Studies on the synthesis of SAPO-5

Silicoaluminophosphate (SAPO-5) molecular sieves have been synthesised from reaction mixtures having a molar composition of: 0.7–1.0 Al₂O₃:0.7–1.0 P₂O₅:0.01–2.0 SiO₂:xR:40 H₂O (where R = (C₂H₃)₃N or (C₂H₃)₄NOH and x = 1.5–2.5 for (C₂H₅)⁵N and 0.5 for (C₂H₅)₄NOH, at 473 K using various sources of alumina and silica. The effects of (i) varying the crystallinity of the alumina source (boehmite) and (ii) the use of different silica sources such as freshly prepared silica either from sodium silicate or paddy husk extract, silica gel from commercial water-glass, and tetraethyl orthosilicate have been studied. The crystallinity of boehmite has been found to have a strong effect on its reactivity towards the formation of SAPO-5. The activity of boehmite for SAPO-5 formation increased with a decrease in its crystallinity (or with increase in its moisture content). Any silica source devoid of sodium ions could be employed for the synthesis of SAPO-5. The process of crystallisation started as early as within 1.5 h of reaction and incorporation of silicon into the AlPO₄ framework has been noted at this stage. Formation of some tridymite phase as impurity has been observed under conditions such as (i) SiO₂ concentration > 1.7 mole and (ii) x > 2.0 when R = (C²H₅)₃N.     

Synthetic Studies toward Communesins

Communesins A–H are a growing family of natural products isolated from a marine fungal strain of Penicillium species. Preliminary biological evaluation has revealed that these compounds possess insecticidal activity and cytotoxicity against several tumor cell lines. Their interesting biological activities and unique structures have attracted considerable attention of synthetic chemists worldwide. To date, several elegant protocols for assembling the core structure of these indole alkaloids have been described, including intermolecular Diels–Alder reaction of methylated aurantioclavine with quinine methide imine and intramolecular hetero Diels–Alder reaction of the azaortho-xylylene intermediates. Recently, three completed total syntheses for communesin F have been disclosed, in which the crucial vicinal quaternary stereogenic centers were constructed by employing an intramolecular cyclopropanation; an intramolecular Heck reaction of a tetrasubstituted alkene, or an oxidative coupling of a 3-substituted indole, as the key step. Accompanying the total synthesis, the absolute configuration of natural communesin F was established as 6R,7R,8R,9S,11R. However, total syntheses of other members of communesin family that contain an epoxide moiety have not been achieved, which will stimulate more synthetic studies.     

碘帕醇的合成工艺研究

以L-乳酸为原料,经两步反应,以55%的收率得到S-2-乙酰氧基丙酰氯。以5-氨基-2,4,6-三碘-1,3-苯二甲酸为原料,使用二氯亚砜转化得到5-氨基-2,4,6-三碘-1,3-苯二甲酰氯,再与S-2-乙酰氧基丙酰氯反应得到5-[(2S)-(2-乙酰氧基)丙酰胺基]-2,4,6-三碘-1,3-苯二甲酰氯,接着与2-氨基-1,3-丙二醇反应得到N,N′-双[2-羟基-(1-羟甲基)乙基]-5-[(2S)(2-乙酰氧基)丙酰胺基]-2,4,6-三碘-1,3-苯二甲酰胺,在碱性条件下脱乙酰基,得到非离子型X射线造影剂碘帕醇,这四步反应收率为50%。     

Studies on the synthesis of norbornadiene

The dimers and trimers of norbornadiene have a unique polycyclic strained structure and are of great practical value. A systematic study of the synthesis of norbornadiene from dicyclopentadiene and acetylene under pressure has been carried out. The effects of various operating parameters on product distribution have been determined. The optimum conditions for the synthesis are: (i) temperature, 290°C; (ii) residence period, 16 min; (iii) mole ratio of C₂H₂:N₂: dicyclopentadiene, 1:1:0.4; and (iv) initial pressure at ambient temperature, 8.894 × 10⁵ nm^?2. Under these conditions the conversion of norbornadiene is 41.74% on the basis of dicyclopentadiene consumed. The loss of dicyclopentadiene due to polymerisation has been estimated from its balance. A kinetic study of the synthesis from cyclopentadiene has also been carried out.     

