6-Amino-3,4-dimethyl-4-phenyl-2H,4H-pyrano[2,3-c]pyrazole-5-carbonitrile

One-pot green synthesis of biologically relevant novel spiro[indolin-2-one-3,4'-pyrano[2,3-c]pyrazoles] and studies on their spectral and X-ray crystallographic behaviors

Syntheses via green route and single-crystal X-ray structural investigations have been carried out for three spiro[indolin-2-one-3,4'-pyrano[2,3-c]pyrazole] derivatives, 6'-amino-2-oxo-3'-propyl-2'H-spiro[indoline-3,4'-pyrano[2,3-c]pyrazole]-5'-carbonitrile dimethyl sulfoxide monosolvate (5a), 6'-amino-5-fluoro-2-oxo-3'-propyl-2'H-spiro[indoline-3,4'-pyrano[2,3-c]pyrazole]-5'-carbonitrile dimethyl sulfoxide monosolvate (5b) and methyl 6'-amino-5-cyano-1-methyl-2-oxo-3'-propyl-2'H-spiro[indoline-3,4'-pyrano[2,3-c]pyrazole]-3'-carboxylate 0.25 hydrate (5c), respectively. Compounds (5a) and (5b) crystallize in the triclinic space group P\bar 1, whereas compound (5c) crystallizes in the monoclinic space group C2/c. In molecules (5a) and (5b) all the rings are practically flat, while in (5c), the heterocyclic pyran ring adopts a flattened-boat conformation. In (5a) and (5b) the cyanide group is oriented in a (-ap) conformation, while the amino group is oriented in a (+ap) conformation with a pyran ring, but in (5c) both the cyanide and amino groups are oriented in a (-ap) conformation with the pyran ring. In the crystal structure of (5a) and (5b), the molecules are linked by an elaborate system of N-H...O and N-H...N hydrogen bonds to generate a zigzag-like construct. In (5c) molecules are linked by N-H...O hydrogen bonds, thereby generating extended chains. The present communication focuses on the detailed and comparative information about spectral behaviors, single-crystal X-ray crystallographic properties and solid-state supramolecular architectures of these synthesized compounds of potential biological interests.

Ethyl 6-amino-5-cyano-4-phenyl-2,4-di-hydro-pyrano[2,3-c]pyrazole-3-carboxyl-ate dimethyl sulfoxide monosolvate

In the asymmetric unit of the title compound, C₁₆H₁₄N₄O₃·C₂H₆OS, there are two independent main mol­ecules (A and B) and two dimethyl sulfoxide solvent mol­ecules. In mol­ecule A, the pyran ring is in a flattened sofa conformation, with the sp³-hydridized C atom forming the flap. In mol­ecule B, the pyran ring is in a flattened boat conformation, with the sp³-hydridized C atom and the O atom deviating by 0.073 (3) and 0.055 (3) Å, respectively, from the plane of the other four atoms. The mean planes the pyrazole and phenyl rings form dihedral angles of 84.4 (2) and 84.9 (2)°, respectively, for mol­ecules A and B. In the crystal, N—H⋯O and N—H⋯N hydrogen bonds link the components of the structure into chains along [010]. In both solvent mol­ecules, the S atoms are disordered over two sites, with occupancy ratios of 0.679 (4):0.321 (4) and 0.546 (6):0.454 (6).