Trifluoroacetic acid → 4-Chloro-1H-pyrazolo[3,4-b]pyridine

Temperature

75 °C

4-chloro-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridine (1.506 g, 5.502 mmol) was dissolved in neat TFA (8.478 ml, 110.0 mmol) and the reaction mixture was stirred at 75° C. for 2 hours. The reaction mixture was concentrated to a dark yellow oil and MeOH was added to give a thick white precipitate that was filtered and washed with MeOH. The filtrate, which contained the desired product, was concentrated to a yellow oil that was dried in vacuo overnight to yield a yellow waxy solid. The crude solid was partitioned between EtOAc and saturated NaHCO3. The phases were separated, and the aqueous layer was re-extracted with EtOAc (1×). The combined organic phases were dried over Na2SO4, filtered and concentrated to yield the desired product (0.845 g, 100%) as a yellow solid. LRMS (APCI pos) m/e 154, 156 (M+, Cl pattern).

1. concentrationThe reaction mixture was concentrated to a dark yellow oil and MeOH
2. additionwas added
3. customto give a thick white precipitate that
4. filtrationwas filtered
5. washwashed with MeOH
6. concentrationwas concentrated to a yellow oil that
7. customwas dried in vacuo overnight
8. customto yield a yellow waxy solid
9. customThe crude solid was partitioned between EtOAc and saturated NaHCO3
10. customThe phases were separated
11. extractionthe aqueous layer was re-extracted with EtOAc (1×)
12. dry with materialThe combined organic phases were dried over Na2SO4
13. filtrationfiltered
14. concentrationconcentrated

ORD record

ord-d6f6944fc6494e3c95f4c266c8410b41

Source dataset

uspto-grants-2010_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07723330B2