New process for the industrial synthesis of the methyl diester of 5-amino-3-carboxymethyl-4-cyano-2-thiophenecarboxylic acid, and application to the synthesis of bivalent salts of ranelic acid and their hydrates.

摘要

Methyl 5-amino-4-cyano-3-(2-methoxy-2-oxoethyl)-2-thiophene-carboxylate (I) is new. Independent claims are included for the following: (1) preparation of (I); (2) synthesis of ranelic acid, its strontium, calcium or magnesium salts involving reaction of 5-amino-4-cyano-3-(2-methoxy-2-oxoethyl)-2-thiophene-carboxylate (I) with an ester of bromoacetic acid to yield the corresponding tetra ester followed by its conversion into ranelic acid, its strontium, calcium or magnesium salts; and (3) new 4,4-dicyano-1-methoxy-3-methoxycarbonylmethyl-but-3-en-1-olatemorpholin-4-ium (II).