Reactions of β-Azolylenamines with Sulfonyl Azides as an Approach toN-Unsubstituted 1,2,3-Triazoles and Ethene-1,2-diamines

The reactions of β-azolylenamines 1 with sulfonyl azides 2 in acetonitrile furnished 1H-4-(azol-5-yl)-1,2,3-triazoles 3 in yields of 52–93 %. β-Benzoylenaminones and β-nitroenamine of type 1 also reacted with tosyl azide to form the same type of products 3, proving the generality and efficiency of the method for the synthesis of N-unsubstituted 1,2,3-triazoles. On the other hand, the reactions of 3-(1-aryl-1,2,3-triazol-5-yl)enamines with tosyl azide in the absence of a solvent afforded a mixture of (E)-1-dimethylamino-2-tosylaminoethenes 5 and N,N-dimethyl-N′-tosylformamidine 6 in yields of 40–50 and 20 %, respectively. The formation of a variety of compounds from the reactions of enamines 1 with sulfonyl azides 2 is rationalized by the various possible transformations of the intermediate 5-dimethylamino-1,2,3-triazolines 7.