N-methyl-2-pyrrolidone → Methyl 3-amino-6-(trifluoromethyl)benzo[b]thiophene-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

A 22-L, 3-necked, round-bottom flask equipped with a mechanical stirrer, nitrogen bubbler, and a thermocouple probe, was charged with 1.20 kg (5.55 mole) of 2-nitro-4-trifluoromethylbenzonitrile, 589.3 g (496 mL, 5.55 mole) of methyl thioglycolate, and 4.3 L of NMP. After the resulting yellow solution was cooled to 2° C., a solution prepared from 466.0 g (11.11 mole, 2.0 eq) of lithium hydroxide monohydrate in 3.36 L of water was slowly added over a period of 78 min while maintaining a temperature of 2-20° C. The brown slurry was allowed to warm to 21° C. over a 2 h period, then was diluted with 8.0 L of water (Texo->27° C.). After stirring for 40 min and cooling to 18° C., product was collected by filtration, rinsing with 10 L of water, then air-drying at ambient temperature to give 1.295 kg (84.7% yield) of 2-carbomethoxy-3-amino-6-trifluoromethylbenzo[b]thiophene, as a light-yellow solid.

Provenance & Evidence