HERSTELLUNG DER 2-OXO-1,3-DIBENZYL-CIS-4,5- IMIDAZOLIDINDICARBONSÄURE BZW. IHRES ANHYDRIDS

The present invention is directed to a process for the production of 2-oxo-1,3-dibenzyl-cis-4,5-imidazolidinedicarboxylic acid and of 2-oxo-1,3-dibenzyl-cis-4,5-imidazolidinedicarboxylic acid anhydride, starting from meso-2,3-bis(benzylamino)succinic acid dialkali metal salt. The process involves reacting meso-2,3-bis(benzylamino)succinic acid dialkali metal salt with phenyl chloroformate in a monophasic solvent system consisting of an about 2:1 to 1:1 mixture of a water-miscible ether and an aqueous alkali metal hydroxide solution, at a temperature not exceeding about 40° C. The resulting 2-oxo-1,3-dibenzyl-cis-4,5-imidazolidinedicarboxylic acid dialkali metal salt is converted, by acidification, into the desired 2-oxo-1,3-dibenzyl-cis-4,5-imidazolidinedicarboxylic acid, which is then either isolated, or converted, by heating with acetic anhydride, in an aromatic hydrocarbon as the organic solvent, into the desired 2-oxo-1,3-dibenzyl-cis-4,5-imidazolidinedicarboxylic acid anhydride, which is in turn, isolated. Each product is an important intermediate in the multi-stage process for the manufacture of biotin (vitamin H).