A facile synthesis of α,α′-bis(substituted benzylidene) cycloalkanones catalyzed by p-TSA under solvent-free conditions

Abstract

Various 2,6-dibenzylidene cycloalkanones were readily prepared in a few minutes with good yields by simply mixing aromatic aldehydes with cycloalkanones in the presence of catalytic amounts of p-toluenesulfonic acid as a solid heterogeneous catalyst under solvent-free condition.     

Efficient and Selective Demethylation of Heteroaryl Methyl Ethers in the Presence of Aryl Methyl Ethers

A new and efficient method for the demethylation of 6-membered aza-heterocyclic methyl ethers is described using lithium chloride and para-toluenesulfonic acid. This process is chemoselective for aza-heterocyclic methyl ethers in the presence of aryl methyl ethers.

Simple and New Protocol for the Synthesis of Novel (z)-3-Arylidenebenzothiazepin-4-ones Using Baylis–Hillman Derivatives

A simple synthesis of novel (Z)-3-arylidene-2,3-dihydrobenzo[b][1,4]thiazepin-4(5H)-ones from bromo compounds derived from Baylis–Hillman adducts involving selective S-alkylation followed by a lactum formation has been described.     

OXIDATIVELY-INDUCED FORMATION OF DIALKYL HYDROGENPHOSPHONATES FROM PHOSPHOROTHIONATES

Abstract

Peracid oxidation of triester and related phosphorothionates and diester phosphorothioic acids with excess magnesium monoperoxyphthalate in water gives, among other products, dialkyl hydrogenphos-phonates in yields of up to 70%. Hydrogenphosphonate formation is facilitated by the presence of a good leaving group in the starting material.     

Catalytic Conversion of Xylose to Furfural by p-Toluenesulfonic Acid (pTSA) and Chlorides: Process Optimization and Kinetic Modeling

Furfural is one of the most promising precursor chemicals with an extended range of downstream derivatives. In this work, conversion of xylose to produce furfural was performed by employing p-toluenesulfonic acid (pTSA) as a catalyst in DMSO medium at moderate temperature and atmospheric pressure. The production process was optimized based on kinetic modeling of xylose conversion to furfural alongwith simultaneous formation of humin from xylose and furfural. The synergetic effects of organic acids and Lewis acids were investigated. Results showed that the catalyst pTSA-CrCl₃·6H₂O was a promising combined catalyst due to the high furfural yield (53.10%) at a moderate temperature of 120 °C. Observed kinetic modeling illustrated that the condensation of furfural in the DMSO solvent medium actually could be neglected. The established model was found to be satisfactory and could be well applied for process simulation and optimization with adequate accuracy. The estimated values of activation energies for xylose dehydration, condensation of xylose, and furfural to humin were 81.80, 66.50, and 93.02 kJ/mol, respectively.     

A Novel Method for Synthesizing 6-Chloro and 6-Methoxy purinenucleoside

Starting from tetraacetylribofuranose and 6-chloropurine, in the presence of was synthesized for the first time under microwave irradiation. The title compound 6-chloro-9-β-D-purinenucleoside (Ⅳ) and 6-methoxy-9-β-D-purinenucleoside (Ⅴ) was easily obtained by treatment of the intermediate (Ⅲ) with Na2CO3 in CH3OH solution refluxing for 8min and 2hr respectively.     

对甲苯磺酰氟/双氧水/碱体系和烯烃环氧化反应的研究

研究了对甲苯磺酰氟和双氧水在碱性条件下原位生成对甲苯过氧磺酸和烯烃尤其是富电子烯烃的环氧化反应的情况. 该氧化体系能将位阻较小的富电子烯烃环氧化, 并以良好的得率给出环氧化产物; 对位阻较大的富电子烯烃, 只以中等得率生成了环氧化产物. 它也能将α,β-不饱和酮环氧化. 实验结果进一步拓展了磺酰氟试剂在有机合成化学中的应用.     

Polymer resin library and the discovery of highly efficient polymer supported reagents and scavengers

Summary This paper is focused on the preparation of a library of highly efficient, tailor made, macroporous resins as supports for reagents and scavengers. From this library a macroporous resin, prepared with 40% cross-linking and with a porogen level of 300% in toluene gave a material superior to those presently available, and was shown to be highly efficient in the preparation of novel highly reactive polymer supported reagents, including scavengers and oxidants.     

Novel One-Pot Synthesis of New Oxindole Derivatives Catalyzed by PTSA

The one-pot synthesis of spirooxindoles via three-component reaction of urea, isatin, and 1,3-dicarbonyl compounds in the presence of a catalytic amount of p-toluenesulfonic acid in acetonitrile has been carried out.