Synthesis of N6-phosphorylated sydnone imines and their functionalization via 4-Li derivatives. Novel bicyclic sydnone imines

Abstract The highly efficient gram-scale method for preparation of up to date hardly available N 6 - phosphorylated sydnone imines based on the reaction of sydnone imine hydrochlorides with substituted phosphinate or phosphonate acids chlorides in the presence of a base was elaborated. A possibility of straight deprotonation of sydnone imines with n- BuLi followed by the reaction 4-Li-derivatives thus obtained with electrophiles was demonstrated. Novel representatives of bicyclic sydnone imines fused via 4,5-edge of the oxadiazolium ring were obtained. Also sydnone imines containing both phosphorus and sulfur functionalities were obtained with high yields.