Hydrochloric Acid → 1-Methyl-1H-pyrazolo[3,4-B]pyridin-5-amine
Reaction equation
C1(C(C2C=CC=CC=2)=[N:8][C:9]2[CH:10]=[C:11]3[CH:17]=[N:16][N:15]([CH3:18])[C:12]3=[N:13][CH:14]=2)C=CC=CC=1.Cl.C(=O)([O-])[O-].[Na+].[Na+]>O1CCCC1>[CH3:18][N:15]1[C:12]2=[N:13][CH:14]=[C:9]([NH2:8])[CH:10]=[C:11]2[CH:17]=[N:16]1Participants
Procedure
1-Methyl-1H-pyrazolo[3,4-b]pyridin-5-amine. A degassed mixture of 5-bromo-1-methyl-1H-pyrazolo[3,4-b]pyridine (880 mg, 4 mmol), diphenylmethanimine (1.08 g, 6 mmol), tris(dibenzylideneacetone)palladium (0) (734 mg, 0.8 mmol), (R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (1.24 g, 2 mmol), and sodium tert-butoxide (576 mg, 6 mmol) in toluene (18 mL) was heated at 115° C. under nitrogen overnight. The reaction mixture was purified by column chromatography on silica gel (eluting with 4% ethyl acetate in petroleum ether) to give N-(diphenylmethylene)-1-methyl-1H-pyrazolo[3,4-b]pyridin-5-amine (1.2 g, crude). The crude N-(diphenylmethylene)-1-methyl-1H-pyrazolo[3,4-b]pyridin-5-amine was dissolved in tetrahydrofuran (10 mL), and hydrochloric acid (2 N, 5 mL) was added. The mixture was stirred at room temperature for 2 h. The mixture was adjusted to pH=8 with saturated sodium carbonate solution, and extracted with ethyl acetate. The organic phase was dried, concentrated, and purified by column chromatography on silica gel (eluting with 33% ethyl acetate in petroleum ether) to give 1-methyl-1H-pyrazolo[3,4-b]pyridin-5-amine (420 mg, 68.4% yield) as an off-white solid.
Workup
- extractionextracted with ethyl acetate
- customThe organic phase was dried
- concentrationconcentrated
- custompurified by column chromatography on silica gel (eluting with 33% ethyl acetate in petroleum ether)
Sources & evidence
- ORD record
- ord-c5f1254cff964fa69327e001dd367513
- Source dataset
- uspto-grants-2012_10
- Patent number
- US08299056B2
Reaction notes
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