Novel method for the synthesis of 4-(azol-5-yl)-1,2,3-triazoles
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We have proposed a novel, general, and efficient method for the synthesis of 4-(azol-5-yl)-1,2,3-tri-azoles by cycloaddition of azides to 2-azolylenamines. It was shown that the enamines 2, 5, 8 take part in [3 + 2] cycloaddition when fused with aromatic azides to give exclusively the bicyclic compounds 3, 6, 9 in high yields. The regiospecificity of the reaction is evidently due to the “push-pull” character of enamines, the reaction of which with zwitterionic azides gives one of two possible regioisomers. It should be noted that, in contrast to condensed 1,2,3-triazoles , the bicyclic groups of compounds of type 3, 6, 9 are poorly available . The transformation described is the first example of cycloaddition of 3-hetarylenamines to azides [1, 3]. The structures of the compounds obtained were confirmed by 1H and 13C NMR spectroscopic data and elemental analysis. Assignments in the 13C NMR spectra were made on the basis of 2D HMBC experimental data for compounds 3 and 8.
The 1H, 13...
Keywordsazides azoles isoxazoles 1,2,3-thiadiazoles 1,2,3-triazoles cycloaddition
The authors thank the Russian Foundation For Fundamental Investigations (grant No. 11-03-00579-a) for financial support.