1H-Pyrazole-3-carboxylicacid,5-ethyl-1-methyl-,ethylester(9CI) synthesis
- Product Name:1H-Pyrazole-3-carboxylicacid,5-ethyl-1-methyl-,ethylester(9CI)
- CAS Number:165744-14-9
- Molecular formula:C9H14N2O2
- Molecular Weight:182.22
13246-52-1
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60-34-4
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128537-26-8
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165744-14-9
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Yield:165744-14-9 95.5% ，128537-26-8 12.6%
Reaction Conditions:
with glacial acetic acid at 0 - 15; for 5 h;
Steps:
5.1 Step 1
To a solution of ethyl 2, 4-dioxohexanoate (10.0 g, 58.1 mmol, 1 eq) in AcOH (65.7 g, 1.09 mol, 62.6 mL, 18.8 eq was added methylhydrazine (7.45 g, 64.7 mmol, 8.51 mL, 40% purity, 1.11 eq) at 0 °C. The mixture was stirred at 15 °C for 5 hours. LCMS showed desired MS in main peak. The mixture was concentrated in vacuum to give crude. The residue was purified by combi flash chromatography (120 g silica gel column, EtOAc in PE from 0% to 50%). Ethyl 5 -ethyl- 1 -methyl -pyrazole-3 -carboxylate (10.1 g, 55.5 mmol, 95.5% yield) was obtained as yellow oil. NMR (400MHz, CDCh) δ = 6.59 (s, 1 H), 4.39 (q, J= 14.4, 7.2 Hz,2 H), 3.85 (s, 3 H), 2.62 (q, J = 14.4, 7.2 Hz, 2 H), 1.39 (t, J = 7.2 Hz, 3 H), 1.28 (t, J = 7.6 Hz,3 H). Ethyl 5-ethyl-2-methyl-pyrazole-3-carboxylate (1.33 g, 7.30 mmol, 12.6% yield) was obtained as colorless oil. 1 H NMR (400 MHz, CDCh) δ = 6.65 (s, 1 H), 4.34 (q, 7=7.2 Hz, 2 H), 4.18 - 4.11 (m, 4 H), 2.65 (q, 7 = 15.2, 7.6 Hz, 2 H), 1.38 (t, 7 = 7.2 Hz, 3 H), 1.25 (t, 7 = 7.6 Hz, 3 H)
References:
WO2022/133037,2022,A1 Location in patent:Paragraph 0685-0686
51943-20-5
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13246-52-1
114 suppliers
$11.00/100mg
165744-14-9
24 suppliers
$45.00/10mg
13246-52-1
114 suppliers
$11.00/100mg
60-34-4
2 suppliers
$65.59/25g
165744-14-9
24 suppliers
$45.00/10mg
13246-52-1
114 suppliers
$11.00/100mg
165744-14-9
24 suppliers
$45.00/10mg