柳叶五层龙正丁醇提取部分中的3个新酚性成分及其α-葡萄糖苷酶抑制活性

采用多种色谱分离方法从柳叶五层龙(Salacia cochinchinensis Lour)的茎叶中分离得到5个化合物. 通过一维(1D)及二维核磁共振波谱(2D NMR), 包括核磁共振氢谱(¹H NMR)、 核磁共振碳谱(¹³C NMR)、 异核单量子相关(HSQC)、 异核多键相关(HMBC)、 氢氢相关(¹H-¹H COSY)和旋转坐标中的欧沃豪斯增强光谱(ROESY), 以及红外光谱(IR)和电喷雾电离高分辨质谱(ESI-HRMS)等方法, 鉴定其结构分别为Salaciacochinoside A(1), 5'-O-3,4,5-trimethoxybenzoyl-β-D-apiofuranoside(2), 5-methoxy-anticerol A(3), 21α,30-dihydroxy-D∶A-friedooleanan-3-one(4)和21α,26-dihydroxyfriedelan-3-one(5). 化合物1~3为新化合物. α-葡萄糖苷酶抑制活性测试结果显示, 化合物1和3对α-葡萄糖苷酶具有显著的抑制作用, 其IC₅₀值分别为0.32和0.59 μmol/L; 化合物2, 4和5未表现出α-葡萄糖苷酶抑制活性.     

新鲜宫颈癌组织的拉曼光谱研究

采用便携式拉曼光谱仪对新鲜宫颈癌组织、 宫颈上皮内瘤变Ⅲ级(CIN Ⅲ)组织及正常宫颈组织进行检测, 通过光谱特征峰分析比较了各组织中化学成分的差异, 归纳了3类组织的拉曼光谱特征及区别. 正常组织以脂类特征峰(817, 1127, 1176, 1450, 1769 cm^-1)为主, 而宫颈癌和宫颈上皮内瘤变Ⅲ级组织则以蛋白特征峰(755, 1003, 1372, 1542, 1577 cm^-1)为主. 病变组织的主要区别在于宫颈上皮内瘤变Ⅲ级组织在853和1542 cm^-1处出现了较明显的蛋白特征峰; 宫颈癌组织则含有明显的核酸特征峰(784, 1094, 1345 cm^-1). 通过特征峰归属及分析发现, 3类组织在磷酸二酯基团形成氢键的能力、 DNA的相对含量、 亚甲基的无序性、 酰胺Ⅰ带的CO变形振动及类胡萝卜素的有无等方面存在显著差异. 表明拉曼光谱可检测宫颈癌组织, 探索宫颈癌与宫颈上皮内瘤变Ⅲ级的联系与区别, 以早期诊断宫颈癌, 具有良好的临床应用潜力.     

胶态磁组装分子印迹光子晶体及其对L-苯丙氨酸的响应性

将胶态磁组装光子晶体与分子印迹技术结合, 通过磁场诱导快速、 可逆地组装得到一种灵敏度高、 选择性强且响应速度快的胶态磁组装分子印迹光子晶体(CMA-MIPCs), 并将其用于L-苯丙氨酸(L-Phe)分子的响应性研究. 结果表明, 细乳液聚合法制得的L-Phe磁性分子印迹纳米粒子(MMIPs)具有规则的球形形貌和明显的核-壳结构, 平均粒径为104.3 nm. CMA-MIPCs对L-Phe分子的识别可直接通过光学信号进行表达, 当L-Phe的浓度从6.0×10^-7 mol/L增加至6.0×10^-4 mol/L时, CMA-MIPCs的衍射色发生从紫色到深黄色的明显变化, 最大衍射峰位置红移181 nm, 响应过程仅需1 min. CMA-MIPCs对L-Phe的结构类似物L-酪氨酸(L-Tyr)和L-色氨酸(L-Trp)均无响应性, 表明CMA-MIPCs具有良好的选择性.     

