卤代吡啶类化合物的合成及应用

一、前言含氟、杂环、手性是现代农药和医药领域新药合成的三大特征。含氟杂环化合物的种类非常多,由于受合成技术的限制,目前应用最多的是吡啶类含氟化合物。吡啶含氟化合物具有含氟、含氮杂环两种特性,它们与一些手性中间体结合所形成的具有含氟、含氮杂环、手性等三大特性的     

卤代吡啶类化合物的合成及应用

介绍了吡啶和卤代吡啶的结构和性质,综述了五氯吡啶、3,5,6,-三氯吡啶-2-酚、2-氯-5-三氟甲基吡啶等几种氯代吡啶化合物的合成及其在农药、医药领域的应用,并对各种合成路线工业化前景作了评价。     

几种卤代吡啶类农药中间体的合成与应用

概述了3,5,6-三氯吡啶-2-醇、2,3-二氯吡啶、2-氯-5-氯甲基吡啶、2,3-二氟-5-氯吡啶和2,3-二氯-5-三氟甲基吡啶5种卤代吡啶类化合物的合成方法,并对其在农药工业中的应用做了简要介绍。     

烷氧基卤代吡啶及其二苯基膦衍生物的合成研究

设计合成了新型手性催化剂的中间体。以氯代吡啶为原料,经烷氧基取代,选择性单溴代,合成了系列烷氧基溴代吡啶,最后利用锂化反应的区域选择性,制备了二苯基膦烷氧基溴代吡啶;并对反应选择性进行了重点讨论。     

从啶虫丙醚到二卤代丙烯类杀虫剂的研发

具二卤代丙烯醚结构的啶虫丙醚是一种结构特异、作用机制独特的新颖杀虫剂。它的成功开发,也促使了人们对二卤代丙烯醚类杀虫剂的研究、开发。     

聚硫代醚合成的研究进展

介绍了聚硫代醚的合成方法(如缩聚法、加聚法等),特别综述了加聚法的制备原理和应用实例。研究表明:缩聚法合成的聚硫代醚较早实现了工业化且原料价廉,但存在副产物多、产率低及产物后处理复杂等缺点;加聚法合成的聚硫代醚工艺简单、合成条件温和且产率高,原料稍贵但仍可接受,故加聚法合成的聚硫代醚之综合性能优于缩聚法合成的聚硫代醚。最后对聚硫代醚的发展方向进行了展望。     

吡啶衍生物及其催化闭环法合成

介绍吡啶衍生物的分类,并详细总结了烷基吡啶和卤代吡啶的应用及其合成路线。简要分析全球吡啶及其衍生物的生产及市场现状,概述了烷基吡啶和卤代吡啶的合成技术进展及其合成方法,并对吡啶衍生物的催化闭环法合成进行了介绍。最后指出我国的科研工作者应重视开发具有自主知识产权的吡啶新化合物。     

耐高温聚硫代醚橡胶的合成研究

以硫代二甘醇为单体,在催化剂作用下进行缩聚、转化反应,研究了催化剂种类和用量、官能度、反应时间、反应温度等因素对缩聚反应的影响,确定了缩聚、转化反应合成条件,在此工艺下合成的聚硫代醚橡胶配合的密封材料,50℃×48 h硫化后拉伸强度≥2.7 MPa,扯断伸长率≥300％;180℃×8h空气老化后拉伸强度≥1.8 MPa,扯断伸长率≥200％,邵A硬度≥35,非常适合应用于耐温性能要求高的领域.     

氯代吡啶化合物的研究应用与展望

介绍了吡啶氯化物分类、合成进展,分析了不同的合成路线之间的优缺点,并简介了其在医药、农药、香料、橡胶和染料方面的应用及预测。     

卤代磷脂的合成研究

以大豆磷脂为原料,利用有机卤代试剂制备出一种新型的卤代磷脂。通过正交试验确定了该反应的最佳反应条件：温度７５℃,引发剂量４％,溶剂量１５０ｍｌ,反应时间１．５ｈ。     

Highly Regioselective,Lewis Acid-Free Electrophilic Aromatic Substitution

By appropriate choice of solid catalyst and stoichiometric reagent it is possible to develop alternative procedures for many electrophilic aromatic substitution reactions that avoid the need for Lewis acid catalysts such as aluminium chloride. Furthermore, the catalysts may be regenerated, the reactions may be more controlled, corrosive by-products may be avoided and the structural features of the solid may lead to much greater regioselectivity than with traditional Lewis acids. Examples where such benefits are found include nitration, chlorination, bromination and acylation. © 1997 SCI.     

