Birch reduction of 3, 4, 5-trimethoxybenzoic acid gives 3, 5-dimethoxy-1, 4-dihydrobenzoic acid. Lithium alumi-num hydride reduction of the dihydroacid followed by tosylation and solvolysis of the tosylate in pyridine gives a mixture of 1, 3-dimethoxycycloheptatrienes which on bromine oxidation gives 8-tropolone in 28% average overall yield. This method has been applied to the synthesis of a-tropolone from 2, 3-dimethoxybenzoic acid, y- ...
