合成光学活性樟脑

目前按所谓“四步法”生产的合成樟脑是消旋的。天然樟脑是光学活性的,大多数为右旋体。左旋天然樟脑较为稀少。藤原羲人,松原羲治等曾报道合成光学活性樟脑,其中龙脑脱氢反应是在有机溶剂的存在下进行的,产物的光学纯度为原料的70%左右。     

冰片中右旋龙脑及其异构体的手性毛细管气相色谱法测定

以CYDEX -B手性毛细管柱 (25m×0.22mm,0.25μm)作为分析柱,用气相色谱法和气相色谱 -质谱联用法对天然冰片、艾片和合成冰片进行测定。合成冰片中的左旋龙脑与右旋龙脑可完全分离 ,左旋异龙脑与右旋异龙脑可部分分离。实验测得 :天然冰片中右旋龙脑的含量为99.13%～99.61 %;艾片中左旋龙脑的含量为95.87 %;合成冰片中左旋龙脑的含量为31.44 %～54.57 %,右旋龙脑的含量6.87 %～25.37 %;合成冰片的比旋度 α30D 为 -17.3°～ -2.3°。     

龙脑化学的进展

本文回顾了龙脑化学发展的历史,简述了合成龙脑的几种主要方法。同时综述了与龙脑合成有关的立体化学和反应机理。     

合成樟脑的现状与发展

从天然精油生产合成樟脑是我国的大宗产品,产量占世界首位,是重要的出口商品。本文介绍了国内外合成樟脑的研究状况,包括合成方法及其改进,主要杂质和提纯方法,以及合成光学活性樟脑等。     

新型α-龙脑烯醛基噻二唑-膦酸酯化合物的合成及其抑菌活性

以α-蒎烯为原料,经环氧化和催化异构反应得α-龙脑烯醛(3);3与氨基硫脲反应制得α-龙脑烯醛基缩氨基硫脲,再环合生成α-龙脑烯醛基噻二唑,最后将其与亚磷酸三苯酯和一系列醛通过类Mannich反应合成了11个新型α-龙脑烯醛基噻二唑-膦酸酯化合物(6a~6k),其结构经1H NMR,13C NMR,IR和ESI-MS表征。抑菌活性测试结果表明:在用药量为50μg·m L~(-1)时,6b对苹果轮纹病菌的抑制率为60.5%。     

三梅片成份分析研究

医药品冰片有天然品与合成品之分,天然品有:由龙脑香科(Dipterocarpaceae)植物龙脑香(Dryobalanops aromatica G aertn,f.)制得的结晶,称龙脑香冰片;白菊科(Compositae)植物艾纳香(Blumea balsamifera DC.)所得的结晶,名艾片。艾片因其晶形似梅花片,又有梅片之称,根据梅花片状又分为大梅片,二梅片,三梅片,天然品化学成分为龙脑(Borneol,Ⅰ),合成冰片(又名合成龙脑),除含龙脑外尚含较大量的异龙脑(ISO-borneol,Ⅱ)     

丙氨酸的双不对称合成

氨基酸的不对称合成是近年来研究热点之一,双不对称合成新设想为高光学纯度物质的合成提供了一条有益的思路。本文考察在手性相转移催化条件下,邻苯二甲酰亚胺钾与手性α-溴代丙酸龙脑酯的Gabriel反应制取光学活性丙氨酸,观察到显著的双不对称诱导效应。 仪器为Perkin-Elmer 241MC型旋光仪、PE240-C型元素分析仪。邻苯二甲酰亚胺钾按文献[3]制备;α-溴代丙酸乙酯为上海试剂总厂产品,(一)-龙脑为贵州罗甸制药厂产品,[αj_D~(25)=—37.2,(C5,乙醇);α-溴代丙酸龙脑酯根据文献制备并经过元素分析和光谱鉴定。(一)-N-苄     

一步法合成龙脑的研究

在强酸性的固体酸催化作用下,龙脑可以从α-蒎烯一步合成。用此法合成的产物中含46％龙脑、11.7％α-松油醇和其它萜烯产物。此反应是立体选择性的,从产物中分离得到的龙脑仅含9.3％异龙脑。文中还考察了温度效应、蒎烯和催化剂及水的配比、溶剂效应、催化剂的寿命和再生等问题。     

