酰基硫脲衍生物的合成、结构表征及生物活性研究

在超声波辐射下, 以PEG-400为固-液相转移催化剂, 用芳胺与双酰基异硫氰酸酯反应, 合成出了15种新的结构不对称的双酰基硫脲类化合物(6和6')和9种新的分子中含酰胺基团的单酰基硫脲类化合物(7和7'). 利用元素分析, IR, ¹H NMR, ¹³C NMR, APT, 1D NOE及2D NMR技术确定了所合成化合物6和6'及7和7'的结构, 并对它们NMR谱中低场C, H进行了归属. 杀菌、杀虫和除草活性筛选测定实验结果表明, 所测试化合物对瓜炭疽病菌均具有抑制作用, 其中6e抑制率最高, 达到62.4%; 目标化合物7a对黄瓜白粉病菌有一定的抑制作用. 单胺氧化酶活性测定实验表明：大部分目标化合物对单胺氧化酶具有一定的抑制活性, 其中浓度在1×10^－3 mol•L^－1时目标化合物6'c和6'd的抑制活性较强, 明显高于其它化合物. 目标化合物没有抗惊厥活性.     

交互模式-电感耦合等离子体质谱(ICP-MS)法测定生态地球化学植物样品中7种金属元素

植物样品中各元素的含量,是评价土壤质量及健康的重要指标。为满足测定大批量生态地球化学植物样品中多金属元素分析要求,建立了交互模式-电感耦合等离子体质谱(ICP-MS)法测定植物样品中7种痕量金属元素的定量分析方法。讨论了ICP-MS的STD、KED(He)、交互模式3种方法测定植物样品中7种金属元素结果。结果表明,利用工作曲线法配制Hg标准溶液,更改⁸²Se在线校正方程系数为1.83,在ICP-MS的交互模式下测定植物样品中⁸²Se、⁶³Cu、⁶⁰Ni、⁶⁶Zn、¹¹¹Cd、⁷⁵As、²⁰²Hg可以得到准确可靠的结果,克服了植物样品中Se和Hg元素测定的难题。基于所建方法各元素校准曲线系数>0.999,方法检出限为0.000 4～0.08 mg/kg,加标回收率在96.2%～107%,测定GBW10010a(大米)、GBW10012(玉米)、GBW10021(豆角)3种标准物质,结果均在参考值范围内,相对标...     

茚磺苯酰胺及其合成中间体的NMR研究

合成了茚磺苯酰胺(Ⅰ),测试了它的¹HNMR谱以及合成中间体(Ⅱ-Ⅶ)的¹H和¹³CNMR谱,常温下观测到了化合物(Ⅲ)的旋转异构现象,讨论了ABX自旋系统中,解析质子化学位移的另一种方法。     

微波消解-微波等离子体炬原子发射光谱法测定无铅汽油中痕量铅的研究

四乙基铅作为一种良好的抗爆添加剂,曾广泛用于汽油生产中,但由于四乙基铅有很强的毒性,目前国际上已停止生产和使用车用含铅汽油,因此在生产车用无铅汽油时严格控制和准确测定铅的含量十分必要.迄今,测定汽油中铅含量的常用方法是铬酸盐容量法^[1]、一氯化碘法^[2]、X射线光谱法^[3]、分光光度法^[4,5]、原子吸收光谱法^[6]和等离子体光谱法^[7].这些方法或操作烦琐,测定时间较长^[4],或灵敏度低^[1～3],或测定误差较大,且在测试中需使用毒性较大的四乙基铅^[5],或所需的氯化甲基三辛基铵不易购买^[6],或处理过程繁琐,且仪器设备昂贵^[7].因此,建立一种简便、快速、灵敏、准确和无毒副作用的测定无铅汽油中痕量铅的方法已显得十分迫切.近年来发展的微波等离子体炬原子发射光谱法^[8]已有商品化仪器问世^[9].本文利用微波等离子体炬原子发射光谱仪研究了无铅汽油中痕量铅的测定方法,并提出用微波消解法预处理无铅汽油样品,将微波消解技术与微波等离子体炬原子发射光谱法相结合,建立了简便、快速、灵敏、准确和无污染的测定无铅汽油中痕量铅的新方法.     

