H), 7.12 (m, 2H),
4.87 (s, 1H), 3.23 (br s, 1H), 2.60 (br s, 1H), 0.80-1.2 (m, 12H)
ppm; CIMS m/ z 340 (MH+). Anal. (C21H25NO3‚0.33H2O) C,
H, N.
(()-N -(2,6-Diisop r op ylp h e n yl)-2-p h e n yl-N ′-(t r id e c-
a n oyla m in o)m a lon a m id e (25b). According to the procedure
described for 25a , compound 25b (84%) was synthesized as a
white solid: mp 182-184 °C; 250 MHz
1H NMR (DMSO-d6) δ
10.2 (br s, 1H), 10.0 (br s, 1H), 9.42 (s, 1H), 7.50 (d, 2H), 7.36
(m, 3H), 7.22 (m, 1H), 7.11 (d, 2H), 4.76 (s, 1H), 2.93 (br s,
2H), 2.13 (t, 2H), 1.50 (m, 2H), 1.23 (m, 18H), 1.02 (d, 12H),
0.85 (t, 3H) ppm; CIMS m/ z 550 (MH+). Anal. (C34H51N3O3)
C, H, N.
(()-N -(2,6-Diisop r op ylp h e n yl)-2-(5-d od e c yl[1,3,4]-
oxa d ia zol-2-yl)-2-p h en yla ceta m id e (26b). According to the
procedure described for 26a , the title compound was synthe-
sized as an oil after concentration from CHCl3. The oil was
dried in vacuo and crystallized on standing to give 26b (30%)
(()-2-P h en yl-N-(2,4,6-t r im et h oxyp h en yl)m a lon a m ic
Acid (23a ). To a stirred solution of KOH (10.70 g, 0.191 mol)
in absolute ethanol (1.1 L) was added 22 (55.3 g, 0.148 mol),
and the mixture was stirred for 2 days. The resulting
suspension was diluted with water (900 mL) and concentrated
to remove ethanol. The solution was washed with ethyl
1
as a yellow solid: mp 82-84 °C; 200 MHz H NMR (CDCl3) δ
8.48 (s, 1H), 7.10-7.51 (m, 8H), 5.29 (s, 1H), 2.86 (m, 4H), 1.79
(m, 2H), 1.25 (m, 18H), 1.06 (m, 12H), 0.87 (m, 3H) ppm; EIMS
m/ z 532 (MH+). Anal. (C34H49N3O2‚0.03CHCl3) C, H, N.

Heterocyclic Amides: Inhibition of ACAT
J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20 3917
2-(3-Dod ecyl[1,2,4]oxa d ia zol-5-yl)-2-p h en yl-N-(2,4,6-tr i-
m eth oxyp h en yl)a ceta m id e (28). Hydroxylamine hydro-
chloride (0.90 g, 0.013 mol) was added to a mixture of Et3N
(1.79 mL, 0.013 mol) and 50% aqueous EtOH (4 mL). The
mixture was stirred for 2 min, then tridecanenitrile (2.02 g,
0.0104 mol) dissolved in EtOH (10 mL) was added, and the
mixture was refluxed for 2 h and then poured into water (100
mL). The precipitate was filtered and washed with hexanes
(2 × 10 mL) to afford N-hydroxytridecanimidamide (0.63 g)
(27) as a white solid which was not further purified.
CDI (0.28 g, 0.0017 mol) was added to a solution of 23a (0.56
g, 0.0016 mol) in THF (20 mL) and the mixture stirred at room
temperature for 1 h. Compound 27 (0.37 g, 1.63 mmol) was
added to the heterogeneous mixture, which was stirred a
further 1.5 h. The pale green solution was concentrated in
vacuo, redissolved in AcOH (20 mL), and refluxed for 1.5 h.