芴甲氧羰基酪氨酸苄醚的合成研究

研究了硫酸铜存在下溴苄与酪氨酸反应生成酪氨酸苄醚,收率45%。反应中,铜盐先与酪氨酸的羧基作用,生成4∶1的酪氨酸铜配合物,从而有效地保护了酪氨酸的羧基,使苄基化反应选择性地发生在侧链酚基氧原子上。酪氨酸苄醚与芴甲氧羰酰氯在THF中反应得标题化合物,收率98%。     

基于铬天青S-铜-邻二氮菲传感体系对焦磷酸根的识别研究

铜离子与邻二氮菲、铬天青S能形成一种简单的化学传感体系,该体系在生理条件下对水溶液中焦磷酸根(PPi)的识别具有很好的选择性,PPi的加入会引起溶液颜色的变化(由蓝到黄),其他阴离子(F~-,Cl~-,Br~-,I~-,HSO_4~-,SO_4~(2-),Ac O~-,CO_3~(2-),C_2O_4~(2-),H_2PO_4~-,HPO_4~(2-),PO_4~(3-))的过量存在对PPi的识别基本无干扰。该体系在波长613 nm处的吸光度变化与PPi浓度在0~40μmol/L区间呈现良好的线性关系(r=0.994 3),检出限为1.69μmol/L,表明该体系可用于检测微量PPi。     

基于铬天青S-铜-邻二氮菲传感体系对焦磷酸根的识别研究

铜离子与邻二氮菲、铬天青S能形成一种简单的化学传感体系,该体系在生理条件下对水溶液中焦磷酸根(PPi)的识别具有很好的选择性,PPi的加入会引起溶液颜色的变化(由蓝到黄),其他阴离子(F^-,Cl-,Cl^-,Br-,Br^-,I-,I^-,HSO_4-,HSO_4^-,SO_4-,SO_4^(2-),Ac O(2-),Ac O^-,CO_3-,CO_3^(2-),C_2O_4(2-),C_2O_4^(2-),H_2PO_4(2-),H_2PO_4^-,HPO_4-,HPO_4^(2-),PO_4(2-),PO_4^(3-))的过量存在对PPi的识别基本无干扰。该体系在波长613 nm处的吸光度变化与PPi浓度在0(3-))的过量存在对PPi的识别基本无干扰。该体系在波长613 nm处的吸光度变化与PPi浓度在0⁴0μmol/L区间呈现良好的线性关系(r=0.994 3),检出限为1.69μmol/L,表明该体系可用于检测微量PPi。     

Studies toward a universal dye for textile fibres

A new organic dye was synthesised as part of an approach to producing a dye that could be applied to any of a variety of widely used fibre types. The dye synthesised is best described as a disperse-reactive dye and was obtained from a sequence of reactions that used an acid yellow dye as a starting compound. Dichlorotriazine was used as the reactive group in the target dye and the chemical structures of the new dye and its precursors were confirmed using ¹H NMR, mass spectrometry and FTIR analyses. In the neutral form, the dye was suitable for polyester, nylon and wool fibres. When the pH was adjusted to 9 it dyed cotton, albeit in a pastel shade only. By adding N, N -dimethylethylenediamine to the dyebath, the dye could be applied to acrylic fabric at pH 5. The fastness of the dyed fibres was also evaluated.     

5'-脱氧-5'-乙酰硫代核苷的一步法合成

一种合成标题化合物的新方法.分别以腺苷、肌苷、尿苷、利巴韦林和硫代乙酸为原料,通过Mitsunobu反应一步法合成了4种标题化合物,收率分别为68.4%,69.8%,73.4%,65.0%,并根据该反应对核苷5'-OH具有较高选择性这一结果提出了该反应可能的机理,所有产物结构均通过1HNMR、ESI-MS确证.     

Studies on the synthesis and characterization of carboxymethylcellulose

Carboxymethylcellulose (CMC) was prepared in a completely heterogeneous procedure in an isopropanol/water slurry and the influence of the reaction conditions on the pattern of functionalization within the anhydroglucose repeating unit as well as due to the formation of the four main repeating units (i. e. unfunctionalized, mono-, di-, and tricarboxymethylated) was checked. The concentration of aqueous sodium hydroxide solution, which is used to activate the cellulose, was varied in the range from 8 to 30% at reaction times from 2 to 6 h at 55°C. The reaction with sodium monochloroacetate leads to the highest degree of substitution (DS_CMC) of 1.24 at a NaOH concentration of 15% and 5 h reaction time. Using a lye concentration of 30%, no influence of the reaction time between 2 h and 6 h was found. From ¹H NMR spectroscopical studies it was concluded that both the concentration of the alkali hydroxide solution and the reaction time influence the partial DS_CMC at positions O-2 and O-6, while position O-3 shows the lowest reactivity in any case, independent of the reaction conditions used. With increasing lye concentration, carboxymethylation occurs preferably at O-6. Information about the content of the differently functionalized repeating units can be obtained by chromatographic analysis after complete depolymerization of the polymer chains. Surprisingly, in any product synthesized a statistic content of the building units of the polymer was found even at low activation of cellulose.     

