A Convenient Procedure for the Synthesis of 3-Substituted 5,6-Dihydro-4H-1,2-oxazines from Nitroethane

ABSTRACT A novel and efficient four-step procedure for the synthesis of C-3-functionalised 5,6-dihydro-4H-1,2-oxazines from nitroethane is described. It includes preparation of 3-methyl-substituted six-membered cyclic nitronates, 3-(bromomethyl)-substituted 5,6-dihydro-4H-1,2-oxazines as intermediates, and nucleophilic substitution of bromine. Total yields of the target C-3-functionalised oxazines are 15-30% from nitroethane.