Synthesis, structure and cytotoxicity of novel tetrazolo[1’,5’-c]-fused 3-aza-A-homosteroids

A series of new 1’H-tetrazolo[1’,5’-c]-fused 3-aza-A- homosteroids were synthesized by azidation of progesterone, testosterone and hydrocortisone acetate in the presence of silicon tetrachloride. According to NMR spectroscopy and X-ray analysis, two double bond positional isomers (double bond in ring A or in ring B) are formed in various ratios; according to quantum chemical calculations, their energies are close within 0.4 kcal mol^-1. Only low cytotoxic activity against Hep-2, MCF-7, HepG2, and Hek293 cell lines was determined in vitro for the compounds obtained.