ethyl 3-Methyl-1-propyl-1H-pyrazole-5-carboxylate synthesis

Yield:39658-15-6 78%

Reaction Conditions:

with potassium carbonate;triethylamine in dimethyl sulfoxide at 100; for 3 h;

Steps:

11.1 Step 1 ethyl 3 -methyl- 1 -propyl- lH-pyrazole-5-carboxylate 11a

To the DMSO solution (~2 mL) of ethyl 3-methyl- 1 //-pyrazole-5-carboxylate (100 mg, 0.65 mmol) was added l-iodopropane (165 mg, 1.0 mmol, 1.5 eq), Triethylamine (150 uL, 1.0 mmol, 1.5 eq) followed with K2CO3 (280 mg, 2.0 mmol, 3 eq), the reaction mixture was heated at l00°C for 3 hours. The Mixture was cooled down to room temperature, water (~25 mL) was added extracted with EtOAc (10 mL X3). Organic layer was combined, washed with brine (10 mLXl), dried over Na₂S0₄, filtered and the filtrated was concentrated under vaccum. The residue was purified by silica gel column (12 g ISCO cartrige with 40% EtOAc in Hexane) to give title compound 1 la ethyl 3-methyl- 1 -propyl- 1 //-pyrazole-5-carboxylate (100 mg, 78%). MS m/z (ESI): 197 [M+l]

References:

WO2020/6432,2020,A1 Location in patent:Page/Page column 75-76