Copper-Catalyzed Reductive Ring-Cleavage of Isoxazoles: Synthesis of Fluoroalkylated Enaminones and Application for the Preparation of Celecoxib, Deracoxib, and Mavacoxib
作者:Chao Wan、Jian-Yu Pang、Wei Jiang、Xiao-Wei Zhang、Xiang-Guo Hu
DOI:10.1021/acs.joc.0c02980
日期:2021.3.19
ring-cleavage of isoxazoles to yield fluoroalkylated enaminones. This protocol has the advantage of using commercially available reagents, ease of setting up, broad tolerance of functionality, and is regiospecific and free of defluorination and reduction of reducible functional groups. The utility was demonstrated by a one-step, regioselective synthesis of fluoroalkylated pyrazole-based drugs such as celecoxib
Reactivity of<i>p</i>-phenyl substituted β-Enamino compounds using K-10/ultrasound.<b>II</b>. Synthesis of isoxazoles and 5-Isoxazolones
作者:Claudete J. Valduga、Denise B. Santis、Hugo S. Braibante、Mara E. F. Braibante
DOI:10.1002/jhet.5570360229
日期:1999.3
condensation of 4-phenyl substitutedβ-enamino ketones 1a-d and β-enamino esters 5a-d with hydroxylamine hydrochloride using K-10 as the solid support under sonication was studied to evaluate the formation of isoxazole and 5-isoxazolone rings from β-enaminocompounds with a substituted aromatic ring. Isoxazoles 2a-c, 3c-d and 5-isoxazolones 6a-c and 7a-d were obtained. The use of K-10/ultrasound in this reaction
Reactivity of<i>p</i>-phenyl substituted β-enamino compounds using k-10/ultrasound. I. synthesis of pyrazoles and pyrazolinones
作者:Claudete J. Valduga、Hugo S. Braibante、Mara E. F. Braibante
DOI:10.1002/jhet.5570350136
日期:1998.1
The reactivity of the β-enamino ketones, 3-amino-1-(p-phenyl-substituted)-2-buten-1-ones 1a-d and β-enamino esters. Ethyl-3-amino-3-(p-phenyl-substituted)-2-propenoates 5a-d were evaluated by systematic studies of the reactions with hydrazine and methylhydrazine by reactions with solid support K-10/ultrasound and homogeneous media (reflux in ethanol or dichloromethane) yielding pyrazole rings 2a-d
Reactivity of<i>p</i>-phenyl substituted β-enamino compounds using K-10/ultrasound.<b>I</b>. Synthesis of pyrazoles and pyrazolinones
作者:Claudete J. Valduga、Hugo S. Braibante、Mara E. F. Braibante
DOI:10.1002/jhet.5570340513
日期:1997.9
The reactivity of the β-enamino ketones, 3-amino-1-(p-phenyl-substituted)-2-buten-1-ones 1a-d and β-enamino esters, ethyl 3-amino-3-(p-phenyl-substituted)-2-propenoates 5a-d was systematically studied when allowed to react with hydrazine and methylhydrazine under solid support K-10/ultrasound conditions and in homogeneous media (reflux in ethanol or dichloromethane). The products were pyrazoles 2a-d
novel iodine-mediated oxidative tandem cyclization reaction of simple enaminones has been developed for the synthesis of substituted furopyridines through C-C/C-N/C-O bond formation in a one-pot procedure. Substituted furopyridines are obtained in moderate to good yield. In addition, I- and Br-substituted furopyridines have been successfully produced by the electrophilic substitution of N-iodo- or N-bromosuccinimide