A series of 1,5,6,7-tetrahydrothiopyrano[2,3-d][1,2,3]triazole 4,4-dioxides, new triazole-based bicyclic ring system, were prepared via base-mediated click reaction of organic azides with the readily available dihydro-2H-thiopyran-3(4H)-one-1,1-dioxide. The reaction proceeded at room temperature in 5-12 h with catalysis by base-solvent system K₂CO₃/DMSO. High purity products were isolated by simple filtration and no formation of side products was observed. The key structure was confirmed by an X-ray study.

Convenient two-step procedure for the synthesis of fused chromenone derivatives was developed. Reduction of the obtained in the Meerwein arylation reaction aryl- and thienylquinones allowed to construct 6H-benzo[c]chromene-6-ones and 4H-thieno[2,3-c]chromen-4-one in a more cost- and time-effective manner in comparison with already known methods. The obtained products have provided a new entry to chromenone derivatives.

Nitrileimines were implemented in practical click protocols with oxopropanenitriles for the straightforward 5-amino-1H-pyrazole synthesis via 1,3-dipolar cycloaddition. The reaction proceeds at room temperature in a short time with base catalysis and no chromatographic purification. High purity products were isolated by simple filtration. The selectivity of the reaction was observed.