3,4-二甲氧基苯甲醛缩乙醇胺席夫碱合成、表征与抑菌活性研究

目的与方法合成了未经报道的3,4-二甲氧基苯甲醛缩乙醇胺席夫碱,并对其进行了结构表征。结果与结论初步确认了其组成,抑菌实验表明该席夫碱对枯草杆菌、大肠杆菌、金黄色葡萄球菌、革兰氏阴性细菌(发荧光Q67)均有较好的抑制作用。     

香草醛缩乙醇胺席夫碱的合成、表征与抑菌活性研究

目的与方法　合成了未经报道的香草醛缩乙醇胺席夫碱,并对其进行了结构表征。结果与结论　初步确认了其组成,抑菌实验表明该席夫碱对枯草杆菌、大肠杆菌、金黄色葡萄球菌、革兰氏阴性细菌(发荧光Q₆₇)均有较好的抑制作用。     

3,4-二甲氧基苯甲醛缩乙醇胺席夫碱合成、表征与抑菌活性研究

目的与方法合成了未经报道的3,4-二甲氧基苯甲醛缩乙醇胺席夫碱,并对其进行了结构表征。结果与结论初步确认了其组成,抑菌实验表明该席夫碱对枯草杆菌、大肠杆菌、金黄色葡萄球菌、革兰氏阴性细菌(发荧光Q₆₇)均有较好的抑制作用。     

含卤席夫碱的合成及抑菌活性观察

本文以水杨醛为主要原料 ,经发烟硝酸硝化合成 5 -硝基水杨醛 ,再分别与对氟苯胺、邻氯苯胺作用 ,合成了两种含卤席夫碱 ,其中与对氟苯胺衍生物作用合成而得的席夫碱未见报道。对所合成的两种席夫碱进行生物活性测试 ,结果表明 ,该两种席夫碱对供试菌种 (大肠杆菌、金黄色葡萄球菌、假丝酵母菌、毛霉菌、鼠伤寒沙门氏菌 )都有较强的抑制作用 ,对细菌的抑制作用强于对霉菌的抑制作用 ,对氟苯胺席夫碱抑菌效果较强     

对氟苯乙醛缩乙醇胺席夫碱抑菌活性研究

目的试验新合成的化合物对氟苯乙醛缩乙醇胺席夫碱(含氟席夫碱)对枯草杆菌等五种细菌的抑菌作用,为寻找具有抑菌、抗癌、抗病毒、杀霉等生物活性的药物提供新药.方法采用国际药典通用的管碟法.首先培养枯草杆菌、大肠杆菌、大肠杆菌(101)、金黄色葡萄球菌、革兰阴性细菌(发荧光Q67)等五种细菌,取其第二代繁殖体作受试对象.将对氟苯乙醛缩乙醇胺席夫碱用适量蒸馏水溶解,配制浓度为0.25,0.5,1,2mg/Ml一系列溶液,加样后革兰阴性细菌(发荧光Q67)在25℃培养箱里培养24h,其余均在室温下培养24h,实验中以蒸馏水作为对照.结果蒸馏水对上述细菌无任何抑制作用,该含氟席夫碱对上述细菌均有不同程度的抑制作用.结论 抑菌活性实验表明该含氟席夫碱对枯草杆菌、大肠杆菌、大肠杆菌(101)、金黄色葡萄球菌、革兰氏阴性细菌(发荧光Q67)等五种细菌均有较好的抑菌作用.     

1,2二取代苯并咪唑化合物的一种高效合成方法

苯并咪唑是一类具有广泛生理活性的化合物,许多药物分子中都含有苯并咪唑结构.笔者研究苯并咪唑化合物新的高效合成方法.以邻苯二胺和酮为原料,在微波条件下,经缩合,形成单席夫碱,然后再与其他醛反应,高产率的得到了5个1位、2位接有不同取代基的苯并咪唑化合物.单席夫碱生成咪唑过程中,发生1,3负氢迁移.     

