ANTIHYPERCHOLESTEROLEMIC BETALACTONES

Abstract: The compounds of the following general structural formula (I) are 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) synthase inhibitors and useful as antihyper­ cholesterolemic agents for the treatment of disease in which the inhibition of cholesterol biosynthesis would be useful, such as arteriosclerosis, hyper­ lipidemia and familial hypercholesterolemia.

Description: The compound of the formula (I), wherein R¹ is hydroxy and R² is hydrogen, 12-hydroxy-13-hydroxymethyl-3,5,7-trimethyltetradeca-2,4-dien-1,14-dioic acid 12,14-lactone, was identified as an antibiotic fungal metabolite in 1970 [Aldridge et al., Chem. Comm. , 1970, p. 639]. The compounds of the formula (I), wherein R¹ is methoxy and the tetrahydro analog wherein R¹ is hydroxy were disclosed in the structure elucidation of the compound of the formula (I) wherein R¹ is hydroxy [Aldridge et al. J. Chem. Soc. (C) , 1971, pp. 3888-3891]. This latter reference also discloses the compound of formula (I) wherein R² is acetate and R¹ is hydroxy. Additionally, US Patent No. 4751237, published June 14, 1988, is directed to the antihypercholesterolemic utility of these known compounds. This invention relates to the novel compounds of the formula (I) and the pharmacological properties of these compounds which have been found to be HMG-CoA synthase inhibitors and useful as antihypercholesterolemic agents either as the sole therapeutic agent or in combination with bile acid sequestrants. The present invention is directed to novel compounds represented by the following general structural formula (I): wherein: R¹ is selected from (1) hydroxy, (2) C₁₋₆ alkoxy, (3) substituted C₁₋₆ alkoxy in which the substituent is a phenyl group, (4) amino, (5) C₁₋₆ alkylamino, (6) substituted C₁₋₆ alkylamino in which the substituent is a hydroxy group, (7) phenylamino, (8) substituted phenylamino in which the substituent is a fluoro, chloro, or bromo, and (9) (2-thio)-pyridine; and R² is selected from (1) hydrogen, (2) C₁₋₆ alkyl, (3) C₂₋₆ alkenyl, (4) formyl, (5) C₁₋₆ alkoxycarbonyl, (6) carboxy C₁₋₆ alkylcarbonyl, (7) anisyldiphenylmethyl, (8) C₁₋₆ alkylsulfonyl, (9) aminocarbonyl, and (10) C₁₋₆ alkylaminocarbonyl; with the proviso that when R² is hydrogen, R¹ is other than hydroxy and C₁₋₃ alkoxy; and pharmaceutically acceptable salts thereof. One embodiment of the compounds of the present invention is the class of compounds of the formula (I) wherein R¹ is amino, C₁₋₆ alkylamino, substituted C₁₋₆ alkylamino, phenylamino or substituted phenylamino. A specific sub-class of this embodiment are the compounds of the formula (I) wherein R² is hydrogen. Exemplifying this subclass are the following compounds: (1) 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienamide; (2) N- n -hexyl 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienamide; (3) N-(4-bromophenyl) 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienamide; and (4) N-(2-hydroxyethyl) 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienamide. A second embodiment of the compounds of the present invention is the class of compounds of the formula (I) wherein R² is C₁₋₆ alkyl, C₂₋₆ alkenyl or anisyldiphenylmethyl. A specific subclass of this embodiment are the compounds of the formula (I) wherein R¹ is hydroxy, C₁₋₆ alkoxy or substituted C₁₋₆ alkoxy in which the substituent is a phenyl group. Exemplifying this subclass are the following compounds: (1) methyl 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; (2) methyl 11-(3-ethoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; (3) methyl 11-[3-(2-propenyloxymethyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate; (4) 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoic acid; (5) 11-(3-anisyldiphenylmethyloxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoic acid; and (6) diphenylmethyl 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate. A third embodiment of the compounds of the present invention is the class of compounds of the formula (I) wherein R² is formyl, C₁₋₆ alkoxy-carbonyl, carboxy C 1-6 akylcarbonyl, aminocarbonyl and C₁₋₆ alkylaminocarbonyl. A specific subclass of this embodiment are the compounds of the formula (I) wherein R¹ is C₁₋₆ alkoxy. Exemplifying this subclass are the following compounds: (1) methyl 11-(3-formyloxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; (2) methyl 11-[3-(3-carboxypropionyloxy-methyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate; (3) methyl 11-(3-urethanylmethyl)-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; and (4) methyl 11-[3-(N-methylurethanylmethyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate. A further compound according to the present invention is