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ChemicalBook CAS DataBase List 5-Hydroxy-1-methylpyrazole
33641-15-5

5-Hydroxy-1-methylpyrazole synthesis

3synthesis methods
-

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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