1H-Pyrazole-5-carboxylic acid, 4-methyl-, ethyl ester synthesis
- Product Name:1H-Pyrazole-5-carboxylic acid, 4-methyl-, ethyl ester
- CAS Number:856061-38-6
- Molecular formula:C7H10N2O2
- Molecular Weight:0
121781-57-5
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856061-38-6
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Yield:856061-38-6 75%
Reaction Conditions:
with hydrazine hydrochloride in ethanol at 85;
Steps:
84.2
Hydrazine hydrochloride (22 g, 321.14 mmol) was added to a solution of (E)-l ,l ,l- trichloro-4-ethoxy-3-methylbut-3-en-2-one (50 g, 215.98 mmol) in ethanol (400 mL) and the reaction was stirred overnight at 85°C in an oil bath. Then it was concentrated in vacuo, diluted with water (300 mL), and extracted with ethyl acetate (3x300 mL). The organic layers were combined and dried over anhydrous sodium sulfate. The organics were concentrated in vacuo to afford ethyl 4-methyl- lH-pyrazole-5-carboxylate as an orange solid ( 25 g, 75%). LC-MS (ES, m/z) [M+H]+ 155 *H NMR (400 MHz, DMSO-i, ppm): δ 7.57 (s, 1H), 4.30-4.24 (q, 7 =8.0Hz, 2H), 2.20 (s, 3H), 1.34-1.30 (t, / =8.0 Hz, 3H)
References:
WO2014/66795,2014,A1 Location in patent:Paragraph 0175
