高效液相色谱法测定硫酸氢氯吡格雷中的有关物质

建立高效液相色谱法测定硫酸氢氯吡格雷中的有关物质的方法。其分解产物的检测,采用SinoChrom ODS-BP（200mm×4.6mm,5μm）色谱柱,以1%（V/V）三乙胺（pH=4.0）-乙腈（25∶75）为流动相,检测波长225nm,流速1.0mL/min。硫酸氢氯吡格雷在0.48—0.72μg范围内线性关系良好（r=0.9999）,定量下限为3ng,检出限为0.6ng,各种破坏性样品的分离度符合规定。其光学纯度的测定采用ULTRON ES-OVM（Analytical）手性柱（150mm×4.6mm,5μm）,色谱填料为L57。以磷酸盐缓冲液（pH=4.67）-乙腈（75∶25）为流动相,检测波长为220nm。硫酸氢氯吡格雷相关物质B分离度均大于2.5,符合要求。本方法简便,灵敏,准确,专属性强,能够满足硫酸氢氯吡格雷对有关物质测定的要求。     

FTIR Spectral Study of Intramolecular Hydrogen Bonding in Thromboxane A2 Receptor Antagonist S-145 and Related Compounds. Part 4

Abstract

An N-methylated compound of S-145, (±)-(5Z)-7-[3-endo-[N-methyl)phenylsulphonyl)amino]bicyclo [2.2.1]hept-2-exo-yl]heptenoic acid 1, its chain analogue 12-[N-methyl(phenylsulphonyl)amino]dodecanoic acid 3, (±)-(5Z)-7-[3-endo-(benzoylamino)bicyclo[2.2.1]hept-2-exo-yl] heptenoic acid 5 and related compounds were synthesized in order to study the formation of a new class of intramolecular hydrogen bond IX (cis-CO₂H…O = Y). Their FTIR spectra were measured in dilute CCl₄ solution and subjected to curve analysis in order to separate overlapping absorption bands. For compounds 1,3 and 5, the intramolecular hydrogen bonds of the IX type involving 14-, 17- and 14-membered rings were found between a carboxyl group, which takes a cis-structure IV, and an oxygen atom of a sulphonyl or benzoylamino group, respectively. The C[dbnd]O stretching vibration bands of these carboxyl groups shifted to lower wavenumbers (ca. 19 cm^?1). The direction of these shifts was contrary to that found for α-keto and α-alkoxycarboxylic acids in which carboxyl groups take a trans-structure III due to the formation of intramolecular hydrogen bonds I and II, respectively.     

Intramolecular Hydrogen Bonding in Bilirubin Amides as Detected by Circular Dichroism Spectroscopy

Analysis of the circular dichroism spectra of bilirubin-IXα amides of S'-(-)-1 -phenylpropylamine reveals a preference in organic solvents for folded, intramolecularly H-bonded conformations involving the amide N-H hydrogen.     

Intramolecular Hydrogen Bonding in Bilirubin Monomethyl Esters Determined by 1H-NMR Spectroscopy

Analysis of the N-H ¹H-NMR chemical shifts of the monomethyl esters of bilirubin-IIIα, IXα and XIIIα reveals a preference in CDCl₃ for folded conformations in which the unesterified propionic acid carboxyl group is intramolecularly H-bonded to the opposing pyrromethenone unit. The remaining pyrromethenone unit may be weakly intramolecularly H-bonded to the propionic ester carbomethoxy group.     

不同体系下氢键对聚丙烯酰胺光谱的影响

采用红外,紫外光谱分析不同体系下氢键对部分水解高分子聚丙烯酰胺光谱的影响。研究表明,高分子聚丙烯酰胺中的酰胺基与部分水解的羧酸基能形成分子内氢键导致酰胺基中游离-NH₂特征吸收峰向低频方向移动;聚丙烯酰胺在水溶液中随浓度的增大主要形成分子内氢键使最大吸收波长发生红移;在含中等浓度钠离子和钙离子的水溶液体系下,分子内氢键和分子间氢键同时存在,在含高浓度钠离子和钙离子体系下,则主要形成分子间氢键。不同体系下,氢键对聚丙烯酰胺光谱的影响不同：在水溶液体系下,其最大吸收波长红移8 nm,在钠离子单独存在的体系下,最大吸收波长红移4 nm,在钙离子和钠离子同时存在的体系下,最大吸收波长红移2 nm。     

