Dimethylformamide → 6-Chloro-1,3-dimethyl-1H-pyrazolo[3,4-b]pyridine-5-carbaldehyde

Temperature

95 °C

A mixture of acetic anhydride (6.62 mL, 70 mmol) and 2,5-dimethyl-2H-pyrazol-3-ylamine (5.0 g, 45 mmol) was heated while stirring at 90-100° C. for 4 h. After evaporation of volatiles in vacuo, phosphorus oxychloride (18.5 mL, 200 mmol) was added and the mixture was heated while stirring at 90-95° C. for 3 h. Thereafter, anhydrous DMF (9.2 mL, 120 mmol) was added slowly over the period of 30 min while maintaining the internal temperature of the mixture at 90-95° C. After stirring for an additional 2 h, the reaction mixture was cooled to RT and poured over crushed ice (100-120 g). The precipitated solid was filtered off, washed with water and dried in vacuo. The yellowish solid product was subsequently dissolved in methylene chloride (100 mL), washed with water, dried over sodium sulfate, and the solvent was evaporated in vacuo to give the desired product as light yellow solid (4.1 g, yield: 44%).

1. temperaturewas heated
2. additionwas added
3. temperaturethe mixture was heated
4. stirringwhile stirring at 90-95° C. for 3 h
5. temperaturewhile maintaining the internal temperature of the mixture at 90-95° C
6. stirringAfter stirring for an additional 2 h
7. temperaturethe reaction mixture was cooled to RT
8. additionpoured
9. filtrationThe precipitated solid was filtered off
10. washwashed with water
11. customdried in vacuo
12. dissolutionThe yellowish solid product was subsequently dissolved in methylene chloride (100 mL)
13. washwashed with water
14. dry with materialdried over sodium sulfate
15. customthe solvent was evaporated in vacuo

ORD record

ord-1a0a085770ab402597ddd0118c753e39

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08604055B2