多取代异噁唑类化合物的合成

异噁唑是一类具有独特化学结构的杂环类化合物,具有广泛的生物活性和药物活性,在医药、农药以及有机合成等方面具有非常广泛的应用前景。目前,对该类化合物的合成与生物活性的研究是合成化学研究热点之一。本论文主要是由α-烷硫亚甲基-β-肟类化合物和氢氧化钾在DMF溶剂中合成了一系列多取代异噁唑类化合物,通过~1H NMR,~(13)C NMR和ESI-MS(ESI-TOF)对所得化合物结构进行了表征。以2a的合成为例,对反应条件进行了优化,结果表明:在最优化化条件[(1a)1 mmol,氢氧化钾2 mmol,DMF 5 mL,80℃条件下,反应20 h],2a产率91%。并对该反应机理进行了探讨。该合成方法具有操作简单,条件温和以及产率高等特点。     

含1,3,4-噁二唑环PPV齐聚物的合成及发光特性研究

含有1,3,4-噁二唑结构单元的PPV齐聚物是一类具有良好电子传输功能的发光材料。通过Wittig—Homer反应合成了2,5-二{4-[2-(取代苯基)乙烯基]苯基}-1,3,4-噁二唑(1)。1的化学结构经元素分析和光谱分析确认,其分析数据表明1分子结构中的C=C双键均为反式结构。苯环上的取代基对1的UV—Vis吸收光谱和PL荧光光谱有显著影响。     

含咔唑、噁二唑及8-羟基喹啉的金属络合物型发光材料

为了得到发光性能优良的有机薄膜发光器件,在有机发光材料化合物的分子结构及器件构筑方面,一个重要的途径是在发光化合物的分子设计或器件的组合中,要既具有空穴传输功能团,又具有电子注入功能团,并使两者的传输效率应尽量达到一个恰当的平衡[1].为此,我们设计并合成了分子中含有发光强度高、稳定性好、载流子传输效率高8-羟基喹啉铝金属配合物型发光单元,并分别与空穴传输功基咔唑环及电子注入基噁二唑环相联的两种化合物[2],对它们的光发射性能进行了初步研究.由它们构成多层结构的发光器件,是下一步的研究工作,合成路线如下:     

噁唑、苯并噁唑及1,3,4-噁二唑硫醚的合成及抗肿瘤活性研究

设计并以噁唑、苯并噁唑及1,3,4-噁二唑硫醇与卤代烃反应合成了14个硫醚类杂环化合物, 其中13个化合物未见文献报道. 目标化合物的结构均通过¹H NMR谱、MS和元素分析进行了表征. 采用MTT [3-(4,5-dimethylthiagol-2-yl)- 2,5-diphenyltetrogolium bromide]法对14个目标化合物进行了体外抗肿瘤活性测定, 结果表明: 在10^－5 mol/L 浓度下, 10个化合物对肿瘤细胞具有抑制活性.     

含1,3,4-噁二唑甲壳型液晶聚合物的合成与表征

甲壳型液晶聚合物（mesogen-jacketed liquid crystal polymer,MJLCP）是1987年由周其凤教授[1]首先提出的概念.从化学结构看,甲壳型液晶聚合物属于侧链型,由烯类单体经链式聚合制得,容易得到高分子量的产物,具有一般柔性侧链型液晶聚合物的一些优点.但是与柔性侧链型液晶聚合物不同的是,MJLCP分子中的刚性液晶基元是通过腰部或重心位置与主链相联结的,在主链与刚性液晶基元的侧基之间只有很短或者没有柔性间隔基.由于在这类液晶聚合物的分子主链周围空间内刚性液晶基元的密度很高,分子主链被由液晶基元形成的外壳所包裹并被迫采取相对伸直的刚性链构象.因此,这类液晶聚合物又和主链型刚性链液晶聚合物相似,具有较明显的链刚性.近年来,周其凤课题组围绕甲壳型液晶聚合物深入开展了分子设计与合成、分子结构与性能等多方面的研究.其中,设计合成具有特定功能的甲壳型液晶聚合物是在以往研究工作和学科交叉融合的基础上发展起来的一项新的研究工作.将一些有特殊功能的基团引入到甲壳型液晶聚合物中会使其具有崭新的特性.     

噁唑类化合物合成研究新进展

含N和O原子的噁唑环是十分重要的五元杂环,其特殊的结构使噁唑类化合物表现出许多独特的性能和生物活性,在医药、农药、材料等多方面具有广阔的潜在应用.因此,噁唑类化合物的合成备受关注,相关研究众多,发展迅速.根据我们唑类的研究工作,并参考国内外近5年文献,系统地综述了噁唑类化合物,包括噁唑、噁唑啉、噁唑烷酮、稠环噁唑类等的合成研究近况.     

