Electro-organic reactions. Part 18. The competition between cleavage at aryl–oxygen and at tetrazol-5-yl–oxygen bonds in the cathodic reduction of aryl tetrazolyl ethers

Abstract

5-Aryloxy-1-phenyltetrazoles are cleaved cathodically in a 2 F mol^–1 process. Initial electron transfer is to the tetrazole ring and the compounds cleave predominantly at the tetrazolyl–oxygen bond. An exception is 5-(p-cyanophenoxy)-1-phenyltetrazole which undergoes 1 F mol^–1 cleavage to 1-phenyltetrazolone and benzonitrile. Competitive electrolysis of pairs of the tetrazolyl ethers, differently substituted in the aryloxy-ring, allows an estimation of relative rates of cleavage. These rates are found to be roughly related to the pK_a values of the corresponding phenols.