CA2186364C - Substituted azetidinone compounds useful as hypocholesterolemic agents - Google Patents

Abstract

Substituted azetidinone hypocholesterolemic agents of formula (I) or a pharmaceutically acceptable salt thereof, wherein: Ar1 is R3-substituted ary l; Ar2 is R4-substituted aryl; Ar3 is R5-substituted aryl; Y and Z are independently -CH2-, -CH(lower alkyl)- or -C(dilower alkyl)-; A is -O-, -S-, - S(O)- or -S(O)2-; R1 is -OR6, -O(CO)R6, -O(CO)OR9 or -O(CO)NR6R7; R2 is hydrogen, lower alkyl or aryl; or R1 and R2 together are =O; q is 1, 2 or 3; p is 0, 1, 2, 3 or 4; R5 is 1-3 substituents independently selected from -OR6, - O(CO)R6, -O(CO)OR9, -O(CH2)1-5OR9, -O(CO)NR6R7, -NR6R7, -NR6(CO)R7, - NR6(CO)OR9, -NR6(CO)NR7R8, -NR6SO2-lower alkyl, -NR6SO2-aryl, -CONR6R7, -COR 6, -SO2NR6R7, S(O)0-2-alkyl, S(O)0-2-aryl, -O(CH2)1-10-COOR6, -O(CH2)0-10CONR6R 7, o-halogeno, m-halogeno, o-lower alkyl, m-lower alkyl, -(lower alkylene)-COOR 6 and -CH=CH-COOR6; R3 and R4 are 1-3 substituents independently selected from R5, hydrogen, p-lower alkyl, aryl, -NO2, CF3 and p-halogeno; R6, R7 and R8 a re hydrogen, lower alkyl, aryl or aryl-substituted lower alkyl; and R9 is lower alkyl, aryl or aryl-substituted lower alkyl; are disclosed, as well as a method of lowering serum cholesterol by administering said compounds, pharmaceutical compositions containing them, the combination of a substitute d azetidinone and a cholesterol biosynthesis inhibitor for the treatment and prevention of atherosclerosis, novel intermediates and methods for preparing said intermediates.

Description

. W O 95/26334 2186364 PCTlUS95/03196 SUBSTITUTED AZETIDINONE COMPOUNDS USEFUL AS
HYPOCHOLESTEROLEMIC AGENTS
BACKGROUND OF THE INVENTION
The present invention relates to substituted azetidinones useful as hypocholesterolemic agents in the treatment and prevention of atherosclerosis, to the combination of a substituted azetidinone of this invention and a cholesterol biosynthesis inhibitor for the treatment and prevention of atherosclerosis, to pharmaceutical compositions comprising said azetidinones and combinations, to a process for preparing intermediates useful in the synthesis of said azetidinones, and to the novel intermediates prepared by said process.
Atherosclerotic coronary heart disease represents the major cause for death and cardiovascular morbidity in the western world. Risk factors for atherosclerotic coronary heart disease include hypertension, diabetes mellitus, family history, male sex, cigarette smoke and serum cholesterol. A total cholesterol level in excess of 225-250 mg/dl is associated with significant elevation of risk.
Cholesteryl esters are a major component of atherosclerotic lesions and the major storage form of cholesterol in arterial wall cells. Formation of cholesteryl esters is also a key step in the intestinal absorption of dietary cholesterol.
A few azetidinone compounds have been reported as being useful in lowering cholesterol and/or in inhibiting the formation of cholesterol-containing lesions in mammalian arterial walls. U.S.
4,983,597 discloses N-sulfonyl-2-azetidinones as anticholesterolemic agents and Ram, et al., in Indian J Chem.. Sect. B. 29B, 12 (1990), p.
1134-7, disclose ethyl 4-(2-oxoazetidin-4-yl)phenoxy-alkanoates as WO 95126334 21 U b3v4 PCT/US95/03196 hypolipidemic agents. European Patent Publication 264,231 discloses 1-substituted-4-phenyl-3-(2-oxoalkylidene)-2-azetidinones as blood platelet aggregation inhibitors. European Patent 199,630 and European Patent Application 337,549 disclose alastase inhibitory substituted azetidinones said to be useful in treating inflammatory conditions resulting in tissue destruction which are associated with various disease states, e.g. atherosclerosis. W093/02048 discloses substituted (3-lactams useful as hypocholesterolemic agents.
In addition to regulation of dietary cholesterol, the regulation of whole-body cholesterol homeostasis in humans and animals involves modulation of cholesterol biosynthesis, bile acid biosynthesis, and the catabolism of the cholesterol-containing plasma lipoproteins. The liver is the major organ responsible for cholesterol biosynthesis and catabolism and, for this reason, it is a prime determinant of plasma ~: Iolesterol levels. The liver is the site of synthesis and secretion of very low density lipoproteins (VLDL) which are subsequently metabolized to low density lipoproteins (LDL) in the circulation. LDL are the predominant cholesterol-carrying lipoproteins in the plasma and an increase in their concentration is correlated with increased atherosclerosis.
When cholesterol absorption in the intestines is reduced, by whatever means, less cholesterol is delivered to the liver. The consequence of this action is a decreased hepatic lipoprotein (VLDL) production and an increase in the hepatic clearance of plasma cholesterol, mostly as LDL. Thus, the net effect of an inhibition of intestinal cholesterol absorption is a decrease in plasma cholesterol levels.
The inhibition of cholesterol biosynthesis by 3-hydroxy-3-methylglutaryl coenzyme A reductase (EC1.1.1.34) inhibitors has been shown to be an effective way to reduce plasma cholesterol (Witzum, Circulation, 80, 5 (1989), p. 1101-1114) and reduce atherosclerosis.
Combination therapy of an HMG CoA reductase inhibitor and a bile acid .sequestrant has been demonstrated to be more effective in human hyperlipidemic patients than either agent in monotherapy (Illingworth, Drugs, 36 (Suppi. 3) (1988), p. 63-71).

= WO 95/26334 218b 3 6 q. PCT/US95/03196 SUMMARY OF THE INVENTION
Compounds of the present invention are represented by the formula I
R' Ar'-A-Yq-C- Ar3 O Ar2 or a pharmaceutically acceptable salt thereof, wherein:
Arl is R3-substituted aryl;
Ar2 is R4-substituted aryl;
Ar3 is R5-substituted aryl;
Y and Z are independently selected from the group consisting of -CH2-, -CH(lower alkyl)- and -C(dilower alkyl)-;
A is -0-, -S-, -S(O)- or -S(O)2-;
R1 is selected from the group consisting of -OR6, -O(CO)R6, -O(CO)OR9 and -O(CO)NR6R7; R2 is selected from the group consisting of hydrogen, lower alkyl and aryl; or Rt and R2 together are =0;
qisl,2or3;
p is 0, 1, 2, 3 or 4;
R5 is 1-3 substituents independently selected from the group consisting of -OR6, -O(CO)R6, -O(CO)OR9, -O(CH2)1_5OR9, -O(CO)NR6R7, -NR6R7, -NR6(CO)R7, -NR6(CO)OR9, -NR6(CO)NR7R8, -NR6SO2-lower alkyl, -NR6SO2-aryl, -CONR6R7, -COR6, -SO2NR6R7, S(O)0-2-alkyl, S(0)0-2-aryl, -O(CH2)1-1o-COOR6,-O(CH2)1-10CONR6R7, o-halogeno, m-halogeno, o-lower alkyl, m-lower alkyl, -(lower alkylene)-COORs, -CH=CH-COOR6;
R3 and R4 are independently 1-3 substituents independently selected from the group consisting of R5, hydrogen, p-lower alkyl, aryl, -NO2, -CF3 and p-halogeno;
= R6, R7 and R8 are independently selected from the group consisting of hydrogen, lower alkyl, aryl and aryl-substituted lower alkyl;
and R9 is lower alkyl, aryl or aryl-substituted lower alkyl.

