烷基-α-D-吡喃葡萄糖苷的合成与性能

以D-葡萄糖为原料,经全乙酰化、在SnCl_4催化下与脂肪醇糖苷化、脱保护3步反应合成了7种不同碳链长度的烷基-α-D-吡喃葡萄糖苷。利用核磁共振、表面张力仪和偏光显微镜等对其进行结构、表面张力和热致液晶等性能测试,结果表明,当烷基-α-D-吡喃葡萄糖苷烷基链长(n)为6~9时,均有发泡和乳化性能,其中正壬基-α-D-吡喃葡萄糖苷具有最佳的发泡和乳化性能;烷基糖苷(n=6~9)的表面张力(γ_(CMC))及临界胶束浓度(CMC)均比较低;饱和吸附量(Γ_(max))随烷基链的增长而减小,饱和吸附面积(A_(min))随烷基链增长而增大;形成胶束时的标准自由能(ΔG_(mic))和吸附自由能(ΔG_(ads))均为负值,其绝对值随烷基链增长而越来越大,其中正辛基-α-D-吡喃葡萄糖苷的表面活性最好;烷基糖苷(n=4~9)对皮肤均无急性刺激作用;所合成的烷基糖苷均具有热致液晶行为,随烷基链长的增加,液晶相的温度范围变宽,液晶相的稳定性越好。     

Gemini型季铵盐阳离子表面活性剂催化双烷基联苯酮的还原

本文报道了通过黄鸣龙还原反应还原长链烷基联苯酮,合成了三种长链烷基联苯,其中的两种化合物首次报道.以联吡啶季铵盐为相转移催化剂对双烷基联苯酮的黄鸣龙还原反应进行催化,产率提高了20%～40%,反应时间从55小时缩短为23小时.作为对比,十六烷基三甲基溴化铵、溴代十六烷基吡啶、十二烷基苯磺酸钠也作为催化剂对双烷基联苯酮进行催化还原,结果表明Gemini表面活性剂在双烷基联苯酮的还原中较上述三种传统表面活性剂具有更好的催化性能.     

4-甲酰基苯基(2,3,4,6-O-四乙酰基)-β-D-葡萄糖苷衍生物的有效合成

为克服目前合成方法存在收率较低,反应时间长、产品分离困难等不足,本文以β-D-葡萄糖、乙酰溴为原料,经乙酰化、溴代反应合成了糖基体2,3,4,6-O-四乙酰基-α-D-溴代葡萄糖,再与4-羟基苯甲醛衍生物经糖苷化反应合成了5种4-甲酰基苯基(2,3,4,6-O-四乙酰基)-β-D-葡萄糖苷衍生物。 在合成4-甲酰基苯基(2,3,4,6-O-四乙酰基)-β-D-葡萄糖苷衍生物的过程中,采用10%(质量分数)NaOH溶液为缚酸剂,三(3,6-二氧杂庚基)胺(TDA-1)为相转移催化剂,反应物的收率为61%~69%,并应用核磁共振技术确定了产品的结构。 该方法具有产品收率较高,反应温和、操作简单等优点。     

系列长链烷氧基苯甲醛的合成研究

以长链正烷基醇为原料与氢溴酸作用 ,合成了长链正烷基溴 6个 ;再与对或间羟基苯甲醛反应 ,合成了烷氧基苯甲醛 9个、间烷氧基苯甲醛 8个 .由于烷基链长的不同 ,其产率为 70 %～ 94% .考察了催化剂、烷基链长、羟基位置对长链烷氧基甲醛合成的影响 .解析了各种产物的红外光谱 .     

饱和开链醚的氧化碳氢炔基化研究

首次报道了饱和开链醚和末端炔的交叉脱氢偶联.在Ph₃CCl/GaCl₃介导的温和氧化条件下,饱和开链醚与一系列芳基和烷基末端炔在室温可发生交叉脱氢偶联,反应收率高达73%.鉴于烷基乙炔反应效率较低的问题,还报道了Ph₃CCl/GaCl₃介导的饱和开链醚和一系列烷基取代的炔基硼试剂的氧化偶联,并获得了较好的反应收率.     

基于荧光素烷基酯荧光增强的甲醇光纤化学传感器的研制

本文合成了荧光素长链烷基酯类化合物荧光素十八烷基脂, 将之固定于增塑的PVC膜中后,将此膜固定在光纤探头上, 制成了用于测定甲醇的荧光光纤化学传感器,该传感器测定甲醇的可逆性好,测定范围为30-80%甲醇(v/v), 响应时间小于2min     

含离子液体介质中酶催化糖基化合成4-羟基苯乙基β-D-葡萄糖苷

探讨了β-葡萄糖苷酶在离子液体/有机溶剂/缓冲溶液介质中催化直接糖基化反应合成4-羟基苯乙基β-D-葡萄糖苷.考察了反应体系组成、反应条件等因素对反应的影响.研究结果表明,1-丁基-3-甲基咪唑六氟磷酸盐(C4MIm·PF6)/1,4-二氧六环/柠檬酸-磷酸盐缓冲溶液是糖基化反应的合适介质.当三者的体积含量分别为17％...     