methyl 11-[3-(2-methylbutyryloxymethyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate. Also illustrative of the compounds of the present invention are the following compounds of the formula (I): (1) methyl 11-(3-methanesulfonyloxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; (2) 2-pyridyl 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienthioate; and (3) tert -butyl 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate. The present invention is also directed to the use of a compound represented by the general structural formula (I) and pharmaceutically acceptable salts thereof for the manufacture of a medicament for inhibiting cholesterol biosynthesis. The present invention is also directed to the use of a compound represented by the general structural formula (I) and pharmaceutically acceptable salts thereof for the manufacture of a medicament for inhibiting the activity of HMG-CoA synthase enzyme. Specifically the compounds of this invention are useful as antihypercholesterolemic agents for the treatment of arteriosclerosis, hyperlipidemia, familial hypercholesterolemia and the like diseases in humans. They may be administered orally or parenterally in the form of a capsule, a tablet, an injectable preparation or the like. It is usually desirable to use the oral route. Doses may be varied, depending on the age, severity, body weight and other conditions of human patients but daily dosage for adults is within a range of from about 20 mg to 2000 mg (preferably 20 to 100 mg) which may be given in two to four divided doses. Higher doses may be favorably employed as required. The pharmaceutically acceptable salts of the compounds of this invention include those formed from cations such as sodium, potassium, aluminum, calcium, lithium, magnesium, zinc, and from bases such as ammonia, ethylenediamine, N-methyl-glucamine, lysine, arginine, ornithine, choline, N,N′-dibenzylethylenediamine, chloroprocaine, diethanolamine, procaine, N-benzylphenethylamine, diethylamine, piperazine, tris(hydroxymethyl)aminomethane, and tetramethyl-ammonium hydroxide. The compounds of this invention may also be coadministered with pharmaceutically acceptable nontoxic cationic polymers capable of binding bile acids in a non-reabsorbable form in the gastrointestinal tract. Examples of such polymers include cholestyramine, colestipol and poly[methyl-(3-trimethylaminopropyl)imino-trimethylene dihalide]. The relative amounts of the compounds of this invention and these polymers is between 1: 100 and 1: 15,000. The intrinisic HMG-CoA synthase inhibition activity of the compounds of this invention is measured by the standard in vitro protocol described below: The livers from male Charles River CD rats (225-350 g) were homogenized in 0.25 M sucrose which was adjusted with phenylmethylsulfonylfluoride (PMSF) and N-p-tosyl-1-lysine chloromethyl ketone (TLCK) so that the final concentration of each was 50 and 25 µg/ml, respectively. The homogenate was centrifuged at 15,000 × g for 20 minutes, the supernatant filtered through a fine nylon screen to remove most of the fat layer and recentrifuged at 100,000 × g for 1 hour. This supernatant was removed and 1 M potassium phosphate, dithiothreitol (DTT) and ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA) added to give a final concentration of 0.1 M (pH 7.2), 0.5 mM and 0.1 mM, respectively. Solid ammonium sulfate was added to 50% saturation to the protein solution, it was centrifuged at 15,000 × g and the supernatant discarded. This precipitated protein could be stored at -70°C for at least one month with very little loss of activity. The ammonium sulfate precipitate was dissolved in an minimal amount of 0.06 M potassium phosphate buffer (pH 7.2) containing 0.5 mM dithiothreitol and 0.1 mM EGTA (referred to as 0.06 M phosphate buffer) and dialyzed overnight against 2 liters of the same buffer to remove the ammonium sulfate and to inactivate HMG-CoA lyase [Clinkenbeard, et al., J. Biol. Chem. 250, 3108-3116(1975)]. The dialyzed extract was added to a column of DEAE-52 (Whatman) which had been equilibrated with 0.06 M phosphate buffer (10 mg of protein to 1 ml bed volume of the resin). The DEAE-cellulose was eluted with 0.06 M phosphate buffer until the optical density at 280 nm was essentially zero. This fraction contained the β-ketoacetyl-CoA thiolase activity. The HMG-CoA synthase was eluted from the column with 0.1 M phosphate buffer (pH 7.2) containing 0.5 mM DTT and 0.1 mM EGTA, and was virtually free of all thiolase activity. The protein was precipitated by the addition of ammonium sulfate to give 50% saturation. This solution was stirred for 10 minutes at 4°C and the precipitate collected by centrifugation at 15,000 rpm for 10 