A Novel One‐Pot Synthesis of UV‐Blue ZnSe Nanocrystals in Aqueous Solution

Described herein is a novel one‐pot aqueous synthesis of ZnSe nanocrystals has featuring the utilization of Na₂SeO₃ and Zn(AC)₂×2H₂O as Se and Zn source, glutathione (GSH) as stabilizing agent and reducing agent. By this approach, the UV‐blue ZnSe QDs with quantum yield (QYs) up to 19% have been synthesized with a molar ratio of Se/Zn/GSH at 1:4:8.5 under aqueous conditions at 110 °C. XRD and TEM show the ZnSe QDs are zinc cubic structure particles with an average diameter of 3–5 nm.     

Unusual Spirodecane Sesquiterpenes and a Fumagillol Analogue from Cordyceps ophioglossoides

Investigation of the cultured mycelia of Cordyceps ophioglossoides resulted in the isolation and characterization of three new unusual spiro[4.5]decane sesquiterpenes, cordycepol A ( 1 ), cordycepol B ( 2 ), and cordycepol C ( 3 ), and a new fumagillol analogue, cordycol ( 4 ). Their structures were established by spectroscopic means. The cytotoxic activities were also evaluated, compounds 3 and 4 showing their IC₅₀ values in the range of 12–33 μg/ml against HeLa and HepG2 (Table 3). In addition, 3 and 4 were not obviously harmful towards normal liver cell lines LO2, showing IC₅₀ values above 80 μg/ml.     

Synthesis and properties of near IR induced self-healable polyurethane/graphene nanocomposites

A series of self-healable polyurethane (SHPU)/modified graphene (MG) nanocomposites were synthesized from poly(tetramethylene glycol) (PTMG) and 4,4′-methylene diphenyl diisocyanate (MDI) with minute amounts (0–1 wt%) of MG which was chemically modified graphene oxide (GO) with phenyl isocyanate and reduced in the presence of phenylhydrazine.     

Synthesis and Anti‐HIV Activity of Triazolo‐Fused 2′,3′‐Cyclic Nucleoside Analogs Prepared by an Intramolecular Huisgen 1,3‐Dipolar Cycloaddition

Triazolo‐fused 2′,3′‐cyclic nucleoside analogs were synthesized by an intramolecular 1,3‐dipolar cycloaddition of nucleoside‐derived azido alkynes in a regio‐ and stereospecific manner. The uracil base in these target compounds was successfully transformed to the corresponding cytosine. The synthesized compounds were examined in a MAGI assay for their anti‐HIV activities, and in a H9 T lymphocytes assay for their cell toxicities.     

Ab initio study of the π–π interactions between CO2 and benzene,pyridine, and pyrrole

The π–π interactions between CO₂ and three aromatic molecules, namely benzene (C₆H₆), pyridine (C₅H₅N), and pyrrole (C₄H₅N), which represent common functional groups in metal‐organic/zeoliticimidazolate framework materials, were characterized using high‐level ab initio methods. The coupled‐cluster with single and double excitations and perturbative treatment of triple excitations (CCSD(T)) method with a complete basis set (CBS) was used to calibrate Hartree–Fock, density functional theory, and second‐order M?ller–Plesset (MP2) with resolution of the identity approximation calculations. Results at the MP2/def2‐QZVPP level showed the smallest deviations (only about 1 kJ/mol) compared with those at the CCSD(T)/CBS level of theory. The strength of π–π binding energies (BEs) followed the order C₄H₅N > C₆H₆ ～ C₅H₅N and was roughly correlated with the aromaticity and the charge transfer between CO₂ and aromatic molecule in clusters. Compared with hydrogen‐bond or electron donor–acceptor interactions observed during BE calculations at the MP2/def2‐QZVPP level of theory, π–π interactions significantly contribute to the total interactions between CO₂ and aromatic molecules. © 2013 Wiley Periodicals, Inc.     

Colorimetric detection of peroxynitrite-induced DNA damage using gold nanoparticles, and on the scavenging effects of antioxidants

We describe a rapid and convenient colorimetric method for the detection of oxidative DNA damage caused by peroxynitrite (ONOO^?) using unmodified gold nanoparticles (AuNPs). AuNPs are stable in the presence of single-stranded DNA (ssDNA) against the aggregation induced by a high ionic strength. If adsorbed ssDNA are cleaved by ONOO^? to form smaller fragments, the AuNPs rapidly aggregate due to electrostatic attraction. As a result, the color of the solution changes from red to blue, and this can be seen with bare eyes. We also have evaluated the activity of the antioxidants gallic acid, ascorbic acid and caffeic acid to scavenge ONOO^?. This method therefore also can be applied to screen for anti-oxidation drugs and agents.

Efficient One-Pot Synthesis of Tetrahydrobenzo[c]xanthene-1,11-dione Derivatives Under Microwave Irradiation

An efficient one-pot condensation of 4-hydroxylcoumarin, aromatic aldehydes, and 5,5-dimethylcyclohexane-1,3-dione has been achieved with molecular iodine as a catalyst via conventional heating and microwave irradiation techniques, and thus a variety of new tetrahydrobenzo[c]xanthene-1,11-dione derivatives were prepared in good yields.     

Efficient Synthesis of 6-(1H-1,2,4-Triazol-1-yl)-thieno[2,3-d]pyrimidin-4(3H)-ones via an Iminophosphorane

Ethyl 2-amino-4-methyl-5-(1H-1,2,4-triazol-1-yl)thiophene-3-carboxylate 2, obtained from Gewald reaction of 1-(1H-1,2,4-triazol-1-yl)acetone 1 with ethyl cyanoacetate and sulfur, was transferred into iminophosphorane 3. Further reaction of 3 with aromatic isocyanates gave carbodiimides 4, which were treated subsequently with a secondary amine to give 6-(1H-1,2,4-triazol-1-yl)-thieno[2,3-d]pyrimidin-4(3H)-ones 6 in good yields in the presence of a catalytic amount of sodium ethoxide.     

Expeditious Approach to Coumarins via Pechmann Reaction Catalyzed by Molecular Iodine or AgOTf

An efficient and facile route for the synthesis of coumarins via the Pechmann reaction catalyzed by molecular iodine or AgOTf was described.     

Microwave-Assisted Esterification of Diverse Carboxylic Acids and Chiral Amino Acids

A facile and efficient synthetic method of esters from their corresponding carboxylic acids and amino acids is described. The esterification reaction of carboxylic acids and amino acids could be greatly accelerated under microwave irradiation because the reactions described in this article took place in only 5 min with almost quantitative yields, and distinct acidity of catalytic acids was well tolerated. Unlike the racemation problem in microwave-assisted N-acylation reactions, the esters of chiral amino acids could be achieved with retention of configuration under this condition.