ali akbari

Silica supported boron trifluoride, BF3.SiO2, which is easy to prepare, shows unusually high acidity which can be controlled by activation temperature, and exhibits considerable catalytic activity,1 enables better accessibility of the reactants to the active sites. The BF3.SiO2 is used in several organic transformations, such as in Claisen-Schmidt condensations,2 in syntheses of 14-aryl or alkyl-14Hdibenzo[ a,j]xanthenes,3 1,2,4,5-tetrasubstituted imidazoles,4 tetrahydrobenzo[a]xanthenes-11-one,5 in the polymerization of styrene,6 the preparation of polyfunctionalized piperidin-4-ones,7 α-amino phosphonates,8 quinoxalines,9 and 3,4-dihydropyrimidin-2(1H)-ones.10 Tetrazoles are an important class of heterocycles with a wide range of applications in medicinal chemistry and materials science.11, 12 The most common method for the preparation of 5-substituted-1H-tetrazoles involves the addition of azide salts to organic nitriles using acid or base catalysis. We report a simple method for the synthesis of 5-substituted-1H-tetrazoles derivatives from the reactions of nitriles with sodium azide in the presence of a catalytic amounts silica supported boron trifluoride (Scheme 1).