minutes. The supernatant was discarded and the precipitate dissolved in a minimum of 0.06 M phosphate buffer, pH 7.2 (about 10 ml) and the enzyme stored at -80°C. HMG-CoA Synthase Inhibition Assay Enzyme protein (ca. 24 µg) was added to a solution containing 117 mM Tris-HCl (pH 8.0), 11.7 mM MgCl₂, 1.17 mM Ethylenediaminetetraacetic acid (EDTA), 0.58 mM dithiothreitol, and the indicated concentrations of the test compound (added as a 2 µg/ml solution in dimethylsulfoxide). The incubation took place in a volume of 0.085 ml at 30° in a shaking water bath. After 5 minutes, 15 µl of a solution containing acetoacetyl-CoA and 0.1 µCi of 1-[¹⁴C]-acetyl-CoA was added to give a final concentrations of 0.1 and 0.4 mM, respectively. The incubation was continued for 10 more minutes and the reaction stopped by the addition of 50 µl of the assay mixture to 0.2 ml of 6N HCl in a glass scintillation vial. The vial was heated for 1 hour at 120° after which time 0.2 ml more of 6N HCl was again added to each vial and the heating continued for another hour. Following this, 1.0 ml of 0.9% saline was added to each vial and finally 10 ml of scintillation liquid. Radioactivity was determined in a Packard Tri-Carb liquid scintillation counter. Percent inhibition is calculated by the formula: 1 - Sample - Blank Control - Blank IC₅₀ values were determined by plotting the log of the concentration of the test compound verses the percentage inhibition and fitting a straight line to the resulting data by using the least squares method. Representative of the intrinsic HMG-CoA synthase inhibitory activities of the compounds of this invention, tabulated below are the IC₅₀ or IC₂₅ (the inhibitory concentration which inhibits 50 percent and 25 percent of the HMG-CoA synthase activity respectively). The compounds of this invention wherein R¹ is hydroxy or C₁₋₆ alkoxy and R² is hydrogen are conveniently prepared as described in J. Chem. Soc. (C) , 1971 3888-3891 by the fermentation of an identified fungus ACC 1233 and the standard chemical transformations disclosed therein. These compounds wherein R¹ is hydroxy may also be prepared by the cultivation of a member of the class of fungi selected from ATCC 20788, ATCC 20789 or ATCC 20790 followed by a standard isolation. The morphological characteristics of the microorganisms ATCC 20788, ATCC 20789, and ATCC 20790 are described below: Fusarium sp. MF5045 ATCC 20788 Cultural Characteristics On Czapek-Dox agar ― mycelia is extensive, white and cottony, becoming felted and white with sectors of faint bluish-green tinge or a pale peach tinge as culture ages. Moist areas faint bluish-green in color develop where macroconidia are abundant. On potato-dextrose agar ― mycelia is extensive, white and cottony, becoming felted and pinkish-tan in color as culture ages. When vegetative inoculum is used, moist areas, tan in color, develop where macroconidia are abundant. On Sabouraud-maltose agar ― mycelia is extensive, velvety and white with peach to light purple tinge. Morphological Characteristics Microconidia are generally unicellular, oval-ellipsoidal, borne singly and held in a gelatinous mass. 1.8-2.4 µ × 3.6 to 4.8 µ. Macroconidia are 3 to 5 celled, thin-walled, ends are tapered and slightly curved. 3.6-4.8 µ × 24-36 µ. Chlamydospores are abundant, terminal and intercalary, globose, generally smooth-walled, usually formed singly but sometimes formed in pairs. Fusarium sp. MF5058 ATCC 20789 Cultural Characteristics On Czapek-Dox agar ― mycelia is extensive, white and cottony, becoming felted and white with sectors of a faint bluish-green tinge or a pale peach tinge as culture ages. Moist areas faint bluish-green in color develop where macroconidia are abundant. On potato-dextrose agar ― mycelia is extensive, white and cottony, becoming felted and pinkish-tan in color as culture ages. When vegetative inoculum is used, moist areas, tan in color develop where macroconidia are abundant. On Sabouraud-maltose agar ― mycelia is extensive, velvety and white with peach to light purple tinge. Morphological Characteristics Microconidia are generally unicellular, oval-ellipsoidal, borne singly and held in a gelatinous mass. 1.8-2.4 µ × 3.6-4.8 µ. Macroconidia are 3 to 5 celled, thin-walled, ends are tapered and slightly curved 3.6-4.8 µ × 24-36 µ. Chlamydospores are abundant, terminal and intercalary, globose, generally smooth-walled, usually formed singly but sometimes formed in pairs. Fusarium sp. MF 5084 ATCC 20790 Cultural Characteristics On Czapek-Dox agar-mycelia is extensive, white and cottony, becoming felted and white with sectors of a faint bluish-green tinge or a pale peach tinge as culture ages. Moist areas faint bluish-green in color develop where macroconidia are abundant. On potato-dextrose agar ― mycelia is extensive, white and cottony, becoming felted and pinkish-tan in color as culture ages. When vegetative inoculum is used, moist areas, tan in color, develop where macroconidia are abundant. On Sabouraud-maltose agar ― mycelia is extensive, velvety and deep-pinkish tan in color. Vegetative growth and medium become purplish-red. Morphological Characteristics Microconidia are generally unicellular, oval-elliposoidal, borne singly and held in a gelatinous mass 1.8-2.4 µ × 3.6-4.8 µ. Macroconidia are 3 to 5 celled, thin-walled, ends are tapered and slightly curved. 