可降解型阳离子表面活性剂的合成

以长链烷基酸,环氧氯丙烷和叔胺为原料,经一步反应合成了一系列含酯基可生物降解的阳离子表面活性剂(1),其结构经1H NMR,IR和元素分析表征。研究了叔胺的碱性和空间位阻对收率的影响。利用滴体积法测定表面张力(γ)和临界胶束浓度(CMC)。当叔胺的碱性较强,空间位阻较小时收率最高(1 e,90%)。分子内有两个烷基长链的阳离子表面活性剂的表面活性最强(1b,CMC25=0.024 mmol.L-1,γCMC=34.20mN.m-1)。     

一类天然糖苷的首次全合成研究

由廉价易得的起始原料经4―6步反应高度立体专一性地合成了烷基类糖苷1和芳香类糖苷2,3, 4. 关键步骤为二羟基苷元或芳基苷元与溴代四乙酰基葡萄糖的偶联反应. 所得产物均为b-构型.     

棘孢曲霉β-葡萄糖苷酶Ⅰ在毕赤酵母中的表达及烷基糖苷的催化合成

将来自棘孢曲霉(Aspergillus aculeatus NO. F-50)的β-葡萄糖苷酶Ⅰ在毕赤酵母中分泌表达. 初步研究表明, 目的蛋白得到较好表达, 以对硝基酚-β-D-葡萄糖苷(4-Nitrophenyl-β-D-glucopyranoside, pNPG)为底物, 重组β-葡萄糖苷酶Ⅰ酶促反应的最适温度为65 ℃, 最适pH为5.0, 50 ℃下反应发酵上清液中的酶活力可达33.8 U/mL, 蛋白表达量最高可达0.388 mg/mL. 该重组酶可通过逆水解或转糖苷反应催化合成烷基糖苷. 在有机-水双相反应体系中, 初步优化了pH 值、 含水量、 葡萄糖浓度及酶量等条件. 结果表明, 在优化的反应条件下, 丁基、 己基、 辛基和癸基葡萄糖苷最大产率分别为51.4%, 28.8%, 6.9%和3.0%.     

以葡萄糖为极性头基的表面活性剂的合成及苯基酮在手性胶束中的不对称还原

合成了三种长链烷基葡萄糖苷即1-O-十二烷基-β-D-葡萄糖(β-DG)、1-O-十二烷基-α-D-葡萄糖(α-DG)以及1-O-十二烷基-β-D葡萄糖醛酸钠(Sβ-DGU)、三种化合物在水中均能形成胶束, 在上述胶束中, 用硼氢化钠对一系列苯基烷基甲酮进行了还原. 在β-DG和α-DG胶束中所得到的还原产物苯基烷基甲醇均具有不同程度的光学活性, 其中苯基乙基甲酮在β-DG胶束中的还原可达到98%e.e.的立体选择性. 根据高疏水性受物不能被还原以及在阴离子胶束(Sβ-DGU)中受物难以还原的实验结果. 得出还原反应在靠近胶束极性头基层的内侧进行, 并提出了二分子糖苷与BH4^-形成的分子间负氢离子配合物是不对称还原得以产生的关键. 上述推论被加入适量的非手性阳离子表面活性剂(CTAB)与β-DG所形成的混合胶束可充分抑制还原反应的立体选择性这一实验事实所证实.     

Characterization of alkyl polyglycosides by both reversed-phase and normal-phase modes of high-performance liquid chromatography

Alkyl polyglycosides today represent the most important sugar surfactant. Nonionic sugar surfactants produced via different synthetic routes are mixtures of alkyl homologues, oligomers, anomers and isomers. Alkyl homologues and oligomers of alkyl mono- and diglucosides were separated by reversed-phase high-performance liquid chromatography (HPLC) with methanol-water as the mobile phase using a gradient elution. The gradient was optimized in respect to a simultaneous separation of alkyl glycosides according to their alkyl chain length and alkyl polyoxyethylene glucosides with regard to their length of the polyoxyethylene spacer. The separation of alkyl glycosides into alpha- and beta-anomers was carried out by normal-phase HPLC with isooctane-ethyl acetate (60:40, v/v)-2-propanol in the gradient mode. Light scattering detection was used. Matrix-assisted laser desorption ionization time-of-flight mass spectra of alkyl glucosides and dodecyl glucosides with oxyethylene spacer groups are presented.     