龙脑合成方法的改进

龙脑合成方法的改进;纳米固体超强酸; α-蒎烯; 草酸; 龙脑     

近临界水中苄叉乙酰苯的合成研究

以近临界水作为反应介质,在无外加催化剂的条件下,苯甲醛与苯乙酮可顺利反应生成苄叉乙酰苯。在最佳条件下,苄叉乙酰苯的收率可达31.4%。该方法避免了常规合成方法中有机溶剂的使用以及NaOH催化剂的加入,产物后处理简单,是一种绿色合成新过程。     

硼酸酯化法分离龙脑、异龙脑与樟脑

用硼酸与异龙脑的异构化产物—龙脑、异龙脑和樟脑的混合物进行反应，得到硼酸莰酯和樟脑。莰酯与樟脑分离后，经水解得到龙脑和异龙脑。     

The effect of camphor and borneol on rat thymocyte viability and oxidative stress

Camphor and borneol are wildly distributed in the essential oils of medicinal plants from various parts of the World. Our study has been carried out to evaluate the effect of these two bicyclic monoterpenes on rat thymocytes. Camphor and borneol at concentrations of 0.5 and 5 μg/mL did not induce significant toxicity on the immune system cells, while a significant increase of thymocyte viability was detected when cells were incubated with 50 μg/mL of camphor. A significant increase of cell viability was similarly detected when thymocytes were cultivated with borneol at concentrations of 0.5 and 5 μg/mL. The role of camphor and borneol in reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP) disturbances in rat thymocytes as well as their potential mechanism(s) of action were also discussed.     

Gas chromatography-mass spectrometry following pressurized hot water extraction and solid-phase microextraction for quantification of eucalyptol, camphor, and borneol in Chrysanthemum flowers

Chrysanthemum flower is a common traditional Chinese medicine (TCM). In this work, pressurized hot water extraction (PHWE) followed by headspace solid-phase microextraction (HS-SPME) and GC-MS was developed for the determination of three main active volatile compounds of eucalyptol, camphor, and borneol in Chrysanthemum flowers from four different growing areas in China by internal standard method. The parameters of PHWE and HS-SPME were optimized. The method was also validated. The results showed that PHWE-SPME-GC-MS is a simple, rapid, efficient, and solvent-free technique for the quantitative determination of eucalyptol, camphor, and borneol in TCMs and is potentially useful for the TCM quality assessment.     

Determination of Camphor and Borneol in Traditional Chinese Medicines by Microwave-assisted Extraction and Gas Chromatography with Flame Ionization Detector

Abstract

In this work, microwave-assisted extraction (MAE) followed by gas chromatography with flame ionization detector (GC–FID) was developed for the rapid determination of camphor and borneol in three traditional Chinese medicines (TCM): Chrysanthemi indici, Flos Chrysanthemi indici and Amomum villosum lour. The optimal MAE conditions obtained were: acetone for solvent, with solvent having sample ratio of 12:1 (v/w); microwave power of 380 W, and an irradiation time of 4 min. Method validations were also studied. To demonstrate the proposed method, ultrasonic-assisted extraction (UAE) and steam distillation (SD), followed by GC-FID, were used to analyze camphor and borneol in thethree TCMs. The close results were obtained by the three methods. The results showed that the proposed MAE–GC–FID is a simple, rapid, and reliable method for quantitative analysis of camphor and borneol in TCM, and is also a potential tool for TCM quality assessment.     

Development of microwave-assisted extraction followed by headspace solid-phase microextraction and gas chromatography-mass spectrometry for quantification of camphor and borneol in Flos Chrysanthemi Indici

In the work, microwave-assisted extraction (MAE) followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) was developed for quantitative analysis of the bioactive components of camphor and borneol in a traditional Chinese medicines (TCM) of Flos Chrysanthemi Indici. After systematical investigation, the optimal experimental parameters microwave power (400 W), irradiation time (4 min), fiber coating (PDMS/DVB fiber), extraction temperature (40 °C), extraction time (20 min), stirring rate (1100 rpm), and salt effect (no salt added) were investigated. The optimized method provided satisfactory precision (RSD values less than 12%), good recovery (from 86% to 94%), and good linearity (R² > 0.999). The proposed method was applied to quantitative analysis of camphor and borneol in Flos Chrysanthemi Indici samples from 11 different growing areas. To demonstrate the method feasibility, steam distillation was also used to analyze camphor and borneol in Flos Chrysanthemi Indici samples from these different growing areas. The very close results were obtained by the two methods. It has been shown that the proposed ME-HS-SPME-GC-MS is a simple, rapid, solvent-free and reliable method for quantitative analysis of camphor and borneol in TCM, and a potential tool for quality assessment of Flos Chrysanthemi Indici.     

