Methyl 3-amino-2-thiophenecarboxylate → Methyl 3-((tert-butoxycarbonyl)amino)thiophene-2-carboxylate

Participants

Reaction Steps

In a 3 L 3 neck flask with a mechanical stirrer, DMAP (11.5 g, 0.10 mmol) was added to a solution of 3-amino-thiophene-2-carboxylic acid methyl ester (105 g, 0.95 mmol) and in pyridine (750 mL). A solution of (BOC)2O (222 g, 1.02 mol) in pyridine (750 mL) was slowly added to the previous solution while the temperature was kept between 20 and 25° C. The mixture was stirred under nitrogen for 20 h. The reaction mixture was evaporated to dryness then triturated in 500 mL of MeOH at rt for 3 h then 30 min at 0° C. The suspension was filtered on a buchner funnel and washed with cold ethanol. The white solid was dried to afford 175 g (70%) of 3-tert-Butoxycarbonylamino-thiophene-2-carboxylic acid methyl ester.

Provenance & Evidence