Two high-yielding strategies for the synthesis of 4H-anthra[1,2-b]pyran antibiotics have been developed giving access to novel antitumor agent (ED(50) 1.5 microm) and to (S)-espicufolin (3). A key step for the assembly of the tetracyclic 4H-anthra[1,2-b]pyran-4,7,12-trione skeleton is the nucleophilic addition of an aryl lithium species onto an aldehyde which allows the introduction of either a...

In the title compound, C23H20N2O6, the fused pyrone and pyran rings each adopt a sofa conformation. The dihedral angle between the mean planes of the pyran and phenyl rings is 61.9 (1)°. In the crystal, mol-ecules are linked by two pairs of C-H⋯O hydrogen bonds, forming dimers. These dimers are linked via a third C-H⋯O hydrogen bond, forming a two-dimensional network parallel to (10-2).

The asymmetric unit of the title compound, C26H28O6·2CH3OH, contains two independent methyl 6-O-trityl-α-d-gluco-pyran-oside mol-ecules and four methanol solvent mol-ecules. The rings of two methyl α-d-gluco-pyran-oside adopt chair conformations. In the crystal, extensive intra- and inter-molecular O-H⋯O and C-H⋯O hydrogen bonds link the mol-ecules into a three-dimensional supra-molecular archi...

In the title compound, C10H5ClO3, a chlorinated 3-formyl-chromone derivative, all atoms are essentially coplanar (r.m.s. deviation = 0.032 Å for the non-H atoms), with the largest deviation from the least-squares plane [0.0598 (14) Å] being for a pyran-ring C atom. In the crystal, mol-ecules are linked through stacking inter-actions along the b axis [shortest centroid-centroid distance between ...

The asymmetric unit of the title compound, C(25)H(22)OS, comprises two similar 4-(4-methoxy-phen-yl)-4-methyl-2,6-diphenyl-4H-thio-pyran mol-ecules. In each, the six-membered thio-pyran ring adopts a planar conformation (r.m.s. deviation of 0.041Å for the ring in one mol-ecule and 0.008 Å in the other). The methoxy-phenyl substituent is in a pseudo-axial position. The crystal studied is an inve...

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 TITLE COMPOUND (SYSTEMATIC NAME 7-oxo-3-phenyl-2,6-dioxabicyclo-[3.3.1]nonan-4-yl acetate), C(15)H(16)O(5), is a styryllactone derivative which was isolated from Goniothalamus macrophyllus. The mol-ecule has two fused rings consisting of a tetra-hydro-2H-pyran and a lactone ring, with the benzene ring and the acetyl group attached to the tetra-hydro-2H-pyran ring. The tetra-hydro-2H-pyran r...

The duration of protection afforded by 5 known interferon inducers was deterw•ined. Groups of mice were given a single dose of statolon, maleic acid-divinyl ether copolymer (pyran), polycytidylic/polyinosinic acid (I/C), Newcastle disease virus (NDV), or bacterial endotoxin. These groups and an untrek,3d control group were uniformly challenged with MM virus. Survival data obtained during 20 day...

In the title mol-ecule, C18H16O7, the dioxolane ring adopts an envelope conformation with the dimethyl-substituted C atom as the flap. The furan ring is almost coplanar with the pyran ring, with a dihedral angle of 1.04 (10)° between the planes, and it makes a dihedral angle of 67.97 (11)° with the mean plane of the dioxolane ring. The latter makes a dihedral angle of 67.15 (10)° with the pyran...