氢钝化对硅纳米晶发光强度的影响

通过热蒸发方法在单晶硅衬底上沉积了SiO/SiO₂超晶格样品,在氮气保护下对样品进行高温退火,得到硅纳米晶/SiO₂超晶格结构。随后将该结构样品分别注入3.0×1014和3.0×1015 cm-2两种剂量的H+。通过对样品的光致发光光谱的分析发现,H+注入后未经过二次退火的样品发光强度急剧下降;二次退火后的样品,随着退火温度的升高,发光强度逐渐增强;注入足够剂量的H+,其发光强度可以远远超过未注入时的发光强度。研究表明,样品发光强度的变化取决于样品内部缺陷面密度的改变,而缺陷面密度是由氢离子的注入剂量和注入后再退火的温度等因素决定的。     

Hydrogen Bonding and the NMR Parameters in Dimethylformamide

The oxygen atom of dimethylformamide (DMF) is a good electron doaor site and in a proton donor solvent the solute-solvent interactions would include hydrogen bonding at this site. As this hydrogen bonding is expected to be relatively strong, it would predominate when both the lMF and the protonic acid are present at very low concentration in a solvent such as carbon tetrachloride, and the effect of this hydrogen bonding on the proton chemical shifts and coupling constants i n LMF can be observed. If the protonic acid is aromatic, such as phenol, and is in excess of the LMF, other form(s) of solut-olvent association would become significant and give rise to aromatic solvent induced shifts (ASIS), which would obscure the effect of hydrogen bonding at the oxygen site of the MF. The ASIS in DMF are well known, and the shifts have been attributed to the diamagnetic ring current effect of the aromatic solvent and specificsolut-olvent association.¹ More recently, the ASIS has been interpreted as the result of time-averaged general solvation around the polar site of the solute.²     

NMR Study of the Hydrogen Bonding of Sterically Hindered Phenols with Alicyclic Ethers and Pyridine

In a preliminary report¹ it was shown that the hydrogen-bond chemical shift, δ_AB, correlates with the change in enthalpy, δH, in the interaction of chloroform with a series of closely related oxygen and nitrogen bases. In this communication, we report the hydrogen bonding parameters for the interaction in cyclohexane medium between 2,4,6-tri-t-butylphenol and tetrahydrofuran, tetrahydropyran and pyridine, and between 2,6-di-1-adamantyl-4-t-butylphenol and pyridine. There is correlation between the δ_AB and δ_AE for the same proton donor (2,4,6-tri-t-butylphenol) and the closely related alicyclic bases, and for the same base (pyridine) and the two closely related sterically hindered phenols. The temperature dependence of the δ_AB in these systems is also reported.     

溶剂分子对甲酰胺及其衍生物分子内氢转移催化作用的研究

在B3LYP/ 6 311++G 水平下 ,通过计算所形成二元团簇的能量来研究水、氨、甲醇、氟化氢等溶剂分子对甲酰胺及其衍生物分子内氢原子转移的催化作用 .简单描绘了在有水、氨、甲醇和氟化氢等溶剂分子存在时 ,甲酰胺及其衍生物分子内氢原子转移的过程 .结果表明 ,当有水、氨、甲醇、氟化氢等溶剂分子存在时 ,从甲酰胺 甲酰胺酸转变的能垒会降低 .而且不同的溶剂分子对甲酰胺 (FA)、N 甲基甲酰胺 (MF)和N ,N 二甲基甲酰胺(DMF)的催化能力各不相同 .在这四种溶剂分子中 ,氟化氢的催化作用最强     

变温过程中二甲基亚砜与水之间氢键行为的拉曼光谱研究

测量了在降温过程中体积比为1∶1的二甲基亚砜(DMSO)水溶液的拉曼光谱,并对DMSO水溶液的拉曼光谱进行了归属。对实验数据进行分析发现: 在降温过程中DMSO分子与水分子的分子间氢键、DMSO分子与DMSO分子和水分子与水分子间氢键的作用行为引起了DMSO的SO双键和水分子的O—H键的拉曼谱带的变化。进一步分析表明：在27～-30 ℃降温过程DMSO与水之间氢键加强,-30～-60 ℃降温过程水与水之间氢键代替DMSO与水之间的氢键。这为丰富水溶液的氢键理论提供了实验依据。     

