Acylation of Heterocyclic Ketene Aminals with Propionyl Chloride

Abstract Heterocyclic ketene aminals 1 or 2 reacted with propionyl chloride to give both the mono-N-and C-acylated products 4 and 5 or 6 and 7. While N-methyl heterocyclic ketene aminals 3 reacted with propionyl chloride under the same condition, the reaction took place in complexity. Besides N-and C-acylation, the O-attack and heterocyclic ring cleavage also occurred to give products 8 and 9.