Albany Molecular Research (Singapore)

Chitosan hydrogel beads were prepared by a precipitation process, and were used to investigate the adsorption of malachite green (MG) oxalate under various conditions. It was found that adsorption equilibrium was most sensitive to the pH value at pH <8 while fixed bed breakthrough kinetics presented asymmetric S-shaped profiles which could not be adequately described by conventional models such as Adams-Bohart and Yoon-Nelson. The possible reasons were discussed and an improved Adams-Bohart model was proposed to better describe the changes in mass transfer mechanisms during adsorption.

3-Alkylindoles on reaction with a cyclohexa-2,4-dien-1-one catalyzed by BF3·OEt2 gave the corresponding 3-alkyl-3-arylindolenines in high yields through a tandem Michael addition/aromatization sequence. In the presence of HCl, these indolenine derivatives underwent a facile Plancher-type C-3 to C-2 aryl rearrangement to deliver the corresponding 2-arylindoles.

Abstract The title compounds are easily obtained by Pd‐catalyzed Michael addition reaction of arylboronic acids to cyclohexa‐2,4‐dienones.

A rapid process for the synthesis of functionally rich benzobicyclo[2.2.2]octadienone derivatives has been realized through oxidative dimerization of commercially/readily available 2-methoxyphenols followed by an aromatization sequence.

In this report, a simple and rapid approach for the synthesis of maskedo-benzoquinone (MOB) heterodimers is presented.

Abstract A facile, general and rapid protocol for the introduction of oxygenated aryls at the 3‐position of indoles is described. This approach consists of a tandem dearomatization, a regioselective Michael addition reaction, and rearomatization in a one‐pot three‐step sequence to obtain 3‐arylindoles in good yields.