In the title compound, C(15)H(14)N(4)O, the pyrazole ring is aligned at 88.23 (4)° with respect to the aromatic ring and at 3.75 (4)° with respect to the pyran ring. In the crystal, N-H⋯N hydrogen bonds link adjacent mol-ecules into a linear chain motif. C-H⋯N inter-actions are also observed.

The asymmetric unit of the title compound, C(26)H(12)ClNO(6), consists of two independent mol-ecules. The central pyran rings and both the 1-benzopyran ring systems are nearly planar in both mol-ecules [r.m.s. deviations of pyan rings = 0.0264 (1) and 0.0326 (1) Å for molecules A and B, respectively; r.m.s. deviations of benzopyran rings = 0.0439 (1) and 0.0105 (1) for molecule A, 0.0146 (1) an...

In the title compound, C(22)H(18)N(2)O(2), the pyran ring of the chromene unit is fused with an isoxazole ring, which adopts an N-envelope conformation with the N atom lying 1.3291 (14) Å from the mean plane of the remaining ring atoms [maximum deviation = 0.341 (2) Å]. The dihedral angle between the isoxazole and chromene units is 43.74 (8)° and that between the iosxazole ring and the naphthal...

In the title compound, C(25)H(30)O(6), the two fused cyclo-hexa-none rings have envelope conformations, whereas the central pyran ring is roughly planar [mximum deviation = 0.045 (2) Å]. The pyran and benzene rings are almost perpendicular to each other, making a dihedral angle of 86.32 (2)°. In the crystal, molecules are linked via pairs of O-H⋯O hydrogen bonds, forming inversion dimers.

The pyran-oside ring in the title compound, C(21)H(24)O(11), has a chair conformation with the substituted benzene ring occupying an equatorial position. The crystal packing is dominated by C-H⋯O inter-actions that lead to the formation of supra-molecular layers in the ab plane.

In the title compound, C11H8O3, the fused-ring system is almost planar (r.m.s. deviation = 0.020 Å), with the largest deviation from the least-squares plane [0.0462 (17) Å] being for a pyran C atom. The dihedral angle between the plane of the fused-ring system and acetyl plane is 5.149 (16)°. In the crystal, the fused rings are linked by aromatic π-π stacking inter-actions [centroid-centroid di...

A stereodivergent synthesis of enantiopure 3,6-dihydro-2H-pyrans is presented. The addition of lithiated enol ethers to carbohydrate-derived nitrones afforded syn- or anti-configured hydroxylamine derivatives 4a-d that were cyclized under Lewis acidic conditions to yield functionalized dihydropyrans cis- or trans-5a-d containing an enol ether moiety. This functional group was employed for a var...

In the title mol-ecule, C11H10O3, the fused dihydro-pyran ring is in a half-chair conformation with the O atom and the methyl-ene C atom positioned 0.1318 (13) and 0.143 (2) Å, respectively, on either side of the mean plane formed by the other four atoms. In the crystal, weak C-H⋯O hydrogen bonds link mol-ecules along [001].

In the biologically active title compound, C26H26O5, the pyran ring of the chromene unit adopts a half-chair conformation. The C=C double bond of the propenone unit exhibits a trans conformation and the carbonyl group is syn conformation to the double bond. The dihedral angle between the benzene ring and the benzopyran-one moiety is 31.54 (4)°. The mol-ecular structure is stabilized by an intra...

In the title mol-ecule, C(18)H(19)N(3)O(2), the fused cyclo-hexenone and pyran rings adopt sofa conformations. Inter-molecular N-H⋯N and N-H⋯O hydrogen bonds link mol-ecules into corrugated layers parallel to the bc plane.