The mixture was concentrated in vacuo, diluted with toluene
(20 mL), concentrated, and partitioned between ethyl acetate
and saturated aqueous NaHCO3. The organic layer was
washed with water and brine, dried over MgSO4, concentrated,
and recrystallized from EtOH/water to give the title compound
28 (0.14 g, 16%) as a white solid: mp 117-119 °C; 250 MHz
1H NMR (CDCl3) δ 8.06 (s, 1H), 7.61-7.58 (m, 2H), 7.39-7.37
(m, 3H), 6.12 (s, 2H), 5.35 (s, 1H), 3.79 (s, 3H), 3.75 (s, 6H),
2.75 (t, J ) 7.5 Hz, 2H), 1.82-1.73 (m, 2H), 1.24 (s, 18H), 0.88
(t, J ) 6.5 Hz, 3H) ppm; EIMS m/ z 538 (MH+). Anal.
(C31H43N3O5) C, H, N.
r-[(H yd r oxya m in o)im in om e t h yl]-N -(2,4,6-t r im e t h -
oxyp h en yl)ben zen ea ceta m id e (29). Benzyl nitrile (20.3
mL, 0.18 mol) was added dropwise to an ice-cooled solution of
NaH (7.04 g, 60% in mineral oil, 0.18 mol) in dry DMF (200
mL) and the mixture stirred for 15 min. 2,4,6-Trimethox-
yphenyl isocyanate (36.8 g, 0.18 mol) was added portionwise
over 2 min, and the mixture was stirred for 0.5 h while being
warmed to room temperature, poured into water (500 mL), and
filtered. The residue was dried in vacuo then stirred with
hexanes (200 mL), filtered, and air-dried to afford a pale purple
solid of 2-cyano-2-phenyl-N-(2,4,6-trimethoxyphenyl)acetamide
(46.7 g) which was not further purified.
water and dichloromethane. The organic layer was dried over
MgSO4, filtered, and concentrated to give a light green oil
which was chromatographed on silica gel, eluting with 10%
ethyl acetate in hexanes to give 5.54 g (58%) of (()-R-phenyl-
1H-pyrazole-1-acetate as a clear oil: 1H NMR (CDCl3) δ 7.58
(s, 1H), 7.41 (s, 6H), 6.27 (s, 1H), 6.23 (s, 1H), 4.31-4.24 (m,
2H), 1.30-1.24 (t, 3H); CIMS m/ z 231 (MH+).
Phosphorus oxychloride (7.0 mL, 0.075 mol) was added
dropwise to 14 mL DMF at 0 °C under an atmosphere of N2.
The resulting solution was stirred for 30 min, and then a
solution of ethyl (()-R-phenyl-1H-pyrazole-1-acetate (5.76 g,
0.025 mol) in 5 mL of DMF was added dropwise. The resulting
orange solution was warmed to 70 °C for 16 h. The reaction
mixture was cooled to 0 °C, carefully quenched with saturated
aqueous Na2CO3, and partitioned between water and diethyl
ether. The organic layer was dried over MgSO4, filtered, and
concentrated to give an orange oil which was chromatographed
on silica gel, eluting with 15% ethyl acetate in hexanes to give
5.73 g (89%) of the title compound as a yellow/green oil which
solidified upon standing: mp 68-70 °C; 1H NMR (CDCl3) δ
9.82 (s, 1H), 8.03 (s, 1H), 7.91 (s, 1H), 7.49-7.42 (m, 5H), 6.22
(s, 1H), 4.36-4.27 (m, 2H), 1.30-1.24 (t, 3H) ppm; CIMS m/ z
259 (MH+). Anal. (C14H14N2O3‚0.2H2O) C, H, N.
