1H-pyrazole-4-carboxylic acid, 1-(6-chloropyridin-2-yl)-5-(trifluoroMethyl)-, ethyl ester synthesis

5synthesis methods

Product Name:1H-pyrazole-4-carboxylic acid, 1-(6-chloropyridin-2-yl)-5-(trifluoroMethyl)-, ethyl ester
CAS Number:1128268-00-7
Molecular formula:C12H9ClF3N3O2
Molecular Weight:319.67

2402-78-0 Synthesis

2402-78-0
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$6.00/25g

571-55-1 Synthesis

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

571-55-1
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$10.00/1g

1H-pyrazole-4-carboxylic acid, 1-(6-chloropyridin-2-yl)-5-(trifluoroMethyl)-, ethyl ester

1128268-00-7
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Yield:1128268-00-7 94.5%

Reaction Conditions:

Stage #1: 2,6-dichloropyridinewith hydrazine in ethanol; for 4 h;Heating / reflux;
Stage #2: ethyl 2-(ethoxymethylidene)-4,4,4-trifluoro-3-oxobutanoate in ethanol; for 3 h;Heating / reflux;

Steps:

50

Description 50: Ethyl 1-(6-chloropyridin-2-yl)-5-trifluoromethyl-pyrazole-4- carboxylate (D50); To a solution of 2,6-dichloropyridine (Aldrich, 5g, 33.78 mmol) in EtOH (80ml) was added dropwise hydrazine hydrate (Aldrich, 8.2ml, 169 mmol). The mixture was heated under reflux during 4 hours and then poured into water. After extraction with CH₂CI₂, the organic phase was dried (Na₂SO₄) and concentrated under reduced pressure. The residue was dissolved in EtOH (100ml) and ethyl-2-(ethoxymethylene)-4,4,4-trifluoro-3-oxo-butyrate(Aldrich, 6.9ml, 35.47 mmol) was added dropwise. The mixture was heated under reflux during 3 hours and then poured into water. After extraction with CH₂CI₂, the organic phase was dried (Na₂SO₄) and concentrated under reduced pressure to give the titled compound as a cream oil which crystallised (10.2g, 94.5%). LC/MS: 320.1 (M+H) , Rt = 3.35 min; ¹HNMR (300MHz, CDCI₃, ppm): 8.05 (s, 1 H), 7.8 (t, 1 H), 7.5 (d, 1 H), 7.4 (d, 1 H), 4.3 (q, 2H),1.3 (t, 3H).