a simple and efficient one-pot three-component synthesis of the biologically important spirooxindole-4h-pyrans was carried out by the reaction of isatin, activated methylene reagents, and 4-hydroxycoumarin in aqueous medium. sba-pr-nh2 was found to be an efficient heterogeneous nanoporous solid basic catalyst (pore size of 6 nm) which can be easily handled and removed from the reaction mixture ...

In the title compound, C(15)H(20)O(4)S, a dioxolane ring is fused to the pyran ring of the sugar which carries a thio-phenyl substituent on the anomeric C atom. The dioxolane ring adopts an envelope conformation and the pyran ring system a distorted (4)C(1) chair. The structure is stabilized by O-H⋯O hydrogen bonds, forming centrosymmetric dimers that generate an R(2) (2)(10) ring motif. Additi...

A tunable circularly polarized distributed feedback (DFB) laser based on reflection grating configuration was realized in a solution of 4- (dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) doped methanol. Chiral photonic DFB structures with tunable photonic bandgap were generated by controlling the state of polarization of the two interfering pump beams. The dual-peak lasing ...

The title compound C28H22O2, basically consists of three ring systems, viz. a central benzene ring, with a lateral napthalene group to which it subtends a dihedral angle of 66.56 (4)° and a tetra-hydro-pyran ring exhibiting a half-chair conformation. The mol-ecular structure is stabilized by a weak intra-molecular C-H⋯O inter-action, while the crystal packing features weak C-H⋯π contacts.

The title compound, C17H11ClN2O2, which contains two stereogenic C atoms, crystallizes in a centrosymmetric space group as a racemate. The pyran ring and the isoxazole ring adopt sofa and twisted conformations, respectively. The dihedral angle between the benzene ring and the mean plane through the near coplanar atoms of the pyran ring is 4.17 (5)°. The mol-ecular conformation features a weak C...

In the title compound, C(23)H(26)O(4), the two cyclo-hexene rings adopt envelope conformations whereas the pyran ring adopts a boat conformation. In the crystal, pairs of inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into inversion dimers.

An operationally simple and efficient protocol for the construction of dihydrofuran derivatives has been accomplished via a sequential addition of N-chlorosuccinimide and a base to 2-amino-4H-pyran derivatives in alcohol medium. The one-pot protocol proceeding via tandem oxidative difunctionalization and ring contraction provides an entirely new strategy for the construction of the dihydrofuran...

The title compound, C(25)H(22)N(2)O(3), with three stereogenic centres, crystallizes in a centrosymmetric space group as a racemate. The pyran ring adopts a sofa conformation and the five-membered isoxazole ring exhibits an envelope conformation. The dihedral angle between the benzene ring and the mean plane through the near coplanar atoms of the pyran ring is 10.54 (9)°. In the crystal, no sig...

In the title compound, C(38)H(37)NO(3), the pyran ring has an envelope conformation with the quaternary C(q) atom as the flap atom. The dihedral angle formed between the meth-oxy-phenyl group and the naphthalene ring system is 67.32 (6)°. The ethyl-amino groups lie to the same side of the plane through the phenyl ring and form dihedral angles of 84.6 (3) and 75.8 (2)° with it.

In the title compound, C(17)H(17)FO(3), the benzene ring of the isochroman unit is inclined at 84.96 (7)° to the fluoro-benzene ring plane, and the pyran ring adopts a half-boat conformation. In the crystal structure, C-H⋯O hydrogen bonds link mol-ecules into rows along the c axis, while C-H⋯O inter-actions and C-H⋯F hydrogen bonds to the fluorine acceptor stack the mol-ecules down the b axis. ...