PPY／PVP催化剂合成11，2，4—三—0酰化红霉素的研究

本文利用4－（1'－四氢吡咯）吡啶（PPY）及聚乙烯吡啶（PVP）复合催化剂催化合成了11,2',4'－三－0酰化红霉素衍生物,与传统方法相比,该法具有简单、快速、收率高等优点。一些影响素及反应机理被讨论,目标物收率为90％以上。     

合成2-(三溴甲磺酰基)吡啶的工艺改进

聚乙二醇-400催化2-氯吡啶(1)与甲硫醇钠反应合成了2-甲硫基吡啶(2);2与次溴酸钠经氧化和溴化反应合成了2-三溴甲磺酰吡啶(3),其结构经1H NMR,IR和元素分析确证。合成2的最佳反应条件为:1 100mmol,甲硫醇钠0.12 mol,聚乙二醇-400(1.2 mL)为催化剂,于80℃反应4 h,收率98%。合成3的最佳反应条件为:2 95 mmol,n(2)∶n(溴素)=1.00∶6.58,于8℃反应5 h,收率95.1%,纯度99.6%。     

1-(2-吡啶偶氮)-2-萘酚-过氧化氢光度法测定土壤中痕量钒

对钒(V)与1-(2-吡啶偶氮)-2-萘酚-过氧化氢-十六烷基三甲基溴化铵显色反应进行了试验,结果表明:在1 mol·L-1盐酸介质中,在十六烷基三甲基溴化铵存在下,钒(V)与1-(2-吡啶偶氮)-2-萘酚和过氧化氢反应生成红色多元络合物,络合物的最大吸收波长为577 nm,表观摩尔吸光率为3.04×104L·mol-1·cm-1,钒(V)的质量浓度在1.0 mg·L-1以内符合比耳定律.络合物的组成比为n钒(V):nPAN:n过氧化氢=1:1:1.方法用于土壤试样中痕量钒的测定,测定值的相对标准偏差(n=6)均小于9%,回收率在97.8%～101.5%之间,测得标准样品(GSS-5)中钒的含量为170.45μg·g-1,与标准值(166±9)μg·g-1之间的相对误差为2.7%.     

D(-)-二吡啶甲基酒石酸酰胺在不对称氧化合成埃索美拉唑中的应用

D(-)-酒石酸二乙酯(1)分别与2-氨甲基吡啶和4-氨甲基吡啶反应,合成了D(-)-二吡啶甲基酒石酸酰胺2和3.分别以1～3为手性配体与钛酸异丙酯配合,催化过氧化氢异丙苯(CHP)不对称氧化埃索美拉唑前体(Eso-I)合成埃索美拉唑.结果表明,由配体2或3构成的催化体系在埃索美拉唑合成上显示出较高的催化活性和对映选择性.例如,当以2为配体,甲苯为溶剂,在优化的条件下进行反应时,Eso-I的转化率达84.7%,埃索美拉唑的选择性达91.8%,对映体过量值达89.0%.     

含三唑结构的新型稠合三环2(5H)-呋喃酮衍生物的合成

利用系列含烯二炔结构的2(5H)-呋喃酮衍生物与叠氮化钠发生串联的成环反应, 在优化的反应条件下, 即反应溶剂为DMF、反应时间48 h、反应温度30 ℃时、NaN₃为1.5 equiv., 以中等产率(42%～62%)合成了系列新型的稠合三环2(5H)-呋喃酮衍生物, 其可以进一步高产率地(94%～96%)衍生为吡啶稠合的2(5H)-呋喃酮化合物. 所有新化合物的结构用IR, ¹H NMR, ¹³C NMR, MS, 元素分析等方法进行了表征. 该串联反应合成途径简捷、反应条件温和, 无需添加催化剂, 可为具有含三唑结构的稠杂环化合物合成提供简便的途径.     

