Synthesis of gallic acid (-14COOH)

A series of reactions was elaborated for the transformation of 1, 2, 3‐trimethoxybenzene into gallic acid‐14CO2H. The intermediate 1‐bromo‐3, 4, 5‐trimethoxybenzene was prepared by nitration, reduction, diazotization, and decomposition of the diazonium salt in the presence of cuprous bromide. The halide‐exchange reaction of the aryl bromide with butyl lithium, decomposition of the inter‐mediate lithio derivative with 14CO2, and demethylation, led to gallic acid‐14CO2H.