烃及其衍生物气相色谱保留指数的定量结构相关性研究

在分子拓扑理论的基础上,定义了原子的价点价δYi,由δYi构建了一个能表征含多重键、杂原子化合物的结构信息价连接性拓扑指数mZY(m=0,1,…,n).发现1ZY与烃及其衍生物的气相色谱保留指数IR有良好的相关性.与其他的指数相比较,新指数的相关性优秀,且新方法还具有计算简单,物理意义明确等优点.对新模型采用Jackknife法予以检验,具有总体稳健性.     

S-四嗪衍生物农药活性的初步筛选

对12个S-四嗪衍生物,包括3个新合成的1,6-二氢-S-四嗪衍生物,除草、杀菌、杀虫活性进行筛选。发现其中5个具有除草活性,1个具有杀虫活性。取代基对活性有明显影响。     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. VI. Über Versuche zur Alkylierung und Arylierung des Titan(III)-chlorids

Experiments on alkylation and arylation of titanium trichloride by means of organometallic compounds are reported. The formation of trimethyl titanium and derivates of triphenyl titanium was proved, and diphenyl titanium chloride was isolated in the crystalline state in form of a complex with diethyl ether.     

ESR study of free radicals in some new hydrazones of terpenoids class

The effect of gamma-irradiation on some new hydrazones of terpenoids using electron spin resonance (ESR) is reported. Gamma-irradiation of three derivates of hydrazone and of compounds resulting from the condensation of these derivates with terpenoids produces stable free radicals at room temperature. The analysis of the ESR parameters (g-factors and hyperfine coupling) and the simulation performed lead us to conclude that free radicals are of form R–N–NH₂ (arising from hydrazine derivates) and R–N–N=R (arising from condensation compounds). The thermal stability of formed radicals is discussed and the activation energy involved in the process of recombination of free radicals is calculated.     

Synthesis and study of polyurethanes and polyurea urethanes based on the diamino derivatives of bis-1,3,4-oxadiazole

Polyurethanes were synthesized by condensation of diamino derivates of bis-1,3,4-oxadiazole with chloroformates, and polyurea urethanes were synthesized from diamino derivaties of bis-1,3,4-oxadiazole, diisocyanates, and ethylene glycol in a solution of dimethylformamide. Certain properties of these compounds were studied.     

The comparative spreading behavior of enantiomeric and racemic tyrosine amphiphiles

Several derivatives of tyrosine or its methyl ester have been synthesized in which the para hydroxyl group on the aromatic side chain has been converted to a long chain alkyl ether or urethane. The surface behavior of these compounds is discussed. Enantiomeric discrimination, the ability of a chiral molecule to distinguish between mirror-image stereoisomers, has been investigated for the urethane derivates by comparing the surface pressure-area isotherms of the enantiomer with that of the racemic compound. Enantiomeric discrimination was demonstrated for the methyl ester analog, but was not conclusively observed for the zwitterionic compounds. Possible structural requirements for enantiomeric discrimination in a chiral molecule are discussed.     

Fluorierungseigenschaften von WF6

WF₆ reacts with aliphatic carbonyl- or carboxyl derivates to form the corresponding difluorides or carbonic acid fluorides. Fluorination of carbonyl compounds makes the presence of a Lewis acid like BF₃ necessary.Trifluoromethyl compounds are not available in this way.Selective fluorination of alcoholes with WE₆ is not possible.     

Electrochemical and crystal structural analysis of alpha- and dehydro-alpha-lapachones

Lapachones are pharmaceutically active compounds generating reactive oxygen species. The crystal structure and redox behaviour of the title lapachones, derivates of quinones, were determined by X-ray diffraction and cyclovoltametric measurements. The observed results were compared with beta-lapachone.     

Determination of carbonyl compounds in pool water with O-(2,3,4,5,6-pentafluorobenzyl)hydroxyamine hydrochloride and gas chromatographic-tandem mass spectrometric analysis

To avoid microbiological decay pool water is disinfected, a procedure which results into a lot of disinfection by-products, like carbonyl compounds, as well as a large number of others. The carbonyl compounds dissolved in pool water were derivatisized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxyamine hydrochloride (PFBHA) and extracted using n-hexane. Measuring with the help of GC-electron-capture detection is hardly possible because of interferents like halogenated organics. Another method to detect the PFBHA derivates is the use of tandem mass spectrometry. Calibration ranges and precision are applicable and sufficient to determine carbonyl compounds in pool water.     

