Methanol → Methyl p-aminosalicylate

Participants

Reaction Conditions

Reaction Steps

To a suspension of 9.18 g (0.06 mole) 4-aminosalicylic acid (7) (Aldrich A7,960-4) in 40 mL of dry methanol was added 8 mL of concentrated sulfuric acid slowly. The mixture was heated under reflux at 70 ° C. for 1.5 hours and then it was cooled in an ice-water bath. Enough concentrated ammonium hydroxide solution was added to adjust the pH to 9 and the precipitate was filtered, rinsed with water and dried to give 6.01 g (60%) of 9 as a solid, mp 118-120° (ref. 120-121°). Infrared (IR) and NMR analysis gave the following results: IR (potassium bromide): 3473 and 3379 (NH2), 1643 (C=O),1284, cm−1. 1H nmr (90 MHz, CDCI3):δ 10.96 (1H, s, OH), 7.6 (1H; d, 3JH5-H6=9 Hz; H-6), 6.20-6.08 (2H, cm, H-3 and H-5), 4.2 (2H; br s; NH2), 3.87 (3H, s, CH3).

Provenance & Evidence