Microcellobospotia grisea中具有强抗肿瘤活性多糖重复单元中心片断的合成

通过应用三氟乙酸酯法和Koenigs-Knorr方法，对Microcellobospotia grisea中具有强抗肿瘤活性多糖重复单元中心二糖片断进行了合成研究，并经元素分析，IR，^1H，^1^3C-NMR，^1H～^1H COSY及FAB-MS确证了合成得到的二糖片断10～13的结构。     

碘催化亚胺与二氢呋喃反应合成四氢喹啉衍生物

碘催化N-苯基苄基亚胺与二氢呋喃反应合成了四氢喹啉衍生物,其结构经~1H NMR,~(13)C NMR和HR-MS表征.     

三苯基锡—O,O—二芳基二硫代磷酸酯的合成和结构表征

本文合成了13种三苯基锡-O,O-二芳基二硫代磷酸酯,测定了它们的IR、~1H、~(31)C、~(119)SnNMR,MS和元素分析,结果表明该类化合物具有单体的四面体四价锡结构。     

新型齐墩果酸糖苷化衍生物的合成及体外抗HCT8活性

为提高齐墩果酸的水溶性和稳定性,以齐墩果酸苷元为起始原料,对其28-COOH进行甲基化修饰后制得齐墩果酸-28-羧甲酯(1)。分别以D-半乳糖、D-葡萄糖、D-氨基葡萄糖为起始原料,通过对糖羟基的保护与去保护,得到一系列的二糖、四糖片段。通过三氯乙酰亚胺酸酯途径和对甲苯硫基途径,利用合成的糖片段对1的3-位羟基进行糖化学结构修饰,合成了4种新型的齐墩果酸糖苷化衍生物(2~5),其结构经1H NMR,13C NMR和MS(ESI)表征。采用MTT法测试了2~5对高表达人结肠癌细胞(HCT8)的体外抑制活性。结果表明:2~5对HCT8有一定的抑制作用,化合物5浓度为1×10^-3 mmol/L时,抑制率达到(98.96±0.10)%。     

2-乙酰噻吩及其新型席夫碱的合成

以磷钨酸为催化剂,噻吩和乙酸酐反应合成了2-乙酰噻吩(1,收率83.5%);1与不同结构的酰肼反应合成了四种新型席夫碱(2a～2d),收率90%～95%,其结构经UV,~1H NMR,~(13)C NMR,IR及元素分析表征.优化了合成1和2的反应条件.     

一种合成脱水糖醇的新方法

以四苄基糖(或2,3:5,6-二异丙叉基-D-甘露糖)为起始原料,经过NaBH4或LiAlH4还原、单对甲苯磺酰化、分子内环醚化反应、脱保护等步骤合成了四个脱水糖醇,总产率55%～75%,其结构经1H NMR,13C NMR,HSQC和NOESY表征.     

三稠环系三唑磷茂啉的化学 Ⅱ.2-苯基-3-N,N-二烷基氨基苯并噻唑并[2,3,d]-2,3-二氢-1,2,4,3-三唑磷茂啉与酚和醇的反应

本文通过2-苯基-3-N,N-二烷基氨基苯并噻唑并[2,3,d]-2,3-二氢-1,2,4,3-三唑磷茂啉(1)与酚和醇的反应合成了三稠环系三唑磷茂啉的两个新的系列化合物2a～2f和3a～3j.测定了这十六个新磷杂环化合物的IR,~(31)P,~(13)C和~1H NMR以及2a的MS和X-ray数据,初步解析了它们的结构.     

