FeCl_3催化合成新型烯丙基醚类化合物

以烯丙基醇类化合物(1a~1i)和乙醇为起始原料,FeCl_3为催化剂,经分子间亲核取代反应合成了9个烯丙基醚类化合物(2a~2i,其中2c,2e~2i为新化合物),收率80%~95%,其结构经1H NMR,13C NMR和HRESI-MS表征。研究了催化剂,溶剂,反应温度和反应时间对2a产率的影响。结果表明:在最优反应条件[1a 0.5mmol,Fe Cl34 mg,Et OH 2.5 mmol,CH2Cl2为溶剂,于室温反应0.8 h]下,2a收率95%。     

不对称烯丙基化反应合成含有三苯胺核心单元的荧光非天然氨基酸衍生物

报道了一种钯催化噁唑酮和烯丙醇的不对称烯丙基化反应合成相应的三苯胺核心非天然氨基酸化合物的方法.反应收率高达95%,对映选择性过量值最高为97%ee.该反应操作简单,条件温和,原子经济性好,水为唯一副产物.     

Thiocyanation of Allylic Alcohols Promoted by Trifluoroacetic Acid

A rapid and efficient acid-promoted strategy to access allylic thiocyanates using allylic alcohols as substrates and easily-available NH₄SCN as the thiocyanate source is presented under metal- and oxidant-free conditions. Through screening of various kinds of acids, organic and strong trifluoroacetic acid (TFA) was found most effective. Testing of substrates showed that the strategy has remarkable functional group tolerance. A possible mechanism is provided, and the gram-scale experiment demonstrate that this novel protocol has potential industrial application value.     

Chlorosulfenylated Carbonic Acid Derivatives

The present article deals first with the synthesis of chlorocarbonylsulfenyl chloride and its imino analogs. The chemical behavior of these bifunctional compounds is illustrated for selected examples. Special attention is given to the syntheses of five-membered heterocycles containing sulfur, oxygen, and/or nitrogen.     

New Phosphorus Derivatives of Salicylic Acid

Abstract

The chemistry of phosphorus derivatives of salicylic acid has been revived and the synthesis of alkadienephosphonate derivatives of salicylic acid is reported.     

Enantioselective Dearomatization of Naphthol Derivatives with Allylic Alcohols by Cooperative Iridium and Brønsted Acid Catalysis

The combination of a transition‐metal catalyst and organocatalyst was designed to achieve a highly enantioselective system for the allylic dearomatization reaction of naphthols with racemic secondary allylic alcohols. The desired β‐naphthalenones, bearing an all‐carbon quaternary center, were obtained in good yields with high chemo‐ and enantioselectivities. The cooperative catalytic system, involving a chiral iridium complex and phosphoric acid, provided measurable improvements in yields, and chemo‐ and enantioselectivities relative to single‐catalyst systems. Control experiments indicated that the chiral iridium complex functions as a key species in the control of the absolute configuration, thus enabling the formation of both β‐naphthalenone enantiomers by simply employing opposite enantiomeric ligands.     

Chemical Strategies towards the Synthesis of Betulinic Acid and Its More Potent Antiprotozoal Analogues

Betulinic acid (BA, 3β-hydroxy-lup-20(29)-en-28-oic acid) is a pentacyclic triterpene acid present predominantly in Betula ssp. (Betulaceae) and is also widely spread in many species belonging to different plant families. BA presents a wide spectrum of remarkable pharmacological properties, such as cytotoxic, anti-HIV, anti-inflammatory, antidiabetic and antimicrobial activities, including antiprotozoal effects. The present review first describes the sources of BA and discusses the chemical strategies to produce this molecule starting from betulin, its natural precursor. Next, the antiprotozoal properties of BA are briefly discussed and the chemical strategies for the synthesis of analogues displaying antiplasmodial, antileishmanial and antitrypanosomal activities are systematically presented. The antiplasmodial activity described for BA was moderate, nevertheless, some C-3 position acylated analogues showed an improvement of this activity and the hybrid models—with artesunic acid—showed the most interesting properties. Some analogues also presented more intense antileishmanial activities compared with BA, and, in addition to these, heterocycles fused to C-2/C-3 positions and amide derivatives were the most promising analogues. Regarding the antitrypanosomal activity, some interesting antitrypanosomal derivatives were prepared by amide formation at the C-28 carboxylic group of the lupane skeleton. Considering that BA can be produced either by isolation of different plant extracts or by chemical transformation of betulin, easily obtained from Betula ssp., it could be said that BA is a molecule of great interest as a starting material for the synthesis of novel antiprotozoal agents.     

双吖啶衍生物与核酸作用的光谱分析

用荧光光谱、紫外可见吸收光谱等方法研究合成的核酸探针与核酸的作用方式,发现DNA对这些物质的荧光具有较强的猝灭效应,其中又以10,10’二乙基-3,3’-二磺酸基-双吖啶（DESAC）、10,10’-二烯丙基-3,3’-二磺酸基-9,9＇-双吖啶（DASAC）、10,10’-二烯丙基-3,3’-二氨基-9,9＇-双吖啶（DAAAC）和10,10’-二乙基-3,3＇-二氨基-双吖啶（DEAAC）这4种物质效果最好,因此有望从这类物质中筛选出良好的核酸探针。     

Amino Acid Derivatives and Oximes of Flavones

4-Ethoxyflavylium tetrafluoroborates with substituents in rings A and B were synthesized. Their reaction with nitrogen-containing nucleophiles was investigated. It was shown that derivatives of flavones at the carbonyl group are formed as a result of these reactions. The major distinctive physicochemical characteristics of the oximes of flavones and isoxazoles were determined.     

