Thiol-Functionalized Mesoporous Silica for Effective Trap of Mercury in Rats

The chance of exposure to heavy metal for human being rises severely today due to the increasing water contamination and air pollution. Here, we prepared a series of thiol-functionalized mesoporous silica as oral formulation for the prevention and treatment of heavy metal poisoning. The successful incorporation of thiol was verified by the FTIR spectra. SBA15-SH-10 was used for the study as it is of uniform mesopores and fine water dispersibility. In simulated gastrointestinal fluid, the thiol-functionalized mesoporous silica can selectively capture heavy metal, showing a very high affinity for inorganic mercury (II). The blood and urine mercury levels of rats fed with a diet containing Hg (II) and material were significantly lower than those of rats fed with the metal-rich diet only. On the contrary, the mercury content in fecal excretion of the treatment group increased more than twice as much as that of the control group. This result indicated that SBA15-SH-10 could effectively remove mercury (II) in vivo and the mercury loaded on SBA15-SH-10 would be excreted out. Hence, SBA15-SH-10 has potential application in preventing and treating heavy metal poisoning via digestive system

Catalytic asymmetric direct alpha-alkylation of amino esters by aldehydes via imine activation

Two types of BINOL-related chiral aldehydes were used as organocatalysts for the direct alpha-functionalization of N-unprotected amino esters. The first chiral aldehyde catalysed alpha-alkylation of 2-aminomalonates with 3-indolylmethanols via imine activation was reported. Various tryptophan derivatives were produced in good yields and with high enantioselectivities. A reasonable mechanism was proposed and the core intermediates were identified by high resolution mass spectroscopy (HRMS)

基于环糊精自组装的纳米聚集体设计、制备及应用

本文报道通过基于环糊精主客体识别的自组装方法设计制备空心纳米球、纳米棒及其应用研究。我们应用改性天然多糖、pluronic、合成高分子PEI-PEG和改性pluronic等与环糊精(CD)的主客体识别及软-硬段自组装形成空心纳米微球及纳米棒。我们深入研究了该类纳米材料的制备方法、基本性能、影响因素等。此外,我们通过改变软-硬段比例可以实现从

Sabian, a novel flavonoid from Sabia yunnanensis

A novel flavonoid, [2-(3,4-dihydroxy-phenyl)-3,5,7-trihydroxy-4-oxo-4 H -chromen-8-yl]-[8-hydroxy-7-( E -4-hydroxy-3-methyl-but-2-enyl)-2,2-dimethyl-chroman-5-yl]-acetic acid methyl ester (10), trivially named sabian, along with 11 known compounds, have been isolated from the stems and leaves of Sabia yunnanensis . Their structures were established on the basis of spectral analysis

Enantioselective cyanosilylation of ketones by a catalytic double-activation method with an aluminium complex and an N-oxide

Double-activation catalysis promises high catalytic efficiency in the enantioselective cyanosilylation of ketones through the combined use of a Lewis acid and a Lewis base. Catalyst systems composed of a chiral salen-A1 complex and an N-oxide have high catalytic turnovers (200 for aromatic ketones, 1000 for aliphatic ones). With these catalysts, a wide range of aliphatic and aromatic ketones were converted under mild conditions into tertiary cyanohydrin O-TMS ethers in excellent yields and with high enantioselectivities (94% ee for aromatic ketones, 90% ee for aliphatic ones). Preliminary mechanistic studies revealed that the salen-A1 complex played the role of a Lewis acid to activate the ketone and the N-oxide that of a Lewis base to activate TMSCN; that is, double activation

One-step synthesis of diphenyhnethanes

The coupling reaction of substituted toluenes themselves and the cross-coupling reaction of substituted toluene and aromatic in the presence of bromine in anhydrous CCl4 under irradiation lead to diphenylmethanes with moderate to good yields. The methylene moiety in diphenylmethanes comes from the toluene with fewer electron-donating groups, and regioselectivity was observed

Two diterpenes and three diterpene glucosides from Phlogacanthus curviflorus

Two new diterpene lactones, phlogacantholides B (1) and C (2), and three new diterpene lactone glucosides, phlogacanthosides A (3), B (4), and C (5), together with lupeol, beta-sitosterol, betulin, P-daucosterol, (+)syringaresinol, and (+)-syringaresinol-4-O-beta-D-glucopyranoside, were isolated from the roots of Phlogacanthus curviflorus. Their structures were elucidated by chemical and spectroscopic evidence. The structure, including the relative configuration of phlogacantholide B (1), was confirmed by X-ray crystallographic analysis of its diacetate (6)

Effective activation of the chiral salen/Ti(OiPr)(4) catalyst with achiral phenolic N-oxides as additives in the enantioselective cyanosilylation of ketones

The activation of chiral titanium(IV) complexes with phenolic N-oxides additives has been found to provide an alternative strategy for the asymmetric cyanosilylation of ketones. By using 10 mol % of chiral salen-titanium(IV) complex in combination with 1 mol% achiral phenolic N-oxide as an additive, aromatic, aliphatic and heterocyclic ketones have been converted into the corresponding cyanohydrin trimethylsilyl ethers in 58-96% yields with 56-82% ee. Several factors concerning the reactivity and enantioselectivity have been discussed. A catalytic cycle based on experimental phenomena and studies has been proposed to explain the origin of this activation and the asymmetric induction

Effects of Increased Salinity on Growth, Development and Survival in Early Life Stages of the Green Toad Bufotes Variabilis (Anura: Bufonidae)

This study examined the effects of increased salinity on growth, development and survival of the Green toad, Bufotes variabilis during embryonic, hatching and early larval periods. Eggs from a single cohort of B. variabilis were subjected to acute and chronic toxicity tests for water salinity ranging from 0.20 to 10 g of salt per liter. Results obtained from this study showed that salinity over 3.70 g/l increased embryonic mortality and reduced percentage of hatching and survival rate of larvae. As larvae tolerated salinity 0.20 to 3.70 g/l with highest survival, but salinity of 10 g/l caused mortality of all individuals within 12 h, 7.70–8.70 (g/l) within 4.5 days, 5.70–6.70 g/l within 10 days and 4.70 (g/l) were tolerated within 14 days. Salinity less than 0.70 g/l did not affect survival and hatching success of the embryos. After a 3-week experiment, size of larvae exposed to salinities over 0.70 g/l was lower compared to larvae reared at lower salinity levels. Meanwhile increases in salinity more than 3.70 g/l caused extension in the hatching period. Larvae reared at salinity of 3.70 to 4.70 g/l had morphological abnormalities, such as distortion of tail

根霉3078的代谢产物的研究

从根霉 30 78菌丝体的甲醇提取物中分离得到 9个化合物 ,通过波谱分析 ,鉴定为 5α,8α 表二氧 (2 0S ,2 2E ,2 4R) 麦角甾 6 ,2 2 二烯 3β 醇 (1)、甘油醇 1 单油酸酯 (2 )、4 羟基苯乙酮 (3)、4 羟基苯乙酸 (4 )、(2 0S ,2 2E ,2 4R) 麦角甾 7,2 2 二烯 3β ,5α ,6 β 三醇 (5 )、(S) 3 羟基 3 苯基丙酸 (6 )、胸腺嘧啶 (7)、尿嘧啶(8)和腺苷 (9