1,2,3—二氮磷杂环戊二烯类化合物的合成及性质

合成了2-乙酰基-1,2,3-二氮磷杂环戊二烯类系列化合物,用~1H、~(13)C、~(31)P NMR和MS确定了其结构,讨论了结构和NMR谱间的关系。     

合成伏格列波糖的工艺改进

对合成伏格列波糖的工艺进行了改进。以葡萄糖为起始原料,经12步反应合成了伏格列波糖,总收率25.3%,其结构经1H NMR和13C NMR确证。     

糖基化青蒿素衍生物的合成

以糖[D-葡萄糖(1a),D-木糖(1b),D-甘露糖(1c),乳糖(1d)和D-半乳糖(1e)]为原料,经溴化、乙酰化一锅法使糖基乙酰化制得相应的溴代乙酰化糖(2a～2e);2在相转移催化剂四丁基硫酸氢铵催化下分别与二氢青蒿素经醚化反应合成了五个糖基化青蒿素衍生物,其结构进行1H NMR,13C NMR,IR和LC-MS表征。     

Studies on the Syntheses of the Side Chains of Brassinolide and Dolicholide

(4R,5S)-2,2-Dimethyl-4-(1',2'-dimethylpropyl)-5-(1'-bromoethyl)--1,3-dioxolane(15) with the side chain of brassinolide and (4R, 5S)--2, 2-dimethyl-4-(l'-methylene-2'-methylpropyl)-5-(1'-bromoethyl) 1,3-dioxolane(14) with the side chain of dolicholide were first synthesized through 11 and 10 stepes from D-mannitol respectively. All of the intermediates 7-13 were first synthesized too.     

Gaussian-3 study of the thermochemistry of the germane and its fluoro chloro derivatives

The thermochemistry of all fluoro and chloro substituted germane molecules have been theoretically studied. Computed G3//B3LYP standard enthalpies of formation at 298 K obtained from isodesmic reaction schemes were compared with values derived via total atomization energies. Bond dissociation energies and energy barriers for the lowest dissociation pathways were estimated at 0 K. From these data, the most probable dissociation products at 0 K were predicted for the thermal decomposition reactions of the gaseous species. Calculated results are compared with experimental determinations as well as other theoretical data when available. The following isodesmic enthalpies of formation in kcal x mol(-1) were calculated for 10 new germane species simultaneously substituted with fluoro and chloro atoms, for which no previously available computations were found in the literature: GeHFCl2, -125.8; GeCl2F, -104.3; GeHFCl, -67.5; GeF2Cl2, -186.3; GeF3Cl, -242.9; GeH2FCl, -89.7; GeCl3F, -159.6; GeHClF2, -168.0; GeF2Cl, -144.3; GeFCl, -81.1.     

Experimental and computational investigation of the energetics of the three isomers of monochloroaniline

The standard (p degrees = 0.1 MPa) molar enthalpies of formation of 2-, 3-, and 4-chloroaniline were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by rotating bomb combustion calorimetry. The Calvet high-temperature vacuum sublimation technique was used to measure the enthalpies of vaporization or sublimation of the three isomers. These two thermodynamic parameters yielded the standard molar enthalpies of formation of the three isomers of chloroaniline, in the gaseous phase, at T = 298.15 K, as 53.4 +/- 3.1 kJ.mol(-1) for 2-chloroaniline, 53.0 +/- 2.8 kJ.mol(-1) for 3-chloroaniline, and 59.7 +/- 2.3 kJ.mol(-1) for 4-chloroaniline. These values, which correct previously published data, were used to test the computational methodologies used. Therewith, gas-phase acidities, proton affinities, electron donor capacities, and N-H bond dissociation enthalpies were calculated and found to compare well with available experimental data for these parameters.     

Experimental correlation between the pKa value of sulfonphthaleins with the nature of the substituents groups

This work presents the results obtained from a spectrophotometry study performed on some indicators of the sulfonphtaleins like phenol red (PR), thymol blue (TB), bromothymol blue (BTB), xylenol orange (XO) and methylthymol blue (MTB). During the first stage the acidity constants of some of the indicators were determined using the data from spectrophotometry, potentiometry and with the use of the software SQUAD. These were as follows: for the equilibrium 2H+BTB<-->H(2)BTB, log beta(2)=15.069+/-0.046 and for H+BTB<-->HBTB, log beta(1)=8.311+/-0.044. For the XO and the MTB five values were calculated for each, namely, for MTB: log beta(5)=42.035, log beta(4)=38.567+/-0.058, log beta(3)=32.257+/-0.057, log beta(2)=23.785+/-0.057, and log beta(1)=12.974+/-0.045 while for XO: log beta(5)=40.120+/-0.102, log beta(4)=35.158+/-0.062, log beta(3)=29.102+/-0.053, log beta(2)=21.237+/-0.044, and log beta(1)=11.682+/-0.044. During the second stage, a study was conducted on the effect of the substituents present in the indicators to determine the effect of different functional groups on the pK(a) value corresponding to the last indicator's dissociation.     