鹅去氧胆酸及其衍生物的制备和应用

鹅去氧胆酸是天然的初级胆汁酸,是鸡、鸭和鹅等家禽胆汁中的主要有机成分,具有杀菌、抗炎和溶解胆结石等作用,是临床上治疗胆固醇结石的药物之一,也是合成临床上治疗胆结石疾病用量最大的药物熊去氧胆酸的原料。鹅去氧胆酸在医药方面的应用价值促使其制备方法逐步完善。近年来,关于鹅去氧胆酸衍生物的研究越来越多,相关研究也延伸到生物医药、分子识别和功能材料等多个领域,尤其在生物医药领域,鹅去氧胆酸衍生物显示出广阔的应用前景。本文系统地综述了鹅去氧胆酸的提取、合成与化学修饰方法,以及鹅去氧胆酸衍生物的合成、性质及应用,并展望了其发展前景。     

Synthesis and Anti-tumor Activity of Novel Amide Derivatives of Ursolic Acid

Ursolic acid was modified at C3 and C28 position to obtain fourteen derivatives including twelve novel compounds, and their chemical structures were characterized by IR, ^1H NMR and MS. Cell growth inhibitory effects of the derivatives against Hela cell were evaluated by MTT assay. All these derivatives were found to have stronger cell growth inhibitory than their parent compound, ursolic acid. The derivatives with a substituted acetyl group at C3 hydroxyl group show better activities than those with an unsubstituted hydroxyl group.     

Corrosion of Copper in Presence of Acetic Acid Derivatives

The anodic corrosion of copper in presence of acetic acid derivatives were determined by measuring the limiting current. It is found that the rate of corrosion increased by decreasing H₃PO₄ concentration and electrode height. The experimental results showed that the inhibition efficiency increased with increasing concentration of the investigated compounds at a fixed temperature, but decreases with increasing temperature. Values of activation energy indicate that the reaction is diffusion controlled. The isotherm Langmuir, Temkin, and Flory Huggins are applied. The values of free energy of adsorption (ΔG_ads) obtained indicate the spontaneous adsorption of the inhibitor. The overall mass transfer correlations under the present conditions have been obtained using dimensional analysis method. The results agreed with the previous studies of mass transfer to rotating cylinder in turbulent flow.At the end of the corrosion process the morphology of the specimens after experiment is monitored using scanning electron microscope (SEM). SEM examination of the copper surface revealed that these compounds inhibited copper from corrosion by adsorption on its surface to form protective film. The presence of these organic compounds adsorbed on the electrode surface was confirmed by SEM investigations.     

Chelate Compounds of a Selected Non-Transition and Transition Metal Ions with Some Salicylic Acid Derivatives

A series of binary complexes of Zn(II), Hg(II), Pb(II), La(III), Ce(III), Th(IV) and UO₂(II) with 3,5-dinitrosalicylic acid and 5-sulphosalicylic acid have been isolated and characterized. The solution equilibria of these complexes have been studied pH-metrically. The formation constants (log K) at 25±1°C and ionic strength of 0.2M NaClC₄ have been calculated. Stability of the complexes formed in relation to ligand molecular structure and nature of the metal ion has been examined and discussed.     

螺环季酮酸衍生物的合成及生物活性研究

为了寻求新颖的螺环季酮酸先导化合物,以3 -(2,4-二氯苯基)-4-羟基-1-氧杂螺[4.5]癸-3-烯-2-酮为原料,合成了21个螺环季酮酸衍生物,其结构经1H NMR,ESI MS和元素分析确认,并测定了化合物6b的晶体结构.初步生物活性测定表明,此类化合物对朱砂叶螨、蚜虫和粘虫都具有很好的生物活性,尤其是化合物5g和5m对朱砂叶螨的LD50分别为35.12和22.39 mg/L,高于螺螨酯的LD50:45.20 mg/L;化合物5b对蚕豆蚜的LD50为21.90 mg/L,而螺螨酯对蚕豆蚜的LD50为174.13 mg/L.     

Catalytic Asymmetric Synthesis of Allylic Alcohols and Derivatives and their Applications in Organic Synthesis

Allylic alcohols represent an important and highly versatile class of chiral building blocks for organic synthesis. This Review summarizes the plethora of methods developed for the catalytic asymmetric synthesis of enantioenriched allylic alcohols. These include: dynamic kinetic resolution (DKR/DKAT), nucleophilic 1,2‐addition to carbonyl groups, allylic substitution, oxidation of C? H bonds, the addition of O nucleophiles to π systems, reduction of unsaturated carbonyl compounds, and an alternative route from enantioenriched propargylic alcohols. Furthermore, these catalytic asymmetric processes are exemplified by their applications in the syntheses of complex molecules such as natural products and potential therapeutic agents.