تفاعل #162554

معادلة التفاعل

8-chloro-3-ethylquinoxalin-2(1H)-one

POCl3

→

3,5-dichloro-2-ethylquinoxaline

المردود 77.2%

ظروف التفاعل

المعالجة

1. 1
   أخرىAfter the removal of most of the POCl3 under reduced pressure
2. 2
   workup.ADDITIONthe residue was poured carefully into ice-water
3. 3
   استخلاصThe resulting suspension was extracted with DCM (3×4 L)
4. 4
   غسيلThe organic phase was washed with brine
5. 5
   تجفيفdried over anhydrous Na2SO4
6. 6
   ترشيحfiltered
7. 7
   أخرىevaporated under reduced pressure
8. 8
   أخرىThe crude was purified by flash column chromatography
9. 9
   غسيلeluting with hexane/EtOAc (30/1)

الإجراء التجريبي

A thick slurry of 8-chloro-3-ethylquinoxalin-2(1H)-one (1.00 Kg, 4.79 mol) in POCl3 (2.68 L, 28.8 mol) was stirred at 100° C. for 2 h. At this time LC-MS analysis showed that the reaction was complete. After the removal of most of the POCl3 under reduced pressure, the residue was poured carefully into ice-water and neutralized with a combination of 2M aq. NaOH and saturated aq. NaHCO3. The resulting suspension was extracted with DCM (3×4 L). The organic phase was washed with brine, dried over anhydrous Na2SO4, filtered, and evaporated under reduced pressure. The crude was purified by flash column chromatography eluting with hexane/EtOAc (30/1) to give 3,5-dichloro-2-ethylquinoxaline (840 g) as a white solid. 1H NMR (DMSO-d6) δ ppm 8.01-8.08 (m, 2H), 7.84 (t, J=8.0 Hz, 1H), 3.10-3.17 (d, J=7.3 Hz, 2H), 1.36 (t, J=7.3 Hz, 3H). Mass Spectrum (ESI) m/z=227.1 (M+1).

المصدر