新型酰胺类化合物的合成及其生物活性

选取原儿茶酸和胡椒酸两种羧酸化合物,通过酰胺键与L-酪氨酸甲酯、D-酪氨酸甲酯、章胺、多巴胺4种具有生物活性的胺类的化合物偶联。成功合成了8个新型酰胺类化合物,其结构经¹H NMR和 ¹³C NMR表征。此外,还测试所有目标分子的体外酪氨酸酶抑制活性和DPPH自由基清除能力,对目标分子的酪氨酸酶抑制活性和抗氧化活性进行了初步评价。      

1,8-二(2-吡咯酰胺)-3,6-二氯咔唑的合成、晶体结构及阴离子识别研究

设计并合成了1,8-二(2-吡咯酰胺)-3,6-二氯咔唑化合物(1), 利用X射线单晶衍射研究了该化合物的固态结构. 利用荧光和紫外-可见光谱技术及¹H NMR滴定法研究了其对阴离子的识别. 研究结果表明, 化合物1对H₂PO₄^-离子有较强的识别能力, 且对H₂PO₄^-离子有明显的荧光增强效应, 可用来识别H₂PO₄^-离子. 同时¹H NMR滴定结果显示, 化合物1在阴离子识别过程中发生了构型转化.     

白杨素甘氨酸类化合物的合成及抗癌活性

以白杨素为起始原料, 通过卤代和水解反应制得中间产物7-O-羧烷基化的白杨素衍生物(6~9); 然后以1-乙基-3-(3-二甲氨基丙基)碳二亚胺(EDCI)、 1-羟基苯并三氮唑(HOBt)和4-二甲氨基吡啶(DMAP)为催化体系, 4个中间产物分别与甘氨酸甲酯盐酸盐进行酰胺缩合反应, 制得白杨素甘氨酸甲酯类化合物12~15; 化合物12~15在pH=10~11和室温下水解得到相应的白杨素甘氨酸类化合物(16~19). 所有目标化合物的结构均经 ¹H NMR, ¹³C NMR, IR以及MS确认. 以顺铂为阳性对照药物, 采用噻唑蓝比色(MTT)法检测了目标化合物对人肝癌细胞HepG2和人胃癌细胞MGC-803的体外增殖抑制作用. 结果表明, 目标化合物14~16, 18和19的体外抗肿瘤活性明显强于白杨素, 且化合物18(IC₅₀=4.36 μmol/L)对MGC-803细胞的增殖抑制作用强于阳性药物顺铂(IC₅₀=4.40 μmol/L).     

煤焦油的拉曼光谱表征和组分识别

用355 nm激光作为激发光源检测了煤焦油常温拉曼光谱;应用两种量子化学计算程序(Gaussian-DFT和ADF)模拟了占总量1%以上的15种煤焦油组分的拉曼光谱,模拟结果与实验光谱能较好匹配,并对振动模式进行了归属分析。研究表明,煤焦油组分主要由共轭六元环构成,其拉曼光谱特征谱带主要在1 660、1 420和1 265 cm^-1附近,当共轭六元环成链式结构时,1 420 cm^-1谱带特征明显;五元环嵌入共轭六元环链式结构会导致其拉曼光谱在1 265和1 660 cm^-1谱带相对强度增大;五元环、杂原子基团和甲基侧链依附在共轭六元环上,则对组分的拉曼光谱影响不显著。     

基于纳米CdS对尿酸的光催化氧化和铜(Ⅱ)配合物对氧的电催化还原的燃料电池性能

以纳米硫化镉薄膜修饰的铟锡氧化物电极(CdS/ITO)作光阳极, 铜(Ⅱ)配合物[Cu(phen)(L-Trp)·(H₂O)]⁺(phen=1,10-菲啰啉, L-Trp=L-色氨酸)修饰单壁碳纳米管(SWCNTs)电极作阴极, 构建了光催化尿酸(UA)燃料电池, 并研究了其性能及热处理温度的影响. 结果表明, 在40 ℃以下获得的纳米CdS修饰电极在320~550 nm波长区间显现明显的吸收和光伏响应, 在可见光辐射下能光催化氧化UA; 较高温度的热处理(200~300 ℃)却降低了纳米CdS对UA的光催化氧化活性. [Cu(phen)(L-Trp)(H₂O)]⁺/SWCNTs电极在-0.131 V电位下呈现一对准可逆的氧化还原峰, 并能电催化还原O₂和H₂O₂. 此外, 基于UA在CdS/ITO电极上的光催化氧化及O₂在[Cu(phen)(L-Trp)(H₂O)]⁺/SWCNTs电极上的电催化还原, 组装了UA(0.2 mmol/L)燃料电池, 其在可见光照射(0.18 mW/cm²)下产生0.52 V开路电压, 13.08 μA/cm²短路光电流, 在0.41 V下呈现的最大功率密度为4.10 μW/cm².     