Palladium‐Catalyzed Highly Regioselective Arylation of Allylamines with Thiophenes and Furans

A palladium‐catalyzed highly regioselective and stereoselective direct arylation of allylamine derivatives with a wide range of thiophenes and furans has been developed. In the presence of palladium(II) acetate [Pd(OAc)₂] catalyst and appropriate oxidants, the coupling reaction proceeded with excellent group compatibility and high efficiency, leading exclusively to γ‐arylated linear (E)‐allylamines. It was found that the choice of solvent, olefin substrate and oxidant had an important influence on reaction efficiency, and the use of sterically demanding N,N‐diprotected allylamines bearing a carbamate moiety is crucial for securing high regioselectivity and stereoslectivity. This method provides a straightforward approach for the efficient synthesis of various γ‐heteroarylated, linear (E)‐allylamines.     

Convenient,Rapid and Highly Regioselective Cycloisomerisation of 4,4-Disubstituted Hepta-1,6-Dienes Employing Neutral Palladium Chloride pro-Catalysts

Optimum conditions for the cycloisomerisation of dimethyldiallylmalonate by complexes of the form [L₂PdCl₂] (L = RCN or DMSO) were found to be [(t-BuCN)₂PdCl₂] in 1,2-dichloroethane at 40°C. These conditions also allow the highly regioselective cycloisomerisation of a range of 4-substituted hepta-1,6-dienes to the corresponding 1-substituted 3,4-dimethylcyclopent-2-enes in good yield. However, substituents at the 4 position that are strongly coordinating inhibit the reaction.     

葡萄糖2位羟基选择性苄基化保护

研究了在哌啶作用下区域选择性地脱除全乙酰化葡萄糖1,2位乙酰基的反应,利用该反应合成了N-(3,4,6-三乙酰基-β-D-吡喃葡萄糖基)-哌啶,经苄基化进一步制备了N-(2-苄基-3,4,6-三乙酰基β-D-吡喃葡萄糖基)-哌啶,此化合物是合成寡聚糖或糖苷时的重要中间体。     

Regioselective combinatorial-type synthesis, characterization, and physical properties of dendronized cellulose

Novel regioselective, homo-(4-6) and heterogeneous (7-10) dendronized cellulose derivatives have been prepared by the reaction of cellulose in a N,N-dimethylacetamide (DMAc)/LiCl solvent system with diverse dendrons (1-3) possessing an isocyanate focal group. The dendronized cellulose derivatives were characterized using Fourier transform infrared (FTIR), ¹³C NMR, thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA). These polyfunctionally coated cellulose-based materials showed diverse solubility characteristics in organic solvents ranging from DMAc to methyl alcohol.     

Zn-Catalyzed Regioselective and Chemoselective Reduction of Aldehydes,Ketones and Imines

An operationally convenient Zn-catalyzed synthesis of alcohols by the reduction of aldehydes, ketones, and α,β-unsaturated aldehydes/ketones is reported. It is a rare example of using mild and sustainable HBpin as a reductant for catalytic reduction of carbonyl compounds in the absence of acid or base as hydrolysis reagent. The reaction is upscalable and proceeds in high selectivity without the formation of boronate ester by-products, and tolerates sensitive functionalities, such as iodo, bromo, chloro, fluoro, nitro, trifluoromethyl, aminomethyl, alkynyl, and amide. The Zn(OAc)₂/HBpin combination has been also proved to be chemoselective for the C=N reduction of imine analogs.     

Regioselective substitution of 2‐isocyanatoethylmethacrylate onto cellulose

Cellulose is a well‐known versatile polymer that presents a wide range of material properties via the substitution and grafting reactions of its hydroxyl groups. Because of their commercial potential, combinations of cellulose and vinyl polymers have been examined with various grafting methods. In this study, the condensation reactions of regioselective and nonregioselective substitution with 2‐isocyanatoethylmethacrylate were performed in a homogeneous solvent system of dimethyl acetamide/lithium chloride. The successful substitution was confirmed by Fourier transform infrared spectroscopy, ¹H‐NMR, cross‐polarization/magic angle spinning ¹³C‐NMR, thermogravimetric analysis, and X‐ray diffraction. The substituted celluloses showed excellent thermal stability and a different polymorph with a depressed cellulose–intrinsic polymorphic phase. The 2‐isocyanatoethylmethacrylate side chain seemed to expand the intermolecular distance with enhanced chain mobility and trigger the formation of a novel crystalline polymorph with a dramatically improved thermal stability. This investigation provided us with a useful understanding of the modification of cellulose with spatial distribution control for advanced future applications requiring a combination of cellulose with vinyl polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

邻氯甲苯选择性硝化合成2-氯-5-硝基甲苯

邻氯甲苯硝化合成CLT酸因其转化率低及选择性差而未能实现工业生产。本文对邻氯甲苯硝化反应进行了研究,采用不同的催化剂体系,获得了成本低且选择性好的的合成条件。用酸性皂土和异丁醇为催化剂的硝化方法,转化率可达100%,2-氯-5-硝基甲苯比率提高到70.1%。