3.6-4.8 µ × 24-36 µ. Chlamydospores are abundant, terminal and intercalary, globose, generally smoothed-walled formed singly but sometimes formed in pairs. The compound of the formula (I) wherein R¹ is hydroxy and R² is hydrogen may be produced by the cultivation of a member of the class of fungi ATCC 20788, ATCC 20789, or ATCC 20790 under the following general conditions. A preserved source of the culture is used to inoculate an agar slant containing a nutrient medium for growth. After incubation at room temperature for 1 to 5 weeks a portion of this growth is used to inoculate a liquid nutrient medium containing sources of carbon, nitrogen, phosphorus and other elements necessary for life. This medium is incubated at 25 to 30°C, usually 28°. The flask containing the culture and liquid nutrient medium is incubated with or without agitation on a rotary shaker from 0 to 400 RPM, most often at 212 RPM. After 1 to 10 days, when growth is abundant, usually between 2 and 4 days, the culture growth is used to inoculate a flask containing a medium which supports production of the product. Such production media contain carbon sources such as corn, glycerol, corn oil, dextrose, cod oil or peanut meal, nitrogen and sulfur sources such as yeast extract, corn steep liquor, corn, lard water, peanut meal, soy flour, tomato paste and the like as well as organic and inorganic ions such as potassium, phosphorous, calcium, tartrate, iron and magnesium. These production media are inoculated with the culture growth and are incubated at from 20 to 30° most often 25° for 3 to 30 days usually 7-14 days with or without agitation. The compound of the formula (I) wherein R¹ is hydroxy may be recovered from the fermentation medium by extraction with a water miscible solvent, such as C₁₋₃ alcohol, especially methanol and water in a ratio from 0.1: 1.0 to 1.0 to 0.1, especially 1: 1 by volume. The extract is portioned between the aqueous phase and a water miscible organic solvent such as ethyl acetate or methylene chloride. The desired compound is further purified by chromatography on silica gel and then Sephadex LH20 (tradename for dextran derivatives used as gel filtrants in organic solvents, manufactured by Pharmacia Fine Chemicals, Inc.). Finally, the product may be crystallized from aqueous alcohol. The compounds of the formula (I) wherein R¹ is amino, C₁₋₆ alkylamino, substituted C₁₋₆ alkylamino, phenylamino or substituted phenylamino are conveniently prepared from the appropriately substituted compound of the formula (I) wherein R¹ is hydroxy by the formation of a mixed anhydride followed by the addition of the appropriately substituted amine or ammonia. The compounds of the formula (I) wherein R² is C₁₋₆ alkyl, C₂₋₆ alkenyl or anisyldiphenylmethyl are conveniently prepared from the appropriately substituted compound of the formula (I) wherein R² is hydrogen and R¹ is alkoxy, substituted alkoxy, amino, alkylamino, substituted alkylamino, phenylamino or substituted alkylamino by reaction with the appropriate diazo compounds. If the free acid of the formula (I) (R¹ is hydroxy) is desired the appropriately substituted ester is hydrolyzed under mild conditions subsequent to the treatment with the diazo compound. In an alternate process these compounds can be prepared by the reaction of the appropriate alkylhalide or alkenylhalide in the presence of silver oxide. The compounds of the formula (I) wherein R² is formyl, C₁₋₆ alkoxycarbonyl, carboxy C₁₋₆ alkoxycarbonyl, aminocarbonyl and C₁₋₆ alkylaminocarbonyl are conveniently prepared from the compounds of the formula (I) wherein R² is hydrogen by the reaction with either an anhydride, acylchloride or an isocyanate. The following examples illustrate the preparation of the compounds and their incorporation into pharmaceutical compositions and as such are not to be construed as limiting the invention set forth in the claims appended hereto. The composition of media employed in the following examples are listed below. Media are prepared in a 250 ml Erlenmeyer flask. The contents are sterilized with steam at 121°C, 20 pounds pressure for 20 minutes. Media