稳定同位素标记1,4-二氢吡啶类药剂的5,6-位及其取代基碳的合成

1,4-二氢吡啶结构是许多生物活性物以及药物分子的重要骨架,同时也是非常重要的有机合成中间体。当前并没有一种适用的方法用于¹³C标记1,4-二氢吡啶的合成.提供了一种¹³C标记1,4-二氢吡啶的合成方法以¹³C2-乙酸钠为标记原料,经磷酸酸化得到¹³C2-乙酸,羰基二咪唑酰化¹³C2-乙酸得到¹³C2-N-乙酰咪唑,随后在咪唑钠的作用下进行克莱森缩合反应获得1,2,3,4-¹³C4-乙酰乙酰咪唑的钠盐,经乙酸酸化得到1,2,3,4-¹³C4-乙酰乙酰咪唑,再通过与醇进行酯化得到1,2,3,4-¹³C4-乙酰乙酸酯,1,2,3,4-¹³C4-乙酰乙酸酯经氨基甲酸铵氨化得到1,2,3,4-¹³C4-3-氨基丁烯酸酯。随后采用Hantzsch改进法合成了5,6-位及其取代基碳标记的¹³C4-尼群地平、¹³C4-苯磺酸氨氯地平和¹³C4-马来酸氨氯地平.该方法操作简单,反应条件温和且产率高,为1,4-二氢吡啶的5,6-位及其取代基引入¹³C同位素标记合成提供了新的思路,满足中国仿制药物一致性评价的稳定同位素内标自主合成需求。     

溶剂对四苯基卟啉氯化锰飞秒瞬态吸收光谱的影响

采用稳态和飞秒瞬态吸收光谱技术研究了四苯基卟啉氯化锰MnⅢ(TPP)Cl在甲苯(TOL)、二氯甲烷(DCM)、乙腈(ACN)和N,N-二甲基甲酰胺(DMF)四种溶剂中的光物理性质.结果表明随溶剂极性的增加,其紫外-可见吸收光谱的B带与Q带与飞秒瞬态对应的漂白信号均发生蓝移.随着MnⅢ(TPP)Cl二氯甲烷溶液浓度的增加, ⁵S₂态寿命无明显变化,⁵S₁态和⁵T₁态寿命依次变短.在四种溶剂中,非极性溶剂甲苯中的⁵S₂态寿命最长而⁵S₁和⁵T₁态寿命最短,这与⁵S₂→⁵S₁能差最大, ⁵S₁→5S0能差最小对应.从弱极性DCM到极性更大的DMF时, ⁵S₁和...     

开系下的极限环线

B-Z反应较早是用分光光度计观察颜色的周期性变化^[1]。Field采用电动势测定E～t或C～t图^[2]。最近大量工作证明上述二种方法仍然是很重要的。B-Z反应是属于非平衡态中存在自组织现象的一个实例,三分子模型^[3]和低浓度三分子模型^[4]至今尚未找到实例,因而Oregonator成了颇为重要的一个实际模型^[5]。原则上直接测到相平面上lg[Br^-]与lg[Ce⁴⁺]的变化。给验证理论提供了一种可靠性。     

水溶液中Ln(Ⅱ)-TTHA络合物的多核NMR研究

通过对11种镧系-三乙烯四胺六乙酸络合物诱导的²³Na、²H、¹⁷O和³⁵Cl的化学位移测定,研究了该系列络合物的位移试剂性质。结果表明,轴对称的Ln(TTHA)^3-络合物是较好的水溶性位移试剂,尤其是²³Na位移与理论偶极位移一致,表明此络合物是最好的正电荷底物之一。     

