1,1'-Carbonyldiimidazole → Rac-Efavirenz

Participants

Reaction Steps

A solution of 2-(2-amino-5-chlorophenyl)-4-cyclopropyl-1,1,1-trifluoro-3-butyn-2-ol (15.00 g, 0.0518 mol) and 41.98 g (0.259 mol) of 1,1'-carbonyldiimidazole in 250 mL of dry THF was stirred under argon at 55° C. for 24 hours. The solvent was removed on a rotary evaporator and the residue was partitioned between 500 mL of ethyl acetate and 400 mL of water. The layers were separated and the aqueous phase was extracted once more with ethyl acetate. The combined ethyl acetate extracts were washed with 2×200 mL of 2% aqueous HCl, saturated aqueous NaHCO3, and brine. Drying over MgSO4, filtration, and removal of the solvent in vacuo provided 16.42 g of the title compound as a solid. Recrystallization from ethyl acetatehexane afforded 12.97 g of analytically pure (±) 6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one as a white crystals. mp: 178°-180° C. 1H-NMR (CDCl3): 0.85 (m, 2H), 0.94 (m, 2H), 1.40 (m, 1H), 6.81 (d, J=8.5 Hz, 1H), 7.37 (dd, J=2.5, 8.5 Hz, 1H), 7.49 (d, J=2.5 Hz, 1H), 8.87 (br s, 1H).

Provenance & Evidence