چکیده
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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).
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