Potassium Carbonate → 5-broMo-2-(1,3-oxazol-5-yl)pyridine

To a stirred suspension of 5-bromopicolinaldehyde (0.412 g, 2.215 mmol, Tetrahedron Letters 2008, 64, 3794-3801) and potassium carbonate (0.3358 g, 2.43 mmol, Rankem) in MeOH (20 mL) was added toluenesulphonylmethyl isocyanide (0.4757 g, 2.43 mmol). The reaction mixture was heated to reflux for about 4 h. The reaction mixture diluted with water (100 mL) and the product was extracted with EtOAc (2×75 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 obtained was purified by silica gel column chromatography eluted with 10% EtOAC in hexane. Relevant fractions containing the target compound were combined and evaporated to dryness under reduced pressure to afford 5-(5-bromopyridin-2-yl)oxazole as an off white solid 0.35 g (70.2%), 1H NMR (400 MHz, DMSO): δ 8.7 (d, J=2.4 Hz, 1H), 8.57 (s, 1H), 8.2 (dd, J=8.4 Hz, 1H), 7.8 (s, 1H), 7.7 (d, J=8.8 Hz, 1H), MS m/z: 226 (M+H)+.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for about 4 h
3. extractionthe product was extracted with EtOAc (2×75 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 obtained
8. customwas purified by silica gel column chromatography
9. washeluted with 10% EtOAC in hexane
10. additionRelevant fractions containing the target compound
11. customevaporated to dryness under reduced pressure

ORD record

ord-4fc3bc5c3d2d4701864144bfaf4736d4

Source dataset

uspto-grants-2015_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09029409B2