The chalcones (1,3-diaryl-2-propenones) and their derivatives are important intermediates in organic synthesis and have widespread applications in medicinal industry. The title choloro chalcone derivative, 3-(3-chloro...The chalcones (1,3-diaryl-2-propenones) and their derivatives are important intermediates in organic synthesis and have widespread applications in medicinal industry. The title choloro chalcone derivative, 3-(3-chloro-4,5-dimethoxyphenyl)-1-(4,5-dimethoxy-2-methyl phenyl) prop-2-en-1-one, has been synthesized. It is characterized by FTIR, 1H NMR, 13C NMR and single crystal X-ray diffraction. Title compound crystallizes in monoclinic space group C2/c with a = 23.540(11) ?, b = 9.738(4) ?, c = 17.305(7) ?, β = 106.37 (3)°, V = 3806(3) ?3 and Z = 8. The mean plane of the two substituted benzene rings are twisted by 66.29 (12)° with respect to each other. Ab-initio and density functional Theory (DFT) calculations have been carried out for the title molecule using RHF/6-311G and B3LYP/6-311G basis set respectively. The calculated results show that the predicted geometry can well reproduce structural parameters. In addition, frontier molecular orbitals and Mullikan charge distributions are carried out by using RHF and B3LYP methods. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecule. Numbers of weak but significant interactions like C-H···O, C-H···π and π-π are involved in the stability of the structure. The weak π-π stacked interaction involves the centroids of the methyl phenyl rings with Cg-Cg separation distance of 3.857(2) ?. Synthesized compound has been screened for its antimicrobial activity against different panels of organisms.展开更多
目的研究利可君的4个非对映异构体及其有关物质的结构。方法利用液相色谱-二极管阵列检测、液相色谱-串联质谱和液相色谱-核磁共振等联用技术研究利可君及有关物质的结构。采用Phenomnex Luna C18色谱柱(250 mm×4.60 mm ID,5μm),...目的研究利可君的4个非对映异构体及其有关物质的结构。方法利用液相色谱-二极管阵列检测、液相色谱-串联质谱和液相色谱-核磁共振等联用技术研究利可君及有关物质的结构。采用Phenomnex Luna C18色谱柱(250 mm×4.60 mm ID,5μm),水-乙腈-冰醋酸(58∶42∶0.3)为流动相。结果确定了在溶液状态下利可君及其有关物质的结构,发现其均有4个非对映异构体;还对利可君的4个非对映异构体在溶液中互变与稳定性进行比较与量子化学计算,证明其稳定构型为3R4S5R。结论利可君在溶液中非对映异构体相互转化,有一种优势构型。展开更多
采用密度泛函法在B3LYP/6-311G(d,p)水平上研究邻羟基二苯甲酮几种构象异构体的相互转化过程。通过研究得到各驻点的几何结构和能量值,发现4种构象异构体在常温下可以相互转换,其中IM1中有分子内氢键,能量最低,为绝对优势构象。为进一...采用密度泛函法在B3LYP/6-311G(d,p)水平上研究邻羟基二苯甲酮几种构象异构体的相互转化过程。通过研究得到各驻点的几何结构和能量值,发现4种构象异构体在常温下可以相互转换,其中IM1中有分子内氢键,能量最低,为绝对优势构象。为进一步确定其在氯仿溶剂中的优势构象,采用GIAO法在相同的水平上对优化好的中间体进行NMR理论计算,通过将理论计算得到的1 H NMR化学位移值与实验值进行对比,发现构象异构体IM1的1 H NMR化学位移计算值与实验值相符合,从而确定IM1也为实际中的最优势构象。展开更多
Nineteen preschisanartane-type schinortriterpenoids(SNTs),among which eleven ones were previously undescribed,were isolated from two Schisandra species,S.sphaerandra and S.rubriflora.Their structures were determined u...Nineteen preschisanartane-type schinortriterpenoids(SNTs),among which eleven ones were previously undescribed,were isolated from two Schisandra species,S.sphaerandra and S.rubriflora.Their structures were determined using 1 D and 2 D NMR spectroscopic analyses,NMR data comparison,quantum chemical calculation of NMR parameters,electronic circular dichroism(ECD),X-ray single crystal diffraction,and chemical derivation.Furthermore,structural re-examination of a few previously reported preschisanartane-type SNTs led to the structural revision of preschisanartanin J.Besides,it is suggested that the reported structures of arisanlactone D and schilancidilactone W should be re-checked.Finally,a few isolated SNTs were found to possess neurite outgrowthpromoting activities,and protective activities against neural injuries.展开更多
