Potassium Carbonate → methyl 4-(1-ethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate

Participants

Role	Name	HCID	Charge
Reactant	Potassium Carbonate	HCID 11430	—
Reactant	Methyl 4-bromothiophene-2-carboxylate	HCID 12752071	—
Reactant	1-Ethylpyrazole-5-boronic acid, pinacol ester	HCID 53217252	—
Catalyst	HCID 178418397	HCID 178418397	—
Solvent	1,4-Dioxane--water (1/1)	HCID 21886435	—
Product	methyl 4-(1-ethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate	HCID 67066137	66%

Reaction Conditions

Temperature	70 °C

Reaction Steps

To a solution of methyl 4-bromo-2-thiophenecarboxylate (1.0 g, 4.52 mmol) in dioxane/H2O (5:1, 6 mL) was added K2CO3 (1.86 g, 13.5 mmol), tetrakistriphenylphosphine Pd(0) (260 mg, 0.23 mmol) and 1-ethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (1.3 g, 5.85 mmol). The reaction mixture was heated to 70° C. in a sealed tube. After 2 h, the reaction mixture was concentrated under vacuum and purified on silica (hex/EtOAc, 20-40%) to afford methyl 4-(1-ethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (0.7 g, 66%) as a light yellow solid: LC-MS (ES) m/z=237 (M+H)+.

Provenance & Evidence

DOI	10.6084/m9.figshare.5104873.v1
Patent number	US08946278B2
Source dataset	uspto-grants-2015_02
ORD ID	ord-5852322e9ad3419d8a8bbc410f7eec8a
Source note	uspto-grants-2015_02