Methyl 3-amino-2-thiophenecarboxylate → Methyl 3-(formylamino)-2-thiophenecarboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-amino-thiophene-2-carboxylic acid methyl ester (25 g, 159 mmol) in 125 mL of formic acid was added ammonium acetate (15.9 g, 207 mmol). The reaction mixture was heated to reflux for 3 hours after which time the solution was cooled to room temperature (20-25° C.). The solid that formed was filtered, washed with water, and dried in vacuo to afford 25.4 g (86%) of 3-formylamino-thiophene-2-carboxylic acid methyl ester. 1H NMR (400 MHz, DMSO) d 10.2 (s, 1H), 8.35 (s, 3H), 7.92 (d, 1H), 7.91 (d, 1H), 3.76 (s, 3H). LC-MS: 186 (MH+); HPLC RT: 2.81 minutes.

Provenance & Evidence