一个简易的2,6-二氨基-3,5-二硝基吡啶-1-氧化物的合成方法

研究了2,6-二氨基-3,5-二硝基吡啶-1-氧化物(DADNP-1-O)的一个简易合成方法. 该方法是以2,6-二氨基吡啶(DAP)为原料, 利用两步法得到高纯度高产率的2,6-二氨基-3,5-二硝基吡啶, 再在三氟乙酸和双氧水作用下进行N-氧化反应得到DADNP-1-O, 总收率在90%以上, 并对主要反应影响因素进行了讨论, 经傅立叶变换红外光谱(FT2IR), 氢核磁(1H NMR), 碳核磁(13C NMR), 高效液相色谱(HPLC), 元素分析, DSC等方法对中间体和DADNP-1-O结构进行了表征.     

1-(2-苯并噻唑)-3-(3,5-二溴吡啶)-三氮烯的合成及其与铜(Ⅱ)的荧光反应

报道了1-(2-苯并噻唑)-3-(3,5-二溴吡啶)三氮烯(BTDPT)的合成及其与Cu(Ⅱ)的荧光反应研究。在pH 9.16的Na2B4O7-NaOH缓冲溶液中,该试剂与Cu(Ⅱ)形成2:1的稳定络合物,体系的激发和发射波长分别为359和401 nm。Cu质量浓度在0.5~80.0μg/L范围内与△F呈良好的线性关系,其线性回归方程为:ΔF=-0.178+0.209ρ(μg/L),相关系数r=0.9956,检出限为0.2μg/L,用于测定环境水中痕量Cu,结果与原子吸收光谱法相符。样品6次测定值相对标准偏差小于5%,加标回收率为98.5%~103.0%。     

高分子(纤维)负载-N-(4-吡啶)哌嗪的合成及其催化性能

以废旧聚丙烯纤维为骨架,通过接枝苯乙烯、氯甲基化和负载N-(4-吡啶)哌嗪,合成了高分子(纤维)负载-N-(4-吡啶)哌嗪(1),其结构经IR和元素分析表征,并通过小分子模拟确证.1(5 mol%)用于催化1-苯基乙醇的乙酰化反应,收率90%,在多次循环使用后催化活性基本不变.     

合成3-(2-吡啶氨基)丙酸乙酯的工艺改进

以2-氨基吡啶(2)和丙烯酸乙酯(3)为起始原料,经一步反应合成了凝血酶因子抑制剂达比加群酯的关键中间体3-(2-吡啶氨基)丙酸乙酯,其结构经1H NMR和ESI-MS确证.最佳反应条件为:2 120 mmol,n(2)∶n(3) =1.00∶1.08,于100℃回流反应24h,收率79.6％.     

4-(5-氯-2-吡啶)-偶氮-1,3-二氨基苯显色光度法测定钯(Ⅱ)

研究了4-(5-氯-2-吡啶)-偶氮-1,3-二氨基苯(5-Cl-PADAB)与Pd的显色反应,在0.48 mol/L H3PO4介质和100℃水浴条件下,5-Cl-PADAB与Pd(Ⅱ)反应生成2:1稳定络合物,其最大吸收波长为570nm,表观摩尔吸光系数为6.39×104 L.mol-1.cm-1。结果表明:Pd含量在0～1.2 mg/L内符合比尔定律,方法已用于矿样中微量Pd的测定,结果与AAS法相符。样品分析结果的相对标准偏差小于4%,加标回收率为98.5%～103.0%。     

Essential Oil Content and Compositional Variability of Lavandula Species Cultivated in the Mid Hill Conditions of the Western Himalaya

The increase in the utilization of Lavandula essential oil in industries led to an impressive rise in the demand for quality essential oils. However, a post-harvest drying of Lavandula species can be a decisive factor to determine the quantity and quality of essential oil. The study was conducted in western Himalayan conditions to assess the essential oil content and composition of two Lavandula species viz., lavender (Lavandula angustifolia Mill.), and lavandin (Lavandula × intermedia Emeric ex Loisel), at four different drying duration (0 h, 24 h, 48 h and 72 h after the harvest). The higher growth attributes viz., plant height (71.7 cm), ear length (8.8 cm), number of spikes (18.1), and number of flowers per ear (47.5) were higher in lavandin, while the number of branches (17.1) was higher in lavender. Essential oil content (%) and moisture reduction (%) were significantly higher at 72 h than at 0 h. The major components of lavender and lavandin essential oil were linalool (33.6–40.5%), linalyl acetate (10.8–13.6%), lavandulyl acetate (2.8–14.5%), and linalyl propionate (5.3–14.1%) in both the Lavandula species. There was a decreasing trend in linalool and an increasing trend in linalyl acetate content in lavandin, with an increase in drying duration up to 72 h; while in lavender, no regular trend was observed in linalool and linalyl acetate content. It was observed that linalool and linalyl acetate levels were the highest at 24 and 0 h of drying in lavender and lavandin, respectively, and essential oil extraction can be done according to the desire of the constituent at varied drying duration.     

