We have developed a novel and efficient iridium-catalyzed hydrogen isotopeexchangereaction method with secondary and tertiary sulfonamides at ambient temperatures. Furthermore N-oxides and phosphonamides have been successfully applied in hydrogen isotopeexchangereactions with moderate to excellent deuterium introduction.
Novel Water-Soluble β-Cyclodextrin−Calix[4]arene Couples as Fluorescent Sensor Molecules for the Detection of Neutral Analytes
作者:Jürgen Bügler、Johan F. J. Engbersen、David N. Reinhoudt
DOI:10.1021/jo9723321
日期:1998.8.1
The synthesis and the host-guest chemistry of two novel fluorescent beta-cyclodextrin-calix[4]arene couples 1 and 2 is described. The compounds were prepared by coupling a beta-cyclodextrin linked with an aminoxylyl spacer with two different calix[4]arene building blocks each bearing a fluorophore. The fluorophores attached to 1 and 2 are the 2-naphthylamine and the dansyl moiety, respectively. The unsymmetric calix[4]arene functionalization was achieved by monoprotection of the 1,3-diformylcalix[4]arene. The host molecules 1 and 2 were used as fluorescent probes for several organic analytes in aqueous solution. 1 shows sensitivity for a series of neutral organic guest species, such as steroids, terpenes, and other natural products. In contrast, compound 2 does not show sensitivity for organic analytes in aqueous solution. The different behavior of the two fluorescent probes 1 and 2 is explained by the different strength of self-inclusion of each fluorphoric group into the beta-cyclodextrin cavity.