Hydrochloric Acid → 4-Hydroxy-3-methylmandelic acid

Participants

Reaction Steps

32.4 g (0.30 mol) of o-cresol are dissolved in 150 ml of 2N sodium hydroxide solution under a nitrogen atmosphere. After cooling to +5° C., 4.8 g (0.12 mol) of sodium hydroxide and 13.3 ml (0.12 mol) of 50% aqueous glycolic acid are added, and the reaction mixture is stirred at room temperature for 4 hours. A further 0.12 mol of sodium hydroxide and glycolic acid (a total of 0.36 mol) is added twice after 4 hours each time. The reaction mixture is then stirred for another 12 hours, neutralised with concentrated hydrochloric acid and washed twice with 75 ml of petroleum ether. The aqueous phase is then acidified with concentrated hydrochloric acid and extracted several times with ether. The organic phases are combined, dried over magnesium sulfate and concentrated on a vacuum rotary evaporator, giving 30.1 g (55%) of 4-hydroxy-3-methylmandelic acid, melting point 115°-120° C.

Provenance & Evidence