季铵盐结构与高氯酸根离子选择电极性能关系的研究

本文报道了由七种长链季铵盐制得的高氯酸根离子选择电极,测定了这些电极的Nernst响应范围和检测下限,并研究了各种阴离子的干扰。通过大量实验测得,随着季铵盐分子中取代烷基碳链的增长,电极电势响应范围增宽、检测下限降低、抗外部阴离子干扰能力增强。若取代烷基碳链过长,则季铵盐纯化困难,在膜相中溶解度降低,不适于电极的研制。根据用上述七种选择电极在相同水相条件下测得的数据表明,阴离子的干扰次序为:PA~->ClO_4~->BF_4~->SCN~->I~->ClO_3~->N_3~->N_3~->CN~-～Br~->H_2PO_4~->F~->Cl~-。这些数据对阴离子选择电极研制与相转移催化反应研究均有现实意义。     

Prediction of the existence of the N2H- molecular anion

We predict the existence of the N(2)H(-) anion from first principle calculations. We present the three-dimensional potential energy surface and the bound states of the N(2)H(-)/D(-) van der Waals anion. The electronic calculations were performed using state-of-the-art ab initio methods and the nuclear motions were solved using a quantum close-coupling scattering theory. A T-shaped equilibrium structure was found, with a well depth of 349.1 cm(-1), where 18 bound states have been located for N(2)H(-) and 25 for N(2)D(-) for total angular momentum J = 0. We also present the absorption spectra of the N(2)H(-) complex. This anion could be formed after low energy collisions between N(2) and H(-) through radiative association. The importance of this prediction in astrophysics and the possible use of N(2)H(-) as a tracer of N(2) and H(-) in the interstellar medium is discussed.     

Composition and enantiomeric analysis of the essential oil of the fruits and the leaves of Pistacia vera from Greece

The essential oils of the fruits and the leaves of pistachio (Pistacia vera L.) were analyzed by GC and GC/MS. Fresh unripe pistachio fruits were richer in essential oil (0.5%, w/w) than the leaves (0.1%, w/w). Twenty one compounds were identified in the essential oil of the fruits and the major components were (+)-alpha-pinene (54.6%) and terpinolene (31.2%). The enantiomeric ratio of the major constituents of the essential oil of the fruits was determined using chiral GC/MS and it was found that the (+)/(-)-alpha-pinene ratio was 99.5:0.5, (+)/(-)-limonene 80:20, (+)/(-)-beta-pinene 96:4, and (+)/(-)-alpha-terpineol 0:100. Thirty three compounds were identified in the essential oil of the leaves and the major components were found to be alpha-pinene (30.0%), terpinolene (17.6%) and bornyl acetate (11.3%).     

Further consideration of the gas-liquid chromatographic method for determining the intramolecular hydrogen bond energies with the example of 2-substituted phenols

The GLC method for determining the intramolecular hydrogen bond (intra-HB) energy as the difference between the heats of dissolution of two isomers, one of which forms an intra-HB and the other has no such bond for steric reasons, in a polar stationary liquid phase was further considered by taking account of a correction for the difference between the energies of nonspecific interactions of the isomers with a polar phase. With 4- and 2-substituted phenols as an example, the differences between their heats of dissolution in polyethylene glycol and in poly-1,4-butanediol succinate were measured. As a first approximation, corrections for the contribution of the energy of nonspecific interactions with a liquid phase to the total magnitude of the difference between the heats of isomer dissolution were found. These corrections were determined as the difference between the heats of dissolution for 1,4- and 1,2-disubstituted benzene derivatives--analogs of the compounds under study that either do not have hydroxyl groups altogether or, in the case of 1,2-isomers with a hydroxyl group, cannot form an intra-HB. On the basis of the obtained results, the average intra-HB energies of 2-fluoro- (1), 2-chloro- (2), 2-bromo- (3), 2-iodo- (4), 2-methoxyphenol (5), salicylaldehyde (6), methyl ether of salicylic acid (7) and 2-nitrophenol (8) were estimated to be 7.4+/-0.3, 13.3+/-0.8, 14.4+/-0.4, 12.8+/-0.3, 17.6+/-0.1, 24.6+/-1.2, 29.8+/-0.3 and 32.5+/-4.7 kJ/mol, respectively. The values were compared with those found in the literature.     

