改性HZSM－5分子筛催化合成巯基乙酸酯的研究

用改性ＨＺＳＭ－５分子筛作催化剂制备了７种巯基乙酸酯：巯基乙酸丙酯、疏基乙酸正丁酯、硫基乙酸正戊酯、巯基乙酸正庚酯、疏基乙酸异辛酯、巯基乙酸二乙醇酯及疏基乙酸苯乙醇酯。收率９０％左右。讨论了影响反应的诸因素。     

阳离子交换树脂催化合成巯基乙酸酯

使用阳离子交换树脂Ｄ６１、Ｄ７２为催化剂，合成了七种巯基乙酸酯。文中对影响反应的诸因素进行了讨论。酯收率为９０％左右。     

巯基乙酸酯官能团修饰的铁氢化酶模拟化合物的合成及表征

对铁氢化酶活性中心进行化学模拟将有可能产生出新型的产氢催化剂.本文利用Sonogashira偶联反应,合成了一种巯基乙酸酯官能团修饰的铁氢化酶活性中心模拟化合物[Fe₂(CO)₆(-μadt)C₆H₄C≡CC₆H₄O(CH₂)₅SC(O)CH₃-4](7),将巯基乙酸酯官能团引入到铁氢化酶活性中心,为进一步制备新型的固载化产氢材料奠定了基础.电化学研究表明,化合物7具有明显的催化产氢特征,在电化学条件下可以催化醋酸放出氢气.     

竹红菌乙素与巯基乙酸、正辛硫醇的反应

本文研究了竹红菌乙素与巯基乙酸、正辛硫醇的反应。在室温下,在含氨水的二甲基亚砜溶液中,乙素同巯基乙酸或正辛硫醇迅速反应,主要产物为乙素母核上5位或/和8位氢被巯基化合物取代的衍生物。有氧参加反应时,还得到乙素母核氢被羟基取代的产物。这些取代产物的吸收光谱都比乙素本身明显地红移。乙素和巯基乙酸的反应产物有较好的水溶性,且保持了乙素所具有的光化学活性。文中还用UV和ESR谱,猝灭实验探讨了反应机制。     

昆虫保幼激素类似物——萜烯基硫醚类化合物的合成

利用香叶基氯、6,7-环氧香叶基氯与巯基乙酸酯类的缩合反应,制得了10个新的萜烯硫醚类化合物:6,10-二甲基3-硫杂十一碳5,9-双烯酸酯(3a,b,c,d,e)和6,10-二甲基9,10-环氧3-硫杂十一碳5-烯酸酯(4a,b,c,d,e).     

含酯基苯并噻唑衍生物的摩擦膜及热膜化学结构

制备了两种苯并噻唑衍生物2-苯并噻唑基-巯基硫代乙酸正辛酯(MBTT)和2-苯并噻唑基-巯基乙酸正辛酯(MBTA), 并用元素分析和核磁共振谱表征其分子结构. 用X光吸收近边结构谱(X-ray absorption near edge structure, XANES)全面地分析了杂环化合物在矿物油和菜籽油中所形成的摩擦膜和热膜的化学态. 分析结果表明, 在矿物油中, 添加剂MBTT和MBTA摩擦反应生成的摩擦膜主要由FeS2组成, 而菜籽油中, 两种添加剂摩擦反应生成的摩擦膜由FeSO4组成; 在两种基础油中, 两种添加剂生成的热膜都是由FeSO4组成的.     

单扫描示波极谱法测定巯基乙酸的研究

在H2SO4－NH4OAc(pH3．5）溶液中，巯基乙酸有一灵敏的还原波。当使用单扫描极谱法时，其二阶导数峰电位位于－0．320V（vs.SCE)。用直流极谱法，单极描极谱法和循环伏安法研究了该体系的极谱行为和电极反应机理。结果表明，当使用单扫描极谱法时，该体系属于有吸附性的准可逆过程，测得电极反应电子转移数n=1,H^ ，反应数n′＝1。用单扫描极谱法可测定巯基乙酸，测定的线性范围为0.04-2.0mg.L^-1，该方法用于冷烫液中巯基乙酸的测定，结果满意。     

右旋糖甙缩硫醛大环螯合剂的合成及解汞毒性能

合成了一种新的选择性螯合汞的水溶性高分子缩硫醛大环树脂,由醛基化右旋糖甙与乙二醇二巯基乙酸酯缩合而得。进行了这种高分子螯合剂的毒性和对氯化汞急性中毒的解毒能力的初步动物试验。结果表明整合剂本身毒性很小,并能提高中毒小白鼠的存活率。如作为处置汞中毒的口服药物,它既可经尿排汞,也可由切断肝肠循环而随粪便排汞。     

水相合成CdX (X＝Te, Te/CdS, Te/ZnS)红色量子点及毒性效应

分别以巯基乙酸(Mercaptoacetic Acid, MA)、还原型谷胱甘肽(Glutathione, GSH)为稳定剂在水相中直接合成了巯基乙酸CdTe (CdTe-MA)、红色巯基乙酸CdTe/CdS (CdTe/CdS-MA)、巯基乙酸CdTe/ZnS (CdTe/ZnS-MA)及谷胱甘肽CdTe (CdTe-GSH)量子点. 其中, CdTe-GSH量子点的量子产率可达47.3%. 体外溶血实验证实CdTe/ZnS-MA和CdTe-GSH量子点的溶血率较CdTe-MA和CdTe/CdS-MA低, 浓度为0.05 mmol/L的量子点溶血率＜5%, 达到了生物医用材料的要求. 活体实验证实: 通过尾静脉方式把量子点注入小鼠体内后, 荧光显微镜观察发现高剂量的量子点(0.4 mmol/10 g)在体内主要在心、肝、脾、肾组织中分布较多, 且引起不同程度的组织病变.     

Pt/巯基乙酸/玻碳电极的表面形貌与电催化性能

以巯基乙酸为偶联层在玻碳(GC)电极上组装 Pt纳米颗粒, 得到Pt /巯基乙酸/GC电极, 利用扫描电镜(SEM)和循环伏安法(CV)研究了不同条件下复合电极的表面形貌和电化学性能. 研究结果表明, 巯基乙酸在GC电极表面具有特性吸附, 形成了具有一定致密性的吸附层. 在0.5 mol/L H2SO4+1.0 mol/L CH3OH溶液中, 组装19 h的复合电极对甲醇氧化表现出较好的电催化性能.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.