4 2 1 U b3= 6 4 PCT1US95/03196 Preferred are compounds of formula I wherein Arl is 193-substituted phenyl, especially (4-R3)-substituted phenyl. Ar2 is preferably R4-substituted phenyl, especially (4-R4)-substituted phenyl.
Ar3 is preferably RS-substituted phenyl, especially (4-R5)-substituted phenyl. Mono-substitution of each of Ar1, Ar2 and Ar3 is preferred.
Y and Z are each preferably -CHZ-. R2 is preferably hydrogen. Rt is preferably -OR6 wherein R6 is hydrogen, or a group readily metabolizable to a hydroxyl (such as -O(CO)Rs, -O(CO)OR9 and -O(CO)NR6R7, defined above). Also preferred are compounds wherein R' and R2 together are =O.
The sum of q and p is preferably 1 or 2, more preferably 1.
Preferred are compounds wherein p is zero and q is 1. More preferred are compounds wherein p is zero, q is 1, Y is -CHZ- and Rl is -OR6, especially when Rs is hydrogen.
Another group of preferred compounds is that wherein Arl is R3-substituted phenyl, Ar2 is R4-substituted phenyl and Ar3 is R5-substituted phenyl. Also preferred are compounds wherein Art is R3-substituted phenyl, Ar2 is R4-substituted phenyl, Ar3 is R5-substituted phenyl, and the sum of p and q is 1 or 2, especially 1. More preferred are compounds wherein Arl is R3-substituted phenyl, Ar2 is R4-substituted phenyl, Ar3 is R5-substituted phenyl, p is zero and q is 1.
A is preferably -0-.
R3 is preferably -COORs, -CONR6R7, -COR6, -SO2NR6R7, S(O)0-2-alkyl, S(O)0-2-aryl, NO2 or halogeno. A more preferred definition for R3 is halogeno, especially ffuoro or chloro.
R4 is preferably hydrogen, lower alkyl, -OR6, -O(CO)R6, -O(CO)OR9, -O(CO)NR6R7, -NR6R7, CORS or halogeno, wherein R6 and R7 are preferably independently hydrogen or lower alkyl, and R9 is preferably lower alkyl. A more preferred definition for R4 is hydrogen or halogeno, especially fluoro or chloro.
R5 is preferably -OR6, -O(CO)Rs, -O(CO)OR9, -O(CO)NR6R7, -NR6R7, -(lower alkylene)-COORs or -CH=CH-COORs, wherein R6 and R7 are preferably independently hydrogen or lower alkyl, and R9 is preferably lower alkyl. A more preferred definition for R5 is -OR6, -(lower alkylene)-COOR6 or -CH=CH-COORs, wherein R6 is preferably hydrogen or lower alkyl.

- -- -------------= WO 95126334 218 6 3 6 4 PCT1US95/03196 The invention also relates to a novel process for preparing chiral 6-amino ester intermediates of formula II
Ar30 0,41s, O10 \Ar20 II

wherein Ar20 is Ar2, a suitably protected hydroxy-substituted aryl or a suitably-protected amino-substituted aryl, Ar30 is Ar3, a suitably protected hydroxy-substituted aryl or a suitably-protected amino-substituted aryl, and -C(O)OR10 is an acyl radical of a chiral alcohol, useful in the preparation of chiral 3-unsubstituted azetidinones of the formula Ar30 O~~
Ar2o III
wherein Ar20 and Ar3fl are as defined above.
The process for preparing the compounds of formula II
comprises:
reacting a bromoacetate of a chiral alcohol of the formula RloOC(O)CH2Br, wherein RtoOH is an optically pure chiral alcohol, an imine of the formula Ar20-N=CH-Ar30, wherein Ar20 and Ar30 are as defined above, and zinc to obtain a 0-amino ester of formula II.
The intermediate of formula II can be converted to the chiral 3-unsubstituted azetidinone of formula III by cyclizing the 6-amino ester of formula II with a Grignard reagent.
This invention also relates to novel intermediates of formula II, that is, compounds of formula II
Ar30 OR ~
Ar2o II
wherein Ar20 is R4-substituted aryl, a suitably protected hydroxy-substituted aryl or a suitably-protected amino-substituted aryl;
Ar30 is R5-substituted aryl, a suitably protected hydroxy-substituted aryl or a suitably-protected amino-substituted aryl;

=

-C(O)OR1o is an acyl radical of an optically pure chiral alcohol selected from the group consisting of 1-menthyl, isopino-campheyl, (1 S)-endo-bornyl, isomenthyl, trans-2-phenylcyclo-hexyl or phenylmenthyl;
R5 is 1-3 substituents independently selected from the group consisting of -OR6, -O(CO)R6, -O(CO)OR9, -O(CH2)1_5OR9, -O(CO)NR6R7, -NR6R7, -NR6(CO)R7, -NR6(CO)OR9, -NR6(CO)NR7RB, -NR6SO2-lower alkyl, -NR6SO2-aryl, -CONR6R7, -COR6, -SO2NR6R7, S(O)0-2-alkyl, S(O)0-2-aryl, -O(CH2)1-1o-COOR6,-O(CH2)1-IoCONR6R7, o-halogeno, m-halogeno, o-lower alkyl, m-lower alkyl, -(lower alkylene)-COOR6, -CH=CH-COOR6;
R4 is 1-3 substituents independently selected from the group consisting of R5, H, p-lower alkyl, aryl, -NO2, -CF3 and p-halogeno;
R6, R7 and R8 are independently selected from the group consisting of H, lower alkyl, aryl and aryl-substituted lower alkyl; and R9 is lower alkyl, aryl or aryi-substituted lower alkyl.
This invention also relates to the use of a compound of formula I as a hypocholesterolemic agent for reducing plasma cholesterol levels and treating or preventing atherosclerosis in a mammal in need of such treatment.
In another aspect, the invention relates to a pharmaceutical composition comprising a substituted azetidinone of formula I in a pharmaceutically acceptable carrier. The invention also relates to the use of said pharmaceutical composition as a hypocholesterolemic agent for reducing plasma cholesterol levels and treating or preventing atherosclerosis, and to a method of preparing said compositions by admixing a compound of formula I and a pharmaceutically acceptable carrier.
The present invention also relates to a method of reducing plasma cholesterol levels, and to a method of treating or preventing atherosclerosis, comprising administering to a mammal in need of such treatment an effective amount of a combination of a substituted azetidinone cholesterol absorption inhibitor of this invention and a cholesterol biosynthesis inhibitor. That is, the present invention relates to the use of a substituted azetidinone cholesterol absorption inhibitor for combined use with a cholesterol biosynthesis inhibitor (and, similarly, WO 95/26334 218 6 3 6 4 pCT/US95/03196 use of a cholesterol biosynthesis inhibitor for combined use with a substituted azetidinone cholesterol absorption inhibitor) to treat or prevent athersclerosis or to reduce plasma cholesterol levels.
In yet another aspect, the invention relates to a pharmaceutical composition comprising an effective amount of a substituted azetidinone cholesterol absorption inhibitor, a cholesterol biosynthesis inhibitor, and a pharmaceutically acceptable carrier. The use of said composition to treat or prevent athersclerosis or to reduce plasma cholesterol levels is also contemplated, as is the preparation of said composition by admixing a substituted azetidinone cholesterol absorption inhibitor, a cholesterol biosynthesis inhibitor, and a pharmaceutically acceptable carrier. In a final aspect, the invention relates to a kit comprising in one container an effective amount of a substituted azetidinone cholesterol absorption inhibitor in a pharmaceutically acceptable carrier, and in a separate container, an effective amount of a cholesterol biosynthesis inhibitor in a pharmaceutically acceptable carrier.

