A simple, efficient and eco-friendly procedure for the selective monohydrolysis of diethyl 2,6-dimethyl-4-aryl-4H-pyran-3,5-dicarboxylates under quaternary ammonium salt catalysis conditions is presented. The catalytic activities of various quaternary ammonium salts were investigated using different molar ratios of NaOH and water-organic solvent mixtures. The results indicate that the combinati...

The focus of our study is the synthesis and biological activity evaluation of a series of 4H-Pyran compounds and schiff bases fused 4H-Pyran derivatives which are known to possess a wide variety of biological activities. In this paper at first a simple and efficient one-pot synthesis of 4H-Pyran s from the three-component reaction between malononitrile, aldehydes, and active methylene compounds...

The focus of our study is the synthesis and biological activity evaluation of a series of 4H-Pyran compounds and schiff bases fused 4H-Pyran derivatives which are known to possess a wide variety of biological activities. In this paper at first a simple and efficient one-pot synthesis of 4H-Pyran s from the three-component reaction between malononitrile, aldehydes, and active methylene compounds...

In the title compound, C(19)H(18)N(2)O(2), the five-membered isoxazole ring adopts an envelope conformation and the deviation of the N atom from the mean plane of the isoxazole ring is -0.3256 (11) Å. The pyran ring adopts a half-chair conformation. The isoxazole ring forms dihedral angles of 44.07 (7) and 84.23 (7)° with the pyran and methyl-benzene rings, respectively. The mol-ecular structur...

In the title compound, C(13)H(12)O(2), the dihedral angle between the pyran-one and phenyl rings is 57.55 (9)°. In the crystal, the mol-ecules are linked by π-π stacking inter-actions between the parallel pyran-one rings of neighboring mol-ecules with distances of 3.5778 (11) Å and 3.3871 (11) Å between the planes. C-H⋯O interactions also occur.

In the title compound, C(21)H(19)ClO(3), the two cyclo-hexenone rings adopt half-chair conformations, whereas the pyran ring adopts a boat conformation. The 4-chloro-phenyl ring is almost perpendicular to the plane through the four C atoms of the pyran ring [dihedral angle = 87.97 (6)°]. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into a chain parallel to the a-axis.

In the title compound, C(12)H(13)N(3)O(6), the dihydro-pyran ring adopts a near screw-boat conformation. The dihedral angle between the mean planes of the benzene and dihydro-pyran rings is 6.35 (5)°. An intra-molecular N-H⋯O hydrogen bond generates an S(6) motif, which stabilizes the mol-ecular conformation. In the crystal, weak inter-molecular C-H⋯O, N-H⋯O and C-H⋯π hydrogen bonds contribute ...

In the title compound, C(17)H(15)NO(2)S(2), the 3H-benzo[f]chromene ring system is distinctly twisted; the dihedral angle between the pyran ring and its opposite benzene ring is 9.11 (8)°. The N,N-dimethyl-carbamodithio-ate residue lies almost perpendicular to the pyran ring [dihedral angle = 85.15 (7)°]. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into C(10) chains propagatin...

In the title compound, C(14)H(20)N(2)O(5)S·CH(4)O, the pyran-ose and pyridine rings are linked through an S atom. The pyran-ose ring has a normal chair conformation. An intra-molecular O-H⋯N hydrogen bond occurs. Inter-molecular O-H⋯O, N-H⋯O, O-H⋯N and weak C-H⋯O hydrogen bonding is present in the crystal structure.

In the title compound, C(17)H(15)N(3)O(4), the atoms of the spiro pyran ring are nearly planar with a maximum deviation of 0.0188 (14) Å. The benzene and pyrrole rings make a dihedral angle of 5.71 (6)°. The indole system and the pyran ring are oriented at a dihedral angle of 82.94 (3)°. The crystal structure is stabilized by inter-molecular classical and non-classical N-H⋯O, N-H⋯N and C-H⋯O hy...