含柔性间隔基和末端烷氧基的双噁二唑衍生物的合成及性质

合成了一系列含柔性间隔基和末端烷氧基的双噁二唑化合物OXDs, 利用1H NMR、 元素分析和FTIR等手段对其分子结构进行了表征, 并用UV-Vis, PL, CV和DSC等方法对其性质进行了研究. 研究结果表明, 对甲氧基苯基与1,3-二(1,3,4-噁二唑基)苯基之间形成分子内激基复合物, 而端位烷氧基会阻碍分子内激基复合物的形成; OXDs化合物具有良好的电子注入、 电子传输及空穴阻挡的特性; 当末端取代基较短(或无末端取代基)时, 固体样品中的晶态结构含量较少, 经热处理后能够形成稳定的非晶态.     

氨基噁唑啉呫吨类BACE1抑制剂的特征结构与作用机制

β-分泌酶(BACE1)是治疗阿尔兹海默症(AD)的潜在靶点,BACE1抑制剂的开发已成为治疗AD的重要方向。本文运用比较分子相似性指数(CoMSIA)和分子对接法对66个氨基噁唑啉呫吨类BACE1抑制剂进行模拟分析,建立了可靠的构效关系预测模型(Q~2=0.86,R_(ncv)~2=0.97,R_(pre)~2=0.88),揭示了影响分子抑制活性的重要特征结构信息,发现抑制剂通过与BACE1之间形成的氢键作用和π-π堆积作用占据了分泌酶的S3、S1和S2'三个活性位点。实验所得模型和信息为后续新型高效BACE1抑制剂的结构优化和改造提供了重要的理论指导。     

新型异噁唑山酮素骨架螺环氧化吲哚类化合物的合成

本文以色酮-氧化吲哚合成子(1)与硝基异噁唑苯乙烯(2),催化剂DBU作用下,经分子间Michael加成,分子内Michael加成环化反应,获得7个新型异噁唑山酮素骨架螺环氧化吲哚类化合物3a~3g,产率87%~93%,dr=8/1~15/1, 其结构经¹H NMR, ¹³C NMR和HR-MS（ESI-TOF）表征。      

基于异噁唑酮类份菁染料的激发态分子内质子转移的研究

运用量子化学理论计算方法研究了3-甲基-4-(1H-吲哚-3-次甲基)-异噁唑-5-酮(A)及其衍生物份菁染料的激发态分子内质子转移性质.研究表明:在基态3种染料AH(R=H),AO(R=—O(H3))和AP(R=—O(H2Ph))只存在酮式构型,在激发态AH与AP存在酮式和烯醇式2种构型,而AO存在酮式、烯醇式和仲胺式3种构型.红外光谱表明化合物从基态跃迁到激发态存在分子内的氢键增强作用,势能曲线显示激发态的质子转移为放热反应且能垒较低,通过分析电子光谱得到具有较大斯托克位移的激发态分子内质子转移的荧光发射峰,前线分子轨道理论计算进一步说明了其质子转移的发生过程.     

UTILIZTION OF THE SUZUKI COUPLING TO ENHANCE THE ANTITUBERCULOSIS ACTIVITY OF ARYL OXAZOLES

Potent antituberculosis aryl oxazoles can be made in an efficient three step process--formation of β-hydroxy amides with serine benzyl ester; cyclization to afford oxazolines; and then dehydration to give the corresponding oxazoles. Furthermore, incorporation of an appropriate aryl halide allows utilization of the Suzuki cross coupling reaction to access new chemical space and more elaborate analogs. The compounds prepared by this method were shown to possess improved activity against M. tuberculosis, extremely low toxicity toward VERO cells and, as a result, high therapeutic indexes.     

RESEARCH ON 2-(2'-SUBSTITUTED VINYL)-5-BIPHENYLYL OXAZOLES

Fifteen of the 2-(2'-substituted vinyl)-5-biphenylyl oxazoles were synthesized respectively by the condensation of corresponding 2-methyl-5-biphenylyl oxazole with benzaldehyde,substituted benzaldehydes or furfural in the presence of alkali or acid.Their m.p.,infrared spectra,λmax of UV spectra and fluorescence spectra,fluorescence quantum yields as well as laser conversion efficiency of the compounds are listed in tables.     

