Synthesis of 3,4,5,6‐Tetrahydro‐2<i>H</i>‐1,3,4‐oxadiazin‐2‐ones Employing a Metal Hydride and Diethyl Carbonate: An Alternative Cyclization Method over 1,1′‐Carbonyldiimidazole

Abstract

Abstract A series of 3,4,5,6‐tetrahydro‐2H‐1,3,4‐oxadiazin‐2‐ones have been synthesized from valine, leucine, ephedrine, and norephedrine. The synthesis is accomplished through a process of nitrosation, reduction, and cyclization. The cyclization protocol employed involves the use of a metal hydride (LiH or NaH) and diethyl carbonate rather than 1,1′‐carbonyldiimidazole.