Synthesis and molecular structure of spirocyclic 2-oxindole derivatives of 2-amino-4H-pyran condensed with the pyrazolic nucleus

4,3′-Spiro[(6-amino-5-R-3-methyl-2H,4H-pyrano[2,3-c]pyrazolo)-2′-oxindoles] were synthesized based on the three-component condensation of isatins with 3-methyl-pyrazolone-5 and respective methylene active nitriles in the presence of basic catalysts. The molecular structure of the resulting compounds was proved unambiguously by X-ray diffraction.