Photosensitization of trans-Vitamin D3 to cis-Vitamin D3 in Heterogeneous System

Two modes of heterogeneous photoisomerization of trans-vitamin D3 to cis-vitamin D3 are described. The occurrence of isomerization on the substrate bounded to the polymeric support gives us the possibility in succession synthesis of 1α-hydroxyvitamin D3. The polymer-bound anthracene can sensitize isomerization of trans-vitamin D3 to cis-vitamin D3 efficiently and ease the separation process.     

Synthesis of Silica-anchored Sensitizer and its Application in the Preparation of Previtamin D3 from Tachysterol

A silica gel-anchored photosensitizer was synthesized with anthracene as sensitizer moiety. The photoisomerization of tachysterol to previtamin D3 was carried out with this heterogeneous photosensitizer in ethanol. The experiment results demonstrate that this solid phase photosensitizer is efficient for the photoisomerization and can be simply separated from the reaction mixture by filtration.     

硅胶固载光敏剂的合成及其在反式维生素D3光敏异构化为顺式维生素D3中的应用

采用丙二酸作为连接体,将9-蒽甲醇连接到硅胶上生成硅胶固载的光敏剂.利用此固相光敏剂分别在乙醇和甲苯溶液中敏化反式维生素D₃.实验结果表明,此固相光敏剂能够有效地敏化反式维生素D₃为顺式维生素D₃的反应,并且非常容易从反应体系中分离出来.     

Synthesis of Polymer-bound Sensitizers and their Applications in the Preparation of Previtamin D3 from Tachysterol

Two kinds of polymer-bound photosensitizers were synthesized, in which anthracene acts as sensitizer moiety,polystyrene (PS) and poly(methyl methylacrylate) (PMMA) serve as solid phase supports, respectively. The photoisomerization of tachysterol to previtamin D3 was carried out with these polymer-bound photosensitizers in ethanol and toluene solutions. The experiment results demonstrate that these solid phase photosensitizers are efficient for the photoisomerization with good recycle property and can be simply separated from the reaction mixtures by filtration.     

3',5'-二溴-2,4-二羟基偶氮苯的合成、晶体结构和光致异构性能

以对硝基苯胺为原料,通过溴代、去氨基、硝基还原和重氮耦合反应合成了3’,5’-二溴-2,4-二羟基偶氮苯,利用FT-IR,1H NMR,13C NMR,MS,元素分析和X射线单晶衍射等方法对标题化合物的结构进行了表征。X射线单晶衍射结果表明,该晶体属于单斜晶系,P1 21/c1空间群,晶胞参数为:a=2.0107(3)nm,b=0.42111(7)nm,c=0.16175(3)nm,β=94.408(2)°,V=1.3655(4)nm3,Z=4,Dc=1.897 g/cm3,μ=5.941 mm-1,F(000)=760,R1=0.0762,wR2=0.2127[I>2σ(I)],标题偶氮苯分子以E型异构体存在。其光致异构性能研究表明,在紫外光的照射下,标题分子可实现E-Z异构转化,其稀溶液E-Z光致异构转化遵循一级动力学方程ln[(A0-Aeq)/(At-Aeq)]=kt×t。     

Effect of Reaction Media on Photoreaction of Provitamin D_3

IntroductionThe photochemistry of provitamin D3 (Pro) has been studied extensively in many years1-4. As shown in Scheme 11, irradiation of provitamin D3 in organic solvents results in its photoisomerization to previtamin D3 (Pre). Previtamin D3 can be thermally transferred into vitamin D3 (VD3), which is of commercial interests. However, previtamin D3 also undergoes the photochemical back reaction leading to the regeneration of provitamin D3 and the photoisomerization resulting in the und…     

新型胰岛素增敏剂的合成及其生物活性评价

以川芎嗪为结构单元,与噻唑烷二酮类降糖药物的药效团组合,设计并合成了一个新的胰岛素增敏剂——2-甲氧基-5-[(2,4-二氧代-5-噻唑烷基)-甲基]-N-[(3,5,6-三甲基-2-吡嗪基)-甲基]-苯甲酰胺(Ⅰ),其结构经1H NMR和MS表征。体外活性测试结果表明,Ⅰ在用药量为1×10-5mol·L-1时对PPAR-γ的激动活性与吡格列酮相当;体内生物活性测试结果表明,Ⅰ有抑制血糖升高的倾向,有一定的血管内皮细胞保护作用。     