DETAILED DESCRIPTION:
As used herein, the term "lower alkyl" means straight or branched alkyl chains of 1 to 6 carbon atoms. Similarly, "lower alkylene"
means a divalent alkyl chain, straight or branched, of 1 to 6 carbon atoms.
"Aryl" means phenyl, naphthyl, indenyl, tetrahydronaphthyl or indanyl.
"Halogeno" refers to fluoro, chloro, bromo or iodo radicals.
The above statement, wherein R6, R7 and Ra are said to be independently selected from a group of substituents, means that R6, R7 and R8 are independently selected, but also that where an R6, R7 or Rs variable occurs more than once in a molecule, those occurrences are independently selected (e.g., if Rl is -OR6 wherein R6 is hydrogen, R4 can be -OR6 wherein R6 is lower alkyl). Similarly, R3, R4 and R5 are independently selected from a group of substituents, and where more than one R3, R4 and/or R5 is present, the substitutents are independently selected; those skilled in the art will recognize that the size and nature WO 95/26334 21 86 3 6 4 PCT/US95/03196 ~
-$-of the substituent(s) will affect the number of substituents which can be present.
Compounds of the invention have at least one asymmetrical carbon atom and therefore all isomers, including diastereomers and rotational isomers are contemplated as being part of this invention. The invention includes d and I isomers in both pure form and in admixture, including racemic mixtures. Isomers can be prepared using conventional techniques, either by reacting optically pure or optically enriched starting materials or by separating isomers of a compound of formula I.
Those skilled in the art will appreciate that for some compounds of formula I, one isomer will show greater pharmacological activity than other isomers.
Compounds of the invention with an amino group can form pharmaceutically acceptable salts with organic and inorganic acids.
Examples of suitable acids for salt formation are hydrochloric, sulfuric, phosphoric, acetic, citric, oxalic, malonic, salicylic, malic, fumaric.
succinic, ascorbic, maleic, methanesulfonic and other mineral and carboxylic acids well known to those in the art. The salt is prepared by contacting the free base form with a sufficient amount of the desired acid to produce a salt. The free base form may be regenerated by treating the salt with a suitable dilute aqueous base solution such as dilute aqueous sodium bicarbonate. The free base form differs from its respective salt form somewhat in certain physical properties, such as solubility in polar solvents, but the salt is otherwise equivalent to its respective free base forms for purposes of the invention.
Certain compounds of the invention are acidic (e.g., those compounds which possess a carboxyl group). These compounds form pharmaceutically acceptable salts with inorganic and organic bases.
Examples of such salts are the sodium, potassium, calcium, aluminum, gold and silver salts. Also included are salts formed with pharmaceutically acceptable amines such as ammonia, alkyl amines, hydroxyalkylamines, N-methylglucamine and the like.
Cholesterol biosynthesis inhibitors for use in the combination of the present invention include HMG CoA reductase inhibitors such as lovastatin, pravastatin, fluvastatin, simvastatin and Cl-- - --- - - -= WO 95/26334 2186364 PCT/US95/03196 981; HMG CoA synthetase inhibitors, for example L-659,699 ((E,E-11-[3'R-(hydroxy-methy1)-4'-oxo-2'R-oxetanyl]-3,5,7R-trimethyl-2,4-undecadienoic acid); squalene synthesis inhibitors, for example squalestatin 1; and squalene epoxidase inhibitors, for example, NB-598 ((E)-N-ethyl-N-(6,6-dimethyl-2-hepten-4-ynyl)-3-[(3,3'-bithiophen-5-yl)methoxy]benzene-methanamine hydrochloride). Preferred HMG CoA
reductase inhibitors are lovastatin, pravastatin and simvastatin.

Compounds of formula I can be prepared by known methods. For example, the preparation of compounds of formula I, wherein Arl, Ar2, Ar3, R2 and Zp are as described above, Y is -CH2-, q is 1, Ri is OH, and A is -O- or -S- (i.e., a compound of formula la), is described in Method 1:
Method 1 O R2 Ar3 OH Ar3 ~Zp Arl-A'-M Arl-A'-CHZ-C-ZP~
0 '~ " ~Arz -- 1 R O '~ " . 2 Ar2 1 la An epoxide-substituted azetidinone of formula 1 can be treated with a compound of formula Arl-A'-M, wherein A' is -0- or -S-, and wherein M is a metal such as sodium, potassium, lithium or magnesium, in an inert solvent such as tetrahydrofuran (THF) at room temperature and under an inert atmosphere such as N2 to obtain a compound of formula Ia. Compounds of formula 1 are prepared immediately before the reaction by treating a solution of Arl-OH or Arl-SH in an inert solvent such as THF with a suspension of alkali metal hydride, or, when M is magnesium, a solution of an alkyl Grignard reagent such as isopropyimagnesium bromide, in the same solvent.
Alternatively, a compound of formula 1 can be treated with Arl-OH or Arl-SH in the presence of a reagent such as ZnC12 to obtain a compound of formula Ia.
Preparation of the starting materials of formula 1 is shown by the following processes (exemplifying compounds wherein p is 0, i.e., Z is not present), wherein Process A prepares compounds of formula 1a, having relative "trans" orientation at the f3-lactam 3- and 4-positions, and WO 95/26334 2186 3 6 4 PCT/US95/03196 =

wherein Process B prepares compounds of formula having relative "cis" orientation at the 13-lactam 3- and 4-positions:
Process A:

