Studies on Kojic Acid and its Related γ-Pyrone Compounds

Part VII. The Alkylation of Kojic Acid and Pyromeconic Acid through their Mannich Base (Synthesis of Maltol-(l))

Abstract

The Mannich reaction of kojic acid in both acidic and basic media was studied. Mono-Mannich derivatives (substitution at position 6) were obtained; the reactivity in basic medium was found to be somewhat greater than in acidic medium. Reduction of the Mannich derivatives with zinc dust and acetic acid gave a 6-methyl kojic acid (6-methyl-5-hydrox y-2-hydrox ymethyl-γ-pyrone).
Mono-Mannich base of pyromeconic acid was also prepared in a manner similar to that of kojic acid. From this Mannich base, maltol (2-methyl-3-hydroxy-r-pyrone) was obtained by the reduction with zinc dust and acetic acid.