Water → 3-Bromo-5-chloropyridin-2-amine

A solution of 257 g (1.61 mol) of bromine in 380 ml of acetic acid was added dropwise over a period of one hour to a solution of 187 g (1.45 mol) of 2-amino-5-chloropyridine in 1.5 l of acetic acid. The reaction mixture was refluxed for 3 h and then allowed to cool to ambient temperature. 1.9 l of demineralized water were added and the mixture was concentrated in vacuo. The residue was partitioned between 4 l of ethyl acetate and 1.8 l of water. The mixture was basified with 3 l of a 10% by weight aqueous sodium hydroxide solution. The organic layer was separated and washed with brine (2×1.5 l), dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was filtered, washed with hexane (2×100 ml) and dried in vacuo to give 192 g of 2-amino-3-bromo-5-chloropyridine. The mother liquor was concentrated in vacuo, filtered, washed with hexane and dried to give further 75 g of the same product.

1. temperatureThe reaction mixture was refluxed for 3 h
2. concentrationthe mixture was concentrated in vacuo
3. customThe residue was partitioned between 4 l of ethyl acetate and 1.8 l of water
4. customThe organic layer was separated
5. washwashed with brine (2×1.5 l)
6. dry with materialdried over magnesium sulfate
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. filtrationThe residue was filtered
10. washwashed with hexane (2×100 ml)
11. customdried in vacuo

ORD record

ord-3ff3dce31711435e883aa8a0d2859a18

Source dataset

uspto-grants-2005_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06914068B2