With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.4576-90-3,Isothiazole-3-carboxylic acid,as a common compound, the synthetic route is as follows.
To a suspension of isothiazole-3-carboxylic acid (2 g, 15.49 mmol) in DCM at 0 C was added oxalyl dichloride (1.3 equiv.) followed by three drops of DMF. Bubbling commenced, and the reaction was warmed to 23 C after 10 min. The mixture was stirred for 3 h, then cooled to 0 C. N,0-dimethylhydroxylamine hydrochloride (1.3 equiv.) was added to the reaction, followed by triethylamine (3.5 equiv.) which was added dropwise via syringe over 10 min. Reactions was warm slowly to 23 C overnight, and stirred for a total of 15 h. Reaction mixture was diluted with IN HC1 solution and dichloromethane (1 :1 ratio). Layers were separated, and the aqueous layer was extracted with DCM (2x). Combined organic layers were dried over magnesium sulfate, filtered, and the solvent was removed in vacuo. Crude reside purified via silica gel chromatography (utilizing a hexane/ethyl acetate mix as eluent) to deliver the desired intermediate, N-methoxy-N-methylisothiazole-3-carboxamide (1 g, 38%> yield) as a pale yellow solid. NMR (400 MHz, CDCI3) delta ppm 8.67 (d, 1 H), 7.69 (br s, 1 H), 3.80 (s, 3 H), 3.46 (br s, 3 H).
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Reference£º
Patent; IRONWOOD PHARMACEUTICALS, INC.; BARDEN, Timothy Claude; SHEPPECK, James Edward; RENNIE, Glen Robert; RENHOWE, Paul Allan; PERL, Nicholas; NAKAI, Takashi; MERMERIAN, Ara; LEE, Thomas Wai-Ho; JUNG, Joon; JIA, James; IYER, Karthik; IYENGAR, Rajesh R.; IM, G-Yoon Jamie; (293 pag.)WO2016/44447; (2016); A1;,
Isothiazole – Wikipedia
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