A dual-catalysis/anion-binding approach to the kinetic resolution of allylic amines

A dual-catalysis approach enables the small-molecule catalyzed kinetic resolution of allylic amines by acylation. By employing 2 mol % of each 4-(pyrrolidino)pyridine (PPY) and a readily available chiral hydrogen-bonding cocatalyst, the first nonenzymatic kinetic resolution of allylic amines was accomplished with s factors of up to 20.     

Two-step,stereoselective synthesis of linalyl oxides by asymmetric allylic O-alkylation

Each of the four tetrahydrofuran linalyl oxides was prepared by a Sharpless asymmetric dihydroxylation of geranyl acetate with AD-mix-α or AD-mix-β, followed by a stereoselective palladium-mediated cyclization using the chiral ligand C₃-TunePhos.     

Catalytic conversions of linalool and linalyl acetate over large-pore zeolites and mesoporous MCM-41

The dehydration, condensation, and isomerization of linalool and linalyl acetate occur over the H-and dealuminated forms of zeolites FAU(Y), BEA, MOR, and OFF and mesoporous aluminosilicate MCM-41 at 373–453 K. The yields of linalool isomerization to geraniol and α-and β-terpineols are low. The use of linalyl acetate enhances isomerization; the highest yields of the products of linalyl acetate rearrangement (geranyl acetate and terpinyl acetate) are achieved over DeAlBEA(277). Dehydration produces various C₁₀H₁₆ terpenic hydrocarbon isomers.     

A novel synthesis of precursors to 3-thienylmalonic acid

Methyl 2-cyano-2-(3-thienyl)acetate can be prepared in 95% yield by treating methyl 2-cyano-2-(3-tetra-hydrothienylidene)acetate with sulfuryl chloride, followed by dehydrohalogenation with pyridine. The product can be hydrolyzed to 3-thienylmalonic acid, a pharmaceutical intermediate.     

Solid-phase microextraction based on polypyrrole films with different counter ions

Solid-phase microextraction (SPME) fiber coatings based on polypyrrole (PPY) films were prepared by electrochemical deposition of PPY films on platinum wires. To evaluate the effects of counter ions in PPY films on their performance in SPME, PPY films with different counter ions were prepared using different electrolytes during the polymerization processes. The results showed that these PPY films had different extraction properties to the compounds studied due to the different functional groups introduced into the films by the counter ions. Unlike the PPY films formed with small counter ions (such as perchlorate ion) that had anion exchange property, the PPY films having large counter ions such as poly(styrenesulfonate) (PSS) ion showed cation exchange property. Compared with the PPY films having small inorganic counter ions, the PPY films having large organic counter ions, such as dodecylsulphate (DS) ion, showed better extraction efficiency towards nonpolar compounds due to the increased hydrophobic interactions between the compounds and the films. In addition, PPY films formed with large aromatic counter ions had better mechanical stability compared with PPY films with small inorganic counter ions. These films could be applied for SPME of a range of analytes.     

16-脱氢孕烯醇酮醋酸酯的环境友好合成法

Instead of environmentally toxic chromium oxidant, singlet oxygen generated photcchemically was used as environmentally friendly and benign oxidizing agent to accomplish the transformation of pseudodiosgenin diacetate to diosone efficiently in a low toxic and less expensive solvent acetone. Accordingly 16-dehydropregnenolone acetate(16-DPA), an important intermediate for preparation of steroidal drugs, was prepared in good yield (75%) when photoreaction was run in acetone/acetic anhydride/pyridine system. The mild reaction condition as well as simple and environmentally friendly process made the method commercially viable and important for production of 16-DPA in industrial scale.     