2,2'-联吡啶二氢双三碘基盐(2,2'-bipyH2)(I3)2的合成、晶体结构和谱学性质

合成了标题化合物并测定其晶体结构.晶体属三斜晶系,P1空间群,α=0.80284(8)nm,b=0.95993(6)nm,c=0.71660(9)nm,α=102.016(9)°,β=111.933(9)°,γ=101.650(8)°,V=0.4767(1)nm³,Z=1,D_c=3.21g·cm^-3,F(000)=404,μ(MoK_a)=98.77cm^-1.晶体中存在反式平面型的(2,2'-bipyH₂)²⁺阳离子和线性的I₃^-阴离子.晶体由[(2,2'-bipyH₂)(I₃)₂]_∞链堆积而成,同一层的链间存在N-H···I氢键,氢键键长N···I为0.349nm.用UV-Vis光谱和¹H NMR谱对标题化合物进行了表征.     

铁(Ⅲ)催化氯代炔烃水化反应合成α-氯代甲基酮类化合物

研究了Fe(Ⅲ)催化氯代炔烃水化生成α-氯代甲基酮化合物的反应, 考察了催化剂的种类、 酸的种类、 反应温度以及溶剂对反应的影响.结果表明, 采用FeCl₃·6H₂O(摩尔分数5%)和甲基磺酸(摩尔分数20%), 在1,2-二氯乙烷溶剂中, 氯代炔烃于80 ℃进行水化反应3 h, 可以高产率得到α-氯代甲基酮产物. 所得化合物的结构采用IR, ¹H NMR, ¹³C NMR及MS等方法进行了表征. 该水化反应合成方法简单、 条件温和且收率良好, 为合成α-氯代甲基酮提供了一种简便途径.     

L-苯丙氨酸聚肽的酶催化合成

聚肽是由人工合成的氨基酸聚合物,具有良好的生物相容性和生物可降解性。本文以菠萝蛋白酶为催化剂,在温和条件下于非水体系中从L-苯丙氨酸甲酯聚合得到齐聚L-苯丙氨酸。通过FT-IR、~1HNMR、MS和MALDI-TOF确定了齐聚L-苯丙氨酸的结构和聚合度。通过单因素考察了菠萝蛋白酶催化聚合反应的最优条件。结果表明,在40℃下用2.44U菠萝蛋白酶于15%DMSO的磷酸缓冲液(pH=8.0)中催化0.43g L-苯丙氨酸甲酯盐酸盐聚合,反应3h后齐聚L-苯丙氨酸得率达到最大值,为35.67%。     

UVRR spectroscopic studies of valinomycin complex formation in different solvents

We investigated the complexation of valinomycin (VM) in different solvent environments with the aid of the UVRR spectroscopy. By probing the 206.5 and 229 nm excited Raman spectra, we showed that new bands are observed around 1700 and 1290 cm(-1). We assigned the 1700 cm(-1) band to the hydrogen bonded ester carbonyl stretching vibration. In a polar solvent, VM-K(+) complexation shows significant intensity changes in amide and ester carbonyl stretching region. Because of the small amount of conformational interconversion, complexation has a negligible effect on other band intensities including, the amide III, C(alpha)H, and amide II. We also showed the effects of the solvent polarity on the solution conformation of VM.     

新型含氨基酸官能团的香豆素衍生物的合成

以L-苯丙氨酸、L-色氨酸、L-酪氨酸和组氨酸为原料,在Me₃SiCl-MeOH(Ⅲ)体系中反应合成了相应的甲酯盐酸盐（2a~2d）;以7-羟基香豆素为原料,经两步反应制得7-(乙酸氧基)香豆素（6）; 6与3a经酰胺化反应合成了一种新型的香豆素衍生物--N-乙酰基-(氧-7-香豆素)-3-苯基-2-氨基-丙酸甲酯,其结构经¹H NMR, ¹³C NMR和FT-IR表征。     