PREPARATION OF 2-SUBSTITUTED OXAZOLES

ABSTRACT

A simple and economical method for 2-substituted oxazole synthesis and its scope are described.     

A convenient oxazole C-2 protecting group: the synthesis of 4- and 5-substituted oxazoles via metalation of 2-triisopropylsilyloxazoles

[reaction: see text] Metalation of oxazoles at the 4 and 5 position was achieved after regioselective C-2 silyl protection. Removal of the protecting group was then accomplished under mild conditions allowing for a straightforward preparation of C-5 monosubstituted and C-4,5 disubstituted oxazoles. The first practical C-2 protecting group of oxazoles has been demonstrated.     

Ethyl 2-chlorooxazole-4-carboxylate: a versatile intermediate for the synthesis of substituted oxazoles

[reaction: see text] By using a sequence of regiocontrolled halogenation and palladium-catalyzed coupling reactions, the synthesis of variously substituted oxazoles from ethyl 2-chlorooxazole-4-carboxylate (2) was accomplished. The methodology was applied to the synthesis of a series of 2,4-disubstituted, 2,5-disubstituted, and 2,4,5-trisubstituted oxazoles.     

Iodine-mediated new strategy for the synthesis of 2,5-disubstituted oxazoles from methyl ketones and TosMIC

A new strategy has been developed for the construction of oxazoles from methyl ketones and TosMIC via self-sorting oxidative domino reaction strategy. In contrast to its usual reactivity as C–N≡C synthon in the synthesis of oxazoles, TosMIC was utilized as ammonium surrogate in the present method. The protocol is attractive in terms of readily available starting materials, metal and base free conditions, operational simplicity, C–N and C–O bond formation. A variety of 2,5-disubstituted oxazoles were prepared in moderate-to-good yields.     

2,5-二取代噁唑的研究

合成了一系列2-苯基和2-取代苯基-5-(4＇-联苯基)(口恶)唑化合物,共三十二种。测定了它们的熔点,紫外吸收光谱,荧光发射光谱和激光转换效率。发现其中二十三种化合物在近紫外区有较高的激光转换效率(和PPO相比)。     

Studies of acyl and thioacyl isocyanates—XII : The reactions of benzoyl and thiobenzoyl isocyanates with sulfonium ylides and with diazoalkanes

Benzoyl isocyanates react with ethyl (dimethylsulfuranilidene) acetate, dimethyl sulfonium phenacylide and dimethyloxosulfonium methylide to give the corresponding stable benzoylcarbamoyl- sulfonium ylides which on pyrolysis, are converted into oxazoles. However, with dimethylsulfonium phenacylide, thioacyl isocyanate affords the thiazole derivative. In connection with the formation of oxazoles, the reaction of benzoyl isocyanates with some diazoalkanes was also investigated: the products are not 1,2,3-triazolones as reported by Neidlein, but instead benzoylcarbamoyldiazo compounds which were thermally decomposed to oxazoles.     

Research progress of oxazole derivatives in the discovery of agricultural chemicals

The search for new scaffolds is one of the important goals in the discovery of new pesticides, and the oxazoles as an important five-membered heterocyclic compound are widely used in the discovery of new pesticides. Oxazoles ring are often used as the scaffolding structure or bridging chain to connect different reactive groups. In recent years, oxazoles have made rapid progress in the discovery of new pesticides, especially in the discovery of fungicides, insecticides, and acaricides. A systematic review of the recent research progress of oxazoles in the discovery of new pesticides is of interest. Therefore, we comprehensively reviewed the application of oxazole compounds in the discovery of new pesticides from 2003 to 2023; summarized the fungicidal, antibacterial, insecticidal, acaricidal, and herbicidal activities of oxazoles; and discussed the structure–activity relationship, physiochemical and mechanism of action, with the aim of providing inspiration and ideas for the discovery of oxazoles as novel agrochemicals.     

Intra- and intermolecular thermal transformations of 2-acyl- and 2-alkoxycarbonyl-N-phthalimidoaziridines

Heating 2-acyl- and 2-alkoxycarbonyl-N-phthalimidoaziridines leads to substituted oxazoles in 45-65% yield. Only esters of oxazolecarboxylic acids are formed when the aziridine contains acyl and alkoxy groups. The thermolysis of the same aziridines in the presence of N-phenylmaleimide and the dimethyl ester of acetylenedicarboxylic acid gives both oxazoles and the products of 1,3-dipolar cycloaddition from aziridines with two substituents at the carbon atoms but only oxazoles from trisubstituted aziridines.