An unusual tetrazole transacylation by tetrazolylacetic acid chlorides

Bis(tetrazolyl)acetones have been obtained instead of the expected 2,5-disubstituted 1,3,4-oxadiazoles from interaction of 5-substituted tetrazoles with chlorides of tetrazolylacetic acids. The mechanism of the reaction is suggested to include N-acyl-intermediate heterolysis resulting in acyl-cation formation followed by transacylation of the methylene group in the second molecule of the acyl halide.