Ipso nitration. XIX. Formation of cyclohexadiene adducts from nitration of 4-ethyltoluene and 1,4-diethylbenzene in nitric acid and acetic anhydride

Abstract

Nitration of 4-ethyltoluene in acetic anhydride at -20° gives the diastereoisomers of 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dienyl acetate and of 4-ethyl-1-methyl-4-nitrocyclohexa-2,5-dienyl acetate. Similar nitration of 1,4-diethylbenzene gives the diastereoisomers of 1,4-diethyl-4-nitro-cyclohexa-2,5-dienyl acetate. Rearomatization of the adducts of p-ethyltoluene in trifluoroacetic acid-trifluoroacetic anhydride gives 4-ethyl-2-nitrotoluene from the 1-ethyl-4-methyl-4- nitro isomers and 4-ethyl-3-nitrotoluene from the 4-ethyl-1-methyl-4-nitro isomers. In aqueous methanol 2-ethyl- 5-methylphenyl acetate is obtained from the 1-ethyl-4-methyl-4-nitro isomers and 5-ethyl-2- methyl-phenyl acetate from the 4-ethyl-1-methyl-4-nitro isomers.