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

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

4synthesis methods
-

Yield: 38%

Reaction Conditions:

with triethylamine in ethanol at 85; for 12 h;

Steps:

1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-amine
A solution of (E)-4-amino-4-ethoxy-1 , 1 , 1 -trifluorobut-3-en-2-one (5 g, 27.3 mmol) in EtOH (30 ml_) was treated with methyl hydrazine sulphate (4.72 g, 32.8 mmol) and Et3N (4.1 g, 41 .0 mmol) at ambient temperature. The resulting reaction mixture was heated at 85 °C for 12 h then cooled to ambient temperature and concentrated in vacuo. The residue obtained was diluted with sat. aq. NaHC03 solution (250 ml_) and extracted with EtOAc (2 x 250 ml_). The combined organics were washed with water (250 mL), brine (250 mL), dried (Na2S04) and concentrated in vacuo. The crude product was purified by column chromatography on silica gel using 20% EtOAc-hexanes eluent to give 1 - methyl-5-(trifluoromethyl)-1 /-/-pyrazol-3-amine as a pale brown liquid (0.17 g, 38%). 1H NMR (400 MHz, CDCI3): δ = 5.93 (s, 1 H), 3.79 (s, 3H), 3.68 (br.s., 2H).

References:

THE UNIVERSITY OF QUEENSLAND;THE PROVOST, FELLOWS, FOUNDATION SCHOLARS, AND THE OTHER MEMBERS OF BOARD, OF THE COLLEGE OF THE HOLY AND UNDIVIDED TRINITY OF QUEEN ELIZABETH NEAR DUBLIN;O'NEILL, Luke;COLL, Rebecca;COOPER, Matt;ROBERTSON, Avril;SCHRODER, Kate WO2016/131098, 2016, A1 Location in patent:Page/Page column 140; 141