The Reaction of 3-(Substituted methylene)phthalides with Amines

Abstract

The ring-opening addition of 3-(substituted methylene)phthalides ([1] and [2]) with amines forming benzamide derivatives [4] was investigated. The reactivity of phthalide was greatly enhanced by the introduction of an exocyclic carbon-carbon double bond onto the 3-position of phthalide, and [1] and [2] a kind of enol lactones, reacted readily in N-methyl- 2-pyrrolidone with aliphatic amines at room temperature, as well as with an aromatic amine at 80°C.3-(Substituted methylene)thiophthalides [3], sulfur analogs of phthalides, were much less reactive than the corresponding 3-(substituted methylene)phthalides toward amines.