Synthesis of l,3-Dioxin-4-ones and Their Use in Synthesis. XI.1) 2,2-Dimethyl-l,3-dioxin-4-one as a Synthetic Equivalent of Formylketene: Synthesis of Heterocyclic Compounds2)

Abstract

Cycloaddition of formylketene generated in situ by thermolysis of 2,2-dimethyl-l,3-dioxin-4-one with N-benzhydrylidenebenzylamine yields 3-benzyl-2,2-diphenyl-l,3-oxazin-4-one. Analogous reactions with a carbodiimide, cyanamide, and keteneacetal afford the corresponding 4 + 2 cycloadducts. Reaction of formylketene with 3-amino-2-butenamides affords 4-hydroxy-2-nyridones having a C-2 unit at the 3-position. © 1986, The Pharmaceutical Society of Japan. All rights reserved.