二异戊基硫醚萃取分离贵金属

二异戊基硫醚（代号Ｓ－２０１）是金钯高效率选择性萃取剂，在硫酸及盐酸酸度为０．０１～７ｍｏｌ／Ｌ介质中，选择性萃取Ａｕ、Ｐｔ、Ｐｄ、Ｒｈ、Ｉｒ、Ｃｕ、Ｎｉ及Ｆｅ时，Ａｕ、Ｐｄ的萃取率均在９９．５％以上，在低酸度下，其它金属不被萃取。经过洗涤，反萃取金，热还原得粗金，含钯液用二氯二氨络亚钯法处理二次，金、钯直收率大于９５％，纯度均在９９．９５％以上。

二异戊基硫醚萃取分离钯

对原二异戊基硫醚萃取分离钯工艺进行了改进，如萃金余液性质调整，萃取剂预先除味，改变有机相、反萃剂及洗液组成以及洗水、再生液、平衡液循环使用等。试验证明，改进后的工艺明显优于二正辛基硫醚（ＤＯＳ）和二正己基硫醚（ＤＮＨＳ）萃取钯。

3种2-甲基-2-烷基-1,3-二硫杂环戊烷类化合物的合成

以对甲苯磺酸为催化剂, 3种酮类化合物和二硫代乙二醇在苯中共沸脱水,合成了 2 -甲基- 2 -乙基- 1, 3 -二硫杂环戊烷、2- 甲基- 2- 异丁基- 1, 3- 二硫杂环戊烷和 -2 -甲基- 2 -异戊基 1, 3 二硫杂环戊烷,产率分别为 71. 5%、74. 3%和 75. 6%,质量分数分别为 98 .8%、99. 1%和 98. 9%。经红外光谱分析、元素分析、核磁共振分析和色 -质联机分析确定了 3种产物的结构。

Acid-catalyzed chemoselective C-and O-prenylation of cyclic 1,3-diketones

The chemoselective C-and O-prenylation of cyclic 1,3-diketones was achieved by tuning the prenyl source and catalyst.In the presence of the solid acid Nafion,the coupling of 1,3-cyclohexanediones with isoprene gave C-prenylated 5-chromenones.Alternatively,using prenol as the substrate with the Lewis acid Al Cl3 as the catalyst resulted in the exclusive O-prenylation of 1,3-cyclohexanediones.Notably,the resulting products could easily undergo aromatization to deliver prenylated resorcinols that are otherwise difficult to prepare.Our methodology is highly selective,atom-economical,operationally simple,easily scalable,and has potential applications throughout organic synthesis.

Occurrence and distribution of hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers(OH-GDGTs) in the Han River system, South Korea

We investigated the occurrence and distribution of terrestrial-derived hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers(OH-GDGTs) in the Han River system and their potential impact on the application of the ring index of OH-GDGTs(RI-OH) as a sea surface temperature(SST) proxy in the eastern Yellow Sea. Thereby, we analyzed various samples collected along the Han River and from its surrounding areas(South Korea, n = 34). The OHGDGTs were found in all samples investigated. OH-GDGT-0 was the dominant OH-GDGT component in the estuary and marine samples while OH-GDGT-2 was generally dominant in the soils, the lake sediments and the river suspended particulate matter(SPM). Our results thus suggests a possible warm bias of the RI-OH-derived summer SSTs in the coastal zone to which a large amount of terrestrial organic matter is being supplied. Further studies are necessary to better assess the applicability of the RI-OH proxy in the eastern Yellow Sea.

Determination of 8,2′-diprenylquercetin 3-methyl ether in plasma by UPLC-MS-MS and its pharmacokinetic application in rats

8,2＇-Diprenylquercetin 3-methyl ether with significant anti-breast cancer activity is the main constituent of Tibetan medicine Sinopodophylli Fructus. In the present study, we developed and validated a rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） method for the determination of 8,2＇-diprenylquercetin 3-methyl ether in rat plasma. 8-Prenylkaempferol was used as the internal standard. The separation was carried out using Waters ACQUITY UPLC BEH C18 column （2.1 mm×100 ram, 1.7 μm） with a mobile phase consisting of acetonitrile and 0.1% formic acid in water on a gradient program at a flow rate of 0.4 mL＇min-1 and temperature of 30 ℃. Triple quadrupole mass spectrometric detection in negative ion mode was used for multiple-reaction monitoring of the transitions at m/z 451.30→177.25 and m/z 353.25→298.15 for 8,2＇-diprenylquercetin 3-methyl ether and 8-prenylkaempferol, respectively. The calibration curves were linear within the concentration range 0.1-2000 ng/mL （r = 0.9954）. The recoveries were 103%-115%, and the results were consistent across low, middle and high concentration levels. The intra- and inter-day precisions were within 15%, and the bias was between --6%-15%. This method was simple, rapid and sensitive, which could be applied to the determination of 8,2＇-diprenylquercetin 3-methyl ether in plasma and pharmacokinetic study in rats. Pharmacokinetic test indicated that the peak plasma concentration occurred in 2 h after the female rats were intragastrically administered with 8,2＇-diprenylquercetin 3-methyl ether at the dose of 100 mg/kg, and the biological half-life was 6.79 h. The blood drug concentration maintained equal amount for 20 h, which was conducive to the in vivo effects of drugs.

When does a diblock copolymer probe the interfacial rheological effect?

Lateral diffusion of diblock copolymer residing on the interfaces between two immiscible liquids is investigated at single molecular level. Fluorescence correlation spectroscopy was used to study the diffusion of fluorescence-labeled diblock copolymer,polystyrene-b-polyisoprene, at the interface formed between two immiscible liquids. The interfaces are formed between N,N-dimethylformamide(DMF) and a few immiscible liquids, n-alkane and polyisoprene. Interfacial diffusion coefficient of the diblock copolymer probe is found to decrease monotonously with the increase of the molecular length of the interface constituting liquids. The decrease of diffusion coefficient follows the prediction by Einstein relation using the viscosity of the constituting liquids as the variables only for interfaces between DMF and very small n-alkanes. For interfaces formed between DMF and bigger alkanes and especially between DMF and polyisoprene, the diffusion coefficient is much higher than the calculated value,indicating that the probe molecule starts to probe the much less viscous interfacial region because the interfacial width gets larger,whose thickness is comparable to the molecule size of the liquids.