With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.91252-54-9,Ethyl 5-(tert-butyl)isoxazole-3-carboxylate,as a common compound, the synthetic route is as follows.
91252-54-9, Step 2: Synthesis of 2-bromo-1-(5-tert-butyl-isoxazol-3-yl)-ethanone The title compound is prepared from 5-tert-butyl-isoxazole-3-carboxylic acid ethyl ester by those skilled in the art by adaptation of a literature procedure (Kaluza et al, Tetrahedron, 2003, 59, 31,5893-5903). To a solution of 5-tert-butyl-isoxazole-3-carboxylic acid ethyl ester (0.5 g, 2.54 mmol) in anhydrous tetrahydrofuran (10 mL) is added under nitrogen dibromomethane (356 muL, 0.88 g, 5.07 mmol). The mixture is cooled to -78 C and 1.6M methyl lithium in diethyl ether (3.2 mL, 5.07 mmol) is added dropwise. The solution is stirred at -78 C for 40 min and then quenched with acetic acid (582 muL, 610 mg, 10.16 mmol). The mixture is warmed to 0 C and poured onto ice/water (40 mL) and extracted with tert-butyl methyl ether (3 x 40 mL). The organic layers are combined, dried (Na2SO4), filtered and concentrated under reduced pressure. The residue is purified by chromatography on silica eluting with a heptane/dichloromethane gradient (1/0 to 1/1) to provide the title compound as a yellow oil (351 mg, 62%), m/z 246 [M+H+]. 1H NMR (400 MHz, CHLOROFORM-d) delta ppm 1.39 (9 H, s), 4.58 (2 H, s), 6.41 (1 H, s).
The synthetic route of 91252-54-9 has been constantly updated, and we look forward to future research findings.
Reference£º
Patent; Boehringer Ingelheim International GmbH; Boehringer Ingelheim Pharma GmbH & Co. KG; EP2418207; (2012); A1;,
Isoxazole – Wikipedia
Isoxazole | C3H3NO – PubChem