Diphosphonic acid derivative, its production and antiphlogistic and antiarthritic pharmaceutical preparation containing the derivative

PURPOSE: To obtain a novel diphosphonic acid derivative which has an excellent antiphologistic and antiarthritic activity and is useful for the treatment of rheumatoid arithritis, osteoarithritis, etc., as the derivative act on the generatability and destructability of the osteocytes. CONSTITUTION: A disphosphonic acid derivative of formula I (R is H, an alkaline metal, etc.; X is H, methyl, etc.; formula II is formulae III, IV etc.); for example, 2-(6-methoxy-2-naphthyl)-1-hydroxy-propane-1,1-bis(dimethyl ester phosphonate). The compd. is obtd. by bringing an acyl phosphonate of formula V into reaction with a dialkyl phosphite of the formula HPO(OR) 2 in the presence of a base (adequately a secondary amine such as diethyl amine). This reaction is usually effected in an inert org. solvent, such as THF. The starting compd. of formula V is recommended to be obtd. by bringing the corresponding acid chloride into reaction with a trialkyl phosphite. COPYRIGHT: (C)1993,JPO