5-Nitro-1H-pyrazole-3-carboxylic acid → HCID 178418848, compound

HRID 550612Notes

Reaction equation

HRID 550612 reaction equation
[N+:1]([C:4]1[NH:8][N:7]=[C:6]([C:9]([OH:11])=[O:10])[CH:5]=1)([O-])=O.[H][H]>[Pd].CO>[NH2:1][C:4]1[NH:8][N:7]=[C:6]([C:9]([OH:11])=[O:10])[CH:5]=1

Participants

5

Reactant 2

HCID 862226845-Nitro-1H-pyrazole-3-carboxylic acidHCID 178418361HCID 178418361, compound

Product 1

HCID 178418848HCID 178418848, compound

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 887MethanolSolvent

Procedure

5-Nitro-1H-pyrazole-3-carboxylic acid 1 is reduced under standard conditions, such as treatment with hydrogen in the presence of palladium(0) on carbon in a solvent such as methanol, to yield 5-amino-1H-pyrazole-3-carboxylic acid 2. Compound 2 is reacted with di-aldehyde 3, carrying a bromo or chloro substituent at the R1 position, under acid conditions, such as acetic acid, at elevated temperatures to give 6-bromo- or 6-chloro-pyrazolo[1,5-a]pyrimidine-2-carboxylic acid (4). A compound of Formula I is prepared from 4 via reaction with an appropriate secondary amine 5 in the presence of a condensation agent, including, for example, O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate (“TBTU”) or N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC).

Sources & evidence

ORD record
ord-1c2db53376c940d1a78508a9444eb408
Source dataset
uspto-grants-2011_05
Patent number
US07947689B2

Reaction notes

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