78740-44-0Relevant academic research and scientific papers
Positional Reactivity of Acylpolymethylbenzenes in Electrophilic Substitution
Matsuura, Kazunori,Kimura, Yasuo,Takahashi, Hisakazu,Morita, Toshio,Takahashi, Ichiro,et al.
, p. 757 - 765 (2007/10/02)
Friedel-Crafts acylation, bromination, deuteration, and nitration of acetylpentamethylbenzene (APMB), 1-acetyl-2,3,4,6-tetramethylbenzene (ATMB), and 1-benzoyl-2,3,4,6-tetramethylbenzene (BTMB) and the resulting product distribution were investigated.Friedel-Crafts acylation, bromination, and deuteration of APMB and Friedel-Crafts acylation of ATMB gave deacetylation-substitution products.On the other hand, bromination and deuteration of ATMB (or BTMB) and Friedel-Crafts acylation of BTMB gave 5-substituted products.In both cases, the positional reactivities were in accordance with the relative ?-complex stability.Conversely, except for Friedel-Crafts-type nitration, the positional reactivities in the nitration of these substrates were strikingly different from those of the above three reactions.Thus, side-chain functionalization at the 6-methyl group occurred in nitration with fuming nitric acid, depending on the solvents in use.The NMDO calculations and the reaction of APMB with single-electron transfer reagents such as tetranitromethane-hν or cerium(IV) ammonium nitrate suggest that the product distribution in nitration can be explained in terms of a single-electron transfer mechanism.
An Interpretation of the Puzzling Dichotomy of the Reaction Modes Observed during the Side-chain Nitration of Alkylaromatics
Suzuki, Hitomi,Koide, Hideki,Taki, Yukiko,Ohbayashi, Eiichi,Ogawa, Takuji
, p. 891 - 894 (2007/10/02)
Nitration of substituted pentamethylbenzenes has been carried out under various conditions using the title nitrating systems in order to elucidate the peculiar dependence of the modes of side-chain substitution on the reagent employed; nitrooxylation with HNO3/CH2Cl2 and nitration with HNO3/(CH3CO)2O.Based on the evidence obtained from product variations with substituents, electrochemical nitrodecarboxylation of arylacetates, and ESR examination of the initial stage of the side-chain reactions, a proposal is made that the side-chain substitution of polysubstituted arenes occurs via a heterolytic path with HNO3/CH2Cl2 and via a homolytic path with HNO3/(CH3CO)2O.
Regioselective Side-Chain Nitration of Polymethylbenzenes Directed by an Acyl Function and Its Application to the Synthesis of Polysubstituted Phthalic Acid Derivatives
Keumi, Takashi,Morita, Toshio,Teramoto, Koichi,Takahashi, Hisakazu,Yamamoto, Hiroshi,et al.
, p. 3439 - 3446 (2007/10/02)
Nitration of three types of tetramethylacetophenones and pentamethylacetophenone with fuming nitric acid in acetic anhydride was carried out.The product distributions were compared with those estimated from substituent effects.A variety of acylpentamethylbenzenes including pentamethylbenzoic acid were reacted with the nitrating system to give regioselectively 2-(nitromethyl)-3,4,5,6-tetramethylacylbenzenes.The selective nitrations of some benzoic acid derivatives followed by an alkaline treatment have been found to provide the N-hydroxyphthalimide derivatives, which a re readily converted to the phthalic anhydrides and the phthalazines.
The Nitration of Acylpentamethylbenzenes and 1,3-Diacyltetramethylbenzenes Bearing, as the Acyl Components, Pivaloyl, Trichloroacetyl, and Tribromoacetyl Groups. Exclusive Attack on the Methyl Group at the Most Crowded Site
Suzuki, Hitomi,Hashihama, Mitsuyuki,Mishina, Tadashi
, p. 1186 - 1190 (2007/10/02)
When treated with concentrated nitric acid in dichloromethane at room temperature, the title compounds undergo an exclusive attack on the methyl group at the most crowded site, giving 6-acyl-2,3,4,5-tetramethylbenzyl nitrates, and 2,6-diacyl-3,4,5-trimeth
