Sodium Nitrite → HCID 12375331, compound

Temperature

-5 °C

3-(5-Chloro-2-methoxyphenyl)pyridin-2-amine (5.00 g, 21 mmol) was dissolved in the mixture of THF (409 mL), HBF4 (50% aqueous solution, 36 mL) and 15 mL of water. The solution was cooled to −5° C., and sodium nitrite (1.70 g in 20 mL of water) was added dropwise. Reaction was kept 1 hour at −5° C., then was allowed to warm up to room temperature and stirred overnight at room temperature. Then pH of the reaction mixture was adjusted to 10, and it was extracted with ethyl acetate (4×25 mL). Organic fractions were combined, dried over sodium sulfate and evaporated. The residue was subjected to column chromatography on silica gel, eluent hexane/ethyl acetate 9/1 mixture. Chromatography product contained 3-(5-chloro-2-methoxyphenyl)-2-fluoropyridine, pure 6-chlorobenzofuro[2,3-b]pyridine (1.52 g, colorless long needles) was obtained by crystallization from hexane/ethyl acetate.

1. customReaction
2. temperatureto warm up to room temperature
3. extractionwas extracted with ethyl acetate (4×25 mL)
4. dry with materialdried over sodium sulfate
5. customevaporated

ORD record

ord-39b1359470e94c6bbfb3d9c35d8de048

Source dataset

uspto-grants-2012_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08221905B2