In the title compound, C20H17N3O4, the central pyran ring adopts a boat conformation with the O atom and diagonally opposite C atoms displaced by 0.1171 (1) and 0.1791 (1) Å, respectively, from the mean plane defined by the other four atoms. The coplanar atoms of the pyran ring and the meth-oxy-benzene ring are nearly perpendicular, as evidenced by the dihedral angle 87.01 (1)°. The amine H ato...

In the title compound, C(19)H(20)O(5), the pyran ring is in an envelope conformation, whereas the benzene and dihydro-pyran ring system is planar with an r.m.s. deviation of 0.0190 (1) Å. The hy-droxy group is coplanar with the attached benzene ring [r.m.s. deviation = 0.0106 (1) Å]. An intra-molecular O-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are linked into ...

In the title compound, C(31)H(38)O(17), the 1,3-dioxane and pyran-oside rings both show (4)C(1) chair conformations while for the d-fructofuran-oside moiety an envelop 3E conformation is observed. The phenyl ring is oriented almost perpendicular to the 1,3-dioxane ring [dihedral angle = 79.3 (2)°], and the acetate groups are equatorial for the pyran-oside ring and axial for the furan-oside ring...

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, C19H17NO5, comprising two stereogenic C atoms of the same configuration, crystallizes in a centrosymmetric space group as a racemate. The pyran ring adopts a half-chair conformation, while the isoxazole ring adopts an envelope conformation with the C atom bonded to the meth-oxy-phenyl group as the flap. The dihedral angle between the mean plane of the pyran ring and the adja...

In the crystal structure of the title compound, C(27)H(27)NO(5)S, the pyran-ose ring adopts a (4)C(1) chair conformation with puckering parameters Q = 0.639 (2) Å, θ = 174.11 (18) and ϕ = 256 (2)°. The presence of the 2,3-trans-oxazolidinone fixes the conformation of the pyran-ose ring. The phenyl group attached to the S atom and the benzyl group bonding to the N atom are each disordered over t...

A copolymer donor PBDTTPTP based on a tetracyclic bislactone unit, thieno[2',3':5,6]pyrano[3,4-d]thieno[3,2-b]pyran-4,9-dione (TPTP), was developed. The single crystal structure of TPTP derivative indicates the π-extended planar geometry and...

The unstable isomeric compounds 5-hydroxy-7-prop-2-en-(E)-ylidene-7,7adihydro-2H-cyclopenta[b]pyran-6-one (1) and 5-hydroxy-7-prop-2-en-(Z)-ylidene-7,7adihydro-2H-cyclopenta[b]pyran-6-one (2), previously described as antimicrobial metabolites from the sponge Ulosa sp., were isolated and identified as major components of the ascidian Diplosoma virens. In this paper, full spectral data for 2 and ...

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 ...