Studies on the synthesis and properties of copolyesterimide

A series of copolyesterimides was prepared from bisphenol A, diacid (terephthalic acid [TPA] or isophthalic acid [IPA]), and 4-carboxy-N-(p or m-hydroxyphenyl) phthalimide (M1 or M2) in the presence of diphenyl chlorophosphate (DPCP) and pyridine as the direct condensation agent. Copolyesterimides derived from M1 showed poorer solubility than that of M2 during polymerization; a lower M1 content should be employed to prevent precipitation of the resulting polymers. The inherent viscosities of copolyesterimides were in the range of 0.33–0.56 dL/g. Some of these copolyesterimides were completely soluble in N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAC), dimethylformamide (DMF), and m-cresol. The thermal properties of copolyesterimides were examined by DSC and TGA. These copolyesterimides had glass transition temperatures in the range of 173–220°C and a 5% weight loss was observed in the range of 435–482°C. © 1994 John Wiley & Sons, Inc.     

双锂体系立构三嵌段聚丁二烯的研制

以双卤代烷烃取代型双锂齐聚物为引发剂,环已烷为溶剂,丁二烯单体一次加入,在聚合反应过程中加入极性添加剂,合成了1,2－1,4－1,2－立构三嵌聚聚丁二烯,并对双锂体系丁二烯聚合反应动力学及聚合物结构性能进行了研究。随着1,2－％的增加,聚丁二烯的无同结构含量逐渐减少,全同和间同结构含量逐渐增加,聚丁二烯的全同含量总是高于间同含量;与丁二烯均聚物相比,在1,2－％相近时,立构嵌段聚丁二烯具有更高的有规结构含量,全同和间同结构含量更高。     

Stabilized gold clusters: from isolation toward controlled synthesis

Bare metal clusters with fewer than ～100 atoms exhibit intrinsically unique and size-specific properties, making them promising functional units or building blocks for novel materials. To utilize such clusters in functional materials, they need to be stabilized against coalescence by employing organic ligands, polymers, and solid materials. To realize rational development of cluster-based materials, it is essential to clarify how the stability and nature of clusters are modified by interactions with stabilizers by characterizing isolated clusters. The next stage is to design on-demand function by intentionally controlling the structural parameters of cluster-based materials; such parameters include the size, composition, and atomic arrangement of clusters and the interfacial structure between clusters and stabilizers. This review summarizes the current state of the art of isolation of gold clusters stabilized in various environments and surveys ongoing efforts to precisely control the structural parameters with atomic level accuracy.     

meso-四(2-氨基-5-磺酸苯基)卟啉的合成及其与钴显色反应的研究

研究了新水溶性 meso-四(2-氨基-5-磺酸苯基)卟啉的合成。提出以冰乙酸加乙酸酐代替常用的丙酸作介质,所得 meso-四(2-硝基苯基)卟啉为紫蓝色片状晶体,再将其还原和磺化得标题试剂。还研究了试剂于氨性介质中,在 Pb(Ⅱ)存在下与钴(Ⅱ)的显色反应。钴的二元配合物的最大吸收波长为429nm,表观摩尔吸光系数为1.50×10~5。可用于维生素 B_(12)注射液中痕量钴的测定。     

Studies toward new anti-cancer strategies based on alpha-mannosidase inhibition

Changes in the glycosylation pattern of cellular glycoproteins constitute a hallmark in human cancer and influence tumor progression, suggesting that inhibitors of selected glycosidases may control cancer progression. Following the studies on swainsonine, a natural inhibitor of Golgi alpha-mannosidase II, which highlighted the inhibition of cellular mannosidases as a potential innovative approach for the treatment of cancer, several dihydroxylated pyrrolidines and analogues were developed as new potent inhibitors of alpha-mannosidases II able to induce antiproliferative effects in human cancer cells.     

5-溴香兰素的绿色合成

以冰醋酸为溶剂,香兰素为原料,AlBr3为催化剂,HBrO3与KBrO3为溴化剂合成了5-溴香兰素.采用正交实验法考察了影响收率的因素.最佳条件为:香兰素、KBrO3与AlBr3的物质的量的摩尔比为1:0.5:0.056,反应时间6.0h,反应温度30℃.在优化条件下收率可达90.4%.产物结构通过IR、1HNMR、熔点测定和元素分析得以确认.     

合成5-硝基苊的一种新方法

在醋酸、聚乙二醇存在下，苊与硝酸铈铵反应生成5－硝基苊。反应条件温和产率较高。     

樟脑衍生物的合成工艺研究

以天然樟脑为起始原料,合成了d-樟脑-10-磺酸和d-樟脑-10-磺酰氯,通过优化反应条件,找到了较好的合成条件。该工艺操作简单、产率高,宜于工业化生产,为开发樟脑资源提供了一个较好的方法。     

二苯基脲衍生物的合成研究

以取代苯胺为原料，经甲酰化、胺解合成了二个二苯基脲衍生物，利用元素分析、红外光谱对目标化合物进行了结构表征，并讨论了反应温度、反应时间对收率的影响。