that contain corn are rehydrated and again sterilized with steam at 121°C, 20 pounds pressure for 20 minutes before inoculation. EXAMPLE 1 Preparation of 12-Hydroxy-13-hydroxymethyl-3,5,7- trimethyltetradeca-2,4-dien-1,14-dioic acid 12,14 lactone (a) Fermentation of ATCC 20790. A culture of ATCC 20790 was inoculated onto YME slant medium. After growth at 25°C, a portion of this slant was used to inoculate a baffled 250 ml Erlenmeyer flask containing KF growth medium (54 ml). The flask was incubated with agitation at 212 rpm on a rotary shaker (2 inch throw) for 3 days at 28°C. Then a portion of the growth (2 ml) was used to inoculate an unbaffled 250 ml Erlenmeyer flask containing Medium F867 (media F870 or F872 may also be employed). After 14 days incubation at 25°C methanol (20 ml) was added and then let stand overnight. Then water (10 ml) was added to the flask. The desired product was contained in the aqueous methanol extract. (b) Fermentation of ATCC 20789. (1) A preserved culture source of ATCC 20789 was used to inoculate a baffled 250 ml Erlenmeyer containing KF growth medium (54 ml). The flask was incubated with agitation at 212 rpm on a rotary shaker (2 inch throw) for 3 days at 28°C. Then a portion of the growth (2 ml) was used to inoculate an unbaffled 250 ml Erlenmeyer flask containing medium F870. After 14 days incubation at 25°C, 50 percent aqueous methanol was added. The aqueous methanol extract was employed in the isolation and purification procedure described below. (c) Fermentation of ATCC 20788. A culture of ATCC 20788 was used to inoculate a baffled 250 ml Erlenmeyer flask containing KF growth medium (54 ml). The flask was incubated with agitation at 212 rpm on a rotary shaker (2 inch throw) for 3 days at 28°C. Then a portion of the growth (2 ml) and remaining medium was used to inoculate an unbaffled 250 ml Erlenmeyer flask containing medium F848. After 7 days incubation at 25°C, the contents of the flask were extracted with methanol (20 ml) in water (10 ml) to obtain the desired product. (d) Isolation and Purification The aqueous methanol extracts (700 ml each) from the fermentation medium from two series of fermentations of the microorganism ATCC 20789 according to the general procedure of Example 1(b) were filtered. The first extract was partitioned with methylene chloride (700 ml) and the second extract was partitioned with ethyl acetate (700 ml). In both cases activity was located in the organic phase. The two organic phases were combined and concentrated in vacuo . The residue was dissolved in ethyl acetate/hexane (4: 6) (2 ml) and chromatographed on silica gel (200 ml) eluted with a step gradient of ethyl acetate: hexane (4: 6, 6: 4, 5: 5 and 7: 3). The desired product was rechromatographed on LH-20 (20 ml) eluted with methylene chloride: hexane: methanol (10: 10: 1) and the desired product eluted from the column with methanol. An analytically pure sample of the title compound was a crystalline compound mp. 76-77°C. The ¹³C NMR spectrum was recorded in CD₃OD at ambient room temperature (25 mg/0.4 ml) on a Varian XL 400. Chemical shifts are given in ppm downfield of tetramethylsilane relative to the solvent peak at 49.0 ppm as standard. In agreement with the mass spectral data, 18 carbon atoms are observed with the following chemical shifts: 18.5, 19.8 (2X), 26.4, 27.8, 32.0, 35.0, 37.8, 49.9, 58.0, 60.0, 76.3, 118.7, 130.6, 142.3, 155.7, 170.4, 171.9 ppm. EXAMPLE 2 Preparation of Methyl 12-hydroxy-13-hydroxymethyl-3,5,7-trimethyltetradeca-2,4-dien-1,14-dioic acid 12,14 lactone To a stirred solution of the compound from Example 1(d) (3.2 mg, 0.01 mmol) in anhydrous diethyl ether (0.5 ml) at ambient temperature was added dropwise, diazomethane dissolved in anhydrous diethyl ether until the reaction mixture maintained a bright yellow color. The excess diazomethane was removed by bubbling nitrogen through the reaction mixture. The desired product was purified by preparative thin layer chromatography on silica gel eluted with 1 percent methanol in methylene chloride to afford above titled compound as an oil. EXAMPLE 3 Preparation of 12-Hydroxy-13-hydroxymethyl-3,5,7-trimethyltetradecan-1,14-dioic acid 12,14 lactone To a solution of the compound from Example 1(d) (32 mg, 0.01 mmol) in glacial acetic acid (0.5 ml) was added platinum oxide (2 mg) and the compound was hydrogenated at ambient temperature under atmospheric pressure. After one hour, the flask was flushed with nitrogen and the reaction mixture filtered. The filtrate was concentrated in vacuo . The residue was purified by preparative thin layer chromatography on silica gel, eluted with 3 percent methanol in methylene chloride to afford the above titled compound as an oil. EXAMPLE 4 Preparation