In the title compound, C(15)H(23)N(3)O(4), the six-membered pyran, cyclo-hexane and trioxane rings adopt chair, chair and boat conformations, respectively, while the seven-membered rings adopt distorted boat and very distorted chair conformations. In the crystal, adjacent mol-ecules are connected by weak C-H⋯N and C-H⋯O inter-actions.

New indeno[1,2-c]pyran-3-ones bearing different substituents at the pyran moiety were synthesized and their photophysical properties were investigated. In solution all compounds were found to be blue emitters and the trans isomers exhibited significantly higher fluorescence quantum yields (relative to 9,10-diphenylanthracene) as compared to the corresponding cis isomers. The solid-state fluores...

The title compound, C11H10O3, is a phenyl-subsituted dihydro-pyran-dione in which the heterocycle adopts a boat conformation with the phenyl substituent canted 72.14 (5)° relative to the mean plane of the heterocycle.

In the title compound, C(20)H(24)O(5), the six-membered pyran-ose ring adopts a chair conformation. The dihedral angle between the planes of the phenyl groups of the benzyl substituents is 63.1°. Two types of inter-molecular O-H⋯O hydrogen bonds lead to the formation of infinite chains along the b axis. Only weak C-H⋯O contacts exist between neighboring chains.

In the title compound, C(31)H(29)NO(5), the methyl carboxyl-ate and dimethyl-amino groups on the naphtho-pyran group are almost coplanar with the naphtho-pyran ring system [r.m.s. deviations = 0.08 (2) and 0.161 (2) Å, respectively]. The dihedral angle between the methyl carboxyl-ate and dimethyl-amino groups is 4.9 (1)°. The pyran ring has an envelope conformation with the quaternary C atom ou...

In the title compound, C(27)H(27)NO(4), the five-membered isoxazole ring adopts an envelope conformation and the six-membered pyran ring adopts a half-chair conformation. The dihedral angle between the mean planes of the isoxazole ring and the chromene ring system is 54.95 (4)°.

In the title compound, C25H27ClO3, each of the cyclo-hexenone rings adopts an envelope conformation, whereas the six-membered pyran ring adopts a flattened boat conformation, with the O and methine C atoms deviating from the plane of the other four atoms. The C=C double bond is in the trans conformation. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into chains running parallel ...

In the title compound, C(16)H(14)O(4)·H(2)O, the dihedral angle betwen the benzene rings is 71.4 (6)°. The pyran ring is in a sofa conformation. In the crystal, O-H⋯O hydrogen bonds connect the components into a two-dimensional network parallel to (010), incorporating C(2) (2)(4) and C(2) (2)(11) chains. In addition, weak C-H⋯O, C-H⋯π and π-π stacking inter-actions [centroid-centroid distance =...

In the title compound, C(23)H(25)NO(5), the pyran ring adopts a flattened boat conformation, while the two cyclo-hexenone rings are in envelope conformations. The 3-nitro-phenyl ring is almost perpendicular to the pyran ring, making a dihedral angle of 87.1 (3)°.