Pemetrexed og farmasoytisk akseptable salter derav

摘要

The present application relates to a series of novel sulfonic acid metal cation salts of the formula which are useful intermediates to prepare antifolate 5-substituted pyrrolo[2,3-d]pyrimidines. The present invention also relates to a novel process for preparing the sulfonic acid metal cation salts and to a novel process for preparing aldehydes of the formula from the corresponding sulfonic acid metal cation salts.