EPA甲酯和DHA甲酯标准样品的制备和结构解析

从鱼油中分离制备得到二十碳五烯酸（EPA）甲酯和二十二碳六烯酸（DHA）甲酯,采用红外光谱、质谱、核磁共振波谱等手段对EPA甲酯和DHA甲酯的结构进行表征,提供了不饱和脂肪酸甲酯标准物质研制基础。样品的红外光谱（IR）、质谱（MS）、核磁共振谱图（1HNMR、13CNMR）所给出的结构信息与EPA甲酯和DHA甲酯的化学结构式相符,并通过DEPT谱和I3C-1H COSY化学位移相关谱（HMBC）对各共振峰进行了指认,样品的谱图数据与文献报道基本一致。     

新型L-酪氨酸二肽衍生物的合成及其抗肿瘤活性

以L-酪氨酸甲酯盐酸盐和对羟基苯甲酸（PHBA）为原料,经缩合、水解和亲核取代反应,设计并合成了9个新型的L-酪氨酸二肽衍生物（3b和4a~4h）,其结构经¹H NMR、 ¹³C NMR和MS（ESI）表征。采用MTT法评价了化合物对白血病细胞（K562）、人肺癌细胞（A549）和人肝癌细胞（HepG2）的体外抑制活性。结果表明：N-[N-(4-苄氧基-苯甲酰基)-O-二甲氨基丙基-L-酪氨酰基]-L-苯丙氨醇(4e)对HepG2和K542细胞的抑制活性均高于阳性对照药阿霉素,IC₅₀分别为0.41和11.77 μmol·L^-1。     

Determination of conformational preferences of dipeptides using vibrational spectroscopy

The NMR coupling constants ((3)J(H(N), H(alpha))) of dipeptides indicate that the backbone conformational preferences vary strikingly among dipeptides. These preferences are similar to those of residues in small peptides, denatured proteins, and the coil regions of native proteins. Detailed characterization of the conformational preferences of dipeptides is therefore of fundamental importance for understanding protein structure and folding. Here, we studied the conformational preferences of 13 dipeptides using infrared and Raman spectroscopy. The main advantage of vibrational spectroscopy over NMR spectroscopy is in its much shorter time scale, which enables the determination of the conformational preferences of short-lived states. Accuracy of structure determination using vibrational spectroscopy depends critically on identification of the vibrational parameters that are sensitive to changes in conformation. We show that the frequencies of the amide I band and the A12 ratio of the amide I components of dipeptides correlate with the (3)J(H(N), H(alpha)). These two infrared vibrational parameters are thus analogous to (3)J(H(N), H(alpha)), indicators for the preference for the dihedral angle phi. We also show that the intensities of the components of the amide III bands in infrared spectra and the intensities of the skeletal vibrations in Raman spectra are indicators of populations of the P(II), beta, and alpha(R) conformations. The results show that alanine dipeptide adopts predominantly a PII conformation. The population of the beta conformation increases in valine dipeptides. The populations of the alpha(R) conformation are generally small. These data are in accord with the electrostatic screening model of conformational preferences.     

Structural analysis and Fourier transform infrared and Raman spectra of dibutoxyphosphoryl benzylisothiourea

A structural analysis for dibutoxyphosphoryl benzylisothiourea (DBBT) was carried out by mass spectrometry, 1H NMR, 13C NMR, infrared and Raman spectroscopy. The Fourier transform infrared and Fourier transform Raman spectra of liquid of DBBT were carried out with the purpose of studying the tautomerism (structures I and II) and the behavior of the more polar absorption's bands in different solvents, i.e., absorption's of the P=O and C=N bands. The results suggest the existence of tautomerism in the pure (liquid) compound and in solution of CHCl(3), CH(2)Cl(2), CHBr(3), and THF, C(2)H(4)Cl(2) and C(2)H(4)Br(2). The solvent interaction with the P=O band was characterized by the presence of a new band in the region of the O-H absorption. A vibrational assignment of the IR bands and Raman shifts was done and is proposed in this paper.     