Kinetics of the unimolecular decomposition of the 2-chloroallyl radical

The thermal decomposition of the 2-chloroallyl radical, CH(2)CClCH(2) --> CH(2)CCH(2) + Cl (1), was studied using the laser photolysis/photoionization mass spectrometry technique. Rate constants were determined in time-resolved experiments as a function of temperature (720-840 K) and bath gas density ([He] = (3-12) x 10(16), [N(2)] = 6 x 10(16) molecule cm(-3)). C(3)H(4) was observed as a primary product of reaction 1. The rate constants of reaction 1 are in the falloff, close to the low-pressure limit, under the conditions of the experiments. The potential energy surface (PES) of reaction 1 was studied using a variety of quantum chemical methods. The results of the study indicate that the minimum energy path of the CH(2)CClCH(2) dissociation proceeds through a PES plateau corresponding to a weakly bound Cl-C(3)H(4) complex; a PES saddle point exists between the equilibrium CH(2)CClCH(2) structure and the Cl-C(3)H(4) complex. The results of quantum chemical calculations, the rate constant values obtained in the experimental study, and literature data on the reverse reaction of addition of Cl to allene were used to create a model of reactions 1 and -1. The experimental dependences of the rate constants on temperature and pressure were reproduced in RRKM/master equation calculations. The reaction model provides expressions for the temperature dependences of the high-pressure-limit and the low-pressure-limit rate constants and the falloff broadening factors (at T = 300-1600 K): k(infinity)(1) = 1.45 x 10(20)T(-1.75) exp(-19609 K/T) s(-1), k(infinity)(-)(1) = 8.94 x 10(-10)T(-0.40) exp(481 K/T) cm(3) molecule(-1) s(-1), k(1)(0)(He) = 5.01 x 10(-32)T(-12.02) exp(-22788 K/T) cm(3) molecule(-1) s(-1), k(1)(0)(N(2)) = 2.50 x 10(-32)T(-11.92) exp(-22756 K/T) cm(3) molecule(-1) s(-1), F(cent)(He) = 0.46 exp(-T/1001 K) + 0.54 exp(-T/996 K) + exp(-4008 K/T), and F(cent)(N(2)) = 0.37 exp(-T/2017 K) + 0.63 exp(-T/142 K) + exp(-4812 K/T). The experimental data are not sufficient to specify all the parameters of the model; consequently, some of the model parameters were obtained from quantum chemical calculations and from analogy with other reactions of radical decomposition. Thus, the parametrization is most reliable under conditions close to those used in the experiments.     

Kinetic and mechanistic study of the gas-phase reactions of a series of vinyl ethers with the nitrate radical

NO(3) oxidation of methyl, ethyl, propyl, and butyl vinyl ethers has been studied under tropospheric conditions (atmospheric pressure and T = 293 +/- 3 K) in the LISA indoor simulation chamber. NO(3) was produced inside the reactor by thermal decomposition of N(2)O(5) previously added to the air-VOC mixture, and concentrations were monitored using FTIR spectrometry. All the kinetic experiments were carried out by relative rate technique using isoprene as reference compound, leading to the rate constants k(1) = (7.2 +/- 1.5) x 10(-13), k(2) = (13.1 +/- 2.7) x 10(-13), k(3) = (13.3 +/- 3.0) x 10(-13), and k(4) = (17.0 +/- 3.7) x 10(-13) cm(3) molecule(-1) s(-1) for methyl, ethyl, propyl, and butyl vinyl ethers, respectively. Main oxidation products have been identified like being formaldehyde and respectively methyl, ethyl, propyl, and butyl formates. Production yields of oxidation products were close to 50%. Oxygenated nitrates and peroxynitrates were also detected.