2-Thiophenecarboxylic acid, 5-chloro-4-(1-methyl-1H-pyrazol-5-yl)-, methyl ester synthesis

5synthesis methods

Product Name:2-Thiophenecarboxylic acid, 5-chloro-4-(1-methyl-1H-pyrazol-5-yl)-, methyl ester
CAS Number:1047630-52-3
Molecular formula:C10H9ClN2O2S
Molecular Weight:256.71

Methyl 4-broMo-5-chlorothiophene-2-carboxylate

1047630-72-7
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847818-74-0 Synthesis

1-Methyl-1H-pyrazole-5-boronic acid pinacol ester

847818-74-0
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2-Thiophenecarboxylic acid, 5-chloro-4-(1-methyl-1H-pyrazol-5-yl)-, methyl ester

1047630-52-3
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Yield:1047630-52-3 70%

Reaction Conditions:

with potassium carbonate;bis(tri-t-butylphosphine)palladium⁽⁰⁾ in 1,4-dioxane;water at 75; for 1.5 h;

Steps:

95.c

To a 300 mL sealed flask was added 1 -methyl-5-(4,4,5,5-tetramethyl-1 ,3,2- dioxaborolan-2-yl)-1 H-pyrazole (8.14 g, 39.1 mmol). potassium carbonate (12.98 g, 94 mmol), methyl 4-bromo-5-chloro-2-thiophenecarboxylate (8 g, 31.3 mmol) and bis(tri-t-butylphosphine)palladium(0) (0.40 g, 0.78 mmol) in 1 ,4-dioxane (50 ml) and H₂O (6 ml). After stirring for 90 min at 75 ⁰C, the reaction solution was diluted with DCM (100 mL) and washed with H₂O. The organic layer was dried Na₂SO₄, filtered and concentrated. The reaction residue was purified on silica gel [hexanes/EtOAc, 2:1 ] to give the product [5.7 g, 70%] as a tan solid: LCMS (ES) m/z 258 (M+H)⁺ .

References:

WO2008/98104,2008,A1 Location in patent:Page/Page column 188-189