5-Hydroxy-1-methylpyrazole synthesis
- Product Name:5-Hydroxy-1-methylpyrazole
- CAS Number:33641-15-5
- Molecular formula:C4H6N2O
- Molecular Weight:98.1
88398-78-1
33641-15-5
The general procedure for the synthesis of 1-methyl-5-hydroxypyrazole-4-carboxylic acid from ethyl 1-methyl-5-hydroxypyrazole-4-carboxylate is as follows: 22 g of sodium hydroxide was dissolved in 300 mL of water, 42.5 g of intermediate (ethyl 1-methyl-5-hydroxypyrazole-4-carboxylate) was added, and the reaction was stirred for 3 hr at 40 °C, then cooled to room temperature. 55 mL of concentrated hydrochloric acid was added dropwise, followed by heating and refluxing for 3 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure, 200 mL of anhydrous ethanol was added to the residue, and the precipitate was collected by filtration after thorough stirring. The filtrate was concentrated under reduced pressure to give 24 g of white solid product (1-methyl-5-hydroxypyrazole) in 98.0% yield and 96.50% HPLC purity.
88398-78-1
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33641-15-5
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Yield:33641-15-5 98%
Reaction Conditions:
Stage #1:1-methyl-5-hydroxypyrazol-4-carboxylic acid ethyl ester with sodium hydroxide in water at 40; for 3 h;
Stage #2: with hydrogenchloride for 3 h;Reflux;
Steps:
1
22g NaOH was dissolved in 300mL of water and 42.5g of Intermediate (A-1-2) was added, stirred at 40°C for 3h and then cooled to room temperature. 55mL of concentrated hydrochloric acid was added dropwise, followed by heating under reflux for 3h. The solved was distilled off under reduced pressure and the residue was added 200mL of absolute ethanol and was stirred sufficiently and filtered the precipitates. The filtrate was concentrated under reduced pressure to give a white solid 24g (A-1-3), yield: 98.0%, HPLC purity: 96.50%.
References:
Qingdao Qingyuan Chemicals Co., Ltd.;Lian, Lei;Zheng, Yurong;He, Bin;Peng, Xuegang;Jin, Tao;Cui, Qi CN105218449, 2016, A Location in patent:Paragraph 0063; 006=5
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33641-15-5
242 suppliers
$12.00/1g