Acetic Anhydride → Methyl 4-acetamidosalicylate

Participants

Reaction Steps

To a suspension of 4.17 g (0.025 mole) methyl 4-aminosalicylate (9) in 20 mL water, was added 3 mL (0.032 mole) acetic anhydride (Aldrich 11,004-3) while stirring. The mixture was heated at 800 for 30 minutes and cooled to room temperature. The precipitate was collected and added into 100 ml of 10% hydrochloric acid. This suspension was stirred at room temperature for 10 minutes, filtered and dried to give 4.3 g (82%) of a crude solid, which was recrystallized from H2O/CH3OH, yielding 3 g (70%) of 10 as white crystals, mp 153-154 . Infrared (IR) and NMR analysis gave the following results: IR (potassium bromide): 3319(NH), 1680 (C=O),1604, 1157 cm−1. 1H nmr (90 MHz, CDCI3 +DMSO-d6):δ 10.80 (1H, S, OH), 9.74 (1H, br s, NH), 7.73 (1H; d, 3JH5-H6=9 Hz; H-6), 7.37 (1H; d, 4JH5-H3=1.8 Hz; H-3),7.11 (1H; dd, 3JH6-H5=9HZ, 4JH3-H5=1.8 Hz; H-5), 3.91 (3H; s; OCH3), 2.15 (3H, s, CH3).

Provenance & Evidence