Vitamin D3对儿童桥本甲状腺炎IL-10、IL-12的调节作用

目的:分别以IL-12、IL-10作为Th1、Th2的代表,在1,α25(OH)2D3的干预下,在单核细胞水平分析人外周血单核细胞(PBMC)中IL-10、IL-12在儿童桥本甲状腺炎(HT)中的细微变化,并探讨1α,25(OH)2D3的免疫调节作用。方法:以27例HT患儿为研究对象,17名健康儿童作对照,采集外周静脉血,一部分用于分离并培养单核细胞,设1,α25(OH)2D3干预组和对照组,收集培养上清液,ELISA检测上清液中IL-10、IL-12水平。另一部分静脉血分离出血清,再提取25(OH)D3,用放射免疫法(RIA)测定25(OH)D3水平。结果:HT组25(OH)D3显著低于健康对照,分别为(21.85±5.73)ng/mL和(27.56±7.46)ng/mL(P<0.01),且HT组PBMC产生IL-12水平显著高于健康对照,分别为(119.18±28.65)pg/mL和(102.84±23.86)pg/mL(P<0.01),而IL-10的表达显著低于健康对照,分别为(132.99±12.04)pg/mL和(171.41±35.72)pg/mL(P<0.01)。1α,25(OH)2D3干预后HT患儿IL-12表达显著下调为(98.57±11.98)pg/mL(P<0.01),IL-10表达在HT组和健康对照组均上调,分别为(184.15±35.34)pg/mL(P<0.01)、(223.77±53.36)pg/mL(P<0.01),HT组ρ(IL-10)/ρ(IL-12)比值显著升高。结论:HT患儿的25(OH)D3水平不足。1α,25(OH)2D3参与单核细胞分泌细胞因子的调节过程,能抑制HT增强的Th1型细胞因子IL-12分泌,增加IL-10表达,纠正n(Th1)/n(Th2)细胞因子失衡。     

有机敏化剂插层层状氢氧化铽纳米复合体的合成与发光性质

选择两种有机物对苯二甲酸(TA)和苯甲酸(BA)作为敏化剂,通过在水热条件下的离子交换反应,成功将其以有机阴离子形式插层至层状铽氢氧化物而获得纳米复合体。荧光性质测定表明TA^2-和BA^-通过有效的能量转移均增强了Tb³⁺的特征绿色荧光发射,并且TA^2-的敏化增强能力大于BA^-。从能级匹配角度讨论了敏化剂和Tb³⁺之间能量转移的机理。     

有机敏化剂插层层状氢氧化铽纳米复合体的合成与发光性质

选择两种有机物对苯二甲酸(TA)和苯甲酸(BA)作为敏化剂,通过在水热条件下的离子交换反应,成功将其以有机阴离子形式插层至层状铽氢氧化物而获得纳米复合体。荧光性质测定表明TA2-和BA-通过有效的能量转移均增强了Tb3+的特征绿色荧光发射,并且TA2-的敏化增强能力大于BA-。从能级匹配角度讨论了敏化剂和Tb3+之间能量转移的机理。     

多巴胺D3受体显像剂的前体合成及其^19F的标记

自从多巴胺D3受体亚型克隆成功[1]以来,对D3受体功能的研究引起了极大的兴趣.它主要分布于哺乳动物大脑中与认知和情感功能相关的边缘脑区,特别是嗅结节、马列加氏岛和前脑基质的侧坐核隔膜,而且与抗精神病药物具有很高的亲和性,具有特殊的神经药理学意义[2].     

A Facile Solid—phase Synthesis of 3—Carboxycoumarins

3-Carboxycoumsrins were synthesized via the solid phase synthesis conviently. The resin bound cyclic malonic ester reacted with o-methoxy or o-hydroxybenzaldehydes. Then cyclization was processed under H2SO4 to afford the products in excellent purities and yields.     

