With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.3209-71-0,Isoxazole-3-carboxylic Acid,as a common compound, the synthetic route is as follows.
a) Ethyl 5-(isoxazol-3-yl)-l,2,4-oxadiazole-3-carboxylate Ethyl aminohydroxyiminoacetate (3.78 mmol, 0.5 g), 3-isoxazolecarboxylic acid (3.78 mmol, 0.428 g) and 1,3-diisopropylcarbodiimide (4.16 mmol, 0.525 g) were dissolved in DCM (70 ml) under nitrogen atmosphere. The mixture was stirred at RT for a day. The solvent was evaporated to dryness and the residue was dissolved in pyridine and refluxed for 6 h and overnight at RT. Pyridine was evaporated and the residue was diluted with DCM and water. The aqueous phase was extracted four times with DCM. The combined organics were washed with aqueous HC1 solution, saturated NaHC03, water and brine. The organic phase was dried, filtered and evaporated. The crude product was purified by flash chromatography. 0.396 g of the title compound was obtained. Rotamers were obtained in 1 H-NMR and analysis was repeated at elevated temperature. 1 H-NMR (400 MHz, DMSO-c?, +60C): 5 1.38 (t, 3H), 4.49 (q, 2H), 7.21 (d, 1H), 9.05 (d, 1H).
As the paragraph descriping shows that 3209-71-0 is playing an increasingly important role.
Reference£º
Patent; ORION CORPORATION; TOeRMAeKANGAS, Olli; WOHLFAHRT, Gerd; SALO, Harri; RAMASUBRAMANIAN, Rathna, Durga; PATRA, Pranab, Kumar; MARTIN, Arputharaj, Ebenezer; HEIKKINEN, Terhi; VESALAINEN, Anniina; MOILANEN, Anu; KARJALAINEN, Arja; WO2012/143599; (2012); A1;,
Isoxazole – Wikipedia
Isoxazole | C3H3NO – PubChem