1H-Pyrazole-4-carboxylic acid, 1-methyl-5-(trifluoromethyl)-, ethyl ester

White solid

Intermediate 65a: ethyl I -methyl-5-(trifluoromethyl)pyrazole-4-carboxylate[00617] Methylhydrazine (1 .2mL, 22.7gmmol) was slowly added to a mixture of conc. HCI(1 .95mL, 23.7Smmol) and EtCH (1 .9mL) at 0 °C and the mixture was stirred at this temperature for30 minutes and then diluted with EtCH (7.7mL). The resulting ethanolic solution of methylhydrazinehydrochloride was slowly added to a solution of ethyl 2-(ethoxymethylene)-4, 4, 4-trifluoro-3-oxo-butanoate (4.OOmL, 20.S7mmol) in EtCH (58mL) at 0 °C. The reaction was allowed to warm to roomtemperature and the mixture was stirred overnight. The light yellow solution was then concentratedin vacuo and the residue was suspended in water (2OmL), basified with sat. aq. Na2CC3 (2OmL) and extracted with EtCAc (3 x 3OmL). The combined organic layers were washed with brine (3OmL), dried over Na2SC4, filtered and concentrated in vacuo. The residue was purified by by column chromatography using an eluent of 0-50percent EtCAc in heptane to give ethyl 1-methyl-5-(trifluoromethyl)pyrazole-4-carboxylate (2.91g, 13.O9mmol, 64percent yield) as a colourless oil.1H NMR (CDCI3, 400MHz) O/ppm: 7.93 (1H, 5), 4.34 (2H, q, J= 7.2Hz), 4.09 (3H, q, J= 1.6Hz), 1.37 (3H, t, J = 7.2Hz). 19F NMR (CDCI3, 400MHz) O/ppm: -57.1.MS Method 2: RT: 1.62 mi mlz 223.0 [M+H]Ethyl 2-(ethoxymethylene)-4, 4, 4-trifluoro-3-oxobutanoate (1Og, 0.042mole) was dissolved in ethanol (120ml) and cooled to O

Molecular Weight:222.16
XLogP3:1.4
Hydrogen Bond Acceptor Count:6
Rotatable Bond Count:3
Exact Mass:222.06161202
Monoisotopic Mass:222.06161202
Topological Polar Surface Area:44.1
Heavy Atom Count:15
Complexity:245
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes