Réaction #457541

Équation de réaction

4-chloro-6-methoxy-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one

n-BuLi

1-butyne

→

4-(1-butynyl)-6-methoxy-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one

Rendement 48.0%

Solvants

—

hexanes

THF

Conditions de réaction

Traitement

1. 1
   Autrewas quenched with 20% aqueous citric acid
2. 2
   ExtractionThe mixture was extracted with ether
3. 3
   Extractionthe organic extract
4. 4
   Lavagewas washed with saturated aq. NaHCO3
5. 5
   ConcentrationThe solution was concentrated under reduced pressure
6. 6
   Autrethe crude product was recrystallized from ethyl acetate-hexanes

Mode opératoire

To a stirred, cooled(-78° C.) solution of 0.5 g(excess) of 1-butyne in 3 mL of anhydrous THF was added 1.6 mL(4.0 mmol) of a 2.5M solution of n-BuLi in hexanes over 3 min. The solution was stirred 5 min. and charged with 266 mg(1.00 mmol) of 4-chloro-6-methoxy-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one as a single portion. The solution was warmed to -10° C. over 20 min., whereupon it was quenched with 20% aqueous citric acid. The mixture was extracted with ether, and the organic extract was washed with saturated aq. NaHCO3 then brine. The solution was concentrated under reduced pressure, and the crude product was recrystallized from ethyl acetate-hexanes to afford 144 mg(48%) of 4-(1-butynyl)-6-methoxy-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one as a white solid, mp 161-162° C. 1H NMR(300 MHz, CDCl3) δ 8.81(br. s, 1H); 7.07(d, 1H, J=2 Hz); 6.94(dd, 1H, J=9, 2 Hz); 6.81(d, 1H, J=8 Hz); 3.82(s, 3H); 2.34(q, 2H, J=7 Hz); 1.22(t, 3H, J=7 Hz).

Source