(()-Eth yl 4-(1-Dod ecen yl)-r-p h en yl-1H-p yr a zole-1-a c-
eta te (32). A solution of n-BuLi (127 mL, 0.254 mol, 2.0 M in
hexanes) was added dropwise to a suspension of n-undecylt-
riphenylphosphonium bromide (121.6 g, 0.244 mol, obtained
from triphenylphosphine and undecyl bromide) in 500 mL of
THF at -78 °C under an atmosphere of N2. The resulting
orange solution was stirred for 1 h before a solution of (()-
ethyl 4-formyl-R-phenyl-1H-pyrazole-1-acetate in 250 mL of
THF was added dropwise. The mixture was warmed to room
temperature and stirred for 16 h, quenched with water (150
mL), and concentrated in vacuo. The residue was partitioned
between water and dichloromethane, and the organic layer was
dried over MgSO4, filtered, and concentrated to give an oily
tan solid which was triturated with boiling hexanes and
filtered to remove triphenylphosphine oxide. The filtrate was
concentrated and chromatographed on silica gel, eluting with
10% ethyl acetate in hexanes to give the title compound as a
yellow oil (1:2 E/Z mixture, 44.4 g, 50%): 1H NMR (CDCl3) δ
7.59 (s, 1H), 7.40-7.26 (m, 6H), 6.17 (s, 1H), 6.16-6.10 (m,
1H), 5.96-5.84 (dt, 0.33H), 5.53-5.43 (dt, 0.66H), 4.34-4.22
(m, 2H), 2.26-2.04 (m, 2H), 1.42-1.26 (m, 19H), 0.90-0.85
(t, 3H) ppm; CIMS m/ z 397 (MH+). Anal. (C25H36N2O2) C,
H, N.
(()-4-(1-Dod ecen yl)-r-p h en yl-N-(2,4,6-tr im eth oxyp h e-
n yl)-1H-p yr a zolea ceta m id e (34). Solid NaOH (6.72 g, 0.168
mol) was added to a solution of (()-ethyl 4-(1-dodecenyl)-R-
phenyl-1H-pyrazole-1-acetate (44.4 g, 0.112 mol) in 500 mL
of 95% ethanol. The resulting yellow solution was stirred for
1 h and then concentrated in vacuo. The residue was
partitioned between water and ether, and the aqueous layer
was acidified with concentrated HCl and extracted with ethyl
acetate. The organic layer was dried over MgSO4, filtered, and
concentrated to give (()-4-(1-dodecenyl)-R-phenyl-1H-pyrazole-
1-acetic acid (33) as a yellow oil (43.4 g) which was used
without further purification.
Hydroxylamine hydrochloride (11.9 g, 0.17 mol) was added
to a solution of Et3N (23.9 mL, 0.17 mol) in 50% aqueous EtOH
(40 mL) and stirred for 0.5 h. 2-Cyano-2-phenyl-N-(2,4,6-
trimethoxyphenyl)acetamide (44.9 g, 0.14 mol) in EtOH (300
mL) was added, and the mixture was refluxed for 8 h, allowed
to cool, and poured into water (1 L). The aqueous solution
was decanted, concentrated to half volume, and allowed to
crystallize to afford the title compound as a white solid (33.7
1
g, 52%): 250 MHz H NMR (DMSO) δ 9.34 (s br, 1H), 9.21 (s,
1H), 7.49-7.23 (m, 5H), 6.25 (s, 2H), 5.47 (s br, 2H), 4.49 (s,
1H), 3.78 (s, 3H), 3.71 (s, 6H) ppm; EIMS m/ z 360 (MH+).
Anal. (C18H21N3O5) C, H, N.
2-(5-Dod ecyl[1,2,4]oxa d ia zol-3-yl)-2-p h en yl-N-(2,4,6-tr i-
m eth oxyp h en yl)a ceta m id e (30). Tridecanoyl chloride (15.1
g, 0.061 mol) was added to a solution of 29 (19.8 g, 0.055 mol)
and diisopropylethylamine (10.6 mL, 0.061 mol) in THF (200
mL). The mixture was stirred for 2 h, concentrated in vacuo,
redissolved in glacial AcOH (100 mL), and refluxed for 2 h.
