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
concentrated nitricacid 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-trimethylbenzyl nitrates and/or (2,6-diacyl-3,4,5-trimethylphenyl)nitromethanes respectively, as the major products. While the predominant mode of the side-chain substitution