Proton-exchanged montmorillonite-mediated reactions of methoxybenzyl esters and ethers

Nucleophilic Deprotection of p-Methoxybenzyl Ethers Using Heterogeneous Oxovanadium Catalyst

Nucleophilic deprotection of p-methoxybenzyl (PMB) [p-methoxyphenylmethyl (MPM)] ethers was developed using a heterogeneous oxovanadium catalyst V-MPS4 and a thiol nucleophile. The deprotection method had a wide reaction scope, including PMB ethers of primary, secondary, and tertiary alcohols bearing various functional groups. In addition, the PMB ether of an oxidation-labile natural product was successfully removed by V-MPS4 catalysis, while a common oxidative method of PMB deprotection afforded a complex mixture. The V-MPS4 catalyst was reusable up to six times without a significant loss in the product yield. The advantages of using the heterogeneous catalyst were further demonstrated by conducting the deprotection reaction in a continuous flow process, which resulted in a 2.7-fold higher catalyst turnover number and 60-fold higher turnover frequency compared to those of the corresponding batch reaction.

Evaluation of Fe3+fixation into montmorillonite clay and its application in the polymerization of ethylenedioxythiophene

An analysis of the sorption process allowed to establish that Fe³⁺sorption into montmorillonite is a chemical process that involves an exchange of cations from the montmorillonite interstitial space between layers.

Reaction control in heterogeneous catalysis using montmorillonite: switching between acid-catalysed and red-ox processes

For a montmorillonite clay modified with a super-acid (CF₃SO₃H), two different modes of behaviour can take place simply by a judicious choice of reaction conditions.

Protonated montmorillonite-mediated highly specific isomerization of oleanolic acid esters: application to the synthesis of Δ13(18)-CDDO-Me

A one-pot highly specific isomerization of oleanolic acid esters (5a–g) to δ-oleanolic acid esters (6a–g) was achieved in the presence of proton-exchanged montmorillonite (H-mont) under mild reaction conditions.

Ammonium persulfate activated DMSO as a one-carbon synthon for the synthesis of methylenebisamides and other applications

Activation of DMSO to work as an economical and environmentally benign one-carbon synthon has been achieved by using a bench-top reagent ammonium persulfate for general and efficient access to symmetrical methylenebisamides from primary amides.