The mixture was concentrated in vacuo, azeotroped with
toluene (2 × 250 mL), chromatographed on silica gel, eluting
with 35% ethyl acetate in hexane, and recrystallized from
EtOH/water to afford the title compound (13.8 g, 47%) as a
Triethylamine (18 mL, 0.13 mol) was added to a suspension
of 2,4,6-trimethoxyaniline hydrochloride (28.48 g, 0.13 mol) in
500 mL of THF and stirred for 1 h before filtering to remove
triethylamine hydrochloride. The filtrate was concentrated
and redissolved in 500 mL of dichloromethane with 33 (43.43
g, 0.118 mol) at -15 °C. Dicyclohexylcarbodiimide (25.53 g,
0.124 mol) was added in one portion, and the resulting
suspension was warmed to room temperature and stirred for
16 h. The mixture was filtered to remove a white solid and
the filtrate partitioned between dichloromethane and 1 M HCl.
The organic layer was dried over MgSO4, filtered, and con-
centrated to give an oily tan solid which was recrystallized
from hexanes to give the title compound as a tan solid (45.43
g, 72%): mp 82-85 °C; 1H NMR (CDCl3) δ 7.92 (s, 1H), 7.65-
7.26 (m, 7H), 6.19-6.13 (m, 4H), 5.58-5.48 (m, 1H), 3.79 (s,
3H), 3.76 (s, 6H), 2.28-2.08 (m, 2H), 1.45-1.26 (m, 16H),
0.90-0.85 (t, 3H) ppm; CIMS m/ z 534 (MH+). Anal.
(C32H43N3O4‚0.2H2O) C, H, N.
1
white solid: mp 98-99 °C; 250 MHz H NMR (CDCl3) δ 7.76
(s br, 1H), 7.61 (m, 2H), 7.37-7.30 (m, 3H), 6.12 (s, 2H), 5.27
(s br, 1H), 3.79 (s, 3H), 3.75 (s, 6H), 2.88 (t, J ) 7.6 Hz, 2H),
1.80 (m, 2H), 1.24 (s, 18H), 0.88 (t, J ) 6.5 Hz, 3H) ppm; EIMS
m/ z 537 (M+). Anal. (C31H43N3O5) C, H, N.
(()-Eth yl 4-For m yl-r-ph en yl-1H-pyr azole-1-acetate (31).
A solution of pyrazole (2.80 g, 0.041 mol) in 75 mL of THF
was added dropwise to a suspension of NaH (1.65 g, 0.041 mol)
in 100 mL of THF at -15 °C under an atmosphere of N2. The
cloudy solution was warmed to room temperature for 15 min,
resulting in a clear solution. The mixture was cooled to -15
°C and added to a solution of ethyl R-bromophenylacetate (7.2
mL, 0.041 mol) in 50 mL of THF. The resulting yellow
suspension was warmed to room temperature for 16 h and then
concentrated in vacuo. The residue was partitioned between

3918 J ournal of Medicinal Chemistry, 1996, Vol. 39, No. 20
White et al.
(()-4-Dod ecyl-r-p h en yl-N-(2,4,6-t r im et h oxyp h en yl)-
1H-p yr a zole-1-a ceta m id e (35). Compound 34 (0.46 g, 0.9
mmol) was dissolved in 75 mL of THF, and 5% Pd/C (0.1 g)
was added. Hydrogen gas (50 psi) was added, and the reaction
mixture was stirred at room temperature for 2 h. The mixture
was filtered to remove the catalyst and the filtrate concen-
trated to give an oil which was triturated with hexanes to give
the title compound as a cream-colored solid (0.45 g, 97%): mp
77-79 °C; 1H NMR (CDCl3) δ 7.95 (s, 1H), 7.54-7.26 (m, 7H),
6.19-6.13 (s, 3H), 3.79 (s, 3H), 3.76 (s, 6H), 2.44 (t, 2H), 1.57-
1.51 (m, 2H), 1.25 (s, 18H), 0.90-0.85 (t, 3H) ppm; CIMS m/ z
536 (MH+). Anal. (C32H45N3O4) C, H, N.
