Phenolic Acids and Nitriles

Salicylic acid O-methyl ether has been submitted to the Birch reduction and the product methylated. This sequence is reminiscent of the synthesis of 

5-dimethoxy-n-pentylbenzene (olivetol dimethylether) in which the pentylated intermediate cartK xylic acid was then oxidatively decarboxylated (ref.86). Thus to 2-methoxybenzoic acid in tetrahydrofuran treated with potassium tert-butoxide followed by tert-butanol and 100% ammonia at -70°C, potassium metal in small pieces was added until the blue colour persisted. After this had been discharged by the addition of a drop of 1,3-pentadiene, the dihydro reduction product was methylated with methyl iodide in tetrahydrofuran and after work-up, 2-methoxy-1-methyl-cyclohexa-2, diene-1-carboxylic acid isolated in 84% yield (ref.87). 

A combined Reimer-Tiemann formylation and Claisen condensation procedure with nitromethane has been described for 4 hydroxybenzoic acid constituting 

Methylolation and cyclic acetal formation has been observed in the reaction of 4-hydroxybenzoic acid with formaldehyde. A mixture of 4-hydroxybenzoic acid 

---