Three-Component Reaction between Kojic Acid and Aroyl Chlorides with Ammonium Thiocyanate: Synthesis of 2-Aryl-6-Hydroxymethyl-4-Thioxo-4<i>H</i>-Pyrano[2,3-<i>e</i>][1,3]Oxazin-8-Ones
A novel method for oxazine ring formation is established using the reaction of ammonium thiocyanate and aroyl chlorides with kojic acid in the presence of N-methylimidazole to afford 2-aryl-6-hydroxymethyl-4-thioxo-4H-pyrano[2,3-e][1,3]oxazin-8-ones in excellent yields.