氨浓度对氨蒸发法制备Pd-Cu/凹凸棒土催化剂常温CO氧化性能的影响

以凹凸棒土(APT)作载体,采用氨蒸发法制备了Pd-Cu/APT催化剂,以CO氧化为探针反应,在连续流动微反应装置上,考察了初始氨浓度对催化剂CO常温催化氧化性能的影响。通过N₂-physisorption、XRD、FT-IR、TEM和H₂-TPR等手段对催化剂的结构和性质进行了表征。结果表明,在较低或过高氨浓度条件下,制备的Pd-Cu/APT中Cu物种均主要以CuO为主,仅有少量Cu₂(OH)₃Cl;适宜的氨浓度有利于稳定Cu₂(OH)₃Cl物相的形成,其薄片状的形貌特征、良好的分散状态以及与Pd物种间较强的相互作用,显著提高了CO催化氧化性能。在空速6 000 h^-1、CO体积分数1.5%、水蒸气体积分数3.3%的反应条件下,Pd-Cu/APT催化剂表现出优异的CO室温催化氧化活性和稳定性。     

固相膜萃取/高效液相色谱法测定环境水体中的磺酰脲类除草剂

建立了一种基于C₁₈固相萃取膜预富集、高效液相色谱法定量分析环境水体中6种痕量磺酰脲类除草剂的快速分析方法。优化了色谱分离条件,考察了洗脱剂种类与体积、水样pH值和盐效应等条件对萃取效率的影响。在优化条件下,6种磺酰脲类除草剂的峰面积与其质量浓度呈良好的线性关系,苯磺隆的线性范围为0.10²0.0μg/L,其余均为0.05²0μg/L,相关系数为0.999 0⁰.999 5,方法检出限为0.019⁰.037μg/L。对地表水和海水的加标回收率分别为92.6%¹05.7%和89.8%¹08.7%,相对标准偏差分别为0.7%⁷.1%和0.5%⁴.0%。该方法操作简单、快速、准确、灵敏度高。     

C and H nuclear magnetic shielding and spin–spin coupling constants of C-enriched bromomethane in the gas phase

¹³C and ¹H NMR spectral parameters are investigated for ¹³CH₃Br in gaseous matrices. It is found that both the ¹³C and ¹H chemical shifts of ¹³CH₃Br are linearly dependent on solvent density. Similar dependence is also detected for one-bond spin–spin coupling, ¹J(CH). For the first time the ¹³C and ¹H magnetic shielding constants and ¹J(CH) spin–spin coupling are obtained for an isolated ¹³CH₃Br molecule together with the coefficients responsible for solute–solvent molecular interactions in gaseous matrices. The present experimental results confirm the accuracy of some recent ab initio calculations of nuclear magnetic shielding performed for bromomethane.     

Fourier transform microwave spectroscopic investigation of a very weakly bound ternary complex: OCS–He2

The rotational spectra of the van der Waals complex of carbonyl sulfide loosely bound to two helium atoms were investigated using a cavity Fourier transform microwave spectrometer and a microwave–microwave double resonance spectrometer. The lowest rotational transitions of seven isotopomers, namely those containing the ¹⁶O¹²C³²S, ¹⁶O¹²C³⁴S, ¹⁶O¹³C³²S, ¹⁶O¹²C³³S, ¹⁸O¹³C³²S, ¹⁶O¹³C³⁴S, and ¹⁷O¹³C³²S subunits, were studied. Hyperfine structures due to the quadrupolar ³³S and ¹⁷O nuclei were also observed and analyzed. The search for higher J transitions was not successful and possible causes are discussed. Information about the OCS–He₂ cluster inferred from the measurements is presented and discussed.     