天然产物结构鉴定对于天然产物化学家来说永远都是最首要的任务之一。特别是多手性中心分子的构型确定,因对天然产物研究者极具挑战,已受到越来越多的关注。在过去10年,量子化学计算(quantum chemical calculation)1H和13C化学位移和1H-...天然产物结构鉴定对于天然产物化学家来说永远都是最首要的任务之一。特别是多手性中心分子的构型确定,因对天然产物研究者极具挑战,已受到越来越多的关注。在过去10年,量子化学计算(quantum chemical calculation)1H和13C化学位移和1H-1H-自旋-自旋偶合常数(spin-spin couping constamts,SSCC)在计算准确度、削减计算成本和可应用性上得到了显著的提升。随着相关理论与技术的不断进步,理论计算辅助结构鉴定必将成为每个化学实验室结构确证的一项标配手段。本文,对计算1H和13C化学位移和SSCC的原理和优势做了简要介绍,并列举几个结构纠正的例子来阐述这些方法在实际结构鉴定中运用。展开更多
文摘The chalcones (1,3-diaryl-2-propenones) and their derivatives are important intermediates in organic synthesis and have widespread applications in medicinal industry. The title choloro chalcone derivative, 3-(3-chloro-4,5-dimethoxyphenyl)-1-(4,5-dimethoxy-2-methyl phenyl) prop-2-en-1-one, has been synthesized. It is characterized by FTIR, 1H NMR, 13C NMR and single crystal X-ray diffraction. Title compound crystallizes in monoclinic space group C2/c with a = 23.540(11) ?, b = 9.738(4) ?, c = 17.305(7) ?, β = 106.37 (3)°, V = 3806(3) ?3 and Z = 8. The mean plane of the two substituted benzene rings are twisted by 66.29 (12)° with respect to each other. Ab-initio and density functional Theory (DFT) calculations have been carried out for the title molecule using RHF/6-311G and B3LYP/6-311G basis set respectively. The calculated results show that the predicted geometry can well reproduce structural parameters. In addition, frontier molecular orbitals and Mullikan charge distributions are carried out by using RHF and B3LYP methods. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecule. Numbers of weak but significant interactions like C-H···O, C-H···π and π-π are involved in the stability of the structure. The weak π-π stacked interaction involves the centroids of the methyl phenyl rings with Cg-Cg separation distance of 3.857(2) ?. Synthesized compound has been screened for its antimicrobial activity against different panels of organisms.
文摘目的研究利可君的4个非对映异构体及其有关物质的结构。方法利用液相色谱-二极管阵列检测、液相色谱-串联质谱和液相色谱-核磁共振等联用技术研究利可君及有关物质的结构。采用Phenomnex Luna C18色谱柱(250 mm×4.60 mm ID,5μm),水-乙腈-冰醋酸(58∶42∶0.3)为流动相。结果确定了在溶液状态下利可君及其有关物质的结构,发现其均有4个非对映异构体;还对利可君的4个非对映异构体在溶液中互变与稳定性进行比较与量子化学计算,证明其稳定构型为3R4S5R。结论利可君在溶液中非对映异构体相互转化,有一种优势构型。
文摘采用密度泛函法在B3LYP/6-311G(d,p)水平上研究邻羟基二苯甲酮几种构象异构体的相互转化过程。通过研究得到各驻点的几何结构和能量值,发现4种构象异构体在常温下可以相互转换,其中IM1中有分子内氢键,能量最低,为绝对优势构象。为进一步确定其在氯仿溶剂中的优势构象,采用GIAO法在相同的水平上对优化好的中间体进行NMR理论计算,通过将理论计算得到的1 H NMR化学位移值与实验值进行对比,发现构象异构体IM1的1 H NMR化学位移计算值与实验值相符合,从而确定IM1也为实际中的最优势构象。
基金supported by the National Natural Science Foundation of China(No.81903520)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(No.2019QZKK0502)
文摘Nineteen preschisanartane-type schinortriterpenoids(SNTs),among which eleven ones were previously undescribed,were isolated from two Schisandra species,S.sphaerandra and S.rubriflora.Their structures were determined using 1 D and 2 D NMR spectroscopic analyses,NMR data comparison,quantum chemical calculation of NMR parameters,electronic circular dichroism(ECD),X-ray single crystal diffraction,and chemical derivation.Furthermore,structural re-examination of a few previously reported preschisanartane-type SNTs led to the structural revision of preschisanartanin J.Besides,it is suggested that the reported structures of arisanlactone D and schilancidilactone W should be re-checked.Finally,a few isolated SNTs were found to possess neurite outgrowthpromoting activities,and protective activities against neural injuries.
文摘天然产物结构鉴定对于天然产物化学家来说永远都是最首要的任务之一。特别是多手性中心分子的构型确定,因对天然产物研究者极具挑战,已受到越来越多的关注。在过去10年,量子化学计算(quantum chemical calculation)1H和13C化学位移和1H-1H-自旋-自旋偶合常数(spin-spin couping constamts,SSCC)在计算准确度、削减计算成本和可应用性上得到了显著的提升。随着相关理论与技术的不断进步,理论计算辅助结构鉴定必将成为每个化学实验室结构确证的一项标配手段。本文,对计算1H和13C化学位移和SSCC的原理和优势做了简要介绍,并列举几个结构纠正的例子来阐述这些方法在实际结构鉴定中运用。
