PROCESS FOR PRODUCTION OF METHANEDIPHOSPHONIC ACID

摘要

A process for producing a 1-alkylthiomethanediphosphonic acid compound or a 1arylthiomethanediphosphonic acid compound by the condensation reaction represented by formula (A), wherein the thiolate as the by-product is removed in the form of an insoluble salt (wherein R'1 represents C1-C6 linear or branched alkyl; R2 represents alkyl or aryl; and R1 represents a pharmacologically acceptable cation, hydrogen, or C1-C6 linear or branched alkyl). As compared with the conventional processes, this process is so improved in the yield that the product can readily be purified, thus being useful from the economic and industrial viewpoints.