of Alkali and Alkaline Earth Salts of Compound I wherein R¹ is hydroxide To a solution of the lactone from Example 1 (42 mg) in ethanol (2 ml) is added aqueous NaOH (1 equivalent). After one hour at room temperature, the mixture is taken to dryness in vacuo to yield the sodium salt of Compound I, wherein R is hydrogen. In like manner, the potassium salt is prepared using one equivalent of potassium hydroxide, and the calcium salt using one equivalent of CaO. EXAMPLE 5 As a specific embodiment of an oral composition of a compound of this invention, 20 mg of the lactone from Example 1 is formulated with sufficient finely divided lactose to provide a total amount of 580 to 590 mg to fill a size 0 hard gelatin capsule. EXAMPLE 6 As a specific embodiment of a parenteral composition of a compound of this invention, 20 mg of the lactone from Example 1, as the sodium salt, is dissolved in sterile water, buffered to a pH of 7 with 1.0 mM potassium phosphate buffer solution to a concentration of 2.0 percent and is placed in a sterile ampule for parenteral administration. EXAMPLE 7 Preparation of N-n-hexyl 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienamide To a solution of the compound from Example 1 (d) (102 mg, 0.3 mmole) in methylene chloride (1 ml) and tetrahydrofuran (14 ml) containing N-methylmorpholine (35 mg, 0.34 mmole) at -20° to -25°C was added isobutyl chloroformate (46 mg, 0.34 mmole) during 10 minutes. To this mixed anhydride mixture at -25° was then added dropwise a solution of n -hexylamine (76 mg, 0.75 mmole) in tetrahydrofuran (0.5 ml). After the addition, the mixture was kept at -20 to -25° for 1 hour and raised to room temperature slowly over a 2 hour period and stirred at room temperature overnight. The reaction mixture was concentrated in vacuo and the residue was purified via preparative TLC using silica gel plates and developed with 6% methanol in methylene chloride to afford the desired product as an oil. Mass spectrum m/e 407 (M⁺); 200 MHz NMR (CDCl₃): δ 0.84 (t, 3H, C H ₃―), 3.28 ( 9 , 2H, ―NH CH ₂―), and 5.57 ppm (t, 1H, CO-N H ―). EXAMPLES 8 TO 10 Utilizing the general procedure described in Example 7 the following compounds were prepared from the compound from Example 1(d) and an equivalent amount of the appropriate amine. EXAMPLE 11 Preparation of methyl 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate Method A : To a solution of the compound from Example 2 (20 mg) in diethyl ether (15 ml) in the presence of trifluoroboron etherate (1 drop) at 0° to 5°C was added large excess of diazomethane ether solution until the discoloration became very slow. The resulting solution was concentrated and purified via preparative TLC using silica gel plate and developed with 3% ethyl acetate in methylene to yield the desired product as an oil. 200 MHz NMR (CDCl₃): 3.38 ppm (C H ₃OCH₂―). Method B : To a solution of the compound from Example 1(d) (200 mg) in diethyl ether (30 ml) in the presence of trifluoroboron etherate (5 drops) at 0° to 5°C was added large excess of diazomethane ether solution. The reaction mixture was concentrated and purified as in Method A to give the desired product. Method C : To a solution of the compound from Example 1(d) (300 mg) in diethyl ether (10 ml) was added methyl iodide (5g) and commercial silver oxide (0.4 g). The mixture was stirred at room temperature for 3 days and added methyl iodide (1g) and silver oxide (0.5g) daily during this period. The mixture was filtered and concentrated. The residue was purified via flash column chromatography to give the desired product. EXAMPLE 12 Preparation of methyl 11-(3-ethoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate To a solution of the compound from Example 2 (12 mg) in diethyl ether (0.5 ml) was added ethyl iodide (400 mg) and silver oxide (80 mg). The mixture was capped tightly and stirred at 48 to 50° for 60 hours. The resulting mixture was purified via preparative TLC to give the desired product. 200 MHz NMR: 2.20 (t, 3H, C H ₃CH₂O) and 3.56 ppm ( 9 , 2H, CH₃C H ₂O). EXAMPLE 13 Preparation of methyl 11-[3-(2-propenyloxymethyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate Utilizing the general procedure of Example 12 but employing allyl chloride in place of ethyl iodide the desired product was obtained. 