Three-component reaction between 4-hydroxycoumarin, ammonium thiocyanate and acid chlorides in the presence of N-methylimidazole under solvent-free conditions

摘要

A novel method for oxazine ring formation is established using the reaction of ammonium thiocyanate and acid chlorides with 4-hydroxy coumarin in the presence of N-methylimidazole to afford oxazine derivatives in excellent yields.