Hydrochloric Acid → 2,3-Diaminobenzoic acid methyl ester

Participants

Reaction Steps

A solution of 2,3-diaminobenzoic acid (0.2 g, 1.32 mmol) in methanol (40 ml) was saturated with hydrogen chloride as described above, and the mixture was subsequently heated under reflux for 2 hours. The solid residue obtained on evaporation of the solvent was dissolved in water, and the solution was adjusted to pH 7.0 with sodium hydrogen carbonate. After extraction with ethyl acetate (2×30 ml), the combined organic layers were dried (MgSO4), and the solvent was removed to give methyl 2,3-diaminobenzoate as a brown oil which solidified on trituration with petrol (40/60) (121.6 mg, 56%), m.p. 62-63° C. Found: C, 58.35; H, 5.80; N, 16.69. C8H10N2O2 requires C, 57.83; H, 6.02; N, 16.87%; δH (d6-DMSO), 200 MHz) 3.87 (3H, s, OCH3). 4.90 (2H, br s, Ar-2-NH2), 6.32 (2H, br s, Ar-3-NH2), 6.46-6.54 (1H, t, Ar-5H), 6.80-6.84 (1H, dd, Ar-4H), 7.18-7.23 (1H, dd, Ar-6H); m/z (EI) 166 (M+), 134, 106, 79.

Provenance & Evidence