The Deprotection of Methyl Carbamates by Sodium Hydrogen Telluride

Methyl carbamates, prepared by reacting primary and secondary amines with chlorocarbonate, react smoothly with sodium hydrogen telluride in DMF and regenerate the amines in moderate yields.     

Palladium-Catalyzed Cross-Coupling of Organozirconium Compounds with Diaryliodonium Salts

The palladium-catalyzed cross-coupling reaction of diaryliodonium salts with organozirconium compounds was achieved for about 1–1.5 hrs at room temperature and the reaction proceeded with retention of configuration to provide a new convenient method for the synthesis of (E)-disubstituted alkenes.     

1,3‐Dichloro‐tetra‐n‐butyl‐distannoxane: a new application for catalyzing the direct substitution of 9H‐xanthen‐9‐ol at room temperature

1,3‐Dichloro‐tetra‐n‐butyl‐distannoxane was firstly used to catalyze the direct substitution of 9H‐xanthen‐9‐ol with indoles at room temperature to afford a class of 3‐(9H‐xanthen‐9‐yl)‐1H‐indole derivatives in good to excellent isolating yield. Moreover, other nucleophiles (such as diketone and pyrrole) could also proceed smoothly in this methodology. Copyright © 2012 John Wiley & Sons, Ltd.     

Gd complexes of diethylenetriaminepentaacetic acid conjugates of low-molecular-weight chitosan oligosaccharide as a new liver-specific MRI contrast agent

This study was to describe the synthesis of complexes of gadolinium diethylenetriaminepentaacetic acid conjugates of low-molecular-weight chitosan oligosaccharide Gd-DTPA-CSn (n = 6, 8, 11) as a new class of contrast agent as well as its magnetic property in a pilot magnetic resonance imaging. The efficacy of the contrast agent was assessed by measuring the longitudinal relaxivity (r₁), FLASH imaging in phantoms in vitro and signal intensity in vivo of the rat abdominal axial imaging. The r₁ of Gd-DTPA-CS₁₁ was up to 11.65 mM^− 1·s^− 1, which was 3 times higher than that of the analogous MRI contrast agent Gd-DTPA in commercial use. In vivo MR images of rat obtained with Gd-DTPA-CS₁₁ showed strong signal enhancement in liver and the vessels of the liver parenchyma during the extended period of time. The present study suggests that the new synthesized gadolinium complexes can be used as a new class of practical liver-specific MRI contrast agent because of its superior performance compared with Gd-DTPA.     

Cu-catalyzed direct C–H amination of 2-alkylazaarenes with azodicarboxylates via nucleophilic addition

An efficient Cu-catalyzed C–H amination of 2-alkylazaarenes with azodicarboxylates has been developed through nucleophilic addition of sp³C–H bond to unsaturated nitrogen–nitrogen double bond. It provides an easy access to azaarene-containing hydrazines from simple and easily available starting materials.     

Improved multiparty quantum key agreement in travelling mode

The need to simultaneously balance security and fairness in quantum key agreement (QKA) makes it challenging to design a flawless QKA protocol, especially a multiparty quantum key agreement (MQKA) protocol. When designing an MQKA protocol, two modes can be used to transmit the quantum information carriers: travelling mode and distributed mode. MQKA protocols usually have a higher qubit efficiency in travelling mode than in distributed mode. Thus, several travelling mode MQKA protocols have been proposed. However, almost all of these are vulnerable to collusion attacks from internal betrayers. This paper proposes an improved MQKA protocol that operates in travelling mode with Einstein-Podolsky-Rosen pairs. More importantly, we present a new travelling mode MQKA protocol that uses single photons, which is more feasible than previous methods under current technologies.