Triethylamine → 2-Benzoxazolamine, N-2-propyn-1-yl-

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Reaction Steps

A solution of 2-chlorobenzoxazole (1.53 g, 10 mmol) in CH3CN (5 mL) was added dropwise to a mixture of propargyl amine (550 mg, 9.9 mmol) and Et3N (2.09 mmol, 15 mmol) and CH3CN (10 mL) under N2, and the resulting mixture was heated to reflux for 4 h, then stirred overnight at rt. The mixture was filtered, and the filtrate was partitioned between EtOAc (100 mL) and brine. The aqueous layer was extracted with EtOAc and the combined organic layers were dried (MgSO4) and concentrated to dryness. The crude solid was diluted with heptane (20 mL) and Et2O (50 mL) and the mixture was heated to boiling and filtered hot. The filtrate was concentrated to dryness, then taken up in boiling Et2O (50 mL) and the solution was cooled and filtered. The filtrate was diluted with hexane (125 mL) and cooled to −20° C. for 4 h, and the crystallized product was collected by filtration (1.1 g, 64%). MS (APCI(+)) m/e 173.0 (M+H)+.

Provenance & Evidence