Catalytic Activity of 1,3-Dibromo-5,5-dimethylhydantoin (DBH) in the One-Pot Transformation ofN-Arylglycines toN-Arylsydnones in the Presence of NaNO2/Ac2O under Neutral Conditions: Subsequent Bromination of these Sydnones to their 4-Bromo Derivatives

Abstract

1,3-Dibromo-5,5-dimethylhydantoin (DBH) has been found to efficiently catalyze the one-pot conversion of various N-arylglycines through N-nitrosation and cyclization to sydnones in combination with NaNO2 and Ac2O in high yields (80-94%) under mild and neutral conditions. Also, it was shown that DBH can conveniently­ promote the bromination of these sydnones to their 4-bromo substituted congeners in excellent yields in DMF at room temperature.