Catalytic Method for Synthesis of Aspirin by a Green,Efficient and Recyclable Solid Acid Catalyst (Preyssler's Anion) at Room Temperature

Synthesis of aspirin at room temperature via O‐acetylation of salicylic acid in the presence of Preyssler type heteropolyacids has been investigated in order to contribute toward clean technology, which is the most important need of the society. All of the catalysts are recyclable and reusable.     

Acid induced reactions of a sydnone ketoxime

3-(2-Acetylphenyl)sydnone oxime 1a reacts with acids (methanesulfonic-, p-toluenesulfonic, trifluoroacetic-acid or Amberlite IR 118) to give products apparently derived from protonation of the oxime oxygen or nitrogen atom followed by cyclization to the sydnone ring or interception by water.     

Use of nanoporous Na+-montmorillonite sulfonic acid (SANM) as an eco-benign, efficient and reusable solid acid catalyst for the one-pot synthesis of 14-aryl-14-H-dibenzo[a,j]xanthenes and 1,8-dioxo-dodecahydroxanthene derivatives

Nanoporous Na⁺-montmorillonite sulfonic acid was found to be an efficient and green catalyst for the synthesis of various 14-aryl-14H-dibenzo[a,j]xanthenes and 1,8-dioxo-dodecahydroxanthene derivatives by the reaction of aldehydes with 2-naphthol and 1,3-cyclohexanedione, respectively. This novel synthetic method has the advantages of high yields, short reaction times and recyclability of the catalyst, simplicity and easy workup compared to the conventional methods reported in the literature.     

AN EASY CONVERSION OF THE BAYLIS-HILLMAN ADDUCTS INTO tert-BUTYLDIMETHYLSILYL ETHERS WITH tert-BUTYLDIMETHYLSILYL CHLORIDE AND Li2S

The hydroxy group of the Baylis-Hillman adducts is protected with the t-butyldimethylsilyl (TBDMS) group using the reaction of adducts 1a–h with tert-butyldimethylsilyl chloride (TBDMSCl) in the presence of lithium sulfide under nearly acidic reaction conditions.     

Facile and Efficient Method for the Synthesis of 14-Substituted-14-H-dibenzo[a,j]xanthenes Catalyzed by Ruthenium Chloride Hydrate as a Homogeneous Catalyst

Synthesis of dibenzoxanthenes through condensation of β-naphthol with various aromatic and aliphatic aldehydes in ethanol as an ecofriendly solvent using Ru^III as catalyst is reported.

A convenient synthesis of 1,5-diarylpyrazoles from Baylis-Hillman adducts using HY-zeolite

<正>A facile and convenient protocol was developed for the synthesis of 1,5-diarylpyrazoles using Baylis-Hillman adducts in the presence of HY-zeolite as an efficient recyclable heterogeneous catalyst in reasonable reaction times(1.5-2.5 h) and high yields (78-90%).     

Oxidative properties of a nonheme Ni(II)(O2) complex: Reactivity patterns for C-H activation, aromatic hydroxylation and heteroatom oxidation

Density functional theory calculations on the reactivity of a Ni(II)-superoxo complex in C-H bond activation, aromatic hydroxylation and heteroatom oxidation reactions have been explored; the Ni(II)-superoxo complex is able to react with substrates with weak C-H bonds and PPh(3).     

Deuterium isotope effect and oxidation of labelled alcohols

Oxidation of alcoholsR-CHD-OH by CrO₃/pyridine gave the aldehydesR-CDO with a relatively small loss of D thus indicating a pronounced isotope effect.     

Naturally reductive homogeneous Randers spaces

In this paper, we study naturally reductive Randers metrics on homogeneous manifolds. We first prove that naturally reductive Randers metrics are of Berwald type. We then give an explicit formula for the flag curvature of naturally reductive Randers metrics. Finally a necessary and sufficient condition for invariant Randers metrics on homogeneous manifolds being naturally reductive is given.