NAr3 ~Ar3 I } 'N
N
O CI Ar2 0 \Ar2 2 ~ 4 L~H Ar3 MCPBA ~ la 4 --~ N
O , Ar2 In the first step, crotonyl chloride (?.)) is refluxed with an imine of formula.2, wherein Ar2 and Ar3 are as defined above, in an inert solvent such as CH2CI2 or THF in the presence of a base such as tri-n-butyl amine, triethylamine or diisopropylethylamine to obtain a trans-substituted 3-vinyl-2-azetidinone of formula 4. The compound of formula 4 is then treated with an oxidizing agent such as MCPBA in an inert solvent such as CH2CI2, the reaction is quenched with a reagent such as aqueous Na2SO3 and conventional extraction and separation techniques are used to obtain a mixture of 3-oxiranyl-2-azetidinone epimers which can be separated by HPLC.
Process B:
1. LDA, -78 C Ar3 2. Bulky Acid 4a O N'Ar2 O H
~ MCPBA A~ ~
N
0 `Ar2 The 3-vinyl-2-azetidinone of formula 4 can be treated with a strohg base such as lithium diisopropylamide (LDA) in a suitable solvent such as THF at low temperatures, e.g., -780C, followed by treatment with a bulky acid such as 2,6-di-tert-butyl-4-methylphenol (BHT), glacial acetic acid or isovaleric acid, to obtain the corresponding cis-3-vinyl-2-azetidinone (43). The compound of formula 4,3 can be = WO 95/26334 21" " 3 ' 4 PCT/US95/03196 oxidized in a manner similar to that described in Process A to obtain the compound of formula lb.
The following Method 2 describes the preparation of compounds of formula I wherein Art, Ar2, Ar3, Rt, R2, Yq and Zp are as described above, and A is -0- or -S- (i.e., a compound of formula Ic):
Method 2:
R' R~ L-Yq C- Zp Ar3 L-Yq-C-ZP CHz-C(O)Q + ~ =- R2 R 2 0 N'~Arz Ri Arl-A'-M' Arl-A'-Yq-C-Z "'rf Ar3 Rz Ic O N Arz An activated carboxylic acid derivative of formula .~, for example an acid chloride, wherein Q is chloro, and wherein L is a leaving group such as a halide, can be reacted with an imine of formula a in the presence of a base such as a trialkylamine (e.g., triethylamine or tri-n-butylamine) at room temperature or elevated temperature in an inert solvent such as CH2CI2 or toluene. The intermediate of formula fi is then reacted with a compound of formula ArI-A'-M as described in Method 1 to obtain a compound of formula Ic.
Method 3 describes the preparation of compounds of formula Id wherein Arl, Ar2, Ar3 and Yq are as described above, Ri is OH, R2 is H, p is zero and A' is -0- or -S-:
Method 3:
Ar3 O OH
A' J Ar3 + Ar~-A'-Yq-C-H -~ Ar`Yq ~
O N ~Arz 7 Id 0 NAr2 A 3-unsubstituted azetidinone of formula Z is treated with a strong base such as LDA or lithiumdicyclohexylamide at low temperatures (e.g. -70 to -780C) in an inert solvent such as THF, followed by reaction with an aldehyde of formula $. When the 3-unsubstituted azetidinone is chiral, the products of the reaction with aldehyde $ are non-racemic.
Starting materials of formulae 2, J, 5, 7 and $ are known or are prepared by methods known in the art.
Chiral starting materials of formula III, of which Z is an example, can be prepared by cyclizing chiral B-amino ester intermediates of formula II, which intermediates are prepared by the novel process described above. The procedure for preparing compounds of formula III is shown in the following reaction scheme:
Ar30 R' OC(O)CH2Br + Ar2 -N=CH-Ar3 Zn; = 12 O OR10N~Ar2 II
Ar30 II EtMgBr/THF
N III
O ~Ar20 wherein Ar20, Ar30 and Ric) are as defined above. Suitable protecting groups for the hydroxy- or amino-substituted aryl groups in Ar20 and Ar30 are exemplified in the table below. Typical R1oOH optically pure chiral alcohols are selected from the group consisting of 1-menthyl, isopino-campheyl, (1 S)-endo-bornyl, isomenthyl, trans-2-phenylcyclo-hexyl and phenylmenthyl. For preparing the preferred compounds of formula III, the preferred optically pure alcohols are 1-menthyl, (-)isopino-campheyl, (1S)-endo-(-)bornyl, (+)isomenthyl, (-)-trans-2-phenylcyclo-hexyl and (-)phenylmenthyl.
In the first step, equimolar amounts of a bromoacetate of formula 2 and an imine of formula a are reacted with zinc dust in an inert solvent such as anhydrous dioxane, THF or diethyl ether, preferably in the presence of a zinc activating agent such as iodine, at a temperature of 10 to 30, preferably 23 to 250C for about 24 to 48 hours. The reaction is also preferably carried out with ultrasonification. The resultant fi-amino ester is purified by conventional methods, for example the zinc dust is filtered off, the excess imine is crystallized out, and the B-amino' ester is then crystallized out; additional 13-amino ester can be recovered by flash chromatography.

WO 95/26334 2~ ~ 6364 PCT/US95/03196 In the second step, the (3-amino ester is cyclized by treatment with a Grignard reagent such as isopropylmagnesium bromide or ethylmagnesium bromide in an ethereal solvent such as THF at -40 to 400C, preferably at 0OC to room temperature.
After cyclization, protecting groups can be removed as necessary by procedures well known to those skilled in the art.
Starting materials of formula $ are prepared by reacting the sodium alkoxide of the corresponding chiral alcohol with bromo acetyl chloride at -400C to room temperature, preferably -200C to room temperature in an inert solvent such as THF or diethyl ether.
For various chiral alcohol starting materials, the following enantiomeric ratios were observed in the corresponding 3-unsubstituted azetidinones:
Chiral alcohol Bati4 Menthol 60:40 Borneol 60:40 Isomenthol 75:25 Isopinocampheol 75:25 Phenyl cyclohexanol 99:1 Phenyl menthol 99:1 Compounds of formula I wherein A is -S(O)- or -S(O)2- can be prepared by treating the corresponding compound wherein A is -S-with an oxidizing agent such as m-chloroperoxybenzoic acid (MCPBA).
Reactive groups not involved in the above processes can be protected during the reactions with conventional protecting groups which can be removed by standard procedures after the reaction. The following Table 1 shows some typical protecting groups:

Table 1 Group to be Group to be Protected and Protected Protecting Group -COOH -COOalkyl, -COObenzyl,-COOphenyl iNH ~ NCOaIkyl, NCObenzyl, ~ NCOphenyi = ~
~NCH2OC}+2CHpSi(CH3)3, NC(O)OC(CIJ)3, \ \ \ CI Hs N-benzyl, NSi(CH3)3, NSi-C(CH)3 -NH2 -N~

I
-O H -OC H3, -OCH20CH3,- OSi(CH3)3, - OSi C(CH)3 or -OCI-4,2phenyl We have found that the compounds of this invention lower serum lipid levels, in particular serum cholesterol levels. Compounds of this invention have been found to inhibit the intestinal absorbtion of cholesterol and to significantly reduce the formation of liver cholesteryl esters in animal models. Thus, compounds of this invention are hypocholesterolemic agents by virtue of their ability to inhibit the esterification and/or intestinal absorption of cholesterol; they are therefore useful in the treatment and prevention of atherosclerosis in mammals, in particular in humans.
In addition to the compound aspect, the present invention therefore also relates to a method of lowering serum cholesterol levels, which method comprises administering to a mammal in need of such treatment a hypocholesterolemic effective amount of a compound of formula I of this invention. The compound is preferably administered in a pharmaceutically acceptable carrier suitable for oral administration.
The present invention also relates to a pharmaceutical composition comprising a compound of formula I of this invention and a pharmaceutically acceptable carrier. The compounds of formula I can ---- - ---- --~ WO 95126334 2186364 PCT/US95/03196 -be administered in any conventional oral dosage form such as capsules, tablets, powders, cachets, suspensions or solutions. The formulations and pharmaceutical compositions can be prepared using conventional pharmaceutically acceptable excipients and additives and conventional techniques. Such pharmaceutically acceptable excipients and additives include non-toxic compatible fillers, binders, disintegrants, buffers, preservatives, anti-oxidants, lubricants, flavorings, thickeners, coloring agents, emulsifiers and the like.
The daily hypocholesteremic dose of a compound of formula I is about 0.1 to about 30 mg/kg of body weight per day, preferably about 0.1 to about 15 mg/kg. For an average body weight of 70kg, the dosage level is therefore from about 5 to about 2000 mg of drug per day, preferably about 5 to about 1000 mg, given in a single dose or 2-4 divided doses. The exact dose, however, is determined by the attending clinician and is dependent on the potency of the compound administered, the age, weight, condition and response of the patient.
For the combinations of this invention wherein the substituted azetidinone is administered in combination with a cholesterol biosynthesis inhibitor, the typical daily dose of the cholesterol biosynthesis inhibitor is 0.1 to 80 mg/kg of mammalian weight per day administered in single or divided dosages, usually once or twice a day: for example, for HMG CoA reductase inhibitors, about 10 to about 40 mg per dose is given 1 to 2 times a day, giving a total daily dose of about 10 to 80 mg per day, and for the other cholesterol biosynthesis inhibitors, about 1 to 1000 mg per dose is given 1 to 2 times a day, giving a total daily dose of about 1 mg to about 2 g per day.
The exact dose of any component of the combination to be administered is determined by the attending clinician and is dependent on the potency of the compound administered, the age, weight, condition and response of the patient.
Where the components of a combination are administered separately, the number of doses of each component given per day may not necessarily be the same, e.g. where one component may have a greater duration of activity, and will therefore need to be administered less frequently.

