反応 #468135

反応方程式

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

収率 48.0%

溶媒

—

hexanes

THF

反応条件

後処理

1. 1
   その他was quenched with 20% aqueous citric acid
2. 2
   抽出The mixture was extracted with ether
3. 3
   抽出the organic extract
4. 4
   洗浄was washed with saturated aq. NaHCO3
5. 5
   濃縮The solution was concentrated under reduced pressure
6. 6
   その他the crude product was recrystallized from ethyl acetate-hexanes

実験手順

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).

出典