Artificial Cytoskeleton Assembly for Synthetic Cell Motility

Imitation of cellular processes in cell-like compartments is a current research focus in synthetic biology. Here, a method is introduced for assembling an artificial cytoskeleton in a synthetic cell model system based on a poly(N-isopropyl acrylamide) (PNIPAM) composite material. Toward this end, a PNIPAM-based composite material inside water-in-oil droplets that are stabilized with PNIPAM-functionalized and commercial fluorosurfactants is introduced. The temperature-mediated contraction/release behavior of the PNIPAM-based cytoskeleton is investigated. The reversibility of the PNIPAM transition is further examined in bulk and in droplets and it could be shown that hydrogel induced deformation could be used to controllably manipulate droplet-based synthetic cell motility upon temperature changes. It is envisioned that a combination of the presented artificial cytoskeleton with naturally occurring components might expand the bandwidth of the bottom-up synthetic biology.     

Kinetics and mechanisms of the tropospheric reactions of menthol, borneol, fenchol, camphor, and fenchone with hydroxyl radicals (OH) and chlorine atoms (Cl)

Relative kinetic techniques have been used to measure the rate coefficients for the reactions of oxygenated terpenes (menthol, borneol, fenchol, camphor, and fenchone) and cyclohexanol with hydroxyl radicals (OH) and chlorine atoms (Cl) at 298 ± 2 K and atmospheric pressure. The rate coefficients obtained for the reactions of the title compounds with OH are the following (in units of 10(-11) cm(3) molecule(-1) s(-1)): (1.48 ± 0.31), (2.65 ± 0.32), (2.49 ± 0.30), (0.38 ± 0.08), (0.39 ± 0.09) for menthol, borneol, fenchol, camphor, and fenchone, respectively. For the corresponding reactions with Cl atoms the rate coefficients are as follows (in units of 10(-10) cm(3) molecule(-1) s(-1)): (3.21 ± 0.26), (3.40 ± 0.28), (2.72 ± 0.13), (2.93 ± 0.17), (1.59 ± 0.10), and (1.86 ± 0.29) for cyclohexanol, menthol, borneol, fenchol, camphor, and fenchone, respectively. The reported error is twice the standard deviation. Product studies of the reactions were performed using multipass in situ FTIR (Fourier transform infrared spectroscopy) and solid-phase microextraction (SPME) with analysis by GC-MS (gas chromatography-mass spectrometry). A detailed mechanism is proposed to justify the observed reaction products.     

Bioinspired Chemical Communication between Synthetic Nanomotors

While chemical communication plays a key role in diverse natural processes, the intelligent chemical communication between synthetic nanomotors remains unexplored. The design and operation of bioinspired synthetic nanomotors is presented. Chemical communication between nanomotors is possible and has an influence on propulsion behavior. A chemical “message” is sent from a moving activator motor to a nearby activated (receiver) motor by release of Ag⁺ ions from a Janus polystyrene/Ni/Au/Ag activator motor to the activated Janus SiO₂/Pt nanomotor. The transmitted silver signal is translated rapidly into a dramatic speed change associated with the enhanced catalytic activity of activated motors. Selective and successive activation of multiple nanomotors is achieved by sequential localized chemical communications. The concept of establishing chemical communication between different synthetic nanomotors paves the way to intelligent nanoscale robotic systems that are capable of cooperating with each other.     

冰片及其酯/酰胺类衍生物的合成和活性研究进展

冰片是重要的芳香开窍类中药,具有开窍醒神,清热止痛等功效,常被作为佐药与其他中药配伍使用。目前,冰片及其衍生物广泛用于医药、农药、化工及香料领域,市场前景好,研究和开发价值高。本文对天然冰片、合成冰片及其酯/酰胺类衍生物的主要合成方法和生物活性方面进行了系统总结,并对冰片酯类衍生物未来的研究方向进行了展望,以期为冰片及其酯/酰胺类衍生物的进一步的研究提供有益参考。