WO 95126334 21 86 3 6 q. PCTIUS95/03196 Since the present invention relates to the reduction of plasma cholesterol levels by treatment with a combination of active ingredients wherein said active ingredients may be administered separately, the invention also relates to combining separate pharmaceutical compositions in kit form. That is, a kit is contemplated wherein two separate units are combined: a cholesterol biosynthesis inhibitor pharmaceutical composition and a substituted azetidinone absorption inhibitor pharmaceutical composition. The kit will preferably include directions for the administration of the separate components.
The kit form is particularly advantageous when the separate components must be administered in different dosage forms (e.g. oral and parenteral) or are administered at different dosage intervals.
Following are examples of preparing 3-unsubstituted azetidinones starting materials and compounds of formula I. The stereochemistry listed is relative stereochemistry unless otherwise noted. The terms cis and trans refer to the relative orientations at the 13-lactam 3- and 4-positions.
Preparation 1 1~ OCHZCsH5 ~~

N_^
O T{`
F
Step 1: Preparation of (+)-trans-2-phenyl cyclohexyibromoacetate Dissolve (+)-trans-2-phenyl cyclohexanol (0.0113 mole) in anhydrous THF, cool to -150C, add NaH (1.2 eq.) in portions and stir for 30 min.
Add bromoacetyl chloride (1.5 eq.) dropwise and stir overnight at room temperature. Cool the reaction mixture to OOC and quench with t-butanol (5 mL) and water, dropwise (10 mL). Warm the mixture to room temperature, dilute with ethyl acetate (EtOAc) and wash in sequence with water (2X50 mL) and brine (2X50 mL). Dry the organic layer over MgSO4, filter and concentrate. Purify the resultant residue by flash silica gel chromatography, eluting with hexane -0-- 5% EtOAc/hexane.

WO 95/26334 21v 6364 PCT/US95/03196 Step 2: Preparation of O1 HN`

(DO C6H5 / F
Reflux a solution of Zn dust (2.88 g, 44 mmol) and iodine (0.3 g, 1.2 mmol) in anhydrous dioxane (50 mL) for 1 h, then cool to room temperature. Immerse the flask in an ultrasonification bath, add a mixture of the product of step 1 (7.4 mmol) and 4-benzyloxybenzylidine-(4-fluoro)aniline (1.87 g, 6 mmol) and sonicate for 48 h at room temperature. Filter off the zinc dust over celite and concentrate the filtrate. Redissolve the resultant residue in a minimum amount of EtOAc;
after 1 h, filter out the crystallized unreacted imine. Concentrate the filtrate under vacuum and redissolve the resulting residue in a minimum amount of CH3OH to crystallize out the desired 8-amino ester (1.2 g, 2.2 mmol). Concentrate the mother liquor and flash chromatograph it on silica gel, eluting with 10% hexane/EtOAc to obtain additional (3-amino ester (0.3 g). M.p. 129-131OC; elemental analysis calc'd for C34H34FN03 is C, 78.01; H, 6.50; N, 2.67; found C, 77.62; H, 6.65;
N, 2.74.
Step 3: Treat a solution of the product of step 2 (0.18 mmole) in THF (5 mL) at OOC with ethylmagnesium bromide (1.2 eq.), stir for 4 h and allow the reaction to warm to room temperature. Quench the reaction with aqueous NH4CI (10 mL) and extract with ether (50 mL). Dry the organic layer over MgSO4 and concentrate. Isolate the product by preparative chromatography on a silica gel plate, eluting with 20% EtOAc/hexane.
Analyze the product using a chiral analytical HPLC AS column, eluting with i-propanol:hexane (20/80): the retention times for the two enantiomers were 15.3 and 16.4 min at a flow rate of 0.5 mUmin.

W O 95/26334 7 1 86 3 6 4 PCTlUS95/03196 ~

Example 1 O H'. H
~
NI\
O

StD 1:

A
N
O
Add a solution of crotonyf chloride (1.81 mL, 0.02 moles) in CH2CI2 (50 mL) dropwise, over a period of 1 h, to a refluxing solution of tri-n-butyl amine (7.23 mL, 0.03 moles) and p-methoxybenzylidine aniline (3.19 g, 0.015 moles) in CH2CI2 (100 mL). Reflux for 16 h after the addition is complete, then cool to room temperature. Wash with water (2x100 mL) and saline (1 x100 mL), then dry over Na2SO4, filter and concentrate.
Stir the resultant oil with excess hexane and filter to obtain a yellow solid (2.5 g). Purify the residue by silica gel chromatography, eluting with EtOAc/hexane (1:5) to obtain a white solid (2.0 g, 49 /, yield), m.p. 119-120 C, EIMS: M+=279.
Steo 2:

O 3:0H O3 O. H OCH3 HA I~ O N 1~
/ /
B-1 (major) B-2 (minor) To a stirred solution of the product of Step 1 (compound A) (1.0 g, 0.0036 moles) in CH2CI2 (40 mL) at room temperature, add MCPBA (1.9 g, 0.01 moles) portionwise. After 36 h, quench the reaction by dropwise addition of aqueous 10% Na2SO3. Separate the aqueous layer and wash the organic layer consecutively with 5% NaHCO3 (2x50 mL), water (1 x50 mL) and saline (1 x50 mL), dry over Na2S04 and concentrate.
Purify the resultant residue by silica gel chromatography, eluting with >~
WO 95/26334 218636PCT/U595l03196 EtOAc/hexane (2:1), to obtain a mixture of epoxide epimers as an off-white solid (1.00 g, 96% yield). Purify further by HPLC, eluting with 5%
EtOAc/CH2CI2 to obtain:
less polar epoxide: 0.27 g, m.p. 85-880C, EIMS: M+295.
more polar epoxide: 0.54 g, m.p. 138-1410C, EIMS: M+295.
Step 3: To a suspensibn of NaH (0.53 g of 60% dispersion in oil, 0.013 moles) in THF (35 mL) at room temperature, add 4-fluorophenol (2.26 g, 0.02 moles) and stir 30 min. until a clear solution is obtained. Add the major product of Step 2 (compound B-1) (2.0 g, 0.0067 moles) and stir at room temperature for 3 days. Dilute the reaction mixture with EtOAc, wash with water (1x30 mL), then saline (2x3 mL), dry over Na2SO4, filter and concentrate to obtain a brown oil (3.1 g). Purify the oil by silica gel chromatography, eluting with EtOAc/hexane (1:2) to obtain the title compound as a racemic mixture (1.23 g, 45% yield) (Rel (1'S, 3S, 4S)-1-phenyl-3-[1 hydroxy-2-(4-fluorophenoxy)ethyl]-4-(4-methoxyphenyl)-2-azetidinone).
Resolve the racemate from Step 3 using a preparative Chiracel AS HPLC column, eluting with hexane-iso ro anol 80:20 to give:
_oH I OCH3 Enantiomer A:
~ O 0.095g; m.p.168-169 C;
~ ~ 22.8 o N
[a)p =+36.7 ; EIMS: M+ 407.1;
High resolution MS: calc'd =
407.1533; obsv'd = 407.1539 OH OCHa Enantiomer B: _ 0.082 g; m.p. 171-172oC;
I ~ N [ajzDZ.e = 41.40 O ~

