1-Chloro-2-iodo-4-nitrobenzene → 2-(2-Chloro-5-nitrophenyl)pyridine

Temperature

60 °C

The 2-chloro-5-nitro-iodobenzene (5 g, 17.6 mmol) was dissolved in 5 mL DMA in an oven dried flask and a 0.5M solution of 2-pyridylzincbromide (53 mL, 26.5 mmol, 0.5 M in THF) was added. The solution was degassed with N2 for ½ hr., the PPh3 (0.185 g, 0.7 mmol) and Pd(PPh3)4 (0.825 g, 0.7 mmol) were added, rinsed in with several mLs THF and the solution was degassed for a further 10 min before heating to 60° C. under N2. The reaction was complete by TLC in ˜8 h, cooled to RT, and poured into a 1:1 mixture of EtOAc/2.5N NaOH (500 mL). This solution was stirred for 10 min, passed through a course fritted filter containing celite to remove the solid, and then extracted. The organics were washed with brine and concentrated to a brown solid. The combined aqueous layers were backextracted with Et2O (1×200 mL). This was used to suspend the crude product, which was extracted with 1N HCl (1×200 mL, 3×100 mL). The combined aqueous extracts were cooled to 0° C., diluted with EtOAc (250 mL), and made basic with 10N NaOH (100 mL). This solution was separated, the aqueous layer extracted with EtOAc, and the combined organics were dried over Na2SO4 and charcoal with stirring. This solution was filtered through celite and concentrated to yield pure 4-chloro-3-(pyridin-2-yl)nitrobenzene (2.47 g, 10.5 mmol, 60% yield) which was used in the next reaction without further purification.

1. customdried flask
2. customThe solution was degassed with N2 for ½ hr
3. washrinsed in with several mLs THF
4. customthe solution was degassed for a further 10 min
5. temperaturecooled to RT
6. additionpoured into a 1:1 mixture of EtOAc/2.5N NaOH (500 mL)
7. additioncontaining celite
8. customto remove the solid
9. extractionextracted
10. washThe organics were washed with brine
11. concentrationconcentrated to a brown solid
12. extractionwas extracted with 1N HCl (1×200 mL, 3×100 mL)
13. temperatureThe combined aqueous extracts were cooled to 0° C.
14. additiondiluted with EtOAc (250 mL)
15. customThis solution was separated
16. extractionthe aqueous layer extracted with EtOAc
17. dry with materialthe combined organics were dried over Na2SO4 and charcoal
18. stirringwith stirring
19. filtrationThis solution was filtered through celite and
20. concentrationconcentrated

ORD record

ord-6a9ae0b3f48e42309512524e43ad017d

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09278961B2