Urea → 1-Methyl-1H-pyrazolo[4,3-b]pyridine

HRID 2261008Notes

Reaction equation

HRID 2261008 reaction equation
N[C:2]1[CH:6]=[C:5]([C:7]([CH3:10])(C)C)O[N:3]=1.ClC(Cl)(OC(=O)OC(Cl)(Cl)Cl)Cl.N[C:24]([NH2:26])=O.[CH3:27][NH:28]N>C(#N)C>[CH3:27][N:28]1[C:6]2[CH:5]=[CH:7][CH:10]=[N:3][C:2]=2[CH:24]=[N:26]1

Participants

6

Reactant 4

HCID 1176UreaHCID 6061MethylhydrazineHCID 94429TriphosgeneHCID 1714733-Isoxazolamine, 5-(1,1-dimethylethyl)-

Product 1

HCID 569722961-Methyl-1H-pyrazolo[4,3-b]pyridineYield 30%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

In analogy to GP 4b, 3-amino-5-tert-butylisoxazole (88.45 mg, 0.63 mmol, 1.23 eq.) was treated with triphosgene (59.44 mg, 0.2 mmol, 0.4 eq.) and Intermediate 3.1 (200 mg, 0.5 mmol, 1 eq.) in 10 mL acetonitril. The crude urea was subsequently cyclized with 48 μL methylhydrazine (0.91 mmol, 1.8 eq.) in 10 mL 1-PrOH to yield 80 mg of the N1-methyl-pyrazolopyridine (0.15 mmol, 30% yield over 2 steps).

Sources & evidence

ORD record
ord-cefebfee81534c7baba4f0e83dbce402
Source dataset
uspto-grants-2010_12
Patent number
US07846928B2

Reaction notes

Loading…