Synthesis of 2,4-dihydrochromeno[3,4-d][1,2,3]triazoles and 5-(2H-chromen-3-yl)-1H-tetrazoles via regioselective 1,3-dipolar cycloaddition of 2H-chromene-3-carbonitriles with NaN3

Conjugated cyano cyclo-olefins modified as highly regioselective dipolarophiles in 1,3-dipolar cycloaddition with NaN3 to synthesize corresponding fused 1,2,3-triazole and 1H-tetrazole derivatives. The first example of catalytic 1,3-dipolar cycloaddition of NaN3 with 2H-chromene-3-carbonitriles and subsequent elimination/cyclization of cyano functionality is designated. In presence of catalytic amount of p-TSA or AgNO3, 2H-chromene-3-carbonitriles react with NaN3 discretely producing 2,4-dihydrochromeno[3,4-d][1,2,3]triazoles or 5-(2H-chromen-3-yl)-1H-tetrazoles respectively, in good to excellent yields (i. e. 51-88 % or 85-97 %) with high regioselectivity and wide substrate scope adequacy.