Simultaneous Construction of C−Se And C−S Bonds via the Visible‐Light‐Mediated Multicomponent Cascade Reaction of Diselenides,Alkynes, and SO2

A visible‐light mediated multicomponent cascade reaction of diselenides, alkynes, and sulfur dioxide was developed, in which multiple C?Se and C?S bonds were constructed, and unexpected β‐sulfonylvinylselane compounds were generated with high selectivity for E configuration. β‐Sulfonylvinylselane transformation into 1,4‐oxathiine‐4,4‐dioxide and sulfonylethyne derivates was then investigated. A plausible mechanism involving a selenium radical‐initiated cascade reaction and sulfur dioxide insertion was proposed.     

N‐Heterocyclic Carbene‐catalyzed Reactions of o‐Aminonitriles with Carbonyl Compounds Approach to 2,3‐Dihydroquinazolin‐4(1H)‐ones

A green, efficient and convenient N‐heterocyclic carbene‐catalyzed procedure for the synthesis of novel 2,3‐dihydroquinazolin‐4(1H)‐one derivates via condensation of o‐aminonitriles and various carbonyl compounds was described.     

Molecular Modeling of Enantioseparation of Phenylazetidin Derivatives by Cyclodextrins

β-Lactams are one of the most widely used types of antibiotics. As β-lactams are chiral, the enantiomeric separation of these compounds was investigated using cyclodextrins, frequently used as chiral separators. Molecular modeling methods were utilized in order to predict possible enantioseparation of four model compounds. Our results revealed that permethylated β-cyclodextrin is more likely to chirally separate the phenylazetidin derivates than the parent β-cyclodextrin. LC experiments using cyclodextrin as chiral stationary phase in most cases confirmed our prediction; however, more experiments and statistical evaluation of the results are needed in order to judge the prediction power of the molecular dynamic method.     

β-环糊精与联苯类衍生物的包合物研究

本文研究了β-环糊精(主体)与联苯及其衍生物(客体)的包合反应。用多种谱学方法对固体包合物进行了表征, 由连续变量法确定了主-客体包合物组成均为2:1, 根据高分辨核磁共振光谱主体内腔质子(3-H)化学位移的变化求出了包合物的稳定常数, 对包合物的形成进行了初步讨论。     

Synthèse de nouveaux réactifs génotoxiques,les dérivés nitrés d'anthrafurannes

We herein descirbe various methods for synthesizing 1-foryml-2-hydroxyanthracene, 2-formyl-1-hydroxyanthracene and 1-formyl-2-hydroxy 6-methoxyanthracene. These compounds are used as starting materials to prepare anthrafuran derivates nitracted on their heterocycles in order to copare their mutagenic properties to that of the corresponding nitro-derivates of naphthofurans.     

Contribution à la phytochimie du genre Gentian,XI Identification de nouveaux dérivés de l'iso-orientine extraits des feuilles de Gentiana burseri Lapeyr

Two new derivates of iso-orientin have been isolated and identified from the leaves of Gentiana burseri, LAPEYR. The structure of the new compounds were established as: trans-cafeoyl-2″-iso-orientin (1) and p-β-D-glucosyl-trans-cafeoyl-2″-iso-orientin-4′-O-β-D-glucoside (2).     

Synthesis, characteristic and theoretical investigation of the structure, electronic properties and second-order nonlinearity of salicylaldehyde Schiff base and their derivatives

A series of asymmetric donor-acceptor substituted salen-type Schiff-bases have been synthesized and their structures, electronic properties and second order nonlinearities were investigated by DFT methods. In order to verify the stable of these Schiff-base derivates, the IR spectrum of these Schiff-base derivates were calculated, the result showed that these compounds are stable. The results of TD-DFT calculation indicate that the derivatives with the electron-donating group (CH3, OCH3 or N(C2H5)2) have a red shift absorption compared to derivatives with the electron-withdrawing group (NO2). The analysis of MOS indicates that the CN group has contribution to the LUMO orbital while the groups of OCH3, N(C2H5)2 and NO2 have contribution to the HOMO orbital. OCH3, N(C2H5)2 as electron rich groups, made the derivates have a larger first static hyperpolarizability. However, the compound (II) with a NO2 substituent, also has a large first static hyperpolarizability. This is probably because of the special transition model, namely the values of two oscillator strength f (fHOMO-1-LUMO=0.405, fHOMO-LUMO=0.321) are almost equal. In order to understand the influence of the energy gap (ΔE) between the HOMO and the LUMO orbitals on the first static hyperpolarizability, we calculated the energy gap (ΔE) of all Schiff-base compounds. The results show that the smaller the HOMO-LUMO energy gap is, the larger the first static hyperpolarizability is.     

Comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry for the identification of organobrominated compounds in bluefin tuna

This study evaluates comprehensive two-dimensional gas chromatography (GC×GC) coupled to time-of-flight mass spectrometry (GC×GC-ToF MS) for the simultaneous analysis of several classes of organobromines (OBs), including polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), methoxylated PBDEs (MeO-PBDEs), several halogenated naturally produced compounds (HNPs) and eight novel brominated flame retardants (NBFRs), polybrominated hexahydroxanthene derivates (PBHDs), 2,4,6-tribromoanisole and a mixed halogenated compound (MHC-1), in bluefin tuna muscles. The proposed methodology maximised separation of both within and among OB families, and among these and other halogenated micropollutants detected in these samples and co-extracted matrix components. Special attention has been paid to solve co-elution problems observed during the analysis of OBs with one-dimensional GC-based techniques. Satisfactory separation among several relevant PBDEs and MeO-PBDEs has been obtained allowing their unambiguous determination in a single run. Additional studies were conducted to identify selected NBFRs and HNPs. 2,4-Dibromoanisole, a dibromophenol isomer and hexabromobenzene were identified in the investigated samples. Several new tri- and tetra-BHD derivates were also identified, indicating that these compounds could apparently exist as structured families in nature. In addition, a tetrabrominated diMeO-biphenyl and two tetrabrominated diMeO-BDEs were also tentatively identified.     

Synthetic pathway for a new series of liquid crystal 2,6-disubstituted imidazo[2,1-b][1,3,4]thiadiazole

Herein, the synthesis of a novel series of liquid crystals 2,6-disubstituted imidazo[2,1-b]-1,3,4-thiadiazoles derivate is reported. These fused heterocyclic compounds were prepared through the cyclodehydration between 5-substituted-1,3,4-thiadiazole-2-amino derivatives and α-bromo aryl ketones. The derivates of 2-amino-thiadiazole were obtained from the condensation reaction between thiosemicarbazide and aryl/alkyl nitriles with good yields (60–83%). The α-bromination of aryl ketones was carried out using NBS as the source of electrophilic bromine, also with good yields (52–85%). For the final compounds, the liquid crystal behaviour was shown to be dependent on the number of chains. Mesomorphism was not observed for compounds without aliphatic chains, with more than two aliphatic chains or when the aliphatic chains are methoxy groups.     

Remarks on the detection of aza arenes in airborne particulates

Summary Suspended particulate matter sampled in the ambient air of Duisburg was investigated for the content of aza heterocyclic compounds. The loaded filters were extracted for 10 hours in a soxhlet apparatus. The concentrated extract was shaken with diluted sulphuric acid. The aqueous layer was adjusted to pH 12 with potassium hydroxide and then extracted with dichloromethane. The organic layer was transfered into cyclohexane and columned on alumina. The separated fraction was then examined by means of GC/MS. Quinoline, benzoquinoline, acridine and some of their alkyl derivates as well as azapyrene/fluoranthene were identified, whereas benzo- and dibenzoacridine could not be detected.     

Two New Aristolochic Acid Analogues from the Roots of Aristolochia contorta with Significant Cytotoxic Activity

Twelve compounds, including two new aristolochic acid analogues with a formyloxy moiety (9–10) and 10 known aristolochic acid derivates (1–8 and 11–12), were obtained from the roots of Aristolochia contorta. Their structures were elucidated using extensive spectroscopic methods. Their cytotoxic activity in human proximal tubular cells HK-2 was evaluated by the MTT method, which has been widely used to assess cell viability. Among these molecules, compounds 3 and 9 were found to be more cytotoxic. Furthermore, molecular modeling was used to evaluate, for the first time, the interactions of compounds 3 and 9 with the target protein organic anionic transporter 1 (OAT1) that plays a key role in mediating aristolochic acid nephropathy. Structure–activity relationships are briefly discussed.