Iodine → 2-Chloro-5-iodopyridin-4-amine

Silver sulfate (7.1 g, 22.8 mmol) and 4-amino-2-chloropyridine (4.06 g, 31.6 mmol) were added to a solution of iodine (5.65 g, 22.3 mmol) in ethanol (100 mL) and the reaction mixture stirred at rt for 72 h. The bright yellow suspension was filtered, washed with methanol and the filtrate concentrated in vacuo. The residue was partitioned between saturated Na2CO3 solution (200 mL) and ethyl acetate (200 ml). After separation the organic layer was washed with Na2S2O3 solution (50 mL, 25%) and brine (50 mL), dried (MgSO4), concentrated in vacuo and purified by chromatography on silica gel eluting with iso-hexane/ethyl acetate (3:1 to 2.5:1) to give the title compound. δH (CDCl3): 4.81 (2H, br s), 6.63 (1H, s), 8.38 (1H, s); m/z (ES+)=254.86 [M+H]+; RT=2.5 min.

1. filtrationThe bright yellow suspension was filtered
2. washwashed with methanol
3. concentrationthe filtrate concentrated in vacuo
4. customThe residue was partitioned between saturated Na2CO3 solution (200 mL) and ethyl acetate (200 ml)
5. customAfter separation the organic layer
6. washwas washed with Na2S2O3 solution (50 mL, 25%) and brine (50 mL)
7. dry with materialdried (MgSO4)
8. concentrationconcentrated in vacuo
9. custompurified by chromatography on silica gel eluting with iso-hexane/ethyl acetate (3:1 to 2.5:1)

ORD record

ord-3d795af9f28446ca924ce3a3aa563dda

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08158622B2