Synthesis of spiro[indole-3,3′-[1,3,4]thiadiazino[3,2-a] benzimidazoles] and spiro[indole-3,6′-[1,2,4]triazolo[3,4-b][1,3,4] thiadiazines]

Article abstract of DOI:10.1007/s11172-010-0170-8

A method for annulation of the tetrahydrothiadiazine ring to benzimidazoles and 1,2,4-tri-azoles was developed. A number of earlier unknown [1,3,4]thiadiazino[3,2-a]benzimidazoles and triazolo[3,4-b][1,3,4]thiadiazines were obtained as spiro compounds with the oxindole fragment. According to NMR and X-ray diffraction data, the formation of the tetrahydrothiadiazine ring is a diastereospecific process.