近年来,基于天然多糖的纳米催化剂的开发受到了广泛关注。壳聚糖(CS)作为一种可生物降解且具有生物相容性的多糖,被认为是设计基于混合生物聚合物的金属氧化物纳米复合材料的绝佳模板。在这种情况下,通过简单的溶液浇铸方法制备了不同重量百分比(5、10、15和20wt%CS/La 2 O 3 )掺杂壳聚糖的氧化镧纳米颗粒。将制备的CS/La 2 O 3纳米复合材料溶液浇注在培养皿中以生产所开发的催化剂,其形状为薄膜。通过 FTIR、SEM 和 XRD 分析工具研究了杂化纳米复合材料薄膜的结构特征。 FTIR 光谱证实了壳聚糖的主要特征峰的存在,该峰通过与La 2 O 3纳米粒子的相互作用而被修饰。此外,SEM图显示壳聚糖表面发生显着的形态变化,这归因于La 2 O 3分子的表面吸附。所制备的CS/La 2 O 3纳米复合薄膜(15%重量)被研究为吡啶和吡唑合成中有效的、可回收的、非均相的碱催化剂。所
Enaminones as building blocks in organic synthesis: A novel route to polyfunctionally substituted benzonitriles, pyridines, eneylbenzotriazoles and diazepines
作者:Abu Zeid A. Hassanien、Said A. S. Ghozlan、Mohamed H. Elnagdi
DOI:10.1002/jhet.5570400205
日期:2003.3
An efficient synthesis of enaminones 1a-c is reported. Compounds 1a-c reacted with diefhyl-3-amino-2-cyanopenten-1,5-dicarboxylate (3) to yield the benzonitriles 6. On the other hand, the reaction of la-c with 3-amino-2-cyano-2-pentene dinitrile (7) afforded a mixture of benzonitriles 10 and pyridines 9. The reaction of la-c with 3-aminocrotononitrile 11 has afforded the 4-substituted-3-cyano-2-methylpyridines
A Route to Dicyanomethylene Pyridines and Substituted Benzonitriles Utilizing Malononitrile Dimer as a Precursor
作者:Noha M. Helmy、Fatma E. M. El-Baih、Monirah A. Al-Alshaikh、Moustafa S. Moustafa
DOI:10.3390/molecules16010298
日期:——
The conditions of the reaction of malononitrile dimer with enaminones and arylidenemalononitrile could be adapted to yield either pyridines or benzene derivatives. A new synthesis of pyrido[1,2-a]pyrimidines from the reaction of malononitrile dimer 1 and 2-phenyl-3-piperidin-1-yl-acrylonitrile (11) is described. Compound 1 condensed with DMFDMA to yield an enaminonitrile that reacted with hydrazine hydrate to yield N',4,6-triamino-2H-pyrazolo[3,4-b]pyridine-5-carboxamidine (17).
Cyclization of 2-dicyanomethylene-1,2-dihydropyridine-3-carbonitriles with amines: a mechanistic rationalization
作者:Francisco Carrión、Núria Mont、Xavier Batllori、José I. Borrell、Jordi Teixidó
DOI:10.1016/j.tet.2006.10.025
日期:2007.1
A mechanistic rationalization for the cyclization of the 1,5-dinitrile system present in pyridines 41-3} with amines to lead to 1,6-naphthyridines is proposed. Three factors play an important role on the direction of cyclization: (1) the cyclization involves nucleophilic attack of an amidine onto a nitrile or amidine; (2) the attack has to fulfill strict geometrical constraints to allow the cyclization to proceed; (3) the cyclization step should involve the nucleophilic attack combined with a tautomerism to achieve the high levels of regioselectivity observed. (c) 2006 Elsevier Ltd. All rights reserved.