1-isopropylpyrazole-3-carboxylic acid ethyl ester synthesis

Yield:1007514-99-9 96%

Reaction Conditions:

with sodium ethanolate in tetrahydrofuran;ethanol; for 16 h;Reflux;

Steps:

10.3

Step 3: l-Isopropyl-lH-pyrazole-S-carboxylic acid ethyl ester[0165] To lH-pyrazole-3-carboxylic acid ethyl ester (23.1g, 165 mmol) in THF (330 mL) was added 2-iodopropane (33.OmL, 330 mmol) followed by NaOEt (21% in EtOH, 65.0 mL, 174 mmol). This solution was then heated to reflux for 16 h. The reaction was then allowed to cool to room temperature. AcOH (10.5 mL, 183 mmol) was added and the reaction was stirred for 5 min. H₂O (400 mL) was added to the solution, and this mixture was extracted with EtOAc (3x150 mL). The combined organic was washed with sat. aq. NaHCO₃, then brine. The organic was dried over MgSO₄, filtered, and concentrated to give the product (28.7Og, 96%) as a brown oil containing a 98:2 mixture of regioisomers by ¹H NMR.

References:

WO2010/54006,2010,A1 Location in patent:Page/Page column 60