Phosphorus oxychloride → 3,6-Dichloropyrido[2,3-b]pyrazine

6-chloropyrido[3,2-b]pyrazin-3(4H)-one (E-27) (9 g, 49.8 mmol) was dissolved in POCl3 (100 mL) and the resulting mixture was stirred at reflux for 3 h. The reaction was complete based on TLC analysis. The mixture was cooled to RT and concentrated in vacuo to remove POCl3. The residue was poured into ice water (150 mL) and extracted with DCM (3×100 mL). The combined organic layers were washed with brine, dried over Na2SO4 and filtered. The filtrate was concentrated in vacuo to give the desired product 3,6-dichloropyrido[2,3-b]pyrazine (E-28) (9 g, 90% yield) as a solid. ESI-MS m/z: 199.97 [M+H]+.

1. temperatureat reflux for 3 h
2. concentrationconcentrated in vacuo
3. customto remove POCl3
4. additionThe residue was poured into ice water (150 mL)
5. extractionextracted with DCM (3×100 mL)
6. washThe combined organic layers were washed with brine
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationThe filtrate was concentrated in vacuo

ORD record

ord-9599de175ee44bc5aa58c152b05d7b02

Source dataset

uspto-grants-2016_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09359352B2