Total Synthesis of Pyrrolnitrin. X. Synthesis of Pyrrolnitrin. (2)

Abstract

Conversion of 2, 5-disubstituted-3-arylpyrrole (II) to pyrrolnitrin (Ia) and the related compounds (I) was investigated. II was transformed by chlorination followed by hydrolysis and oxidation to 3-aryl-4-chloro-2, 5-pyrroledicarboxylic acids (IV), which were decarboxylated to I in sulfuric acid. Dialkyl 3-aryl-4-chloro-2, 5-pyrroledicarboxylate (XI), alkyl β-aryl-4-chloropyrrolecarboxylates and halfesters of IV afforded Ia directly, when heated in sulfuric acid.