4-(1-Dod ecen yl)-1-(tr ip h en ylm eth yl)im id a zole (36). A
solution of n-BuLi (4.1 mL, 0.0065 mol, 1.6 M in hexanes) was
added dropwise to a suspension of n-undecyltriphenylphos-
phonium bromide (3.09 g, 0.0062 mol, obtained from triph-
enylphosphine and undecyl bromide) in 100 mL of THF at -78
°C under an atmosphere of N2. The resulting orange solution
was stirred for 45 min before a solution of 1-(triphenylmethyl)-
4-imidazolecarboxaldehyde28 (2.0 g, 0.0059 mol, in 75 mL of
THF was added dropwise. The mixture was warmed to room
temperature and stirred for 16 h, quenched with saturated
aqueous NH4Cl (50 mL), and concentrated. The residue was
partitioned between water and dichloromethane, and the
organic layer was dried over MgSO4, filtered, and concentrated
to give a yellow oil which was chromatographed on silica gel,
eluting with 10% ethyl acetate in hexanes to give the title
compound (1.8 g, 64%) as a clear oil: 1H NMR (CDCl3) δ 7.46
(s, 1H), 7.35-7.12 (m, 15H), 6.75 (s, 1H), 6.29-6.25 (d, 1H),
5.62-5.52 (dt, 1H), 2.33-2.24 (m, 2H), 1.38-1.23 (m, 16H),
and 0.90-0.85 (t, 3H) ppm; CIMS m/ z 477 (MH+). Anal.
(C34H40N2‚0.26H2O) C, H, N.
mL) was added to a suspension of 2,4,6-trimethoxyaniline
hydrochloride (1.6 g, 0.0073 mol) in THF (500 mL) and stirred
for 1 h before being filtered to remove triethylamine hydro-
chloride. The filtrate was concentrated and redissolved in
dichloromethane (500 mL) with (()-4-dodecyl-R -phenyl-1H-
imidazole-1-acetic acid (2.45 g, 0.0066 mol) at 0 °C. Dicyclo-
hexylcarbodiimide (1.43 g, 0.0069 mol) was added in one
portion, and the resulting suspension was warmed to room
temperature and stirred for 16 h. The mixture was filtered
and the filtrate partitioned between dichloromethane and 1
M HCl. The organic layer was washed with 1 M NaOH, dried
over MgSO4, filtered, and concentrated. The resulting residue
was chromatographed on silica gel, eluting with 20% ethyl
acetate in hexanes to give the title compound as a white solid
1
(1.25 g, 35%): mp 95-102 °C; H NMR (CDCl3) δ 7.53-7.29
(m, 6H), 6.75 (s, 2H), 6.12 (s, 2H), 5.96 (s, 1H), 3.79 (s, 9H),
2.57-2.52 (t, 2H), 1.64-1.57 (m, 2H), 1.29-1.24 (m, 18H),
0.89-0.85 (t, 3H); CIMS m/ z 536 (MH+). Anal. (C32H45
N3O4‚0.45H2O) C, H, N.
-
4-Dod ecyl-1,2,3-tr ia zole (41). A mixture of 1-tetradecyne
(6.6 g, 0.034 mol) and trimethylsilyl azide (4.1 g, 0.035 mol)
was autoclaved at 135 °C for 14 h and then at 150 °C for 14 h.
The resulting mixture was rinsed with ether, and the ether
solution was washed with water, dried over MgSO4, filtered,
and concentrated to give a brown oil which was triturated with
cold hexanes to give the title compound as a tan solid (4.02 g,
50%): mp 64-67 °C; 1H NMR (CDCl3) δ 8.45 (bs, 1H), 7.53 (s,
1H), 2.78-2.72 (t, 2H), 1.71-1.66 (m, 2H), 1.31-1.25 (s, 18H),
0.90-0.85 (t, 3H) ppm; CIMS m/ z 238 (MH+). Anal. (C14H27N3)
C, H, N.
