Stannous chloride dihydrate → 5-Bromo-2-methoxypyridin-3-amine

To a solution of 5-bromo-2-(methyloxy)-3-nitropyridine (45 g, 193 mmol) in ethyl acetate (1 L) was added tin(II) chloride dihydrate (174 g, 772 mmol). The reaction mixture was heated at reflux for 4 h. LC/MS indicated some starting material remained, so added 20 mol % tin (II) chloride dihydrate and continued to heat at reflux. After 2 h, the reaction was allowed to cool to ambient temperature and concentrated in vacuo. The residue was treated with 2 N sodium hydroxide and the mixture stirred for 1 h. The mixture was then with methylene chloride (1 L), filtered through Celite, and washed with methylene chloride (500 mL). The layers were separated and the organics dried over magnesium sulfate and concentrated to give 5-bromo-2-(methyloxy)-3-pyridinamine (23 g, 113 mmol, 58.7% yield). The product was used crude in subsequent reactions. MS(ES)+ m/e 201.9, 203.9 [M+H]+.

1. temperatureThe reaction mixture was heated
2. temperatureat reflux for 4 h
3. temperatureto heat
4. temperatureat reflux
5. concentrationconcentrated in vacuo
6. additionThe residue was treated with 2 N sodium hydroxide
7. filtrationwith methylene chloride (1 L), filtered through Celite
8. washwashed with methylene chloride (500 mL)
9. customThe layers were separated
10. dry with materialthe organics dried over magnesium sulfate
11. concentrationconcentrated

ORD record

ord-5a9720a95e3e4ecca1143991d8d99452

Source dataset

uspto-grants-2012_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08138347B2