排序方式: 共有2条查询结果,搜索用时 31 毫秒
1
1.
Thirawat Sirijindalert Kunlayanee Hansuthirakul Paitoon Rashatasakhon Mongkol Sukwattanasinitt Anawat Ajavakom 《Tetrahedron》2010,66(27-28):5161-5167
The reactions of Boc-β-amido- and β-amino acrylates, in which the CC possesses both nucleophilic and electrophilic sites, were investigated under acidic conditions. The trifluoroacetic-acid induced cyclization of the β-amido acrylates to the corresponding oxazolidin-2-ones involves a rarely seen nucleophilic attack of the carbamate carbonyl group. The cyclotrimerization of β-amino acrylates to N-substituted 1,4-dihydropyridines was observed in the presence of a Lewis acid. High yields of 1,4-dihydropyridines (70–83%) were readily obtained by using substoichiometric amount TiCl4 under mild condition. The cyclotrimerization is presumably occurring via a Hantzsch related mechanism involving three addition/elimination reactions of the amphiphilically reactive CC. 相似文献
2.
Daranee Homraruen Thirawat Sirijindalert Luxsana Dubas Mongkol Sukwattanasinitt Anawat Ajavakom 《Tetrahedron》2013,69(5):1617-1621
Novel 1,4-dihydropyridine (DHP) derivatives containing 3 carboxylic acid units are synthesized via cyclotrimerization of N-substituted β-aminoacrylates followed by basic hydrolysis of the triester. These DHP derivatives are readily soluble in aqueous media buffered at pH 8.0 and the solutions give blue fluorescent signals with quantum yields of 7–23%. One of these compounds, bearing a p-methoxyphenyl N-substituted group, shows specific fluorescent quenching with the mercuric ion (Hg2+). The fluorescent signal of the DHP derivative decays over a period of minutes to hours depending on the Hg2+ concentration, which implies that the sensing mechanism involves chemical reaction between the Hg2+ ion and the DHP compound. The 1H NMR and MS data suggest that Hg2+ mediates the oxidation of the DHP ring into a pyridinium ring. The event is useful for fluorescent detection of Hg2+ at the micromolar level within 30 min, with a detection limit of 0.2 μM in aqueous medium. 相似文献
1