(()-E t h yl 4-Dod ecyl-r-p h en yl-1H -1,2,3-t r ia zole-1-a c-
eta te (42). A solution of 4-dodecyl-1,2,3-triazole (0.99 g,
0.0042 mol) in THF (50 mL) was added dropwise to a
suspension of sodium hydride (0.18 g, 0.0046 mol, 60%
dispersion in mineral oil) in THF (50 mL) at 0 °C. The
resulting suspension was warmed to room temperature, stirred
for 1 h, and then cooled to 0 °C. A solution of ethyl R-bro-
mophenylacetate (1.01 g, 0.0042 mol) in THF (50 mL) was
added dropwise, and the reaction mixture was stirred at room
temperature for 16 h, concentrated in vacuo, and partitioned
between water and ethyl acetate. The organic layer was dried
over MgSO4, filtered, and concentrated to give a clear oil which
was chromatographed on silica gel, eluting with 10% ethyl
acetate in hexanes to give the title compound as a white solid
(0.61 g, 36%): mp 68-70 °C; 1H NMR (CDCl3) δ 7.44-7.40
(m, 6H), 6.54 (s, 1H), 4.37-4.23 (q, 2H), 2.71-2.65 (t, 2H),
1.66-1.61 (m, 2H), 1.32-1.24 (m, 21H), 0.90-0.85 (t, 3H) ppm;
CIMS m/ z 400 (MH+). Anal. (C24H37N3O2) C, H, N.
4-Dod ecylim id a zole (37). 20% Pd/C (1 g) was added to a
solution of 4-(1-dodecenyl)-1-(triphenylmethyl) imidazole (2.39
g, 0.005 mol) in glacial acetic acid (100 mL) and 50 psi of
hydrogen gas. The mixture was stirred for 16 h and concen-
trated in vacuo and the residue made basic with saturated
aqueous Na2CO3 and neutralized with 1 M HCl. The reaction
was extracted with diethyl ether, dried over MgSO4, filtered,
and concentrated to give an oily white solid which was
recrystallized from hexanes to give the title compound as a
1
white solid (1.06 g, 90%): mp 69-71 °C; H NMR (CDCl3) δ
9.02 (s, 1H), 7.57 (s, 1H), 6.78 (s, 1H), 2.64-2.58 (t, 2H), 1.66-
1.58 (m, 2H), 1.30-1.25 (s, 18H), 0.90-0.85 (t, 3H) ppm; CIMS
m/ z 237 (MH+). Anal. (C15H28N2‚0.4H2O) C, H, N.
(()-Eth yl 4-Dod ecyl-r-p h en yl-1H-im id a zole-1-a ceta te
(38). A solution of ethyl R-bromophenylacetate (5.14 g, 0.021
mol) in DMF (50 mL) was added dropwise to a suspension of
4-dodecylimidazole (5.0 g, 0.021 mol) and triethylamine (3.0
mL, 0.021 mol) in DMF (100 mL). The mixture was stirred
for 16 h at room temperature and concentrated in vacuo. The
residue was partitioned between ethyl acetate and water, and
the organic layer was dried over MgSO4, filtered, and concen-
trated to give an orange oil which was chromatographed on
silica gel, eluting with 10% ethyl acetate in hexanes to give
4.57 g (54%) of the title compound as an orange oil: 1H NMR
(CDCl3) δ 7.52 (s, 1H), 7.41-7.25 (m, 5H), 6.73 (s, 1H), 5.83
(s, 1H), 4.32-4.24 (q, 2H), 2.57-2.50 (t, 2H), 1.64-1.56 (m,
2H), 1.31-1.25 (m, 21H), and 0.90-0.85 (t, 3H) ppm; CIMS
m/ z 399 (MH+). Anal. (C25H38N2O2‚0.57H2O) C, H, N.
(()-4-Dodecyl-r-ph en yl-1H-im idazole-1-acetic acid (39).
