Trifluoroacetic acid → ethyl 6-cyclopropyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylate

To a 20 mL microwave vial were combined ethyl 6-cyclopropyl-1-{[4-(methyloxy)phenyl]methyl}-1H-pyrazolo[3,4-b]pyridine-4-carboxylate (2.05 g, 5.83 mmol), trifluoroacetic acid (6.74 ml, 88 mmol) and anisole (1.912 ml, 17.50 mmol). The reaction vessel was sealed and irradiated (microwave) at 100° C. for 5 minutes. After cooling to room temperature, the reaction mixture was concentrated in vacuo. The residue was diluted with water (20 mL) and then saturated NaHCO3 until basic. The contents were extracted with DCM (4×20 mL). The combined organic layers were washed with water, brine, dried over MgSO4, filtered and concentrated in vacuo. The crude product was purified via silica gel chromatography (eluent: 0 to 20% EtOAc:Hex). The final product was obtained as 1.06 g (79%). LCMS E-S (M+H)=232.2. 1H NMR (400 MHz, DMSO-d6) δ ppm 0.95-1.21 (m, 4 H) 1.41 (t, J=7.07 Hz, 3 H) 2.33-2.46 (m, 1 H) 4.44 (q, J=7.07 Hz, 2 H) 7.67 (s, 1 H) 8.26 (d, J=1.26 Hz, 1 H) 13.75 (s, 1 H).

1. customThe reaction vessel was sealed
2. customirradiated (microwave) at 100° C. for 5 minutes
3. concentrationthe reaction mixture was concentrated in vacuo
4. additionThe residue was diluted with water (20 mL)
5. extractionThe contents were extracted with DCM (4×20 mL)
6. washThe combined organic layers were washed with water, brine
7. dry with materialdried over MgSO4
8. filtrationfiltered
9. concentrationconcentrated in vacuo
10. customThe crude product was purified via silica gel chromatography (eluent: 0 to 20% EtOAc:Hex)

ORD record

ord-055bc855e0db436d9cd3cd2f581dff31

Source dataset

uspto-grants-2015_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09073924B2