Stevens rearrangement of thioethers with arynes: a facile access to multi-substituted ß-keto thioethers.

An effective method for the synthesis of multi-substituted ß-keto thioethers via Stevens rearrangement of simple ß-keto thioethers with arynes has been developed. In these reactions, successive C-S/C-H/C-C bonds were formed in one pot under mild and transition-metal free conditions to afford multi-substituted ß-keto thioethers in moderate to good yields.

Time-dependent enantiodivergent synthesis via sequential kinetic resolution.

The preparation of both enantiomers of chiral molecules is among the most fundamental tasks in organic synthesis, medicinal chemistry and materials science. Achieving this goal typically requires reversing the absolute configuration of the chiral component employed in the reaction system that is being used. The task becomes challenging when the natural source of the chiral component is not available in both configurations. Herein, we report a time-dependent enantiodivergent synthesis, in which an Ir-catalysed allylic substitution reaction uses one catalyst sequentially to promote two kinetic resolution reactions, enabling the synthesis of both enantiomers of the product using the same enantiomer of a chiral catalyst. The appropriate permutation of individual reaction rates is essential for the isolation of the chiral products in opposite configurations with high enantiopurity when quenched at different reaction times. This work provides an alternative solution for the preparation of both enantiomers of chiral molecules.

A new ternary copper(II) complex derived from 2-(2'-pyridyl)benzimidazole and glycylglycine: synthesis, characterization, DNA binding and cleavage, antioxidation and HSA interaction.

A new ternary copper(II)-dipeptide complex [Cu(glygly)(HPB)(Cl)]⋅2H2O (glygly=glycylglycine anion, HPB=2-(2'-pyridyl)benzimidazole) has been synthesized and characterized. The DNA interaction of the complex was studied by spectroscopic methods, viscosity, and electrophoresis measurements. The antioxidant activity was also investigated using the pyrogallol autoxidation assay. Besides, the interaction of the complex with human serum albumin (HSA) in vitro was examined by multispectroscopic techniques. The complex partially intercalated to CT-DNA with a high binding constant (Kb=7.28×10(5) M(-1)), and cleaved pBR322 DNA efficiently via an oxidative mechanism in the presence of Vc, with the HO· and O2(-) as the active species, and the SOD as a promoter. Furthermore, the complex shows a considerable SOD-like activity with the IC50 value of 3.8386 µM. The complex exhibits desired binding affinity to HSA, in which hydrogen bond or vander Waals force played a major role. The alterations of HSA secondary structure induced by the complex were confirmed by UV-visible, CD, synchronous fluorescence and 3D fluorescence spectroscopy.

[Voice fatigue test analysis in secondary school teachers].

OBJECTIVE: To investigate the status of voice fatigue and throat disease in the secondary school teachers in Urumqi. METHODS: This study included 11 689 teachers from 109 secondary schools offered by Teaching and Researching Center of Urumqi as the second-stage random sampling. Among them, 3217 teachers were selected to carry out voice fatigue test and routine examination of throat. For those with abnormal routine inspection results, the stroboscopic laryngoscopy were added. RESULTS: The failure rate difference of 3217 secondary school teachers voice fatigue tests during different periods had statistical significance (F = 202.653, P < 0.05). The failure rate difference of voice fatigue test among different throat diseases groups had statistical significance (F = 9.516, P < 0.05). There was statistical significance in failure rates of the voice fatigue tests between 908 cases of disease group and 2309 cases of normal group among different genders and periods (P < 0.05). Female teachers had higher failure rates than male teachers in voice fatigue tests. High failure rates appeared when high volume required for male and female teachers in voice fatigue tests. There was statistical significance in mean value sound pressure level (MVSPL) and mean value fundamental frequency (MVF0) of the voice fatigue tests between different gender and periods (P < 0.05). Male teachers had higher MVSPL than female teachers, female teachers had higher MVF0 than male teachers. There was statistical significance in failure rates of the voice fatigue tests among teachers from different tribes in different periods (P < 0.05). The Uighur had the highest failure rate, while Han had the lowest. Make further pairwise comparisons, failure rates difference of the Han and the Uighur in the voice fatigue tests during different periods had statistical significance. Comparison among other tribes had no statistical significance (P > 0.05). CONCLUSIONS: Voice fatigue is common in secondary school teachers. Female teachers tend to get voice fatigue more easily, when required high volume, the voice fatigue is more serious. Uighurs teachers have highest degree of voice fatigue.