PRODUCTION OF 4,5-DIALKYL-3-ACYL-PYRROLE-2-CARBOXYLIC ACID DERIVATIVE BY FISCHER-FINK TYPE SYNTHESIS AND SUBSEQUENT ACYLATION

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a compound useful for synthesis of a protease inhibitor.SOLUTION: The method for the improved synthesis of pyrrole capping group precursors of formula I-a (wherein, Rand Rare each 1C-12C aliphatic, 3C-12C alkyl-cycloaliphatic, 3C-12C alkyl-aryl, 3C-12C alkyl-heteroaryl, or 3C-12C alkyl-cycloaliphatic) includes reacting a keto-enol type compound with a β-keto-α-oxime-carboxylic ester type compound in the presence of zinc, water, and optionally an additional suitable solvent.