~ i High resolution MS: calc'd =
407.1533; obsv'd = 407.1547 , Example 2 OH OH
OH~... H H

F N ~
O
~ F
Stec) 1: _ O HH H

O N
F
O
~. H +
F O., ~' H H
C

O
F
To a solution of compound C(5.0 g, 13.4 mmols) in CH2CI2 (70 mL), add MCPBA (7 g, 40 mmols) and NaHCO3 (3 g). Stir under N2 for 36 hr (reaction about 95% complete), then add a small amount of (CH3)2S
(approx. 1 mL) and stir for 30 min. Extract acidic by-products into aqueous NaHCO3 solution and discard. Wash the organic layer with brine, dry over MgSO4 and remove the solvent under vacuum. Purify the crude residue by silica gel chromatography, eluting with 20% ethyl acetate (EtOAc)/hexane -*30% EtOAc/hexane to obtain:
isomer 1 (compound D-1), 1.7 g, EIMS: M+=389;
isomer 2 (compound D-2), 2.3 g, EIMS: M+=389.
Step 2:

H H H O
O

D-1 FI~ N
p i~ E
~ F

= WO 95126334 21863U 4 PCT/US95/03196 To a solution of 4-fluorophenol (0.715 g, 6.38 mmols) in THF (20 mL), add a suspension of 80% NaH (100 mg, 3.5 mmols, prewashed with hexane) in THF. After the bubbling ceases, to this solution, add a solution of the product of Step 1(compound D-1) (0.45 g, 0.00115 moles) in THF and keep the reaction under N2 at room temperature for 2 days. Treat the reaction mixture with aqueous Na2C03 (20 mL), extract the product with EtOAc, dry over MgS04 and remove the solvent under vacuum. Purify the resultant residue by silica gel chromatography, eluting with 5% EtOAc/CH2CI2 -440%
EtOAc/CH2CI2.
SteI2 3: Treat a solution of the product of Step 2 (compound E) (0.185 g, 0.00037 moles) in ethanol with 10% Pd/C (120 mg). Stir under aspirator vacuum, then introduce N2 gas, repeating this procedure several times to eliminate oxygen. Introduce hydrogen gas and maintain at 1 atm for 18 h. Remove hydrogen under vacuum and reintroduce N2. Filter the reaction mixture through Celite and concentrate to a glass. Purify by preparative TLC, eluting with 15% EtOAc/CH2CI2 to obtain 0.102 g of the title compound (rel (1'S, 3S, 4S)-1-(4-fluorophenyl)-3-[1-hydroxy-2-[4-fluorophenoxy]ethyl)-4-(4-hydroxyphenyl)-2-azetidinone). HRMS
FAB: C23H2oNO4F2 (M+1) calc 412.1360; found 412.1368. Elemental analysis: Calculated: C=67.15, H=4.64, N=3.41, F=9.25; Found:
C=67.00, H=4.87, N=3.26, F=9.09.
Racemic 1-(4-fluorophenyl)-3-[1-hydroxy-2-[4-fluorophenoxy]-ethyl)-4-(4-hydroxyphenyl)-2-azetidinone is resolved using a preparative Chiracel AS HPLC column, eluting with hexane-iso ro anol (70:30) to give:
OH OH EnantiomerA (1'R. 3R. 4R):
/ .
I ~ 0 =` [a]p1 _ +33.2 (CHCI3) F
OH OH Fnantiomer B(~'S. 3S. 4S1:
\ 0j==. ~ [a]o1 = -39.0 (CHCI3) JI~
F ~ N
O
~ F

WO 95/26334 2186364 PCT/US95/03196 .

Example 3 OH ,. I OCH3 H
~O ~..
O
Using the less polar isomer of Step 2 of Example 1 (compound B-2), carry out the procedure of Step 3 of Example 1 to obtain the title compound (Rel (1'R, 3S, 4S)-1-phenyl-3-[1 hydroxy-2-(4-fluorophenoxy)ethyl]-4-(4-methoxyphenyl)-2-azetidinone) as a racemate. M.p. 125-1290C, HRMS FAB: M+1 calc'd.=408.1611, obs.=408.1600.
Example 4 S H
O N
O \
i Use a procedure similar to Example 1, Step 3, substituting 4-fluorothiophenol for 4-fluorophenol and diluting with ether instead of EtOAc. After concenrating the extracted product, crystallize from ether-hexane to obtain a white solid (0.3 g, 70%), m.p. 129-1300C, MS:
HRMS FAB: calc'd. 424.1383, found 424.1394.
Example 5 OH ENk OCH3 0 OH ,,. OCH3 T~AH O~ 1 .~~H ~ B
Si,. ~ S'FO ~ and FI ~

o 1 5A ~ 5B
To a solution of the product of Example 4 (0.27 g, 0.637 mmols) in CH2CI2 (20 mL) at OOC, add MCBPA (0.12 g, 0.695 mmols) in portions and stir for 2 h. Quench the reaction with (CH3)2S (0.5 mL), dilute with CH2CI2, wash with 5% NaHCO3 (2x20 mL), water (1 x20 mL) and saline (1 x20 mL), dry over Na2SO4, filter and concentrate. Purify the resultant residue by silica gel chromatography, eluting with EtOAc/hexane (1:1) and (2:1) to obtain two components:
5A, more polar component: 0.22 g;
5B, less polar component: 0.0259 g, HRMS FAB: calc'd.
456.1281, obs. 456.1280.
Further purify 5A by HPLC, eluting with 25% hexane/EtOAc to obtain isomers A and B:
Isomer A(less polar, 5A-1): m.p. 141-143OC; HRMS FAB: calc'd.
440.1332, obs. 440.1348;
Isomer B(more polar, 5A-2): m.p. 176-179OC; HRMS FAB:
calc'd. 440.1332, obs. 440.1352.
Example 6 OH OH
.%\H
i F ~ N
O
~ F
stop 1: N` ^ F

O T~~`
~ F

I 1. LiN [-O]

O
2. O~=H
F ~

OH i O I
~ I
~
li G
F O N I \

~ F
Prepare a solution of lithiumdicyclohexylamide (5.7 mmols) in THF

wO 95126334 218V J6"T PCT/U595103196 (40 mL) by treating a cold (OOC) solution of dicyclohexylamine in THF
with 1 eq. of n-butyllithium (5.7 mmols, 3.6 mL of 1.6M hexane solution).
Cool the solution to -700C and add a pre-cooled (-700C) solution of compound F (1.74 g, 5 mmols) in THF via cannula. After 15 min., slowly, and with stirring, add a solution of 4-fluorophenoxyacetaldehyde (1 g, 6.5 mmols) in THF. After 30 min. at -780C, quench the reaction with glacial acetic acid (0.6 mL). Extract the product into ether, wash the ether layer with aqueous NaHCO3, dry over MgSO4 and evaporate the solvent under vacuum. Purify the resultant residue by chromatography on silica gel, eluting with 3:1 hexane/EtOAc -0:1 EtOAc/hexane.
Concentrate the desired fractions to obtain three compounds, G1, G2 and G3:

H H_ I : H H
~ O
O
F i~ N F i~ N ~
G1 O F G2 0 i~F

H H
O = : ~
FN
O
~ ~~

F
Step 2: Use a procedure similar to that described in Example 2, Step 3 to remove the benzyl group from compounds G1, G2 and G3 to obtain compounds 6a, 6b and 6c:
OH OH OH OH
H H~' H H_ I \ O O

