4-BROMO-3-ETHYL-1-METHYL-1H-PYRAZOLE-5-CARBOXYLIC ACID ETHYL ESTER synthesis
- Product Name:4-BROMO-3-ETHYL-1-METHYL-1H-PYRAZOLE-5-CARBOXYLIC ACID ETHYL ESTER
- CAS Number:128537-28-0
- Molecular formula:C9H13BrN2O2
- Molecular Weight:261.12
128537-26-8
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Yield:128537-28-0 80%
Reaction Conditions:
with bromine in dichloromethane at 0 - 10; for 3 h;
Steps:
Ethyl 4-bromo-3-ethyl-1 -methyl-1 H-pyrazole-5-carboxylate
To a solution of ethyl 3-ethyl-1 -methyl-1 H-pyrazole-5-carboxylate (see intermediate 17, 250 g, 1 .37 mol, 1 eq) in dichloromethane (3800 mL) was added bromine (658 g, 4.12 mol, 212.18 ml_, 3 eq) dropwise at 0 O. The mixture was stirred at 10 O for 3 hours. The reaction was stopped by the addition of an aqueous sodium hydrosulfite solution (1500 mL), and the mixture was then diluted with water (500 mL), and was extracted with dichloromethane (800 mL) thrice. The combined organic layers were washed with brine (800 mL), dried over sodium sulfate, filtered and concentrated under reduced pressure to give the title compound (300 g, 80% yield, 96% purity) as a yellow solid.1H NMR (MeOD, 400MHz) d [ppm]: 4.33 - 4.43 (m, 2H), 4.07 (s, 3H), 2.61 (q, J = 7.65 Hz, 2H), 1 .40 (t, J = 7.15 Hz, 3H), 1 .17 - 1.24 (m, 3H)
References:
WO2019/96907,2019,A1 Location in patent:Page/Page column 140
26308-40-7
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13246-52-1
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