ChemicalBook CAS DataBase List 1-METHYL-1H-PYRAZOLE-3-CARBALDEHYDE

1-METHYL-1H-PYRAZOLE-3-CARBALDEHYDE synthesis

6synthesis methods

Product Name:1-METHYL-1H-PYRAZOLE-3-CARBALDEHYDE
CAS Number:27258-32-8
Molecular formula:C5H6N2O
Molecular Weight:110.11

25016-20-0 Synthesis

25016-20-0
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$9.00/100mg

27258-32-8
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$22.00/1g

Yield: 63%

Reaction Conditions:

Stage #1:1-methylpyrazole-3-carboxylic acid with thionyl chloride;N,N-dimethyl-formamide for 2 h;Heating / reflux;
Stage #2: with hydrogen;palladium 10% on activated carbon in toluene for 8 h;Heating / reflux;

Steps:

3
A suspension of the acid (90 g, 0.71 mol) and DMF (1 drop) in thionyl chloride (250 mL) was stirred at reflux under nitrogen for 2 h. The solvent was evaporated from the reaction mixture, the residue azeotroped with toluene (3X200 mL), diluted into toluene (250 mL), added to a suspension OF PD-C (10 wt%, 9.3 g) in toluene (500 mL), and the mixture stirred at reflux for 8 h with a gentle flow of hydrogen gas through the suspension. After cooling to room temperature, the suspension was filtered through celite, washed with toluene, and concentrated in vacuo. The residue was fractionally distilled under vacuum to provide the title compound (50 g, 63%) as a low melting white solid (bp = 92 °C &COMMAT; 8 mmHg)

References:

MERCK & CO., INC. WO2004/58702, 2004, A2 Location in patent:Page 31; 24