| abstract |
A phosphonic diester derivative represented by the following formula (1): (see formula I) wherein R1 represents a cycloalkyl group; a phenyl group which may have 1 to 3 substituents selected from the group consisting of a lower alkoxy group, a lower alkyl group, a halogen atom, a halogen-substituted lower alkyl group, a lower alkanoyl group, a nitro group, a benzoyl group, a cyano group, an N-lower alkylcarbamoyl group, an N-phenyl-lower alkylcarbamoyl group, an N-(halogen-substituted phenyl)carbamoyl group and an N,N-di-lower alkylcarbamoyl group; a 1,3,4-thiadiazol-2-yl group having a halogen-substituted lower alkyl group as a substituent; a thiazolyl group; a pyridyl group which may be,substituted by a halogen atom; a benzothiazol-2-yl group having 1 to 2 lower alkoxy groups on the phenyl ring; or a 4,5-dihydrothieno[3,2-e]benzothiazol-2-yl group; R2 represents a hydrogen atom or a phenyl lower alkyl group; R3 and R4 each represents a lower alkyl group; and A represents a heterocyclic ring selected from the group consisting of a pyrazine ring, a thiophene ring and a phenyl-substituted thiazole ring; the derivative being of value as an agent for treating and preventing hyperlipidemia, diabetes and cataract, or as an antitumor agent. |