Rh(III)-catalyzed annulation of azobenzenes and α-Cl ketones toward 3-acyl-2H-indazoles
作者:Huan Li、Yuxuan Han、Zi Yang、Zhenyu Yao、Lianhui Wang、Xiuling Cui
DOI:10.1016/j.cclet.2020.12.027
日期:2021.5
afforded in up to 97% yields for more than 30 examples. The obtained products are potentiallyvaluable in organic synthesis and drug discovery. This protocol featured with high efficiency, extensive functional group tolerance and mild reaction conditions. The one-step efficient construction of an anti-inflammatory agent confirms the practicability of this procedure.
Synthesis of Azobenzenes from Quinone Acetals and Arylhydrazines
作者:M. Carmen Carreño、Gerardo Fernández Mudarra、Estíbaliz Merino、María Ribagorda
DOI:10.1021/jo0498011
日期:2004.5.1
Direct reaction between quinone bisacetals and arylhydrazines gives azobenzenes. The presence of catalytic amounts of cerium ammonium nitrate strongly accelerates the reaction. When the bisacetal has a substituent at the 2,5-cyclohexadiene framework, only one regioisomer is formed. The method represents a simple, mild, and novel synthetic access to differently substituted azocompounds in high to excellent
Novel Route to Azobenzenes via Pd-Catalyzed Coupling Reactions of Aryl Hydrazides with Aryl Halides, Followed by Direct Oxidations
作者:Young-Kwan Lim、Kang-Sang Lee、Cheon-Gyu Cho
DOI:10.1021/ol027311u
日期:2003.4.1
[reaction: see text] N-Boc aryl hydrazines undergo Pd-catalyzed coupling reactions with arylhalides to provide N-Boc diaryl hydrazines in excellent yields. The resulting N-Boc diaryl hydrazines were directly oxidized with NBS/pyridine in CH(2)Cl(2) at room temperature to the azobenzenes.
Colorimetric detection of cyanide with a chromogenic oxazine
申请人:Raymo Francisco M.
公开号:US20090258429A1
公开(公告)日:2009-10-15
A chromogenic oxazine compound for the colorimetric detection of cyanide was designed. Indeed, the [1,3]oxazine ring of our compound opens to form a phenolate chromophore in response to cyanide. The heterocyclic com-pound may be comprised of fused benzooxazine and indoline rings:
wherein R
1
is an alkyl (e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl), a substituted alkyl, a cycloalkyl (e.g., cyclopentyl, cyclohexyl), a substituted cycloalkyl, an aryl (e.g., phenyl), or a substituted aryl and R
2
is a chromophore (e.g., nitroso, nitro, azo dyes). This quantitative chromogenic transformation permits the detection of micromolar concentrations of cyanide in water. Furthermore, our chromogenic oxazine is insensitive to the presence of large concentrations of fluoride, chloride, bromide or iodide anions, which are generally the principal interferents in the colorimetric detection of cyanide.