Reference of 5203-77-0, These common heterocyclic compound, 5203-77-0, name is 1,3-Dimethyl-1H-pyrazol-5-ol, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
Weigh 4.0g (0.036mol) 1,3- dimethyl-5-pyrazolone-ol in 250mLthree-necked flask was added 50mL1,2-Dichloroethane was dissolved, weighing 12g (0.12mol) oftriethylamine in the system. Under ice cooling, the mixture of intermediate(b-2)The reaction solution (0.030mol press note) was addeddropwise to the system, a solution process using argon. After the reaction 1hHPLC trace transShall, after completion of the reaction raw reaction solutioncontaining the intermediate (b-3) a. To the reaction solution containingintermediate (b-3) in additional3.0g (0.030mol) of triethylamine and 0.5mL acetonecyanohydrin, temperature control and the use of argon, the reaction 2h at 50 ~60 ,The reaction was followed by HPLC. After completion of thereaction was added 100mL of water was slowly added dropwise HCl, stirring atroom temperature, until pH = 3 or so. ExtractionThe aqueous layer was removed, and the organic layer waswashed twice with 200mL of water, dried over anhydrous sodium sulfate, theorganic solvent was removed by rotary evaporation to afford 8.1gA tan solid, a powdered compound b.
The synthetic route of 5203-77-0 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; Lian, Lei; Zheng, Yurong; He, Bin; Pengxue, Gang; Jin, Tao; Cui, Qi; (63 pag.)CN105503728; (2016); A;,
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