Ammonia → Methyl 5-aMino-6-broMopicolinate

To a solution of 5.00 g 5-amino-pyridine-2-carboxylic acid methyl ester in 75 mL of a 48% aqueous solution of hydrobromic acid, 3.39 mL of a 32% aqeous solution of hydrogen peroxide were added. The mixture was stirred at room temperature for 2 hours, then additional 0.80 mL hydrogen peroxide solution were added. After stirring for 1 hour the reaction mixture was cooled down and brought to pH 8 by addition of concentrated aqueous ammonia. The mixture was extracted with 300 mL ethyl acetate. The aqueous layer was washed with additional ethyl acetate and then the combined organic phases were dried over sodium sulfate. After filtration the solvent was removed under reduced pressure and the residue was purified by chromatography on silica gel eluting with a n-heptane/ethyl acetate gradient. Yield: 2.83 g MS(ES+): m/e=231.

1. stirringAfter stirring for 1 hour the reaction mixture
2. temperaturewas cooled down
3. extractionThe mixture was extracted with 300 mL ethyl acetate
4. washThe aqueous layer was washed with additional ethyl acetate
5. dry with materialthe combined organic phases were dried over sodium sulfate
6. filtrationAfter filtration the solvent
7. customwas removed under reduced pressure
8. customthe residue was purified by chromatography on silica gel eluting with a n-heptane/ethyl acetate gradient

ORD record

ord-a3765cea00dd4730999612a399ca58a4

Source dataset

uspto-grants-2008_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07317027B2