Nitration of p-cymene in acetic anhydride gives a mixture of cis- and trans-1-isopropyl-4-methyl-4-nitro-1,4-dihydrophenyl acetate as the main product as well as 2- and 3-nitro-p-cymene and p-nitrotoluene. Acid-catalysed methanolysis of the acetoxynitro adduct gives a mixture of the cis- and trans-methoxynitro adducts. Under basic conditions the acetate adduct is converted into the corresponding alcohol which is in turn rearomatized to 2-isopropyl-4-methylphenol. The adducts rearomatize to 2-nitro-p-cymene in strong acid.
Nitration of p-tert-butyltoluene in acetic anhydride gives 5-tert-butyl-2-methyl-2-nitro-1,2-dihydrophenyl acetate (43%), cis- and trans-1-tert-butyl-4-methyl-4-nitro-1,4-dihydrophenyl acetate (16%) and 4-tert-butyl-2-nitrotoluene (41%). Reaction of either of the 1,2 or 1,4 nitroacetoxy adducts with hydrogen chloride gives a mixture of the 1,2 and 1,4 nitrochloro adducts. The 1,2 (secondary) acetate adduct eliminates nitrous acid to form 5-tert-butyl-2-methylphenyl acetate under mildly acidic conditions. Under more vigorously acidic conditions 4-tert-butyl-2-nitrotoluene is formed. The same products are formed from the 1,4 (tertiary) acetate adducts but p-tolyl acetate is also obtained. The 1,2 and 1,4 adducts couple with anisole to form 5-tert-butyl-4′-methoxy-2-methylbiphenyl.
Nitration of 3,4-dimethylacetophenone in acetic anhydride gives a mixture of cis-and trans-2-acetyl-4,5-dimethyl-4-nitro-1,4-dihydrophenyl acetate as the main product, together with 3,4-dimethyl-2-, 3,4-dimethyl-5-, and 3,4-dimethyl-6-nitroacetophenone. Analogous products are obtained from 3,4-dimethylbenzophenone. Rearomatization of the adducts under mildly acidic conditions occurs via 1,4-elimination of nitrous acid to form 2-acetyl- and 2-benzoyl-4,5-dimethylphenyl acetate, respectively. In strongly acidic conditions elimination of acetic acid accompanied by 1,2- and 1,3-shifts of the nitro group occurs to form the 2- and 5-nitro derivatives of the parent ketones. The rearomatization to the nitro derivatives involves the intermediate formation of an ipso-cyclohexadienyl cation which may be trapped by anisole or mesitylene to form biphenyl derivatives.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.