Synthesis and Properties of Aryloxy-terminated Polydimethylsiloxanes

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有机硅连接体在固相有机合成中的应用

固相合成方法具有传统液相反应无可比拟的优越性,已被越来越多的化学家认可.反应物与高分子支持体的连接则是固相合成中的重要环节,连接体在其中扮演着重要的角色.近20多年来发展起来的有机硅连接体基本满足了理想连接体的要求,具有广阔的应用发展前景.本文从直接法和间接法两方面综述了26年来具有代表性的多种有机硅连接体的设计、制备及其在固相有机合成中的应用.     

Synthesis of novel 3-oxa-chromanol type antioxidants

Condensation of trimethylhydroquinone with aldehydes provides 2,4-disubstituted 5,7,8-trimethyl-4H-benzo[1,3]dioxin-6-ols in a straightforward one-pot reaction. These compounds are 3-oxa-derivatives of α-tocopherol (vitamin E) and represent an interesting novel class of phenolic antioxidants. The formation reaction proceeds according to a two-step mechanism consisting of electrophilic substitution and acetalization, and provides the product as a cis/trans-mixture of diastereomers.     

Synthesis and characterization of crosslinked chitosan formed by γ irradiation in the presence of carbontetrachloride as a sensitizer

Synthesis of crosslinked chitosan using γ irradiation in the presence of carbon tetrachloride as a sensitizer is carried out. The resultant crosslinked product, which is yellow in color, is characterized by elemental analysis, which shows the presence of chlorine. Crosslinked chitosan on hydrolysis with alkali results in the formation of another product that retains the crosslinked structure but does not have chlorine in it. Gel formatting characteristics of both these products have been studied. The crosslinked chitosan and its hydrolysis product are further characterized by various physical methods such as X‐ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and thermogravimetry. Based on the results, a probable mechanism of crosslinking whereby chitosan chains are crosslinked by a >CCl₂ group is suggested. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3897–3909, 2004     

秩为3的Jacobian的性质和它在热力学中的应用

描述了秩为3的Jacobian的性质,探讨了应用Mathematica软件及秩为3的Jacobian来研究单组分、单相系统热力学一阶偏微商和二阶偏微商的方法.     

反相高效液相色谱法测定补钙保健品中的维生素D_3

用氯仿作提取剂直接提取补钙保健品中的维生素Ｄ３，提取液经浓缩后进行高效液相色谱分析，并对皂化和直接提取的样品中维生素Ｄ３的含量进行了比较。采用μ－ＢｏｎｄａｐａｋＣ１８作分离柱，甲醇－水（８７１３）作流动相，检测波长为２６４ｎｍ，回收率为９５．６３％。     

Efficient Synthesis of 2—Ethyl—A—ring Analogues of 19—Nor—1α,25—dihydroxy Vitamin D3

The novel 19-nor-1α,25-dihydroxy vitamin D3 analogues possessing an ethyl at the 2-position(4 and 5).were synthesized by coupling 25-hydroxy Windaus-Grundmann ketone derivative 20 with A-ring synthons(15 and 19)respectively.The enantioselective synthesis of substituted bicyclic[3,1,0]hexanes structure A-ring synthons,started from all-cis-3,5-dihydroxy-4-ethyl-1-(methoxycarbonyl)cyclohexane via lipase-catalyzd asymmetrization,was demonstratcd.     

Chemical Synthesis, 3D Structure,and ASIC Binding Site of the Toxin Mambalgin‐2

Mambalgins are a novel class of snake venom components that exert potent analgesic effects mediated through the inhibition of acid‐sensing ion channels (ASICs). The 57‐residue polypeptide mambalgin‐2 (Ma‐2) was synthesized by using a combination of solid‐phase peptide synthesis and native chemical ligation. The structure of the synthetic toxin, determined using homonuclear NMR, revealed an unusual three‐finger toxin fold reminiscent of functionally unrelated snake toxins. Electrophysiological analysis of Ma‐2 on wild‐type and mutant ASIC1a receptors allowed us to identify α‐helix 5, which borders on the functionally critical acidic pocket of the channel, as a major part of the Ma‐2 binding site. This region is also crucial for the interaction of ASIC1a with the spider toxin PcTx1, thus suggesting that the binding sites for these toxins substantially overlap. This work lays the foundation for structure–activity relationship (SAR) studies and further development of this promising analgesic peptide.