二甲基亚砜水溶液表面张力及粘度与氢键的拉曼光谱研究

利用ZL-10型全自动界面张力仪(柏金环法)和NDJ-5S型数显粘度计测量体积分数为5%～100%的二甲基亚砜(DMSO)水溶液及超纯水,得到表面张力和粘度的变化规律。用拉曼光谱仪测量不同浓度DMSO水溶液的拉曼光谱,得到体系中含氢键作用的拉曼频移变化规律。实验结果表明,DMSO水溶液的表面张力随浓度的变化受DMSO水溶液中氢键作用的影响,且与氢键强度成反相关。DMSO与水的氢键作用对粘度的影响较表面张力更为复杂,粘度随浓度的变化呈二次函数的反常现象,影响因素包含氢键强度,氢键网络结构和空间方向性多个方面。该研究探索一种利用拉曼光谱研究水溶液微观结构与宏观物理性质关系的实验方法。     

On the determination of the intramolecular potential energy surface of polyatomic molecules: Hydrogen sulfide and formaldehyde as an illustration

We present here an approach for determining the Hamiltonian of polyatomic molecules that allows one to successfully solve the problem of potential energy surface (PES) determination via construction and diagonalization of a Hamiltonian matrix of large dimension. In the suggested approach, the Hamiltonian is very simple and can be used both for any “normal” polyatomic molecule and for any isotopic species of a molecule. Molecules with two to four equivalent X-Y bonds are considered, and for illustration of the efficiency of the suggested approach, numerical calculations are made for the three-atomic (hydrogen sulfide) and four-atomic (formaldehyde) molecules.     

木犀草素与腺嘌呤相互作用的理论研究

本文采用密度泛函理论中的B3LYP方法,在6-31+G~*基组水平上对木犀草素—腺嘌呤复合物进行结构优化和振动频率分析,得到了16种稳定的木犀草素—腺嘌呤复合物.应用分子中的原子理论(AIM)分析、自然键轨道(NBO)理论分析得到复合物氢键性质和特征.通过基组重叠误差(BSSE)校正后的相互作用能、成键临界点电荷密度、二阶稳定化能综合分析,得出三氢键复合物C-11结构是最稳定的.综合比较DNA的四个碱基与木犀草素间的相互作用,木犀草素与胸腺嘧啶的相互作用最强,木犀草素-腺嘌呤相互作用最弱,DNA的四个碱基与木犀草素间的相互作用能均比木犀草素与水间相互作用能大,这说明木犀草素作为抗癌药物能有效的发挥作用.     

Spectroscopic Studies of Intra- and Inter-Molecular Hydrogen Bonding of Some O-Hydroxylbenzenesulfonanilides in Solutions

The effect of solvent on the electronic spectra of some fasciolici-dal o–-hydroxylbenzenesulfonanilides is examined and discussed. It is revealed that in solution these compounds exist in both intramolecular hydrogen bond form and intermolecular hydrogen bond form occurring between solute and solvent molecule. In solutions containing large amount of apolar aprotic solvents such as dioxane, compounds studied are mainly intramolecular hydrogen bond form and exhibit a weak transition band which is presumably attributed to the transition of n-electrons of oxygen atom in the intramolecular hydrogen bonded six-membered ring of the compounds.     

Low Temperature Observations of Hydrogen Bonding in 4-Amino-3-pentene-2-one

Dramatic enhancement of the strength of absorption has been demonstrated for vibrations related to hydrogen bonding. The NH₂ deformations have been shown to be extremely temperature dependent. The vibrational spectrum of 4-amino-3-pentene-2-one is reported at room temperature and at liquid N₂ temperature. Spectra recorded in CCl₄ are also reported.     

Near Infrared Spectrophotometric Study of Hydrogen Bonding in Primary Aliphatic Amines

The aim of this report is to demonstrate that the combination bands of NH₂ are useful to compare the association interactions of the NH₂ group of primary aliphatic amines with the recognized weak proton donor solvents, chloroform and isopropyl alcohol for example and with the weaker π-electron donors benzene and pyridine, for example. Examples of families of isosbestic curves characteristic of typical equilibrium reactions of an amine with the complexing solvents are presented including the proton donor-acceptor system, 4-phenylbutylamine with benzene.     

