反应详情

Dissolve 5-chloropyrazine-2-carboxamide (Example 389, Part A) (0.0878 g, 0.557 mmol) in POCl3 (5.6 mL) and heat at reflux for 35 minutes. Concentrate the reaction mixture. Take up the dark oil in saturated aqueous NaHCO3 (15 mL) and extract with dichloromethane (2×25 mL). Wash the organic layer with brine (1×15 mL), dry over Na2SO4, filter and concentrate. Purify by flash chromatography, eluting with 10% ethyl acetate in hexanes to give the title compound (0.0498 g, 64.0%): GC/MS, MS ES+ 139 (M)+, time 10.6 min, % of total 100%; HPLC [YMC-Pack Pro C-18 (150×4.6 mm, S-5 microm), 0.1% TFA/acetonitrile in 0.1% TFA/water at 1.0 mL/min, 20-99% over 23 min], tR 8.2 min, 100% purity.

1. temperatureheat
2. temperatureat reflux for 35 minutes
3. concentrationConcentrate the reaction mixture
4. extractionextract with dichloromethane (2×25 mL)
5. washWash the organic layer with brine (1×15 mL)
6. dry with materialdry over Na2SO4
7. filtrationfilter
8. concentrationconcentrate
9. customPurify by flash chromatography
10. washeluting with 10% ethyl acetate in hexanes