F / O N F / O N
6a F 6b F
OhH OH o O
6c F

WO 95/26334 210(, 7, L fi PCT/US95/03196 -25- Uv/U`f Separate racemic compound 6a into its enantiomers by chromatography on a Chiracel AS preparative HPLC column, eluting with hexane/iso-propyl alcohol (70:30). (Compound 6a is the same as the product of Example 2).
6b: M.p.130-131oC.
6c: HRMS FAB: calc'd. 412.1360, obs. 412.1364.
Example 7 . J-=
~ OCH3 N 7A
O'jt' H F O 01 N +
0 i~ LDA, -78 C OH / OCH3 H O~/~=. I
I`
~ 7B
F N
O

The azetidinone, compound H, (1.7 g, 7 mmol) is dissolved in anhydrous THF (50 mL) and cooled to -780C. Add fresh LDA (1.2 eq.) as a THF
solution (10 mL) and stir for 45 min. at -780C. Add, dropwise, fluoro-phenoxacetaldehyde (1.3 g, 1.2 eq.) in THF (5 mL) and stir for 4 h.
Warm the reaction mixture to 0OC and quench with aqueous NH4CI (50 mL). Extract with ether (200 mL), dry the organic phase over MgSO4, filter and concentrate. Purify the resultant residue by silica gel flash chromatography, eluting with hexane -a 15% EtOAc/hexane. NMR and chromatographic analysis show that 7A is the same as the product of Example 1, and 7B is the same as the product of Example 3.

Example 8 .CH3 p ~ OCH3 O I~

Treat a solution of the product of Example 1, Step3 (0.15 g, 0.37 mmols) in THF with a suspension of NaH (0.017 g of 60% in oil, 0.42 mmols) at WO 95/26334 21863_6`t PCT/US95/03196 ~

room temperature. After 15 min., add CH31 (0.07 mL, 1.12 mmols) with stirring and keep at room temperature for 16 h. Dilute the mixture with EtOAc, extract with brine, dry the organic layer over NaSO4 and evaporate the solvent under vacuum. Purify the resultant oil by preparative thick layer chromatography on silica gel, eluting with EtOAc/hexane (1:3) to obtain 60 mg of the title compound. HRMS FAB
(M+1): calc. 422.1768; obs. 422.1763.
Example 9 O~ I
I`
N
O
(M+1) 390.
Treat a solution of the product of Example 1, Step 3 (0.3 g, 0.7 mmols) in CH2CI2 with pyridinium chlorochromate (0.55 g, 2.5 mmols) and basic alumina (0.4 g). Stir at room temperature for 3 days, filter through a pad of celite and wash with CH2CI2. Purify the product by silica gel chromatography, eluting with EtOAc/hexane (1:3) to obtain 0.23 g of the title compound. HRMS FAB (M+1): calc. 406.1455; obs. 406.1422.
Example 10 OH
O
Treat the epoxide of Example 1, Step 2 (compound B-1) in a manner similar to that described in Example 1, Step 3, substituting phenol for 4-fluorophenol, to obtain the title compound, m.p. 132-1350C, MS FAB:
(M+1) 390.
Example 11 F ~ OH OH F OH / OH
O^ O_ +

11A N i~ F 11B F

Treat the azetidinone of Preparation 1 according to the procedure described in Example 7, followed by removal of the benzyl protecting group as described in Example 2, step 3, to obtain the title compounds.
= Isomer A: m.p. 147-150 C; HRMS FAB (M+1): calc'd. 426.1517, obs.
426.1520.
Isomer B: m.p. 146-148 C; HRMS FAB (M+1): calc'd. 426.1517, obs.
426.1508.
Example 12 OH H~ OH
/''~ ' ~ I
. ~
~I
F' v O N `

~ F
Treat the product of Example 2, step 2, according to the procedure described in Example 9, followed by removal of the benzyl protecting group as described in Example 2, step 3, to obtain the title compound:
m.p. 129-130 C; HRMS FAB (M+1): calc'd. 410.1216, obs. 410.1204.
Example 13 O
OAl O 1-f O
H H
O
I
F
O N
~ F
To a solution of enantiomer B from Example 2 (0.025 g, 0.06 mmole) and pyridine (0.024 mL, 0.296 mmole) in CH2CI2 (5 mL), add excess acetyl chloride (0.01 mL, 0.14 mmole) and stir for 2 h at room temperature. Dilute the mixture with CH2CI2, wash with water and brine, dry over Na2SO4 and evaporate the solvent. Purify the resultant oil by preparative HPLC, eluting with EtOAc:hexane (1:3) to obtain the title compound: HRMS calc'd: 496.1558; found: 496.1572.

The following formulations exemplify some of the dosage . forms of this invention. In each, the term "active compound" designates a compound of formula I.

EXAMPLE A
Tablets Ingredient ma[tablej ma/tablet 1 Active Compound 100 500 2 Lactose USP 122 113 3 Corn Starch, Food Grade, as a 10% 30 40 paste in Purified Water 4 Corn Starch, Food Grade 45 40 Magnesium Stearate a Z
Total 300 700 Method of Manufacture Mix Item Nos. 1 and 2 in suitable mixer for 10-15 minutes.
5 Granulate the mixture with Item No. 3. Mill the damp granules through a coarse screen (e.g., 1/4", 0.63 cm) if necessary. Dry the damp granules.
Screen the dried granules if necessary and mix with Item No. 4 and mix for 10-15 minutes. Add Item No. 5 and mix for 1-3 minutes. Compress the mixture to appropriate size and weight on a suitable tablet machine.
EXAMPLE B
Cosules N~L n r i n mg/tablet ma/tablet 1 Active Compound 100 500 2 Lactose USP 106 123 3 Corn Starch, Food Grade 40 70 4 Magnesium Stearate NF 4 Z
Total 250 700 Method of Manufacture Mix Item Nos. 1, 2 and 3 in a suitable blender for 10-15 minutes. Add Item No. 4 and mix for 1-3 minutes. Fill the mixture into suitable two-piece hard gelatin capsules on a suitable encapsulating machine.
Representative formulations comprising a cholesterol biosynthesis inhibitor are well known in the art. It is contemplated that where the two active ingredients are administered as a single WO 95126334 21C~ y~ ( Z L/~UJU t PCT/US95/03196 composition, the dosage forms disclosed above for substituted azetidinone compounds may readily be modified using the knowledge of one skilled in the art.
The in vivo activity of the compounds of formula I can be determined by the following procedure.
In Vivo Assay of Hypolioidemic Agents Usin the he Hy e~rli idR emic Hamster Hamsters are separated into groups of six and given a controlled cholesterol diet (Purina Chow #5001 containing 0.5%
cholesterol) for seven days. Diet consumption is monitored to determine dietary cholesterol exposure in the presence of test compounds. The animals are dosed with the test compound once daily beginning with the initiation of diet. Dosing is by oral gavage of 0.2mL of corn oil alone (control group) or solution (or suspension) of test compound in corn oil.
All animals moribund or in poor physical condition are euthanized.
After seven days, the animais are anesthetized by IM injection of ketamine and sacrificed by decapitation. Blood is collected into vacutainer tubes containing EDTA for plasma lipid analysis and the liver excised for tissue lipid analysis. Data is reported as percent reduction of lipid versus control.

Using the hamster in vivo test procedures substantially as described above, the following data were obtained for representative compounds of formula I. Compounds are referred to in the following table by the corresponding example numbers; data is reported as percent change versus control, therefore, negative numbers indicate a positive lipid-lowering effect.

