Isovanillin (3-hydroxy-4-methoxybenzaldehyde) (10 g, 0.066 mole) isdissolved in dry chloroform (100 ml) and the solution cooled to 0°.Performic acid (obtained as given in 1.36) (50 ml) is added dropwise to thevigorously stirred solution.Addition of performic acid is stopped as soon asan aliquot showed the absence of isovanillin on TLC. The mixture isstirred for 3 hr and the solvent removed in vacuo.The residue consisting ofthe formate of isovanillin is treated with alcoholic potassium hydroxidesolution (10%) till the solution is alkaline.Finally, the reaction mixture isrefluxed for 1 hr with a solution of potassium hydroxide (10%，100 ml) inaqueous ethanol (80%). The solvent is removed in vacuo and theremaining solution is acidified with dilute hydrochloric acid.It is extractedwith ether (4 × 100 ml). The ether extract is dried (anhydrous sodiumsulphate) and distilled. 4-Methoxyresorcinol is obtained as an oil. Yield 7 g(76%),b.p.132-5/4 mm.It solidifies on cooling, m.p. 66-7°.
