A carbon-13 and proton nuclear magnetic resonance study of annular tautomerism and interannular conjugation in some substituted-5-aryl-tetrazoles

Abstract

A comparison of 13C spectra for a series of substituted 5-phenyltetrazoles, (RC6H4; R = H, p-Me, p-NO2, o-NO2), with their 1-N- and 2-N-methyl derivatives suggested that the tetrazoles exist predominantly in the 1-H form. Both 1H and 13C n.m.r. spectra suggested the presence of interannular conjugation in 5-aryl-2-methyltetrazoles and 5-aryl-1H-tetrazoles. This was either reduced or absent in 5-aryl-1-methyletetrazoles and also in 5-(o-nitrophenyl)-1H-tetrazole.