Xi-Cun Wang

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.

CBr4-Mediated Cross-Dehydrogenative Coupling Reaction of Amines

A novel CBr4-mediated dehydrogenative Povarov/aromatization tandem reaction of glycine derivatives with alkenes, leading to complex quinoline derivatives, and a CBr4-mediated dehydrogenative C-H functionalization of N-aryl tetrahydroisoquinolines with nucleophiles to form C-C and C-P bonds are reported. The reactions were performed under very simple and mild reaction conditions; only CBr4 was used as a promoter. A plausible mechanism involving a radical process is proposed.

SYNTHESIS OF 2-(4-METHOXYLPHENYLOXY-ACETYLAMIDO)-5-ARYLOXYMETHYL-1,3,4-OXADIAZOLES UNDER MICROWAVE IRRADIATION

ABSTRACT 2-(4-Methoxylphenyloxyacetylamido)-5-aryloxymethyl-1,3,4-oxadiazoles (4a–h) are synthesized by cyclization of 1-aryloxyacetyl-4-(4-methoxylphenyloxyacetyl)-thiosemicarbazides (3a–h) in the presence of mercuric acetate under microwave irradiation.

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.

A highly selective colorimetric sensor for Hg2+ based on nitrophenyl-aminothiourea

A simple and highly selective colorimetric sensor (L1) bearing thiosemicarbazide moiety as binding site and nitrophenyl moiety as signal group were synthesized. Sensor L1 showed great colorimetric single selectivity and high sensitivity for mercury cation in DMSO and DMSO/H(2)O binary solutions. When Hg(2+) was added to the DMSO solution of L1, dramatic color change from brown to colorless was observed. While the cations Ca(2+), Mg(2+), Cd(2+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Pb(2+), Ag(+) and Cr(3+) could not cause any distinct interferer toward the recognition process for Hg(2+). The detection limit is allowable to 5.0 × 10(-6) and 1.0 × 10(-7)M level of Hg(2+) according to visual color change and UV-vis change, respectively. The recognition mechanism of the sensor toward mercury cation was evaluated in DMSO solutions by UV-vis and (1)H NMR. The sensor selectively sense Hg(2+)via the formation of a stable 1:1 complex through CS and CO group with Hg(2+). When these complex bonds formed, the sensor carried out an ICT transition induced color change.

Phase Transfer Catalyzed Synthesis of Diaryl 1,4—Phenylene Dioxydiacetate

Abstract The title compounds 3a—3o were prepared with high yield via the reaction of 1, 4-phenylenedioxydiacetyl chloride with various substituted phenols under the condition of liquid-liquid phase transfer catalysis, using polyethylene glycol—400 as the catalyst.

SYNTHESIS OF 2-(5-(2-CHLOROPHENYL)-2-FUROYLAMIDO)-5-ARYLOXYMETHYL-1,3,4-THIADIAZOLES UNDER MICROWAVE IRRADIATION

2-(5-(2-chlorophenyl)-2-furoylamido)-5-aryloxymethyl-1,3,4-thiadiazoles (IIa–j) are synthesized under microwave irradiation via the cyclization of 1-aryloxyacetyl-4-(5-(2-chlorophenyl)-2-furoyl)-thiosemicarbazides (Ia–j) in the presence of glacial acetic acid.

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.