Phosgene → Ethyl 3h-furo[2,3-f]benzoxazole-2-one-6-carboxylate

Participants

Reaction Steps

A mixture of 0.9 g (4.2 mmol) of ethyl 5-hydroxy-6-aminobenzofuran-2-carboxylate [Helv. Chim. Acta 77, 100. (1994)], 60 ml of tetrahydrofuran, 3.1 ml of 20% phosgene in toluene solution and 2.0 ml of triethylamine is stirred at room temperature for 1 h. The tetrahydrofuran is distilled off in vacuum, water is added to the residue and the product is extracted with ethyl acetate. The combined organic layers are washed with 5% aqueous sodium hydrogencarbonate solution, water, 1 N hydrochloric acid solution and again with water, dried over sodium sulfate and concentrated to yield 1.0 g (96%) of the title compound as oil.

Provenance & Evidence