Triethylamine → Efavirenz

Participants

Reaction Conditions

Reaction Steps

A solution of (1S,4R)-N-(4-chloro-2-((S)-4-cyclopropyl-1,1,1-trifluoro-2-hydroxybut-3-yn-2-yl)phenyl)-4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carboxamide (10, 30 g, 63.9 mmol), dichloromethane (150 mL) and triethylamine (7.11 g, 70.2 mmol) was stirred at 0-5° C. for 20 minutes, then 1-chloroethyl chloroformate (10.0 g, 70.2 mmol) was added dropwise. The mixture was stirred at 5-10° C. for 1 hour. Then N,N-dimethylformamide (150 mL) was added and further evaporated to 220 mL, then K2CO3 (13.3 g, 95.8 mmol) was added. The reaction mixture was stirred at room temperature overnight. Methyl t-butyl ether (300 mL) and water (200 mL) were added to the mixture, and the resulting layers were separated. The organic layer was washed with brine, and concentrated to 60 mL whereupon petroleum ether (200 mL) was added and stirred. The resulting precipitate was filtered and rinsed with petroleum ether to provide 18.4 g (S)-6-chloro-4-(cyclopropylethynyl)-4-(trifluoromethyl)-1,4-dihydro-2H-3,1-benzoxazin-2-one (Efavirenz, 1) as an off-white solid.

Provenance & Evidence