ChemicalBook CAS DataBase List 1-Methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol

1-Methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol synthesis

10synthesis methods

Product Name:1-Methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol
CAS Number:122431-37-2
Molecular formula:C5H5F3N2O
Molecular Weight:166.1

Pentanoic acid, 5-fluoro-4,4-bis(fluoromethyl)-3-oxo-, ethyl ester

944546-18-3
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60-34-4
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1-Methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol

122431-37-2
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$12.00/250mg

Yield:122431-37-2 97%

Reaction Conditions:

Stage #1: ethyl-4,4,4-trifluoromethylacetoacetate;methylhydrazine in ethanol at 20 - 80; for 15 h;
Stage #2: with sodium hydroxide in ethanol at 20; for 1 h;

Steps:

3.1

Preparation of compound 3a: l-Methyl-3-trifluoromethyl-lH-pyrazol-5-ol. Methylhydrazine (3.42 mL, 65.1 mmol) was added all at once to a stirred solution of ethyl 4,4,4- trifluoromethylacetoacetate (9.53 mL, 65.1 mmol) and ethanol (261 mL) at rt under nitrogen. The reaction mixture was heated to 80 ⁰C for 15 h then cooled to rt. NaOH (5.22 g) was added all at once and the mixture stirred for 1 h at rt. The reaction mixture was concentrated under vacuum, diluted with ethyl acetate (2 x 300 mL) and washed with IM HCl (300 mL). The combined organics were dried over MgSO₄, filtered and concentrated to afford 10.5 g (97%) of l-methyl-3-trifluoromethyl-lH-pyrazol-5-ol as a yellow solid

References:

WO2007/84868,2007,A2 Location in patent:Page/Page column 26

372-31-6 Synthesis