92693-64-6Relevant articles and documents
Solvolysis of K-region arene oxides: Substituent effects on reactions of benz[a]anthracene 5,6-oxide
Nashed, Nashaat T.,Balani, Suresh K.,Loncharich, Richard J.,Sayer, Jane M.,Shipley, David Y.,Mohan, Ram S.,Whalen, Dale L.,Jerina, Donald M.
, p. 3910 - 3919 (2007/10/02)
The solvolytic reactivity and products formed from benz[a]anthracene 5,6-oxide (BA-O) on substitution of a methyl group at positions 1 (1-MBA-O), 4 (4-MBA-O), 7 (7-MBA-O), 11 (11-MBA-O), and 12 (12-MBA-O), on 7,12-dimethyl substitution (7,12-DMBA-O), and on 7-bromo substitution in 1:9 dioxane-water and in methanol at 25°C are reported. These substitutions result in > 150-fold differences in their rates of acid-catalyzed solvolysis and cause marked changes in the distribution of solvent adducts and phenols resulting from isomerization. Optically pure BA-O, 7-MBA-O, 12-MBA-O, and 7,12-DMBA-O as well as their optically pure trans dihydrodiols were utilized to determine the point of attack by water in the hydrolysis reactions. In general, the reactions in aqueous dioxane (0.1 M NaClO4) obeyed the rate equation kobsd = kH[H+] + k0, where kH is the second-order rate constant for acid-catalyzed reaction and k0 is the first-order rate constant for spontaneous reaction, to provide biphasic pH-rate profiles. When ionic strength was maintained with 0.5 M KCl, however, more complex pH-rate profiles were observed for some of the arene oxides due to attack of chloride on the neutral epoxide to produce steady-state concentrations of chlorohydrins. Rate enhancement on methyl substitution is largest (kH, ca. 5-fold) when the methyl group is present in the hindered bay region (C1 or C12) or adjacent to the epoxide at C7. The combined effect of two methyl groups (7,12-DMBA-O) is additive (ca. 25-fold). Theoretical calculations (molecular mechanics by PCMODEL-PI and ab initio by GAUSSIAN 86 and 88 programs) of carbocation stability indicate the importance of steric factors in determining relative reactivity and types of products formed from substituted benz[a]anthracene 5,6-oxides.
Resolution and Absolute Configuration of K-Region Trans Dihydrodiols from Polycyclic Aromatic Hydrocarbons
Balani, S. K.,Bladeren, P. J. van,Shirai, N.,Jerina, D. M.
, p. 1773 - 1778 (2007/10/02)
K-region trans dihydrodiols of benzophenanthrene, chrysene, pyrene, and dibenzacridine have been resolved as their diastereomeric diesters with (-)-(menthyloxy)acetic acid, and their absolute configuration have been assigned by the application of circular dichroism and excition chirality methods.For these as well as the K-region trans dihydrodiol derivatives from five other hydrocarbons, a consistent pattern of physical properties has emerged.The R,R diastereomers are less retained on silica gel HPLC columns when eluted with ether-cyclohexane mixtures and show negative values of D in tetrahydrofuran, the degree of magnetic nonequivalence between HA and HB in the -OCHAHBCO2- portion of the diesters (100 MHz, C6D6) is generally much higher for the S,S enantiomers of the dihydrodiols, and the free R,R dihydrodiols have positive values of D in tetrahydrofuran provided their hydroxyl groups do not have a marked preference for the pseudodiaxial conformation.
Direct Enantiomeric Resolution of Some 7,12-Dimethylbenzanthracene Derivatives by High-Performance Liquid Chromatography with Ionically and Covalently bonded Chiral Stationary Phases
Yang, Shen K.,Weems, Henry B.
, p. 2658 - 2662 (2007/10/02)
The direct resolution of the enantiomers of trans-3,4-dihydrodiol, trans-5,6-dihydrodiol, cis-5,6-dihydrodiol, trans-8,9-dihydrodiol, and 8,9,10,11-tetrahydro-trans-8,9-diol of 7,12-dimethylbenzanthracene was evaluated by high-pepformance liquid chromatography using commercially available columns packed with (R)-N-(3,5-dinitrobenzoyl)phenylglycine and (S)-N-(3,5-dinitrobenzoyl)leucine either ionically or covalently bonded to γ-aminopropylsilanized silica.The enantiomers of all diol derivatives were resolved by one or more, but not all, of the chiral stationary phases tested.Resolution of enentiomers was confirmed by ultraviolet-visible absorption, mass, and circular dichroism spectral analyses.