Carboxylate binding in polar solvents using pyridylguanidinium salts

A series of thiourea and guanidinium derivatives have been prepared and their ability to bind a carboxylate group has been investigated. Guanidinium 33, featuring two additional amides and a pyridine moiety, proved to be the most potent carboxylate binding site and was able to bind acetate in aqueous solvent systems (K(ass) = 480 M(-1) in 30% H(2)O-DMSO). The pyridine moiety is critical to obtaining strong binding, and comparison with the binding properties of analogous compounds in which the pyridine is replaced by a benzene ring provides a striking example of enthalpy-entropy compensation.     

Essential oil polymorphism of wild growing Hungarian thyme (Thymus pannonicus) populations in the Carpathian Basin

The volatile oil compositions of Thymus pannonicus All. from nineteen different localities of Hungary were analyzed by GC/MS. The essential oil content of the Hungarian thyme samples varied between very low (0.14 mL/100 g DW) and fairly high (1.9 mL/100 g DW) values. Significant essential oil polymorphism was found: altogether twelve chemovarieties may have been determined, representing a way of adaptation to different habitat conditions. The main volatile compound of chemotype 1 was thymol (24.6-67.5%), while in the case of chemotype 2, thymol (36.5-63.7%) and p-cymene (11.5-27.3%) predominated. Thymol (28.4-63.7%), p-cymene (11.5-31.8%) and gamma-terpinene (9.7-20.9%) were identified as the chief monoterpenes of chemotype 3, while chemotype 4 contained thymol (36.5%), p-cymene (27.3%) and neral (11.2%). Chemotype 5 accumulated thymol (38.5%), p-cymene (20.6%), gamma-terpinene (12.0%) and beta-bisabolene (10.3%) as its main volatiles. The oil of chemotype 6 can be characterized by thymol (41.9%), p-cymene (20.2%), isoborneol (10.3%) and gamma-terpinene (9.9%), while that of chemotype 7 consisted of thymol (27.7%), linalyl acetate (18.8%), gamma-terpinene (18.6%) and alpha-cubebene (13.9%). In the oil of chemotype 8, p-cymene (45.0%), geraniol (13.6%) and linalyl acetate (9.9%) were found in higher percentages, while chemotype 9 mainly produced linalyl acetate (36.2%) and geranyl acetate (20.2%). Chemotype 10 accumulated germacrene-D (43.4) and beta-caryophyllene (15.0%), while the oil of chemotype 11 contained caryophyllene oxide (45.2%), alpha-cubebene (15.7%) and linalool (13.8%) in high proportions. Germacrene-D (29.7%), beta-caryophyllene (22.0%) and farnesol (10.4%) were identified as main essential oil compounds of chemotype 12. The last nine chemotypes were new for the literature, while the first seven contained thymol as their chief compound. The role of certain sesquiterpenes was found to be considerable.     

聚吡咯/硝酸活化碳气凝胶纳米复合材料的制备表征及其在超级电容器中的应用

通过化学氧化聚合法制备出不同比例的聚吡咯(PPY)/硝酸活化碳气凝胶(HCA)复合材料。采用傅里叶变换红外光谱(FT-IR)和扫描电子显微镜(SEM)表征材料的成分和形貌,结果表明,通过硝酸活化及与聚吡咯的复合,并未破坏碳气凝胶的多孔形貌,硝酸活化碳气凝胶及聚吡咯/硝酸活化碳气凝胶都仍然保持着原碳气凝胶的三维纳米多孔结构。采用对照实验的方法,设计并合成五组不同配比的复合材料,聚吡咯与硝酸活化碳气凝胶的质量比例分别为3:1、2:1、1:1、1:2、1:3,通过循环伏安法,恒流充放电,交流阻抗及循环性测试等考察材料的电化学性能。结果证明,当聚吡咯与硝酸活化碳气凝胶比例为1:1时,复合材料显示出最优电化学性能:比电容高达336 F·g^-1,是纯碳气凝胶(103 F·g^-1)的三倍有余,除此还显示出卓越的导电性与循环稳定性, 2000次循环后仍保持初始电容的91%,具备优良的超级电容器电极材料性能。因此聚吡咯/硝酸活化碳气凝胶复合纳米材料是超级电容器的理想电极材料。