Benzophenone imine → Benzhydrylidene-(1-methyl-1H-pyrazolo[3,4-b]pyridin-5-yl)-amine

HRID 2070870Notes

Reaction equation

[CH3:1][N:2]1[C:6]2=[N:7][CH:8]=[C:9]([NH2:11])[CH:10]=[C:5]2[CH:4]=[N:3]1.BrC1C=C2C=NN(C)C2=NC=1.[C:23]1([C:29]([C:31]2[CH:36]=[CH:35][CH:34]=[CH:33][CH:32]=2)=N)[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1.C1C=CC(P(C2C=CC3C(=CC=CC=3)C=2C2C3C(=CC=CC=3)C=CC=2P(C2C=CC=CC=2)C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.CC(C)([O-])C.[Na+]>C1(C)C=CC=CC=1>[C:23]1([C:29]([C:31]2[CH:32]=[CH:33][CH:34]=[CH:35][CH:36]=2)=[N:11][C:9]2[CH:10]=[C:5]3[CH:4]=[N:3][N:2]([CH3:1])[C:6]3=[N:7][CH:8]=2)[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1

Participants

Conditions

Temperature: 115 °C

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

customThe reaction mixture was purified by column chromatography on silica gel (eluting with 4% ethyl acetate in petroleum ether)

Sources & evidence

ORD record: ord-404a0bc812464ce0b78567061c9ed323
Source dataset: uspto-grants-2012_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08299056B2

Reaction notes

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