Extraction of water miscible organic dyes by reverse micelles of alkyl glucosides

The extraction of methyl orange or methylene blue from an aqueous phase to an organic phase of reverse micelles of alkyl glucosides was investigated. Dodecyl glucoside, a biodegradable and biocompatible surfactant, was employed as a kind of alkyl glucosides, since a stable Winsor II system consisting of the water-in-oil type microemulsion and aqueous phases was formed when an organic solution containing dodecyl glucoside was contacted with an aqueous solution. The water content in the reverse micellar organic phase increased with an increase in the concentration of dodecyl glucoside. The extraction ratio of dyes also increased with increasing the concentration of dodecyl glucoside. Furthermore, the extraction ratio of dyes was dramatically dependent upon the pH of an aqueous phase and temperature.     

离子液体对β-糖苷酶催化合成红景天苷的影响(英文)

研究了混合溶剂体系中阴离子分别为BF4-,PF6-,Cl-,Br-和I的14种离子液体对来源于黑布林糖苷酶催化合成红景天苷反应的影响.结果表明,在最佳反应条件下,β-糖苷酶的反应初速度和红景天苷的产率分别为3.3mmol/(L·h)和24.5%.离子液体咪唑阳离子的烷基链长(C2~C10)对β-糖苷酶的活性影响较大,当烷基链长为C6时,糖苷酶表现出较高的催化活性.     

An efficient one-step chemoselective reduction of alkyl ketones over aryl ketones in β-diketones using LiHMDS and lithium aluminium hydride

β-Hydroxy ketones were synthesized in one-pot from β-diketones by reducing alkyl ketones chemoselectively by keeping aryl ketone intact. Initially, β-diketones were enolized using LiHMDS and later alkyl ketone was chemoselectively reduced efficiently by lithium aluminium hydride. This method produces β- hydroxyl ketones from the corresponding β-diketones in high yield.     

葡萄糖苷特异性固相萃取固定相的合成、表征及应用

以马来酰亚胺基修饰凝胶载体,通过β-葡萄糖胺和2-亚氨基硫代烷盐酸盐将作为配基的β-葡萄糖脒连接到载体上,合成了一种葡萄糖苷特异性固相萃取固定相,并对其固相萃取性能进行了表征.该固定相对葡萄糖苷具有特异性识别,并成功用于固相萃取分离葡萄糖苷.     

Influence of the hydrophobic tail of alkyl glucosides on their ability to solubilize stratum corneum lipid liposomes

The lytic interactions of a series of alkyl glucosides (alkyl chain lengths ranging from C₈ to C₁₂) with liposomes formed by a mixture of lipids modeling the stratum corneum (SC) lipid composition were investigated. The surfactant-to-lipid molar ratios (Re) and the normalized bilayer/aqueous phase partition coefficients (K) were determined by monitoring the changes in the static light-scattering (SLS) of the system during solubilization. The fact that the free surfactant concentrations were always similar to their critical micelle concentrations indicates that the liposome solubilization was mainly ruled by the formation of mixed micelles. At the two interaction levels studied (100 and 0% SLS) the nonyl glucoside showed the highest ability to saturate and to solubilize liposomes (lowest Re values), whereas the dodecyl glucoside showed the highest degree of partitioning into liposomes or affinity with these structures (highest K values). Comparison of the data for octyl glucoside with that reported for the interaction of this surfactant with phosphatidylcholine (PC) liposomes shows that whereas the SC lipid liposomes were more resistant to the action of this surfactant (higher Re values), its degree of partitioning into SC bilayers was both in the saturation and solubilization of liposomes similar to that exhibited in PC vesicles (similar K values). Received: 27 November 2000/Accepted: 19 February 2001     

Improved Yields in the Synthesis of Alkyl Glycosides

Recent syntheses of alkyl glycosides have involved a rnodification of the Koenigs-Knorr reaction in which a sugar peracetate is first brominated and finally reacted with the desired alcohol in the presence of silver ion as a catalyst. In 1980 Rosevear et a1.² reported a simplified synthesis of alkyl glycosides in which the acetobromosugar was not isolated, but was reacted with the alcohol and the deacetylated final product was purified using column chromatography on Dowex 1. While yield s obtained for alkyl glucosides by this procedure were as high as 60%, those for alkyl maltosides were only 25%. More recently Landauer et a1.3 have reported yields of 55 to 68% in the preparation of alkyl malto-sides. However, their procedure involves t h e isolation and purification of the acetobromosugar intermediate and reported yields are calculated on the basis of this intermediate.