The role of maltosyl residue of maltosyl-β-cyclodextrin in the inclusion with dehydrocholic acid

Ruthenium(II)-catalyzed C-H activation and (4+2) annulation of aromatic hydroxamic acid esters with allylic amides

A (4+2) annulation under Ru(II)-catalysis is reported using aromatic hydroxamic acid esters as the oxidizing directing group and allylic amides as unactivated olefin coupling partners, delivering a wide variety of aminomethyl isoquinolinones in good to excellent yields. This annulation is distinctive as allylic congeners typically result in allylation and not the annulation. Late-stage derivatization of a bioactive synthetic bile acid has been showcased.

A comparative study of photoresponsive molecularly imprinted polymers with different shell thicknesses: Effects on 6-O-α-maltosyl-β-cyclodextrin separation

Photoresponsive surface molecularly imprinted polymers (PSMIPs) with controlled nanoshell thicknesses were synthesized using different amounts of precursor materials to determine the effects of polymer shell layer thickness on the separation and purification of 6-O-alpha-maltosyl-beta-cyclodextrin (Mal-β-CD). The physicochemical properties and adsorption and desorption capacities of PSMIPs with different shell thicknesses were studied. Interestingly, the uniform thickness of the imprinted polymer shell layer could be adjusted from 10 to 60 nm by varying the amount of polymerization precursors, and the average mesopore diameter of PSMIPs was not significantly affected by shell thickness. However, the removal efficiency and selective capacity of PSMIPs on Mal-β-CD were strongly correlated to their shell thickness. The adsorption behavior of PSMIPs on Mal-β-CD fitted well with the Langmuir adsorption model and pseudo-second-order kinetic model. Based on the obtained results, PSMIPs with a 30-nm imprinted layer were found to be an excellent adsorbent for Mal-β-CD separation, with an adsorption capacity of 18.12 mg/g. They can therefore be used for industrial chromatographic separations of Mal-β-CD in the future. PRACTICAL APPLICATION: This article clearly demonstrated that the shell thickness of core-shell molecularly imprinted materials affected the degree and rate of cyclodextrin separation. Determining the optimal thickness is of great significance for the material in the separation and purification of cyclodextrin.