Selective N(2) alkylation of tetrazole and 5-substituted tetrazoles by alcohols

Alkylation of tetrazole and its 5-substituted derivatives by 5-tert-butyl, isopropyl, and cyclohexyl alcohols in concentrated H₂SO₄ results in high yields of the corresponding 2-alkyltetrazoles alone, irrespective of electronic properties and size of the substituent at the 5-position of the tetrazole ring. The tert-butylation of tetrazole in phosphoric acid results in the formation of a mixture of isomeric 1- and 2-substituted derivatives, the concentration of the 1-isomer increasing with decrease in the concentration of the acid in the mixture.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1643–1647, December, 1990.