An Investigation of 13C-NMR Spectra of Some Intramolecular Hydrogen Bonded and Non-Bonded Azo Dyes

The ¹³C-NMR spectra of the azo dyes which were synthesized by reacting substituted benzenediazonium chloride with derivatives of some phenol have been measured. The spectral data of these compounds were described considering intramolecular hydrogen bond and not. The chemical shift assignments were made regarding substituent effects.     

2'-脱氧鸟苷在水溶液中激发态氢键动力学的密度泛函理论研究

用密度泛函理论和含时密度泛函理论研究了2'-脱氧鸟苷在水溶液中形成的一水和二水复合物在基态和激发态的氢键性质．计算了两种复合物的稳定构型、红外光谱、前沿分子轨道以及密里根电荷等光物理参数．结果表明,两种水合物的分子内氢键在光激发下变化不一致,分子间氢键变化相似．一水复合物的分子内氢键N3···H4-O2 在激发态是加强的,二水复合物的是减弱的．两种水合物的分子间氢键N2-H2···O3和O3-H5···O2及O3···H7-O4和H5···O1-C1在激发态全是减弱的．两种复合物红外光谱的计算结果与实验值一致．二水复合物中分子间氢键O4···H1-N1在激发态断裂,形成了新的分子间氢键O4···H3-N2,这种变化可能与鸟嘌呤部分的结构弯曲有关．最后分析了一水和二水复合物分子的分子内电子转移特性．     

受限于对称性破缺狭缝间氢键流体的相平衡研究

利用密度泛函理论并结合改进的基本度量理论研究了受限于对称性破缺狭缝间氢键流体的相平衡. 首先根据氢键流体的吸附-脱附等温线及相应巨势获得不同条件下氢键流体的相图. 进一步讨论了氢键作用、狭缝间距、狭缝与流体分子间相互作用及对称性破缺程度等因素对氢键流体相平衡的影响. 结果表明, 由于狭缝与流体分子及流体分子间的相互作用存在竞争, 使得受限于对称性破缺条件下的氢键流体呈现更为复杂的相态特征.     

TD-DFT investigation of the potential energy surface for Excited-State Intramolecular Proton Transfer (ESIPT) reaction of 10-hydroxybenzo[h]quinoline: Topological (AIM) and population (NBO) analysis of the intramolecular hydrogen bonding interaction

Here, we report a Density Functional Theoretical (DFT) study on the photophysics of a potent Excited-State Intramolecular Proton Transfer (ESIPT) molecular system, viz., 10-hydroxybenzo[h]quinoline (HBQ). Particular emphasis has been rendered on the assessment of the proton transfer reaction in HBQ in the ground and excited-states through elucidation and a careful perusal of the potential energy surfaces (PES). The non-viability of Ground-State Intramolecular Proton Transfer (GSIPT) process is dictated by a high-energy barrier coupled with no energy minimum for the proton transferred (K-form) form at the ground-state (S₀) PES. Remarkable reduction of the barrier along with thermodynamic stability inversion between the enol (E-form) and the keto forms (K-form) of HBQ upon photoexcitation from S₀ to the S₁-state advocate for the operation of ESIPT process. These findings have been cross-validated on the lexicon of analysis of optimized geometry parameters, Mulliken’s charge distribution on the heavy atoms, and molecular orbitals (MO) of the E- and the K-forms of HBQ. Our computational results also corroborate to experimental observations. From the modulations in optimized geometry parameters in course of the PT process a critical assessment has been endeavoured to delve into the movement of the proton during the process. Additional stress has been placed on the analysis of the intramolecular hydrogen bonding (IMHB) interaction in HBQ. The IMHB interaction has been explored by calculation of electron density ρ(r) and the Laplacian ∇²ρ(r) at the bond critical point (BCP) using Atoms-In-Molecule (AIM) method and by calculation of interaction between σ? of OH with the lone pair of the nitrogen atom using Natural Bond Orbital (NBO) analysis.