Regioselective Alkylation of 5-Substituted Tetrazoles with 3-Chlorobut-2-en-1-ol in Acid Medium

The alkylation of 5-R-tetrazoles (R = H, Me, Ph) with 3-chlorobut-2-en-1-ol was studied in 1,2-dichloroethane, chlorofom, and methylene chloride in the presence of boron trifluoride—diethyl ether complex, as well as in trifluoroacetic acid and in ethyl acetate in the presence of sulfuric acid. The reaction in 1,2-dichloroethane catalyzed by BF3 · Et2O gave 70–80% of the alkylation products containing no less than 99% of the 2-substituted isomer.