Solid NaOH (0.9 g, 0.0226 mol) was added to a solution of ethyl
(()-4-dodecyl-R-phenyl-1H-imidazole-1-acetate (4.5 g, 0.0113
mol) in 95% ethanol (150 mL). The resulting solution was
stirred for 2 h and then concentrated in vacuo. The residue
was partitioned between water and ether, and the aqueous
layer was acidified with concentrated HCl and extracted with
dichloromethane. The dichloromethane solution was dried
over MgSO4, filtered, and concentrated to give a white solid
(()-4-Dod ecyl-r-p h en yl-1H-1,2,3-tr ia zole-1-a cetic Acid
(43). Solid NaOH (0.44 g, 0.011 mol) was added to a solution
of ethyl (()-4-dodecyl-R-phenyl-1H-1,2,3-triazole-1-acetate (2.92
g, 7.3 mmol) in 95% ethanol (100 mL). The resulting yellow
solution was stirred for 1 h and then concentrated in vacuo.
The residue was partitioned between water and ether. The
aqueous layer was acidified with concentrated HCl and
extracted with ethyl acetate. The organic layer was dried over
MgSO4, filtered, and concentrated to give an off-white solid
1
(2.74 g, 99%): mp 94-98 °C; H NMR (CDCl3) δ 7.56 (s, 1H),
7.46-7.37 (m, 5H), 6.59 (s, 1H), 2.68-2.62 (t, 2H), 1.60-1.54
(m, 2H), 1.24 (s, 18H), 0.90-0.85 (t, 3H) ppm; CIMS m/ z 372
(MH+). Anal. (C22H33N3O2) C, H, N.
(()-4-Dod ecyl-r-p h en yl-N-(2,4,6-t r im et h oxyp h en yl)-
1H-1,2,3-tr ia zole-1-a ceta m id e (44). Triethylamine (1.2 mL,
0.0084 mol) was added to a suspension of 2,4,6-trimethoxya-
niline hydrochloride (1.68 g, 0.0077 mol) in THF (100 mL), and
the mixture was stirred for 1 h before filtering to remove
triethylamine hydrochloride. The filtrate was concentrated
and redissolved in dichloromethane (100 mL) with (()-4-
dodecyl-R-phenyl-1H-1,2,3-triazole-1-acetic acid (2.59 g, 0.007
mmol) at 0 °C. Dicyclohexylcarbodiimide (1.51 g, 0.0073 mol)
was added in one portion, and the resulting suspension was
warmed to room temperature and stirred for 16 h. The
mixture was filtered and the filtrate partitioned between
chloroform and 1 M HCl. The organic layer was dried over
MgSO4, filtered, and concentrated to give a pale lavender solid
which was recrystallized from ethyl acetate-hexanes (4:1) to
1
(2.53 g, 55%): mp 110-118 °C; H NMR (DMSO-d6) δ 14.00
(bs, 1H), 9.18 (s, 1H), 7.56-7.49 (m, 6H), 6.63 (s, 1H), 2.64-
2.59 (t, 2H), 1.58 (m, 2H), 1.24 (m, 18H), 0.89-0.84 (t, 3H)
ppm; CIMS m/ z 371 (MH+). Anal. (C23H34N2O2‚HCl) C, H,
N.
(()-4-Dod ecyl-r-p h en yl-N-(2,4,6-t r im et h oxyp h en yl)-
1H-im id a zole-1-a ceta m id e (40). Excess triethylamine (2

Heterocyclic Amides: Inhibition of ACAT
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give the title compound as a white solid (2.8 g, 75%): mp 123-
1
125 °C; H NMR (CDCl3) δ 7.70-7.19 (m, 7H), 6.70 (s, 1H),
6.10 (s, 2H), 3.78 (s, 3H), 3.73 (s, 6H), 2.67-2.61 (t, 2H), 1.61-
1.55 (m, 2H), 1.24 (s, 18H), 0.90-0.85 (t, 3H) ppm; CIMS m/ z
537 (MH+). Anal. (C31H44N4O4‚0.27H2O) C, H, N.
Ack n ow led gm en t. We thank Dr. G. A. McClusky
and staff for spectral and analytical determinations.
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