21169-71-1, Isoxazole-5-carboxylic acid is a Isoxazoles compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated,21169-71-1
Procedure S: Ethyl 2-(isoxazol-5-yl)-2-oxoacetate; To a solution of 4.7 g (40.7 mmol, 1.0 eq.) of isoxazole-5-carboxylic acid in 70 mL of anhydrous THF at -78 C under an argon atmosphere was added 4.5 mL (40.7 mmol, 1.0 eq.) of iV-methylmorpholine followed by 5.3 mL (43 mmol, 1.05 eq.) of isobutyl chloroformate. The mixture stirred at -78 C for 20 min. The mixture was filtered and the filtrate was allowed to warm to 0 C and excess diazomethane added slowly. The mixture was allowed to warm to room temperature and stirred for 16 h. A solution of 25 mL of 33% HBr in acetic acid was added and the mixture stirred at room temperature for 10 min. The mixture was diluted with 400 mL of EtOAc and washed with 10% citric acid followed by sat. NaHCO3 and sat. brine. The organic phase was dried (Na2SO4) and the solvent removed in vacuo. The residue was purified by flash chromatography to provide 5.2 g of 2-bromo-l-(isoxazol-5- yl)ethanone as a white solid. The 2-bromo-l-(isoxazol-5-yl)ethanone was redissolved in 300 mL of ethanol and 3.3 g (30 mmol) of selenium dioxide added. The mixture heated at 100 C for 16 h. The mixture was allowed to cool to room temperature and filtered. The solvent was removed in vacuo and the residue partitioned between EtOAc and sat. NaHCO3. The layers were separated and the aqueous phase extracted with EtOAc. The combined organic extracts were washed with sat. brine, dried (Na2SO4) and the solvent removed in vacuo. The residue was purified by flash chromatography to provide 1.8 g of ethyl 2-(isoxazol-5-yl)-2- oxoacetate. deltaH (300 MHz, CDCl3) 1.43 (t, 3H), 4.47 (q, 2H), 7.40 (d, IH), 8.45 (d, IH).
The synthetic route of 21169-71-1 has been constantly updated, and we look forward to future research findings.
Reference£º
Patent; LIGAND PHARMACEUTICALS INC.; COLE, Andrew; MCGUINNESS, Brian, F.; SHAO, Yuefei; DONG, Guizhen; HENDERSON, Ian; WO2010/8775; (2010); A1;,
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