Benzaldehyde → 4-Benzylamino-phthalic acid dimethyl ester

Participants

Reaction Steps

Benzaldehyde (1.64 ml, 16.2 mmol) and sodium cyanoborohydride (1.02 g, 16.2 mmol) were added to a solution of 4-aminophthalic acid dimethyl ester (1.7 g, 8.1 mmol) in dry methanol (50 ml) and pH was adjusted to 5.5-5 with 2 M hydrogen chloride in methanol (approx. 1 ml). The reaction mixture was stirred at room temperature for 20 hours and evaporated to dryness in vacuo. The residue was partitioned between methylene chloride (50 ml) and water (30 ml). pH was adjusted to 8 and the organic phase was isolated, dried over magnesium sulphate and evaporated to dryness in vacuo. The crude product was purified on silica gel (eluent: ether:heptane (1:1)) to give 4-benzylaminophthalic acid dimethyl ester as a golden oil (yield: 0.94 g, 39%). 1H—NMR (CDCl3) in ppm: γ 3.82 (3H,s); 3.88 (3H,s); 4.35 (2H,d); 4.66 (1H, broad d); 6.57 (1H,d.d.); 6.65 (1H,d); 7.23-7.35 (5H,m); 7.73 (1H,d).

Provenance & Evidence