Reacción #468135

Ecuación de reacción

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

Rendimiento 48.0%

Disolventes

—

hexanes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrowas quenched with 20% aqueous citric acid
2. 2
   ExtracciónThe mixture was extracted with ether
3. 3
   Extracciónthe organic extract
4. 4
   Lavadowas washed with saturated aq. NaHCO3
5. 5
   ConcentraciónThe solution was concentrated under reduced pressure
6. 6
   Otrothe crude product was recrystallized from ethyl acetate-hexanes

Procedimiento

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).

Fuente