Potassium Carbonate → 2-Chloro-5-(5-oxazolyl)pyridine

To a stirred suspension of 6-chloronicotinaldehyde (1.5 g, 10.59 mmol, Organic Letters 2005, 7(14) 2965-2967) and potassium carbonate (1.46 g, 10.5 mmol) in MeOH (50 mL) was added toluenesulphonylmethyl isocyanide (2.06 g, 10.59 mmol, Aldrich). The reaction mixture was heated to reflux for about 4 h. The reaction mixture diluted with water (50 mL) and the product was extracted with EtOAc (2×150 mL). The combined organic layers were washed successively with water (2×50 mL) and brine (1×50 mL), dried over sodium sulphate and evaporated to dryness. The crude material was purified by silica gel column chromatography eluted with 15% EtOAC in hexane. Relevant fractions containing the required compound were combined and evaporated to dryness under reduced pressure to afford 5-(6-chloropyridin-3-yl)oxazole as an off white solid 1.2 g (42.8. %), 1H NMR (400 MHz, CDCl3): δ 8.7 (d, J=2.0 Hz, 1H), 7.98 (s, 1H), 7.91 (d, J=2.4 Hz, 1H), 7.45 (s, 1H), 7.42 (d, J=8.4 Hz, 1H), MS m/z: 181 (M+H)+.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for about 4 h
3. extractionthe product was extracted with EtOAc (2×150 mL)
4. washThe combined organic layers were washed successively with water (2×50 mL) and brine (1×50 mL)
5. dry with materialdried over sodium sulphate
6. customevaporated to dryness
7. customThe crude material was purified by silica gel column chromatography
8. washeluted with 15% EtOAC in hexane
9. additionRelevant fractions containing the required compound
10. customevaporated to dryness under reduced pressure

ORD record

ord-7805fadb6b634c9bb64dc1cba8ebb53f

Source dataset

uspto-grants-2015_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09029409B2