The complete assignment of the h and C nmr spectra of the alkali metal salts of salinomycin and narasin

The preparation of the alkali metal salts of salinomycin and narasin, apart from lithium narasin, is described. The complete assignment of their ¹H spectra based on two dimensional COSY and NOESY spectra is reported. These asignments are then used in two dimensional ¹³C/¹H correlations via direct and long range couplings to assign the ¹³C spectra. Assignments in the ¹³C spectrum of sodium salinomycin differ in important details from those in a previous report.     

Reactions of 3,10-epoxycyclo[10.2.2.0.0]hexadeca-4,6,8,13-tetraene: a new intramolecular 1,5-oxygen migration

Bromination of 3,10-epoxycyclo[10.2.2.0^2,11.0^4,9]hexadeca-4,6,8,13-tetraene gave 13-bromo-11-oxapentacyclo[8.7.0.0^2,4.0^12,17]heptadeca-4,6,8-triene-3-ol, 12-bromo-1,2,3,4-tetrahydro-1,4-ethano-antracen-11-ol, 13-hydroxy-3,14-dibromotetracyclo[10.2.2.0^2,11.0^4,9]hexadeca-2,4,6,8,10-pentaene, and 13-hydroxy-3,10,14-tribromotetracyclo[10.2.2.0^2,11.0^4,9]hexadeca-2,4,6,8,10-pentaene by cleavage of the carbon–oxygen bonds and intramolecular 1,5-migration of the oxygen atom of 1,4-epoxide. Reactions of epoxide 14,18-dioxahexacyclo[10.3.2.1^3,10.0^2,11.0^4,9.0^13,15]octadeca-4,6,8-triene obtained from 3,10-epoxycyclo[10.2.2.0^2,11.0^4,9]hexadeca-4,6,8,13-tetraene gave also similar products, in acidic media. Compound 3,10-epoxycyclo[10.2.2.0^2,11.0^4,9]hexadeca-4,6,8,13-tetraene was converted into tetracyclo[10.2.2.0^2,11.0^4,9]hexadeca-2(11),3,9-triene in two ways. The reactions, especially intramolecular oxygen migration, are discussed.     

Nuclear motion effects on the C, F and H shielding in methyl fluoride

The ¹⁹F , ¹³C and ¹H shielding in methyl fluoride and its deuterated isotopomers has been calculated from ab initio shielding surfaces for selected temperatures. In each case it is the stretching which contributes most to the nuclear motion corrections which total −9.425 ppm for the ¹⁹F shielding, −4.558 ppm for the ¹³C shielding and −0.601 ppm for the proton shielding. However, some second-order stretching and bending contributions are significant. The deuterium induced isotope shifts are substantial and should be easily measurable. There is a predicted nonadditivity in the ¹⁹F and ¹³C isotope shifts which can be traced to two of the bending contributions.     

Direkte und indirekte metallierung von endo-dicylopentadien. Sn- und C-NMR studie stannylierter folgeprodukte

endo-Dicyclopentadiene (1) can be metalated by use of simple procedures with good overall yields. The attack occurs at the various vinyl, rather than at the allyl, positions of 1 as was confirmed by trapping the carbanions with Me₃SnCl. When t-BuLi/TMEDA are used, the 8- and 9-stannyl derivatives (3 and 4) are formed, whereas an excess of n-BuLi/t-BuOK leads to doubly stannylated derivatives with Me₃Sn groups in position 4/8 (6), 4/9 (7), and 3/9 (8) in addition to 3 and 4. Furthermore the latter reaction yields 5,5-bis(trimethylstannyl)cyclopentadiene (5). With stoichiometric amounts of n-BuLi/t-BuOK the formation of 3 and 4 predominates over that of 5–8. 5 is obtained from 1 after deprotonation at the allyl position, followed by an extremely fast retro-Diels-Alder reaction and then by further deprotonation. This follows from two experiments: (1) exo- and endo-5-trimethylstannyl-endo-dicyclopentadiene (11 and 12) which are synthesized from 1 in three steps give cyclopentadienyllithium and 1 when treated with methyllithium at −78°C; (2) cyclopentadiene reacts with an excess of n-BuLi/t-BuOK and Me₃SnCl to give 5. When 12 is heated syn-10-trimethylstannyl-endo-dicyclopentadiene (13) is obtained. The eight stannyl derivatives of 1 are identified mainly from the following NMR parameters: δ(¹¹⁹Sn), δ(¹³C), δ(¹H), ⁿJ(^119/117Sn---¹³C), and ⁶J(¹¹⁹Sn---^119/117Sn). The ¹³C NMR satellite spectrum of 1 yields the isotope shifts ¹Δ¹³(i(¹³C(j)) and ¹J(¹³C---¹³C). The latter lead to the revision of earlier signal assignments.     

