Phosphorus oxychloride → 7-Chlorothieno[3,2-b]pyridine

Temperature

105 °C

A stirred suspension of thieno[3,2-b]pyridin-7-ol (5.0 g, 33.1 mmol) in POCl3 (15 mL) was heated at 105° C. in an oil bath for 4 hrs. The resultant solution was cooled to room temperature and the POCl3 was removed under reduced pressure. The residue was cooled in an ice/water bath and cold water was added. The mixture was made basic with concentrated NH4OH solution and extracted with EtOAc. The organic extract was dried over anhydrous sodium sulfate and concentrated to produce oil, which was purified by column chromatography (eluent EtOAc-hexane, 1:4) to afford the title compound as a brown solid (4.5 g, 72% yield). 1H NMR (400 MHz, CDCl3) δ (ppm): 8.60 (d, J=4.9 Hz, 1H), 7.80 (d, J=5.5 Hz, 1H), 7.60 (d, J=5.5 Hz, 1H), 7.30 (d, J=4.9 Hz, 1H).

1. customthe POCl3 was removed under reduced pressure
2. temperatureThe residue was cooled in an ice/water bath
3. additioncold water was added
4. extractionextracted with EtOAc
5. extractionThe organic extract
6. dry with materialwas dried over anhydrous sodium sulfate
7. concentrationconcentrated
8. customto produce oil, which
9. customwas purified by column chromatography (eluent EtOAc-hexane, 1:4)

ORD record

ord-cdad092c0b444319b81d2e88c299cb5c

Source dataset

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08093264B2