Pyridine-functionalized MCM-41 catalyzed reactions between tetracyanoethylene and various activated CH-acid compounds are described. These reactions afford the corresponding pyran annulated heterocyclic ring systems in high yields at room temperature within a few minutes. The work-up procedure is very simple and the products do not require further purification. The catalyst can be recycled and ...

In the title compound, C12H15IO7, the 3,4-di-hydro-2H-pyran ring is in a distorted half-boat conformation with the atom bearing the acet-yloxy group adjacent to the C atom bearing the methyl-acetate group lying 0.633 (6) Å above the plane of the remaining ring atoms (r.m.s. deviation = 0.0907 Å). In the crystal, mol-ecules are linked into a supra-molecular chain along the a axis through two C-H...

The title compound, C(21)H(21)BrO(7)·C(2)H(6)O, was synthesized by the Claisen-Schimidt reaction of helicid (systematic name: 4-formyl-phenyl-β-d-allopyran-oside) with 4-bromo-aceto-phenone in ethanol. The pyran ring adopts a chair conformation. In the crystal structure, mol-ecules are linked into a three-dimensional network by inter-molecular O-H⋯O hydrogen bonds.

In the title compound, C(23)H(22)N(2)O(3), the pyran ring adopts a twisted boat conformation. The tolyl rings and carboxyl-ate group are attached to the pyran ring with torsion angles of -77.1 (2), 59.5 (3) and 17.8 (3)°, respectively. The ethyl group is disordered over two orientations with a site-occupancy ratio of 0.508 (5):0.492 (5). In the crystal, mol-ecules are linked by N-H⋯N and N-H⋯O ...

The title compound, C20H47NO6Si4, was synthesized by per-O-tri-methyl-silylation of N-acetyl-d-glucosa-mine using chloro-tri-methyl-silane in the presence of hexa-methyl-disiloxane. The tri-methyl-silyl group and acetamido group are located on the same side of the pyran ring, showing an α-configuration glycoside. One of the tri-methyl-silyl groups is disordered over two orientations, with site-...

In the title compound, C(20)H(23)N(3)O(3), the dihydro-pyran ring adopts half-chair conformation. The chromene system makes a dihedral angle of 87.35 (5)° with the adjacent benzene ring. 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 hydrogen bonds contribute to the stabilization of the pac...

In the title compound, C(19)H(18)N(2)O(2), the dihedral angle between the mean planes of the fused chromeno and isoxazole units is 43.71 (7)°. The isoxazole and pyran rings exhibit envelope and half chair conformations, respectively. The crystal packing is stabilized by inter-molecular C-H⋯π inter-actions.

The crystal structure of the title compound, C(28)H(38)O(11), solved and refined against synchrotron diffraction data, contains two formula units in the asymmetric unit. In both mol-ecules, the dihydro-pyran ring along with its methyl substituents is disordered and adopts two alternative half-chair conformations. The occupancy of the major conformers of the two mol-ecules refined to 0.858 (5) a...

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(20)H(15)N(3)O(3)S, the thia-zole ring is approximately planar, with a maximum deviation of 0.003 (1) Å, and makes dihedral angles of 7.44 (6) and 1.88 (6)° with the hy-droxy-substituted phenyl ring and the pyran ring, respectively. The hydroxyl group is disordered over two sets of sites, with an occupancy ratio of 0.567 (3):0.433 (3). In the crystal, the major disorder ...