884501-93-3Relevant academic research and scientific papers
Silver-Catalysed Domino Approach to 1,3-Dicarbo-Substituted Isochromenes
Dell'Acqua, Monica,Pirovano, Valentina,Peroni, Stefano,Tseberlidis, Giorgio,Nava, Donatella,Rossi, Elisabetta,Abbiati, Giorgio
supporting information, p. 1425 - 1433 (2017/04/01)
We report herein the first example of the silver triflate catalysed synthesis of 1,3-dicarbo-substituted isochromene derivatives starting from 2-alkynyl(hetero)arylaldehydes and enolizable ketones. The reaction proceeds in a cascade fashion under mild heating with complete regioselectivity and moderate-to-good yields. In some cases, the reaction gives unexpected homodimeric products. Two competitive mechanistic paths for the formation of the desired isochromene derivatives and the homodimeric products are described.
Silver comes into play: Henry reaction and domino cycloisomerisation sequence catalysed by [Ag(i)(Pc-L)] complexes
Tseberlidis, Giorgio,Dell'Acqua, Monica,Valcarenghi, Daniele,Gallo, Emma,Rossi, Elisabetta,Abbiati, Giorgio,Caselli, Alessandro
, p. 97404 - 97419 (2016/10/25)
We report herein the synthesis of new pyridine-containing macrocyclic ligands (Pc-L) bearing a non-innocent pendant arm, by exploiting both chiral and functional properties of natural amino acids. The obtained macrocyclic ligands were employed to synthesize well-defined cationic silver(i) complexes that were shown to be competent catalysts for the Henry (nitroaldol) reaction. Good to excellent yields and full selectivity in the β-nitroalcohol product were obtained starting from electron-poor aromatic aldehydes or other activated aldehydes such as furfural under mild reaction conditions. The straightforward synthesis of the macrocyclic ligands starting from cheap commercially available starting materials allowed the introduction of a suitable basic functionality into the ligand pendant arm, thus providing a bifunctional catalyst. Based on our previous experience in the [Ag(i)(Pc-L)] catalysed domino addition/cycloisomerisation reaction of o-alkynylbenzaldehydes and nucleophiles, the synthesis of isochromenes coupling the Henry reaction and the cycloisomerisation in a single step was subsequently explored. Although with low selectivity, [Ag(i)(Pc-L)] cationic complexes were able to promote such a cascade reaction and a possible mechanism based on experimental evidence has been proposed.
AgI-catalyzed cascade strategy: Regioselective access to diversely substituted fused benzimidazo[2,1-a]isoquinolines, naphthyridines, thienopyridines, and quinoxalines in water
Rustagi, Vineeta,Tiwari, Rakesh,Verma, Akhilesh Kumar
supporting information, p. 4590 - 4602 (2012/11/07)
An environmentally benign and operationally simple one-pot approach to the regioselective tandem synthesis of diversely substituted fused benzimidazo[2,1-a]isoquinolines, naphthyridines, thienopyridines, and quinoxalines from o-alkynylaldehydes and arylamines with tethered nucleophiles using AgI as catalyst in water is described. The reaction showed selective N-C bond formation on the more electrophilic alkynyl carbon, resulting in the regioselective 6-endo-dig cyclized products in good to excellent yields. The proposed mechanistic pathway for the synthesis of fused heterocycles proceeding through formation of ring A prior to ring B, which formed through a second intramolecular attack of the nitrogen onto the alkynyl carbon, was supported by mechanistic experiments and X-ray crystallographic studies of isolated intermediate U and cyclized product 5a. Comparative experiments showed the viability of intramolecular nucleophilic attack over intermolecular attack of an external nucleophile. This catalytic, green protocol has been efficiently applied for the bis-tandem cyclization in water. An eco-friendly, one-pot cascade approach to benzimidazoles and quinoxalines in water using AgNO 3 as catalyst from o-alkynyl aldehydes and amines with tethered nucleophiles, has been developed. Selective 6-endo-dig regioselectivity and structural diversity are accomplished in good yields with a range of substrates. X-ray crystallographic studies and mechanistic experiments are also presented. Copyright
COMPOUNDS FOR THE PREVENTION AND TREATMENT OF CARDIOVASCULAR DISEASES
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Page/Page column 23, (2008/12/07)
The present disclosure relates to compounds, which are useful for regulating the expression of apolipoprotein A-I (ApoA-I), and their use for treatment and prevention of cardiovascular disease and related disease states, including cholesterol- or lipid-related disorders, such as, for example, atherosclerosis.
