Zheng-Jun Quan

PEG‐SO3H as Catalyst for 3,4‐Dihydropyrimidones via Biginelli Reaction Under Microwave and Solvent‐Free Conditions

Abstract An efficient and environmentally friendly process for the synthesis of 3,4‐dihydropyrimidones via the Biginelli‐type condensation reaction using poly(ethylene glycol)‐bound sulfonic acid as catalyst irradiated by microwave has been developed. The functionalized poly(ethylene glycol) acted simultaneously as catalyst and as solvent in the condensation. The workup was easy, and the products were obtained in good to excellent yields and high purities.

Poly(4-vinylpyridine) supported acidic ionic liquid: A novel solid catalyst for the efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones under ultrasonic irradiation

A novel poly(4-vinylpyridine) supported acidic ionic liquid catalyst was synthesized by the reaction of 4-vinylpyridine with 1,3-propanesultone, followed by the polymerization and the addition of the heteropolyacid. Due to the combination of polymer features and ionic liquid, it acted as a heterogeneous catalyst to effectively catalyze the cyclocondensation reaction of anthranilamide with aldehydes under ultrasonic irradiation and afforded the corresponding 2,3-dihydro-4(1H)-quinazolinones compounds in good to excellent yields. In addition, the catalyst could be easily recovered by the filtration and reused six times without significant loss of catalytic activity. More importantly, the use of ultrasonic irradiation can obviously accelerate the reaction.

Conversion of carbohydrates into 5-hydroxymethylfurfural using polymer bound sulfonic acids as efficient and recyclable catalysts

52–94% yields of 5-hydroxymethylfurfural (HMF) from carbohydrates such as monosaccharides, disaccharides and polysaccharides were achieved using PEG-OSO3H or PS-PEG-OSO3H as reusable catalysts in a DMSO/H2O reaction system. Using polymer-supported catalysis, corn stover could also be effectively transformed into HMF and furfural.

A Neat and Rapid Synthesis of 2‐Aryloxymethylene‐6‐Arylimidazo[2,1‐b]‐1,3,4‐Thiadiazole Under Microwave Irradiation

Abstract A neat and rapid procedure is reported for the synthesis of a variety of 2‐aryloxymethylene‐6‐arylimidazo[2,1‐b]‐1,3,4‐thiadiazole (3a–3r) by condensation reaction of 2‐amino‐5‐aryloxymethylene‐1,3,4‐thiadiazole (1a–1f) with ω‐bromoacetophenone (2a–2c) in ethanol solvent under microwave irradiation, which yielded a series of novel compounds. The yields are good to excellent. The procedure is simple and does not need any added catalyst or dehydrating reagent. Moreover, the crystals do not require further purification to give the products.

Solvent-Free Synthesis of 2-Furyl-5-aryloxyacetylamido-1,3,4-thiadiazoles Under Microwave Irradiation

Abstract A practical solvent-free method for the preparation of 2-furyl-5-aryloxyacetylamido-1,3,4-thiadiazoles under microwave irradiation is described.

An efficient and clean synthesis of 1-aroyl-3-aryl-4-substituted imidazole-2-thiones in water

Treatment 1-aryl-3-aroyl/benzofuroyl thioureas with α-bromo substituted carbonyl compounds in water affording 1-aroyl/benzofuroyl-3-aryl-4-substituted imidazole-2-thiones in excellent yields within short time.

Dehydration of biomass to furfural catalyzed by reusable polymer bound sulfonic acid (PEG-OSO3H) in ionic liquid

Polymer bound sulfonic acid (PEG-OSO3H) is active for the dehydration of biomass to furfural. The furfural yield is improved when MnCl2 is added to the reaction mixture. The catalyst was mild, non-volatile, and non-corrosive and can be recycled multiple times (>10) without an intermediate regeneration step and no significant leaching of –OSO3H groups is observed.

One-Pot, Three-Component Synthesis of 1,4-Dihydropyridines in PEG-400

Abstract A series of Hantzsch 1,4-dihydropyridines were synthesized by one-pot condensation of aldehyde, β-dicarbonyl compound, and ammonium acetate in polyethylene glycol (PEG-400) at 90 °C. This method has the advantages of good yields, less pollution, and simple reaction conditions.

Synthesis of stilbene derivatives via visible-light-induced cross-coupling of aryl diazonium salts with nitroalkenes using –NO2 as a leaving group

The straightforward visible-light-induced synthesis of stilbene compounds via the cross-coupling of nitroalkenes and diazonium tetrafluoroborates under transition-metal-free conditions is described. The protocol uses green LEDs as light sources and eosin Y as an organophotoredox catalyst. Broad substrate scope and exclusive selectivity for the (E)-configuration of stilbenes are observed. This protocol proceeds via a radical pathway, with nitroalkenes serving as the radical acceptor, and the nitro group is cleaved during the process.

Synthesis of 2-(5-Substituted-1,3,4-thiadiazolo-2-ylimino)-4-thiazolidinones under Microwave Irradiation

Abstract Fifteen 2‐(5‐substituted‐1,3,4‐thiadiazolo‐2‐ylimino)‐4‐thiazolidinones were efficiently synthesized from the reaction of ammonium thiocyanate with 2‐chloro‐N‐(5‐substutited‐1,3,4‐thiadiazolo‐2‐yl)acetamides under microwave irradiation. The target compounds were obtained in better yields (75–98%) and shorter time (5 min) than with conventional heating.