Reaction of 5-Aryloxytetrazoles with Dimethyl Sulfoxide and DMSO-Acetic Anhydride. Structure and Quantum-Chemical Calculations of 1-Methylsulfanylmethyl-5-(4-nitrophenoxy)tetrazole

Decomposition of methyl 5-(4-nitrophenoxy)tetrazole-2-carboxylate in dimethyl sulfoxide at room temperature yields a mixture of 1-methylsulfanylmethyl-5-(4-nitrophenoxy)tetrazole, 1- and 2-methyl-5-(4-nitrophenoxy)tetrazoles, and 5-(4-nitrophenoxy)tetrazole. Methyl 5-aryloxytetrazole-2-carboxylates containing electron-donor substituents in the aryloxy group do not give rise to the corresponding products under analogous conditions. The reactions of 5-aryloxytetrazoles [Ar = 4-O2NC6H4, C6H5, 2,6-(MeO)2C6H3] with dimethyl sulfoxide in the presence of acetic anhydride lead to mixtures of 1- and 2-methylsulfanylmethyl-5-aryloxytetrazoles whose yield and ratio depend on the substituent in the aryloxy group. The structure of 1-methylsulfanylmethyl-5-(4-nitrophenoxy)tetrazole was studied by X-ray analysis, two-dimensional NMR spectroscopy (HSQC, HMBC, NOESY), and quantum-chemical methods (ab initio, AM1, PM3). A highly selective procedure was developed for the synthesis of 5-(4-nitrophenoxy)tetrazole.