200 MHz NMR 4.04 ppm (m, 2H), 5.3 ppm (m, 2H) and 5.9 ppm (m, H). EXAMPLE 14 Preparation of 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoic acid Step A: Preparation of Diphenylmethyl 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate To a solution of the compound from Example 1(d) (324 mg, 1.0 mmole) in diethyl ether (10 ml) was added diphenyl diazomethane (230 mg, 1.2 mmole). The mixture was stirred at room temperature for 2 days until complete disappearance of the starting material by TLC. The desired intermediate was isolated via preparative TLC purification 200 MHz NMR: 6.96 (s, 1H, Ph₂C H -OOO) and 7.22-7.44 ppm (m, 10H, Ar H ). Step B: Preparation of Diphenylmethyl 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate To a solution of the compound from Step A (50 mg, 0.1 mmole) in diethyl ether (0.5 ml) was added methyl iodide (720 mg, 5.0 mmole) and silver oxide (100 mg, 0.43 mmole). The mixture was capped tightly and heated at 45-50° with stirring for 18 hours. The mixture was filtered, and the filtrate was purified via preparative TLC using silica gel plates and developed with 5% ethyl acetate in methylene chloride to yield the desired intermediate. 200 MHz NMR: 3.39 ppm (s, 3H, C H ₃OCH₂). Step C: Preparation of 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoic Acid To a solution of the compound from Step B (20 mg) and anisole (150 mg) in methylene chloride (2 ml) at 0° to 5°C was added a solution of 10% trifluoroacetic acid in methylene chloride (0.2 ml). The mixture was stirred at ambient temperature for 1 hour and purified via preparative TLC to give the desired product. IR (CHCl₃): 1814 cm⁻¹; mass spectrum (FAB) m/e 339 (M⁺ + H); 200 MHz NMR: in accord with the structure. EXAMPLE 15 Preparation of 11-(3-anisyldiphenylmethoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoic acid To a solution of the compound from Example 1(d) (100 mg) in pyridine (1.5 ml) was added anisylidiphenylmethyl chloride (113 mg). The mixture was stirred at room temperature for 17 hours, and pumped to dryness. The residue was purified via preparative TLC using silica gel plates and developed with 5% methanol in methylene chloride to give the desired product. 200 MHz NMR 3.80 (s, 3H, CH₃OØ) and 7.2-7.5 ppm (m, 14H, ArH). EXAMPLE 16 Preparation of methyl 11-(3-methanesulfonyloxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate To a solution of the compound from Example 2 (100 mg) and triethylamine (150 mg) in methylene chloride (5 ml) at 0° to 5° was added a solution of methanesulfonyl chloride (150 mg) in methylene chloride (0.5 ml) during 10 minutes. The mixture was stirred at 0 to 5° for 1/2 hour and then at room temperature for 1/2 hour. The desired product was isolated via preparative TLC purification. 200 MHz NMR 3.08 ppm (s, 3H, C H ₃SO₃―). EXAMPLE 17 Preparation of methyl 11-(3-formyloxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate Diethyl azidocarboxylate (0.04 ml, 2 eg) was added dropwise to a stirred solution of the compound from Example 2 (0.034 g, 0.1 mmol) triphenylphosphine (0.053 g, 0.2 mmol), and formic acid (0.01 ml, 2.7 eg) in anhydrous tetrahydrofuran (0.6 ml) at ambient temperature. After one hour, at ambient temperature the reaction mixture was evaporated in vacuo and purified by preparative thin layer chromatography on silica gel eluted with ethyl acetate: hexane (30: 70) to afford the desired product as a viscous gum. EXAMPLE 18 Preparation of methyl 11-[3-(2-methylbutyryloxymethyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate A solution of the compound from Example 2 (0.034 g, 0.1 mmol) and 2-methylbutyryl anhydride (0.055 g, 0.3 mmol) in anhydrous pyridine (0.25 ml) at ambient temperature under nitrogen for 20 hours. The reaction mixture was diluted with methylene chloride evaporated in vacuo and then washed with toluene several times to provide a colorless viscous gum. The crude product was purified by preparative thin layer chromatography over silica gel eluted with ethyl acetate: hexane (30: 70) to afford the desired product. EXAMPLE 19 Preparation of methyl 11-[3-(N-methylurethanylmethyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate To a solution of the compound of Example 2 (37 mg, 0.11 mmol) in pyridine (0.5 ml) was added methyl isocyanate (1 ml) and the reaction mixture heated at about 55°C for about 16 hours. The excess methyl isocyanate was removed and the residue was purified by preparative thin layer chromatography on silica gel eluted with ethyl acetate: hexane (30: 70) to afford the desired product. EXAMPLE 20 Preparation of tert-butyl 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate Three portions of O- t -butyl-N,N′-diisopropylisourea (200 mg) were added at 3 hour intervals to a solution of the compound from Example 1 (310 mg, 0.96 mmol) in methylene chloride (2.5 ml) at room temperature. After stirring for an additional 16 hours, the solids were filtered and washed twice with methylene chloride. The residue after evaporation in vacuo was purified by preparative thin layer chromatography to afford the desired product. NMR (CDCl₃) δ 1.50 (S, 9H), 3.41 (d of t, 1H), 3.8-4.1 (m, 2H), 4.58 (m, 1H) IR 1820 cm⁻¹, 1730 cm⁻¹.

