Imidazole as organocatalyst for multicomponent reactions: diversity oriented synthesis of functionalized hetero- and carbocycles using in situ-generated benzylidenemalononitrile derivatives
作者:Md. Nasim Khan、Suman Pal、Shaik Karamthulla、Lokman H. Choudhury
DOI:10.1039/c3ra45252b
日期:——
The multicomponent reaction of malononitrile, aldehyde and a third reaction partner such as naphthol/4-hydroxycoumarine/2-hydroxynaphthoquinone/kojic acid/enolizable ketone or thiol in the presence of imidazole as an organocatalyst provides very interesting molecular diversity. In an almost neutral reaction medium, this protocol provides easy access to highly functionalized 2-amino-4H-chromenes, dienes and 2-amino pyridines using in situ-generated aryl/alkylylidenemalononitrile derivatives obtained from the reaction of aldehydes and malononitrile along with various nucleophiles under reflux conditions in ethanol. This methodology is useful for the easy access of a wide range of structurally diverse functionalized molecules having potential application in biological systems.
A novel magnetically recyclable semi‐dendrimer catalyst‐based ethanolpyridole supported on ferrite nanoparticles (HNPs@Py) for the synthesis of biscoumarin and dihydropyrano[3,2‐
<i>c</i>
]chromene derivatives
作者:Fatemeh Afsharnadery、Kaveh Khosravi、Mohammad Ali Zolfigol
DOI:10.1002/aoc.6297
日期:2021.8
The novel organic–inorganic nanohybrid magneticnanoparticles (HNPs@Py) were prepared by a simple method and characterized by FT-IR, XRD, FE-SEM, TGA, VSM, EDX, and MAP. The catalytic activity of this new (HNPs@Py) was studied for green synthesis of biscoumarin and 3,4-dihydropyrano[c]chromenederivatives. The short reaction time, high yields, simple workup, and easy separation of catalyst from the
A Laccase Heterogeneous Magnetic Fibrous Silica-Based Biocatalyst for Green and One-Pot Cascade Synthesis of Chromene Derivatives
作者:Mehdi Mogharabi-Manzari、Mohammad Hossein Ghahremani、Tabassom Sedaghat、Fatemeh Shayan、Mohammad Ali Faramarzi
DOI:10.1002/ejoc.201801784
日期:2019.2.28
A heterogeneousbiocatalyst was prepared by laccase immobilization on the surface of KCC‐1 functionalized magnetic nanoparticles. The catalyst was applied in a one‐pot, greencascadesynthesis of chromenes in the presence of TEMPO as a shuttle redox mediator.
Ni(II)-Schiff base/SBA-15: a nanostructure and reusable catalyst for one-pot three-component green synthesis of 3,4-dihydropyrano[3,2-c]chromene derivatives
base/SBA-15-catalyzed one-potthree-component cyclocondensation process was described via the reaction between malononitrile, 4-hydroxycoumarin, and various aldehydes in aqueous media for the synthesis of 3,4-dihydropyrano[3,2- c ]chromene derivatives. This nanocatalyst was characterized using FT-IR, SEM, TGA, TEM, BET, AFM, and XRD techniques. It is possible to reuse the heterogeneous catalystwithout any marked
通过丙二腈,4-羟基香豆素和各种醛在水性介质中的反应,描述了一种高效,快速且环境友好的Ni(II)-席夫碱/ SBA-15催化的单锅三组分环缩合工艺3,4-二氢吡喃并[3,2- c ]亚甲基 衍生物。使用FT-IR,SEM,TGA,TEM,BET,AFM和XRD技术对这种纳米催化剂进行了表征。可以重复使用多相催化剂而其催化活性没有任何显着变化至少五倍。该方法的其他显着特点包括纯净形式收率高,操作简便,操作温和得多,反应时间短,后处理简单并避免了危险试剂/溶剂的使用。
Serendipitous Observation of Liquid-Phase Size Selectivity inside a Mesoporous Silica Nanoreactor in the Reaction of Chromene with Formic Acid
product switches from pyrimidine to enol lactones and δ‐keto acids inside the nanoreactor. The shape/size selectivity in the liquid phase is a highly desired phenomenon in organic synthesis. We prepared four different varieties of porous silica materials to obtain this product selectivity. Very high yields of these biologically relevant compounds surpass that achieved by existing methodologies. Again