% Reduction Ex. No. Serum Cholesterol Dose Cholesterol Esters m /k 6b 0 -39 10 For racemic compounds of formula I or active diastereomers or enantiomers of compounds of formula I, compounds administered at dosages of 1-10 mg/kg show a range of -96 to -15% reduction in cholesterol esters, and a -51 to 0% reduction in serum cholesterol. The reduction in cholesterol esters is the more important measure of activity, and active compounds preferably show a range of -30 to -96%, and more preferably, a range of -50 to -96% reduction in cholesterol esters.

Claims (8)

CLAIMS:

1. A compound represented by the structural formula:
or a pharmaceutically acceptable salt thereof, wherein:
Ar1 is R3-substituted aryl;
Ar2 is R4-substituted aryl;
Ar3 is R5-substituted aryl;
Y and Z are independently selected from the group consisting of -CH2-,-CH(C1-C6 alkyl)- and -C(diC1-C6 alkyl)-;
A is -O-, -S-, -S(O)- or -S(O)2-;
R1 is selected from the group consisting of -OR6, -O(CO)R6, -O(CO)OR9 and -O(CO)NR6R7 ; R2 is selected from the group consisting of hydrogen, C1-C6 alkyl and aryl; or R1 and R2 together are =O;
q is 1, 2 or 3;
p is 0, 1, 2, 3 or 4;
R5 is 1-3 substituents independently selected from the group consisting of -OR6, -O(CO)R6, -O(CO)OR9, -O(CH2)1-5OR9, -O(CO)NR6R7, -NR6R7, -NR6(CO)R7, -NR6(CO)OR9, -NR6(CO)NR7R8, -NR6SO2-C1-C6 alkyl, -NR6SO2-aryl, -CONR6R7, -COR6, -SO2NR6R7, S(O)0-2C1-C6-alkyl, S(O)0-2-aryl, -O(CH2)1-10-COOR6, -O(CH2)1-10CONR6R7, o-halogen, m-halogen, o-C1-C6 alkyl, m-C1-C6 alkyl, -(C1-C6 alkylene) COOR6 and -CH=CH-COOR6;
R3 and R4 are independently 1-3 substituents independently selected from the group consisting of R5, hydrogen, p-C1-C6 alkyl, aryl, -NO2, -CF3 and p-halogen;
R6, R7 and R8 are independently selected from the group consisting of hydrogen, C1-C6 alkyl, aryl and aryl-substituted C1-C6 alkyl; and R9 is C1-C6 alkyl, aryl or aryl-substituted C1-C6 alkyl;

wherein aryl herein is phenyl, naphthyl, indenyl, tetrahydronaphthyl or indanyl.

2. A compound of claim 1 wherein Ar1 is R3-substituted phenyl, wherein R3 is -COOR6, -CONR6R7, -COR6, -SO2NR6R7, S(O)0-2- C1-C6 alkyl, S(O)0-2-aryl, NO2 or halogen; Ar2 is R4-substituted phenyl, wherein R4 is hydrogen, C1-C6 alkyl, -OR6, -O(CO)R6, -O(CO)OR9, -O(CO)NR6R7, -NR6R7, COR6 or halogen, wherein R6 and R7 are independently hydrogen or C1-C6 alkyl, and R9 is C1-C6 alkyl; and Ar3 is R5-substituted phenyl, wherein R5 is -OR6, -O(CO)R6, -O(CO)OR9, -O(CO)NR6R7, -NR6R7, -(C1-C6 alkylene)-COOR6 or -CH=CH-COOR6, wherein R6 and R7 are independently hydrogen or C1-C6 alkyl, and R9 is C1-C6 alkyl; and aryl is as defined in claim 1.

3. A compound of claim 1 or 2, wherein Y and Z are each -CH2- and wherein the sum of p and q is 1 or 2.

4. A compound of claims 1, 2 or 3, wherein R1 is -OR6, wherein R6 is hydrogen and R2 is hydrogen, or wherein R1 and R2 together are =0.

5. A compound of claim 1 selected from the group consisting of:
rel-3(S)-[2-(4-fluorophenoxy)-1(S)-hydroxyethyl]-4(S)-(4-methoxy-phenyl)-1-phenyl-2-azetidinone;
3(S)-[2-(4-fluorophenoxy)-1 (S)-hydroxyethyl]-4(S)-(4-methoxyphenyl)-1-phenyl-2-azetidinone;
rel-3(S)-[2-(4-fluorophenoxy)-1(S)-hydroxyethyl]-4(S)-(4-hydroxy-phenyl)-1-(4-fluorophenyl)-2-azetidinone;
3(S)-[2-(4-fluorophenoxy)-1 (S)-hydroxyethyl]-4(S)-(4-hydroxyphenyl)-1-(4-fluorophenyl)-2-azetidinone;
rel-3(S)-[2-(4-fluorophenoxy)-1 (R)-hydroxyethyl]-4(S)-(4-methoxy-phenyl)-1-phenyl-2-azetidinone;
rel-3(S)-[2-[(4-fluorophenyl)thio]-1 (S)-hydroxyethyl]-4(S)-(4-methoxy-phenyl)-1-phenyl-2-azetidinone;
rel-3(S)-[2-[(4-fluorophenyl)sulfinyl]-1 (S)-hydroxyethyl]-4(S)-(4-methoxy-phenyl)-1-phenyl-2-azetidinone;

rel-3(S)-[2-[(4-fluorophenyl)sulfinyl]-1 (S)-hydroxyethyl]-4(S)-(4-methoxy-phenyl)-1-phenyl-2-azetidinone;
rel-3(S)-[2-(4-fluorophenyl)sulfonyl]-1 (S)-hydroxyethyl]-4(S)-(4-methoxy-phenyl)-1-phenyl-2-azetidinone;
rel-3(S)-[2-(4-fluorophenoxy)-1 (S)-methoxyethyl]-4(S)-(4-methoxy-phenyl)-1-phenyl-2-azetidinone;
rel-3(S)-[2-(4-fluorophenoxy)-1-oxo-ethyl]-4(S)-(4-methoxyphenyl)-1-phenyl-2-azetidinone;
rel-3(S)-(1(S)-hydroxy-2-phenoxyethyl)-4(S)-(4-methoxyphenyl)-1-phenyl-2-azetidinone;
rel-3(S)-[3-(4-fluorophenoxy)-1 (R)-hydroxypropyl]-1-(4-fluorophenyl)-4(S)-(4-hydroxyphenyl)-2-azetidinone;
rel-3(S)-[3-(4-fluorophenoxy)-1 (S)-hydroxypropyl]-1-(4-fluorophenyl)-4(S)-(4-hydroxyphenyl)-2-azetidinone;
(3S,4S)-3-[2-(4-fluorophenoxy)-1-oxoethyl]-4-(4-hydroxyphenyl)-1-(4-fluorophenyl)-2-azetidinone;
rel-3(S)-[2-(4-fluorophenoxy)-1 (R)-hydroxyethyl]-1-(4-fluorophenyl)-4(S)-(4-hydroxyphenyl)-2-azetidinone; and 3(S)-[1(s)-(acetyloxy)-2-(4-fluorophenoxy)ethyl]-4(S)-[4-(acetyloxy)-phenyl]-1-(4-fluorophenyl)-2-azetidinone.

6. A compound of any one of claims 1 to 5, for use in treating or preventing atherosclerosis or reducing plasma cholesterol levels in a mammal in need of such treatment.

7. A pharmaceutical composition comprising a cholesterol-lowering effective amount of a compound of claim 1, 2, 3, 4, or 5, in combination with a pharmaceutically acceptable carrier.

8. The use of a compound of claim 1, 2, 3, 4, or 5, for the preparation of a medicament for the treatment or prevention of atherosclerosis, or for the reduction of plasma cholesterol levels.