- Cascade Knoevenagel and aza-Wittig reactions for the synthesis of substituted quinolines and quinolin-4-ols
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A [4 + 2] annulation involving cascade Knoevenagel, aza-Wittig and dehydrofluorination reactions is developed for the synthesis of substituted quinolin-4-ols including analogs bearing CF2H, CF3, and C2F5 groups. This simple and highly efficient method is also applicable for the synthesis of substituted quinolines. A number of reported biologically active compounds can be readily prepared by this one-pot synthesis. Green chemistry metrics analysis of the new reaction processes provided favorable results.
- Zhang, Xiaofeng,Ma, Xiaoming,Qiu, Weiqi,Evans, Jason,Zhang, Wei
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p. 349 - 354
(2019/01/28)
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- A copper(I)-complexed magnetic nanoparticle catalyst for enaminone synthesis
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The synthesis of a copper(I)-complexed magnetic nanoparticle catalyst is described. The catalyst was characterized using Fourier transform infrared spectroscopy (FT–IR), energy-dispersive X-ray spectroscopy (XPS), atomic absrobtion spectroscopy (AA), thermogravimetric analysis (TGA), vibrating sample magnetometery (VSM), X-ray photoelectron spectroscopy (XPS), scanning electron miscroscopy (SEM) and transmission electron microscopy (TEM). The catalyst coupled thioamides and diazocarbonyl compounds to produce diverse enaminones. The catalyst reduced the reaction times and temperature and provided enaminones in high yields and selectivity. Moreover, the catalyst can be separated by a magnet and recycled.
- Mohammadi, Leila,Zolfigol, Mohammad Ali,Ebrahiminia, Mahsa,Roberts, Kenneth P.,Ansari, Samira,Azadbakht, Tahereh,Hussaini, Syed R.
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- Copper-catalyzed chemoselective cross-coupling reaction of thioamides and α-diazocarbonyl compounds: Synthesis of enaminones
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The development of operationally simple and cost-effective methods for C[sbnd]C bond formation reactions are highly important in pharmaceutical, agrochemical and material research. In this article we describe the first copper-catalyzed cross-coupling reaction of thioamides with acceptor/acceptor-substituted and acceptor-only substituted α-diazocarbonyl compounds to yield enaminones. The reaction shows broad substrate scope in terms of thioamides and diazocarbonyl compounds. Primary, secondary and tertiary thioamides all give enanminones when reacted with α-diazodiesters, α-diazoketoesters, α-diazodiketones, α-diazoketoamides, α-diazoesteramides, α-diazoketosulfones and α-diazomonoketones.
- Pal, Arpal,Koduri, Naga D.,Wang, Zhiguo,Quiroz, Erika Lopez,Chong, Alexandra,Vuong, Matthew,Rajagopal, Nisha,Nguyen, Michael,Roberts, Kenneth P.,Hussaini, Syed R.
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supporting information
p. 586 - 589
(2017/01/16)
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- Enaminones via ruthenium-catalyzed coupling of thioamides and α-diazocarbonyl compounds
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Enaminones can be prepared via the Rh2(OAc)4- catalyzed coupling of α-diazocarbonyl compounds with thioamides. However, rhodium is the most expensive and least abundant among the dominant precious metals used for catalysis. Furthermore, a very limited substrate scope is known for the intermolecular rhodium catalyzed coupling reaction. Therefore, there is a need to find a more economical catalyst substitute with a broad substrate scope. In this paper, we describe the use of Ru(II) catalysts for the synthesis of enaminones. The reaction can be performed efficiently with the Grubbs first-generation catalyst or [(Ph)3P]3RuCl2 in a sealed tube. Both catalysts are much less expensive than Rh 2(OAc)4. Secondary and tertiary thioamides, when reacted with α-diazodiesters, α-diazoketoesters, α-diazodiketones, and α-diazomonoketones give enaminones. Primary thioamides give thiazole derivatives when reacted with α-diazomonoketones. However, with other diazo compounds, primary thioamides also give enaminones. All enaminones are obtained in good yields and with good diastereoselectivity. Accordingly, the method described in this paper is an efficient and economical alternative to the Rh2(OAc)4-catalyzed coupling process.
- Koduri, Naga D.,Wang, Zhiguo,Cannell, Garrett,Cooley, Kate,Lemma, Tsebaot Mesfin,Miao, Kun,Nguyen, Michael,Frohock, Bram,Castaneda, Maria,Scott, Halee,Albinescu, Dragos,Hussaini, Syed R.
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p. 7405 - 7414
(2014/09/17)
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- Structure-activity relationship of quinoline derivatives as potent and selective α2c-adrenoceptor antagonists
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Starting from two acridine compounds identified in a high-throughput screening campaign (1 and 2, Table 1), a series of 4-aminoquinolines was synthesized and tested for their properties on the human α2- adrenoceptor subtypes (α2A, α2B, and α2C). A number of compounds with good antagonist potencies against the α2C-adrenoceptor and excellent subtype selectivities over the other two subtypes were discovered. For example, (R)-{4-[4-(3,4-dimethylpiperazin-1-yl)phenylamino]quinolin-3-yl}methanol 6j had an antagonist potency of 8.5 nM against, and a subtype selectivity of more than 200-fold for, the α2c-adrenoceptor. Investigation of the structure-activity relationship identified a number of structural features, the most critical of which was an absolute need for a substituent in the 3-position of the quinoline ring. The 3-position on the piperazine ring was also found to play an appreciable role, as substitutions in that position exerted a significant and stereospecific beneficial effect on the α2C- adrenoceptor affinity and potency. Replacing the piperazine ring proved difficult, with 1,4-diazepanes representing the only viable alternative.
- H?glund, Iisa P. J.,Silver, Satu,Engstr?m, Mia T.,Salo, Harri,Tauber, Andrei,Kyyr?nen, Hanna-Kaisa,Saarenketo, Pauli,Hoffrén, Anna-Marja,Kokko, Kurt,Pohjanoksa, Katariina,Sallinen, Jukka,Savola, Juha-Matti,Wurster, Siegfried,Kallatsa, Oili A.
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p. 6351 - 6363
(2007/10/03)
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