ETHYL 3-(TRIFLUOROMETHYL)PYRAZOLE-4-CARBOXYLATE synthesis

5synthesis methods

Product Name:ETHYL 3-(TRIFLUOROMETHYL)PYRAZOLE-4-CARBOXYLATE
CAS Number:155377-19-8
Molecular formula:C7H7F3N2O2
Molecular Weight:208.14

571-55-1 Synthesis

Ethyl 2-(ethoxymethylene)-4,4,4-trifluoroacetoacetate

571-55-1
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$10.00/1g

ETHYL 3-(TRIFLUOROMETHYL)PYRAZOLE-4-CARBOXYLATE

155377-19-8
172 suppliers
$6.00/250mg

Yield:155377-19-8 95%

Reaction Conditions:

with hydrazine hydrate in ethanol at 0 - 20; for 4.5 h;

Steps:

2.10. Ethyl 3-(trifluoromethyl)-1H-pyrazole-4-carboxylate (3f)
Hydrazine hydrate (10 g, 0.199 mol) was dissolved in ethanol (400 mL). This was cooled to 0 °C and a solution of ethyl 2-(ethoxymethylene)-4,4,4-trifluoro-3-oxobutanoate (47.03 g, 0.19 mol) in ethanol (200 mL) was added drop-wise over 90 min at 0 °C. The solution was left to warm to room temperature for 3 h and concentrated to dryness. The residue was dispersed in boiling cyclohexane (200 mL) and left to cool to room temperature. The precipitate was filtered, washed with cyclohexane and dried under vacuum at 75 °C to yield compound 3f as a yellow powder (38.67 g, 95%); mp 145 °C ¹H NMR (CDCl₃): 1.40 (t, 3H, J=7.0 Hz); 4.39 (q, 2H, J=7.0 Hz); 8.26 (s, 1H); 13.2 (s (br), 1H). ¹³C NMR (CDCl₃): 14.0; 61.2; 113.4; 121.0 (q, J=268 Hz); 135.3; 142.0 (q, J=38 Hz); 160.8. HRMS: calcd For C₇H₇F₃N₂O₂-H: 207.0381; Found: 207.0377.

References:

Guillou, Sandrine;Bonhomme, Frédéric J.;Ermolenko, Mikhail S.;Janin, Yves L. [Tetrahedron,2011,vol. 67,# 44,p. 8451 - 8457] Location in patent:experimental part

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