Nitrite → 2-Chloropyridine-3,5-dicarbonitrile

Temperatur

0 °C

Acetic acid (37 mL) was added over 10 min to sodium nitrite (13.4 g, 0.194 mol) with stirring. Concentrated sulfuric acid (12.3 mL) was added over 5 min to the resulting thick slurry which was then cooled to 0° C. In a separate flask, pyridinium hydrochloride (14.4 g, 0.125 mol) was added to a stirred mixture of 2-amino-3,5-dicyanopyridine (4.0 g, 27.75 mmol) in acetic acid (55 mL) and the resulting mixture was cooled to 0° C. to give a thick slurry. The nitrite slurry was added to the aminopyridine slurry over 5 min with stirring at 0° C. Acetic acid (50 mL) was added and the thick slurry was warmed to rt. After 1 h at rt the mixture was warmed to 50° C. and after a further 1 h, it was poured into an ice/water mixture (500 mL). The aqueous mixture was extracted with methylene chloride (4 times) and the combined extracts were dried (Na2SO4) and evaporated to a yellow solid. The crude product was purified by chromatography on silica (chloroform/methanol gradient, 1-3% methanol) to give the title compound as a solid:

1. temperaturethe resulting mixture was cooled to 0° C.
2. customto give a thick slurry
3. stirringwith stirring at 0° C
4. temperaturethe thick slurry was warmed to rt
5. temperatureAfter 1 h at rt the mixture was warmed to 50° C. and after a further 1 h
6. extractionThe aqueous mixture was extracted with methylene chloride (4 times)
7. dry with materialthe combined extracts were dried (Na2SO4)
8. customevaporated to a yellow solid
9. customThe crude product was purified by chromatography on silica (chloroform/methanol gradient, 1-3% methanol)

ORD-Eintrag

ord-776e8a69ae014a50b6323e1008fa6882

Quelldatensatz

uspto-grants-2002_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06376499B1