Photoinitiated polymerization of columnar stacks of self-assembled trialkyl-1,3,5-benzenetricarboxamide derivatives

A disk-shaped molecule, N-(5-sorbyl-pentyl)-N',N"-di(n-octyl)benzene-1,3,5-tricarboxamide (1), has been synthesized and assembled into a columnar stack in cyclohexane. Using a photoinitiated process, we polymerized monomer 1 in its self-assembled state and analyzed the resulting poly-1. On cooling a boiling cyclohexane solution of 1, the molecules aggregate via amide hydrogen bonds, as supported by the position of the N-H stretching band in FT-IR spectroscopy. Evidence of helical columnar stacking of 1 in the aggregate is provided by an induced CD effect upon blending 1 with a chiral side-chain homologue 3 in a so-called "sergeants and soldiers" experiment. The columnar assembly in cyclohexane was polymerized by UV light (365 nm) irradiation in the presence of 2,2-dimethoxy-2-phenylacetophenone as radical photoinitiator. The polymerization occurs selectively to give 1,4-polymer with isolated trans C=C bonds, as shown by FT-IR, and (1)H and (13)C NMR spectroscopy. Lack of polymerization of methyl sorbate (4) under identical conditions, and low incorporation of 4 in copolymerizations with 1 in cyclohexane, suggests that the polymerization preferentially occurs within the columnar assembly. Size exclusion chromatography shows that the degree of polymerization (X(n)()) based on number average molecular weight is approximately 65. Incorporation of small amounts of nonpolymerizable derivatives 2 and 3 into the columns has no effect on X(n)() and conversion. Molecular models show that the polymerizable sidearm of 1 is long enough to span the distance between the monomers in the chiral stack. Under the atomic force microscope (AFM), purified samples of polymerized 1 displayed nanometer-sized fibrous morphologies with a high-axial-ratio (>150), uniform width (60 nm), and a thickness (1.0 nm) which corresponds to the width of the benzene tricarboxamide core of 1, whereas aggregates of nonpolymerized 1 yield a featureless image due to their instability.     

Microwave step‐growth polymerization of 5‐(4‐methyl‐2‐phthalimidylpentanoylamino)isophthalic acid with different diisocyanates

The utilization of microwave energy in polymer synthesis is a fast growing field of research leading to a more rapid and cleaner polymerization process. In order to synthesize novel optically active monomer 5‐(4‐methyl‐2‐phthalimidylpentanoylamino)isophthalic acid ( 6 ), the reaction of phthalic anhydride with l ‐leucine was carried out in an acetic acid solution and 4‐methyl‐2‐phthalimidylpentanoic acid as an imide acid was obtained in good yield. Then, it was converted to 4‐methyl‐2‐phthalimidylpentanoyl chloride by treatment with thionyl chloride. This acid chloride was reacted with 5‐aminoisophthalic acid and the novel bulky aromatic amide‐imide chiral monomer 6 was obtained in high yield and was characterized with spectroscopy techniques as well as specific rotation and elemental analysis. Polycondensation of monomer 6 with different diisocyanates such as 4,4′‐methylenebis(phenyl isocyanate), toluene‐2,4‐diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate was performed by two different methods: microwave irradiation and classical heating polymerization techniques in the presence of various catalysts and without a catalyst. The microwave polymerization technique provides a new way for the production of polymers at high rates. The resulting novel optically active polyamides have inherent viscosities in the range of 0.25–0.63 dl/g. They show good thermal stability and are soluble in amide‐type solvents. The obtained polyamides were characterized by FT‐IR, ¹H‐NMR spectroscopy, elemental analyses, specific rotation, and thermal analyses methods. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis of Poly(methyl methacrylate) Labeled with Fluorescein Moieties via Atom Transfer Radical Polymerization

Fluorescein chromophore‐labeled poly(methyl methacrylate) (PMMA) was prepared via atom transfer radical polymerization (ATRP) with two novel bromine‐containing fluorescein derivatives, 3,6‐bi(2′‐bromo‐2′‐methyl‐propionic acid) fluorescein ester (Fla‐Br) and 3‐(2′‐bromo‐2′‐methyl‐propionic acid) fluorescein ester (Flb‐Br), as the functional initiators, and CuBr/PMDETA as the catalyst, respectively. The above mentioned fluorescein containing bromine were synthesized in our lab. The ATRP of PMMA was proved in a controlled fashion. The resultant PMMA with narrow molecular weight distribution was endowed with the fluorescein chromophore incorporated into the polymer backbone. The presence of the fluorescein labeling of the polymers was confirmed by ¹H‐NMR and GPC trace under UV detector. The UV spectroscopy and fluorescence measurements of the resultant polymer gave further evidence of the functionality of the fluorescein labeling.