Poly Caprolactam Supported Hexaethylene Glycolic Imidazolium Ionic Liquid as a Heterogeneous Promoter for Nucleophilic Fluorination

Hexaethylene glycolic vinyl imidazolium (hexaEGVIM) was supported on N-vinyl caprolactam via covalent bonds through simple copolymerization to form poly caprolactam-supported hexaethylene glycol-substituted imidazolium salts (PCLS-hexaEGIM). The resulting heterogeneous PCLS-hexaEGIM promoter was active, selective, and stable for aliphatic nucleophilic substitution reactions using alkali metal salts. The alkali metal salts dramatically enhanced the reactivity of this heterogeneous catalyst with easily isolable higher product yields, reducing the formation of by-products. Therefore, nucleophilic fluorination and other substitution reactions can act as highly efficient catalysts in various sulfonyloxyalkanes and haloalkanes with regard to their corresponding fluorinated products.

Sulphated alumina tungstic acid (SATA): a highly efficient and novel heterogeneous mesostructured catalyst for the synthesis of pyrazole carbonitrile derivatives and evaluation of green metrics

A novel mesostructured catalyst sulphated alumina tungstic acid (SATA) has been prepared by an easy route. Various techniques such as IR, XRD, SEM, EDX, TEM, TGA and BET were used to characterize the synthesized catalyst. The catalytic activity of the meso material has been explored by synthesizing a series of new pyrazole carbonitrile derivatives from aromatic aldehydes, ethylcyanoacetate, phenylhydrazine/hydrazine hydrate in ethanol under reflux conditions. Furthermore, the “greenness” of this protocol when estimated by green metrics, displayed satisfactory results. The protocol is free from column chromatography, and toxic solvents and is more efficient as compared to reported ones.

A novel mesostructured catalyst sulphated alumina tungstic acid (SATA) has been prepared by an easy route.

Sn-Based Porous Coordination Polymer Synthesized with Two Ligands for Tandem Catalysis Producing 5-Hydroxymethylfurfural

5-Hydroxymethylfurfural (HMF) is a biomass-derived important platform compound. Developing an efficient catalyst for producing HMF from a biomass source is important. Herein, using the ligands 5-sulfoisophthalic acid (SPA) and imidazole (Imd), a tin-based porous coordination polymer was synthesized, namely SPA-Imd-TinPCP. This novel material possesses a multifunctional catalysis capability. The coordinated tin (IV) can catalyze the isomerization of glucose to fructose. The ligand imidazole, as an additional base site, can catalyze glucose isomerization. The sulfonic group of the ligand SPA can catalyze the dehydration of fructose to HMF. SPA-Imd-TinPCP was used as a catalyst for the conversion of glucose to HMF. HMF yields of 59.5% in dimethyl sulfoxide (DMSO) and 49.8% in the biphasic solvent of water/tetrahydrofuran were obtained. Consecutive use of SPA-Imd-TinPCP demonstrated that, after reusing it five times, there was no significant activity loss in terms of the glucose conversion and HMF yield.

High acidity cellulose sulfuric acid from sulfur trioxide: a highly efficient catalyst for the one step synthesis of xanthene and dihydroquinazolinone derivatives

A cellulose sulfonate catalyst (HS-cellulose sulfonate) with high stability, excellent catalytic activity and high acidity value (about 1.55 mmol g⁻¹) was successfully prepared by SO₃ gas phase sulfonation. The basic morphology and nanostructure of the catalyst were determined by HRTEM, XRD, IR, TG, etc. In addition, the catalyst was applied to the catalytic reaction of a dihydroquinazolinone derivative and a xanthene compound, and very valuable results were obtained. The development and preparation of cellulose sulfonate catalysts provide a good approach for the development and application of cellulose, and also an important application of green organic catalytic synthesis methodology.

The HS-cellulose sulfonate catalysed green and efficient one-step synthesis of xanthene and dihydroquinazolinone derivatives.

Novel Bifunctional Mesoporous Catalysts Based on Preyssler Heteropolyacids for Green Pyrrole Derivative Synthesis

In this paper, we report the synthesis of Preyssler heteropolyacids supported on mesoporous alumina in order to obtain materials with acid–base properties. A series of pyrrole derivatives were synthesized using a suitable procedure under solvent-free conditions. Using the alumina-supported material, more complex pyrrole derivatives can be obtained through a tandem one-pot process that involves the formation of 2-amino-3-cyano 4-H-chromenes by a multicomponent reaction and their subsequent conversion to pyrrole using a Paal–Knorr reaction.

Poly(ethylene glycol)s as Ligands in Calcium-Catalyzed Cyclic Carbonate Synthesis

Herein the use of CaI₂ in combination with poly(ethylene glycol) dimethyl ether (PEG DME 500) as an efficient catalyst system for the addition of CO₂ to epoxides is reported. This protocol is based on a nontoxic and abundant metal in conjunction with a polymeric ligand. Fifteen terminal epoxides were converted at room temperature to give the desired products in yields up to 99 %. Notably, this system was also effective for the synthesis of twelve challenging internal carbonates in yields up to 98 %.

Covalently anchored sulfamic acid on cellulose as heterogeneous solid acid catalyst for the synthesis of structurally symmetrical and unsymmetrical 1,4-dihydropyridine derivatives

A novel heterogeneous solid acid catalyst has been prepared by covalent grafting of chlorosulphonic acid on amino-functionalized cellulose (Cell–Pr-NHSO₃H).

Deep eutectic solvent mediated synthesis of quinazolinones and dihydroquinazolinones: synthesis of natural products and drugs

A mild and greener protocol was developed to synthesize substituted quinazolinones and dihydroquinazolinones via deep eutectic solvent mediated cyclization with aliphatic, aromatic, and heteroaromatic aldehydes in good to excellent yields.

Melamine trisulfonic acid (MTSA): an efficient and recyclable heterogeneous catalyst in green organic synthesis

Melamine trisulfonic acid (MTSA) as a highly efficient heterogeneous solid acid catalyst catalyzes various organic transformations.