Sodium Iodide → 2-Ethyl-3-iodopyrazolo[1,5-a]pyridine

To a mixture of 2-ethylpyrazolo[1,5-a]pyridine (360 g, 2.46 mol), ethyl acetate (3600 mL), water (1800 mL) and sodium iodide (480 g, 3.20 mol, 1.3 equivalent) was added N-chlorosuccinimide (411 g, 3.08 mol) over a period of 30 minutes under cooling in an ice water bath, then, the reaction mixture was stirred at room temperature for 2 hours and 20 minutes. To the reaction mixture was added water and ethyl acetate, and the resulting mixture was extracted with ethyl acetate. The separated organic layer was washed twice with a 10% sodium thiosulfate aqueous solution, and concentrated under reduced pressure. To the resulting residue was added hexane, the residue was dissolved with heating. The hexane solution was filtrated to remove an insoluble substance. The hexane solution was washed with water, and concentrated under reduced pressure. Then, the resulting residue was dissolved in ethyl acetate, and the solvent was distilled off under reduced pressure, to obtain 663 g of a title compound (yield: 98.9%).

1. temperatureunder cooling in an ice water bath
2. extractionthe resulting mixture was extracted with ethyl acetate
3. washThe separated organic layer was washed twice with a 10% sodium thiosulfate aqueous solution
4. concentrationconcentrated under reduced pressure
5. additionTo the resulting residue was added hexane
6. dissolutionthe residue was dissolved
7. temperaturewith heating
8. filtrationThe hexane solution was filtrated
9. customto remove an insoluble substance
10. washThe hexane solution was washed with water
11. concentrationconcentrated under reduced pressure
12. dissolutionThen, the resulting residue was dissolved in ethyl acetate
13. distillationthe solvent was distilled off under reduced pressure

ORD record

ord-648d3b67b6604fe9b3f9d214687bc5ae

Source dataset

uspto-grants-2010_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07858809B2