CLAY-CATALYZED NITRODECARBOXYLATION OF AROMATIC-ACIDS

Nitration of p-anisic acid in clay microenvironment yields 2,4-dinitro anisole in about 40-60% yield, in addition to the conventional nitrati on product, namely 3-nitro-4-methoxybenzoic acid. While clay directed nitration of p-methoxyacetophenone gives only 3-nitro-4-methoxy-acetop henone, with m-nitrobenzoic acid, nitrodecarboxylation yielding m-dini trobenzene is the only reaction course. The observed greater ipso-nitr ation facilitated by a nitro group may be attributed to the greater ea se with which the Wheland intermediate may decompose via a cyclic six- membered transition state.