Smenoqualone a novel sesquiterpenoid from the marine sponge Smenospongia sp.

Smenoqualone, a novel quinonic terpenoid with a rearranged drimane skeleton was isolated from a marine sponge Smenospongia sp. The stereostructure was determined by detailed analyses of ¹H and ¹³C NMR spectra, ¹H-¹H COSY, ¹H-¹³C correlations via HMQC, HMBC and NOE difference NMR experiments.     

Calculation of second-order properties with improved virtual orbitals

¹³C---H nuclear spin coupling and ¹³C shielding constants of CH₄, C₂H₆, C₂H₄, C₂H₂ are calculated by means of the second-order perturbation theory and MO LCAO wavefunctions. The aim of this paper is to test the ability of the recently proposed virtual orbitals to accelerte the convergence of the sum over states, compared to the calculation with canonical MO's. The ¹³C---H nuclear spin coupling constants show a significant improvement, the changes of the ¹³C shielding are insignificant.     

1,3,2-Diazastanna-[3]ferrocenophanes bearing alkyn-1-yl groups at tin and their 1,1-organoboration with triethylborane—molecular structure of a novel spirotin compound

2,2-Dichloro-1,3-bis(trimethylsilyl)-1,3,2-diazastanna-[3]ferrocenophane (3) reacts with lithium alkynides LiCCR¹ to give the corresponding di(alkyn-1-yl)tin derivatives 4a (R¹=^tBu) and 4b (R¹=SiMe₃). 1,1-Organoboration of 4 with triethylborane affords the spirotin compounds 5 which contain both a ferrocenophane and a stannacyclopentadiene ring. The crystal structure of 5b was determined by X-ray analysis. The compounds 4 and 5 were characterised in solution by multinuclear magnetic resonance (¹H-, ¹¹B-, ¹³C-, ¹⁵N-, ²⁹Si-, ¹¹⁹Sn-NMR), using pulsed field gradients in HMBC experiments for the ¹H detected ¹⁵N- and ¹¹⁹Sn-NMR signals. The compound 5b was also studied by solid-state ¹³C, ²⁹Si and ¹¹⁹Sn MAS NMR in order to correlate liquid and solid-state NMR data with the structural evidence.     

C, N and H magnetic relaxation and anisotropic molecular reorientation of nitrobenzene

Magnetic relaxation rates of ¹³C and ¹⁴N have been measured for neat nitrobenzene and several 50% (v/v) solutions thereof. Using known values of the ¹⁴N quandrupole coupling constant and asymmetry parameter and the ¹³CH bond distances we have determined the three reorientational correlation times and the orientation of the ¹⁴N quadrupole coupling tensor. The correlation times are compared with those previously obtained for nitrobenzene from a combination of depolarized Rayleigh scattering ad ¹³C relaxation data. Knowledge of the principal components of the rotational diffusion tensor permits determination of the quadrupole coupling constant for the ortho deuterons in nitrobenzene-d₅ and the unambiguous assignment to molecular axes of previously determined components of the chemical shift tensor for ¹⁵N in nitrobenzene ¹⁵N. In addition, the implications of our assignment of the ¹⁴N quadrupole coupling tensor components for earlier studies of the alignment of nitrobenzene by electric fields and in a liquid crystal are discussed.