A new synthesis of pyridazines.

Synthesis and pharmacology of 3,4-dihydro-3-oxo-1,4-benzoxazine-8-carboxamide derivatives, a new class of potent serotonin-3 (5-HT3) receptor antagonists.

A Convenient New Synthesis of Benzo[ a ]pyrene | …

New strategies for the synthesis of pyrene derivatives have been developed in recent years [,].

A Convenient New Synthesis of Benzo[ a ]pyrene

A more promising synthetic route to the BP quinones of interest is via oxidation of the individual BP phenol isomers. In a prior study we showed that oxidation of 8-HO-BP with the hypervalent iodine reagent o-iodoxybenzoic acid (IBX) provided convenient synthetic access to BP 7,8-dione., We now report that oxidation of 9-HO-BP with IBX by a similar procedure furnished BP 9,10-dione in good yield (82%).

acid, a convenient new reagent for the synthesis of …

Only three of the PAPs employed in this investigation (1- and 2-naphthol and 9-phenanthrol) were available from commercial sources. Although procedures for the synthesis of the remaining PAPs have been reported, they use classical synthetic methods that entail large numbers of steps and/or have other practical disadvantages. We, therefore, undertook to develop more convenient new synthetic approaches.

Synthesis of new 2-substituted pyrido[2,3-]pyrimidin-4(1)-ones and their antibacterial activity.

CAS 79839-49-9 2-Bromobenzene-1,3-dialdehyde - BOC …

The most convenient synthetic precursors of 6-HO-BP and 13C2-6-HO-BP are BP and 13C2-BP themselves. An efficient synthesis of 13C2-BP from was recently reported. Direct synthesis of 6-HO-BP from BP was accomplished via initial Vilsmeier-Haack reaction of BP with POCl3 and DMF to furnish 8-formylbenzo[a]pyrene (23) (). Baeyer-Villager oxidation of 23 with m-chloroperbenzoic acid provides 8-formyloxybenzo[a]pyrene (24). The formate ester derivative was relatively stable in contrast to 6-HO-BP which exhibited a strong tendency to undergo oxidative decomposition on exposure to air. The ease of auto-oxidation of 6-HO-BP accords with the earlier findings of Lorentzen et al who showed the principal products of auto-oxidation of 6-HO-BP to be the the BP 1,6-, 3,6-, and 6,12-diones.

A convenient new synthesis of benzo[a]pyrene

Zajc, B.: Synthesis of (±)-trans-7,8-dihydrodiol of 6-fluoro-benzo[a]pyrene via hydroxyl-directed regioselective functionalization of substituted pyrene, J. Org. Chem. 1999, 64, 1902-1907.

Corannulene is a polycyclic aromatic hydrocarbon with chemical ..

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants produced in the combustion of organic matter. PAHs are present in automobile exhaust and tobacco smoke, and they have recently been designated as human carcinogens. Current evidence indicates that PAHs are activated enzymatically to mutagenic metabolites that interact with DNA. There is evidence for three pathways of activation, the diol epoxide path, the radical-cation path, and the quinone path. The relative importance of these paths for human lung cancer has not been established. We now report syntheses of the principal phenol and quinone isomers of the prototype PAH carcinogen benzo[a]pyrene (BP) that are known or are suspected to be formed as metabolites of BP in human bronchoalveolar cells. The methods of synthesis were designed to be adaptable to preparation of the 13C-labelled analogues of the BP metabolites. These compounds are needed as standards for sensitive LC-MS/MS methods for analysis of BP metabolites formed in lung cells. Efficient novel syntheses of the 1-, 3-, 6-, 9-, and 12-BP phenols, and the BP 1,6-, 3,6-, 6,12-, and 9,10-quinones are now reported. The syntheses of the BP phenols (except 6-HO-BP) involve in the key steps Pd-catalyzed Suzuki-Miyaura cross-coupling of a naphthalene boronate ester with a substituted aryl bromide or triflate ester. The BP quinones were synthesized from the corresponding BP phenols by direct oxidation with the hypervalent iodine reagents IBX or TBI. These reagents exhibited different regiospecificities. IBX oxidation of the 7- and 9- BP phenols provided the ortho-quinone isomers (BP 7,8-, and 9.10-dione), whereas TBI oxidation of the 1-, 3-, and 12-BP phenols furnished BP quinone isomers with carbonyl functions in separate rings (BP 1,6-, 3,6-, and 6,12-dione).

The first indirect method of pyrene synthesis we will ..

In order to further probe the scope of IBX/BTI oxidation of PAPs for the synthesis of PAQs, several additional examples were investigated (). The phenol and quinone isomers of benzo[a]pyrene (BaP) were of particular interest because several phenol and quinone isomers are among the principal metabolites of this widespread environmental carcinogen, and recent research has implicated BaP-7,8-dione (10) as an active metabolite of BaP that contributes to induction of lung cancer., Oxidations of the 7- and 8-phenols of BaP (9 and 12) with IBX both took place ortho-regiospecifically to furnish 10. Analogous oxidations of the BaP 9- and 10-phenols (13 and 15) with IBX also took place ortho-regiospecifically to furnish BaP-9,10-dione (14).