Allyl 6-amino-4-(4-chlorophenyl)-5-cyano-2-methyl-4H-pyran-3-carboxylate

In the title compound, C17H15ClN2O3, the 4H-pyran ring exhibits a shallow-boat conformation and the chlorobenzene ring occupies an axial position. The O-allyl side chain is disordered over two orientations in a 0.585 (14):0.415 (14) ratio. In the crystal, inversion dimers linked by pairs of weak N—H...N hydrogen bonds generate R 2 2(12) loops and N—H...O hydrogen bonds link the dimers into [001] chains.

Allyl 6-amino-5-cyano-2-methyl-4-phenyl-4H-pyran-3-carboxylate

In the title compound, C17H16N2O3, the 4H-pyran ring adopts a boat conformation. In the crystal, N—H...N and N—H...O interactions link the molecules, forming an infinite ribbon running along the a-axis direction with N—H...N interactions forming centrosymmetric R 2 2(12) graph-set motifs. The allyl side chain is disordered over two sets of sites with occupancies of 0.720 (7) and 0.280 (7).

Conformational polymorphs of isobutyl-6-amino-5-cyano-2-methyl-4-phenyl-4H-pyran-3-carboxylate: spectroscopic, structural and DFT approach

The crystal structure of a new crystalline phase, polymorph (II) of isobutyl-6-amino-5-cyano-2-methyl-4-phenyl-4H-pyran-3-carboxylate, was accurately determined by single-crystal X-ray diffraction analysis providing a clean identification of polymorphic forms. Comparison with a known phase, referred to as polymorph (I), reveals the type of supramolecular assembly. Inter- and intramolecular hydrogen-bonding interactions exhibit various supramolecular architectures in crystal packing and these variations confirm well the polymorphism in isobutyl-6-amino-5-cyano-2-methyl-4-phenyl-4H-pyran-3-carboxylate (IAPC) crystal structure. Crystal cohesion is achieved by N-H...N, N-H...O and C-H...H-C interactions, responsible for the formation and strengthening of the supramolecular assembly. The objective of this investigation is to study crystalline forms which can offer enhanced physicochemical properties, and also to recognize the molecular orientations between such forms. The conformational polymorphs of IAPC were compared spectroscopically by FT-IR and FT-Raman. The bulk phases were studied by X-ray powder diffraction patterns. External morphology was investigated using scanning electron microscopic images. The molecular interactions were quantified using Hirshfeld surface and fingerprint analysis. Density functional theory (DFT) computations were used to optimize the structure. The optimized structure is further subjected to an analysis of Mulliken population, natural population and electrostatic potential.

Crystal structure of isobutyl 4-(2-chlorophenyl)-5-cyano-6-{(E)-[(dimethylamino)methylidene]amino}-2-methyl-4H-pyran-3-carboxylate

In the title compound, C₂₁H₂₄ClN₃O₃, the dihedral angle between the pyran ring (r.m.s. deviation = 0.037 Å) and the chloro­benzene ring is 88.56 (14)°. In the crystal, the mol­ecules are linked by C—H⋯O inter­actions, generating C(7) (001) chains.