A new family of ring-annulated inositols with "locked" conformations has been designed to deliver a range of these biologically important entities in "unnatural conformations" while retaining their "natural configurations". The simple "tool" of trans ring fusion has been used to "lock" the conformation of the annulated inositols. Short, simple syntheses of a range of these novel cyclitols have ...

In the title compound, C24H15BrO3, the pyran-ochromenone ring is essentially planar, while the 2-bromo-phenyl group is almost perpendicular to it [85.58 (6)°]. In the crystal, inversion dimers linked by pairs of weak C-H⋯π bonds occur; there is also a short inter-atomic contact found between the Br and carbonyl O atoms [3.016 (1) Å].

Asymmetric allylic alkylation is a powerful reaction that allows the enantioselective formation of C-C bonds. Here we describe the asymmetric alkylation of alkylzirconium species to racemic 3,6-dihydro-2H-pyrans. Two systems were examined: 3-chloro-3,6-dihydro-2H-pyran using linear optimization (45-93% ee, up to 33% yield, 5 examples) and 3,6-dihydro-2H-pyran-3-yl diethyl phosphate with the ass...

Synthesis Reaction of 1a,b with 2-aminothiophenol and sodium ethanolate in ethanol does not give the expected tetracyclic ring systems, but surprisingly the spirocompounds 2 are obtained. A [2+4] cycloaddition of the intermediately formed 1,2-benzoquinone-2-imine-1-thione with the aurone was postulated. Under these conditions the thioaurones 1c,d showed no reaction. After reaction of 1with 2-am...

The chemical nature of the edge periphery essentially determines the physical properties of graphene. As a molecular-level model system, large polycyclic aromatic hydrocarbons, that is, so-called nanographenes, can be chemically modified through either edge functionalization or doping with heteroatoms. Although the synthetic methods for edge substitution are well-developed, incorporation with h...

Pyran copolymer (NSC 46015) was found to potentiate strongly the immune response of C57BL/6J X DBA/2 F1 mice to 10(4) live L1210 tumor cells following suboptimal vaccination with 10(7) radiation-inactivated L1210 cells. Optimal immunity to challenge was produced by concomitant i.p administration of pyran and L1210 vaccine, and activity was dependent upon both pyran and vaccine dosages. In addit...

Diversity-oriented synthesis of novel benzimidazole linked indolo-benzodiazepine/quinoxaline ring systems using poly(ethylene glycol) as soluble polymer support is described. Commercially available 4-fluoro-3-nitrobenzoic acid and indoline were utilized for the construction of these annulated biheterocyclic compound libraries having multiple privileged structures with three-point structural div...

Oxidative annulations for the synthesis of carbocycles were developed using a catalytic palladium(II) system. Indoles with pendant olefin tethers were oxidatively cyclized to form annulated products. Electron-rich aromatic systems were also investigated, culminating in the synthesis of benzofurans and dihydrobenzofurans by a similar protocol. These reactions were demonstrated to proceed by an i...

Some novel annulated pyrido[2,3-d]pyrimidines 6 and 7 were synthesized stereoselectively by intramolecular hetero Diels-Alder reactions involving 1-oxa-1,3-butadienes.