Claims: 1. A compound represented by the following structural formula (I): wherein: R¹ is selected from (1) hydroxy, (2) C₁₋₆ alkoxy, (3) substituted C₁₋₆ alkoxy in which the substituent is a phenyl group, (4) amino, (5) C₁₋₆ alkylamino, (6) substituted C₁₋₆ alkylamino in which the substituent is a hydroxy group, (7) phenylamino, (8) substituted phenylamino in which the substituent is a fluoro, chloro, or bromo, and (9) (2-thio)-pyridine; and R² is selected from (1) hydrogen, (2) C₁₋₆ alkyl, 3) C₂₋₆ alkenyl, (4) formyl, (5) C₁₋₆ alkylcarbonyl, (6) carboxy C₁₋₆ alkylcarbonyl, (7) anisyldiphenylmethyl, (8) C₁₋₆ alkylsulfonyl, (9) aminocarbonyl, and (10) C₁₋₆ alkylaminocarbonyl; with the proviso that when R² is hydrogen, R¹ is other than hydroxy and C₁₋₃ alkoxy; and pharmaceutically acceptable salts thereof. 2. A compound of Claim 1 wherein: R¹ is selected from (1) amino, (2) C₁₋₆ alkylamino, (3) substituted C₁₋₆ alkylamino, (4) phenylamino and (5) substituted phenylamino; and R² is hydrogen. 3. A compound of Claim 2 which is (1) 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienamide; (2) N- n -hexyl 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienamide; (3) N-(4-bromophenyl) 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl- 2,4-undecadienamide; and N-(2-hydroxyethyl) 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienamide. 4. A compound of Claim 1 wherein: R² is selected from (1) C₁₋₆ alkyl, (2) C₂₋₆ alkenyl, and (3) anisyldiphenylmethyl; and R¹ is selected from (1) hydroxy, (2) C₁₋₆ alkoxy, and (3) substituted C₁₋₆ alkoxy in which the substituent is a phenyl group. 5. A compound of Claim 4 which is (1) methyl 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; (2) methyl 11-(3-ethoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; (3) methyl 11-[3-(2-propenyloxymethyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate; (4) 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoic acid; (5) 11-(3-anisyldiphenylmethyloxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoic acid; (6) diphenylmethyl 11-(3-methoxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate. 6. A compound of Claim 1 wherein: R² is selected from (1) formyl, (2) C₁₋₆ alkoxycarbonyl, (3) carboxy C₁₋₆ alkylcarboxyl, (4) aminocarbonyl, and (5) C₁₋₆ alkylaminocarbonyl; and R¹ is C₁₋₆ alkoxy. 7. A compound of Claim 6 which is (1) methyl 11-(3-formyloxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; (2) methyl 11-[3-(3-carboxypropionyl-oxymethyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate; (3) methyl 11-(3-urethanylmethyl)-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; (4) methyl 11-[3-(N-methylurethanyl-methyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate; 8. A compound which is methyl 11-[3-(2-methylbutyryl-oxymethyl)-4-oxo-2-oxetano]-3,5,7-trimethyl-2,4-undecadienoate. 9. A compound of claim 1 which is (1) methyl 11-(3-methanesulfonyloxy-methyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; (2) 2-pyridyl 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienthioate; and (3) tert -butyl 11-(3-hydroxymethyl-4-oxo-2-oxetano)-3,5,7-trimethyl-2,4-undecadienoate; 10. A pharmaceutical composition for the treatment of hypercholesterolemia which comprises a non-toxic effective amount of a compound of Claim 1 and a pharmaceutically acceptable carrier. 11. The use of a compound of formula (I) as defined in claim 1 or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for inhibiting cholesterol biosynthesis and/or for inhibiting the activity of HMG-CoA synthase enzyme.

Inventors: CHABALA, JOHN C., CHANG, MICHAEL N., CHIANG, YUNA-CHING P., GIROTRA, NARINDAR N., GRAHAM, DONALD W., YANG, SHU S.
Applicants: MERCK & CO. INC.
Application year: 1988
Main classification: C07D305
IPC codes: C07D305, C07D405, A61K31, A61P3