Methanol → 3,5-Diamino-2-methylbenzoic acid

Participants

Reaction Steps

To the stirred suspension of commercial 3,4-diaminobenzoic acid (10.3 g) in methanol (150 ml) conc. sulphuric acid (5 ml) was added cautiously. The mixture was stirred under reflux for 3 h. About half of the solvent is removed by distillation and dichloromethane (150 ml) is added. The organic layer was poured in ice water (300 ml) and with vigorous stirring the pH was adjusted to 11 with 10M NaOH. The organic layer was separated and the aqueous layer extracted with dichloromethane (150 ml). The combined organic layers were dried over sodium sulfate and concentrated. The residue was purified by fractional crystallisation from dichloromethane to give methyl 3,4-diaminobenzoate (7.05 g) as beige coloured solid.

Provenance & Evidence