With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.5625-67-2,Piperazin-2-one,as a common compound, the synthetic route is as follows.
5625-67-2, 1) 3-Oxopiperazine-1-carboxylic acid tert-butyl ester Triethylamine (3.83 mL) and di-tert-butoxydicarbonate (6.32 mL) were added at room temperature to piperazin-2-one (2.5 g) in a mixture of tetrahydrofuran (50 mL) and methanol (50 mL), followed by stirring for 4 hours. The reaction solvent was evaporated under reduced pressure. The residue was partitioned between water and ethyl acetate. The organic layer was sequentially washed with water and saturated brine. The aqueous layers obtained through washing were combined, and the combined layer was extracted with ethyl acetate. The organic layers were combined, followed by drying over magnesium sulfate anhydrate. After a filtration step, the solvent was evaporated under reduced pressure. Subsequently, ethyl acetate-hexane was added to the residue, followed by drying to solid, to thereby give 3-oxopiperazine-1-carboxylic acid tert-butyl ester (3.6 g, 72%). 1H-NMR(400MHz,CDCl3)delta:1.48(9H,s), 3.37-3.40(2H,m), 3.62-3.65(2H,m), 4.01(2H,s), 6.32(1H,br s). [Referential Example 40] 1-Ethyl-2-oxopiperazine hydrochloride [Show Image] 1) 3-Oxopiperazine-1-carboxylic acid tert-butyl ester Piperazin-2-one (5.07 g) was dissolved in tetrahydrofuran (50 mL) and methanol (50 mL), and, at room temperature, triethylamine (7.76 mL) and di-tert-butyl dicarbonate (12.17 g) were added to the solution, followed by stirring for 4 hours. The reaction solvent was evaporated under reduced pressure, and diethyl ether was added to the residue. The precipitated solid was collected through filtration, to thereby give 3-oxopiperazine-1-carboxylic acid tert-butyl ester as a solid product (9.36 g, 92%). 1H-NMR(400MHz,DMSO-d6)delta:1.40(9H,s), 3.15(2H,br), 3.45(2H,br), 3.81(2H,br), 8.03(1H,br). ESI-MS m/z:201(M+H)+.
As the paragraph descriping shows that 5625-67-2 is playing an increasingly important role.
Reference£º
Patent; DAIICHI PHARMACEUTICAL CO., LTD.; EP1762568; (2007); A1;,
Piperazine – Wikipedia
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