Boron trifluoride etherate → Ethyl 4-ethylthiazole-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a 0° C. solution of ethyl 2-amino-4-ethyl-1,3-thiazole-5-carboxylate (2.6 g, 13.0 mmol) in anhydrous THF (40 mL) was added boron trifluoride diethyl etherate (2.0 mL, 16.5 mmol). After 15 minutes of stirring at 0° C., tert-butyl nitrite (7 mL, 59 mmol) was added. The mixture was stirred at 0° C. for 3 hours, and then an aqueous solution of sodium hypophosphonate (4.1 g, 47 mmol, 15 mL) was added. The mixture was stirred at 0° C. for 2 hours and at room temperature overnight. The solution was basified to pH 8-9 with 5 N NaOH and then was extracted with EtOAc (3×75 mL). The organic extracts were combined, dried over MgSO4, filtered, evaporated, and dried in vacuo, affording ethyl 4-ethyl-1,3-thiazole-5-carboxylate (1.91 g, 80% yield). The product was used without further purification.

Provenance & Evidence