新型双核Cu(Ⅱ)席夫碱化合物的合成及其模拟超氧化物歧化酶活性研究

用双乙酰丙酮和席夫碱半体(H2L0)合成得到双席夫碱配体(I)及其双核Cu(II)配合物(II),通过元素分析、1HNMR、IR、UV-vis和MS等对其进行了表征,并采用邻苯三酚自氧化法测定了它们模拟超氧化物歧化酶(SOD)活性。结果表明,它们均具有良好的SOD活性。     

木犀草素缩苯胺席夫碱配合物的合成及抑菌活性

目的：基于木犀草素的生物活性和席夫碱的特有性质基础上，设计与金属形成一系列新型席夫碱金属配合物。方法：利用缩合反应，在无水乙醇中合成未见报道的黄酮类席夫碱过渡金属配合物。并通过元素分析、紫外光谱、红外光谱、摩尔电导等手段对其进行了结构表征和抗菌活性实验。结果：通过分析，初步确定了其分子式、结构和其．生物活性。结论：结构式为：配合物MLx．nC2H5OH。形成配合物后抑菌活性大大增强。     

木犀草素缩磺胺甲恶唑席夫碱及金属配合物的研究

目的:寻找新型席夫碱和新的抑菌药物。方法:以木犀草素和磺胺甲恶唑进行缩合反应制成新的黄酮席夫碱化合物;并以此为配体合成了新的金属配合物。进行了初步的抗菌活性实验。结果:经元素分析、红外光谱、紫外光谱确证其结构组成。结论:结果表明,新化合物对多种菌株有明显的抑菌活性且优于各自的母体。     

对氟苯乙醛缩乙醇胺席夫碱抑菌活性研究

目的　试验新合成的化合物对氟苯乙醛缩乙醇胺席夫碱(含氟席夫碱)对枯草杆菌等五种细菌的抑菌作用,为寻找具有抑菌、抗癌、抗病毒、杀霉等生物活性的药物提供新药。方法　采用国际药典通用的管碟法。首先培养枯草杆菌、大肠杆菌、大肠杆菌(101)、金黄色葡萄球菌、革兰阴性细菌(发荧光Q₆₇)等五种细菌,取其第二代繁殖体作受试对象。将对氟苯乙醛缩乙醇胺席夫碱用适量蒸馏水溶解,配制浓度为0.25,0.5,1,2mg/mL一系列溶液,加样后革兰阴性细菌(发荧光Q₆₇)在25℃培养箱里培养24h,其余均在室温下培养24h,实验中以蒸馏水作为对照。结果　蒸馏水对上述细菌无任何抑制作用,该含氟席夫碱对上述细菌均有不同程度的抑制作用。结论　抑菌活性实验表明该含氟席夫碱对枯草杆菌、大肠杆菌、大肠杆菌(101)、金黄色葡萄球菌、革兰氏阴性细菌(发荧光Q₆₇)等五种细菌均有较好的抑菌作用。     

Inhibition mechanism of trypsin by Schiff base metal chelate inhibitors

Studies on trypsin-specific compounds are useful for the design of clinically useful compounds. It is well known that several benzamidine derivatives are potent competitive inhibitors of trypsin and trypsin-like enzymes. Many kinds of Schiff base metal chelate containing either amidine or guanidine have been synthesized and their inhibitory activities against trypsin have been characterized. Recently, the interactions of the Schiff base metal chelate inhibitors with trypsin enzyme have been determined by X-ray crystal structure analysis. The structural information and inhibitory activity data for amidine- and guanidine-containig Schiff base metal chelate inhibitors provide new avenues for designing novel inhibitors against physiologically important trypsin-like serine proteases.     

Selective irreversible inhibition of fructose 1,6-bisphosphate aldolase from Trypanosoma brucei

An irreversible competitive inhibitor hydroxynaphthaldehyde phosphate was synthesized that is highly selective against the glycolytic enzyme fructose 1,6-bisphosphate aldolase from Trypanosoma brucei (causative agent of sleeping sickness). Inhibition involves Schiff base formation by the inhibitor aldehyde with Lys116 followed by reaction of the resultant Schiff base with a second residue. Molecular simulations indicate significantly greater molecular geometries conducive for nucleophilic attack in T. brucei aldolase than the mammalian isozyme and suggest Ser48 as the Schiff base modifying residue.     

香草醛葡萄糖苷希夫碱衍生物Ⅳ的合成与结构表征

目的合成一种兼有香草醛活性和希夫碱功效的化合物,筛选具有镇静、抗癫疒间、抗癌的药物。方法用葡萄糖、香草醛为原料,经过乙酰化、溴代等步骤合成了中间体四乙酰葡萄糖香草醛苷,然后与对氯苯胺反应。结果合成了目标化合物Ⅳ。对目标化合物Ⅳ用IR、1HNMR、MS进行结构表征,分析证实所合成的化合物与预期结构一致。结论依据药物拼合原理,可以对香草醛进行结构改造和修饰,合成其希夫碱类化合物。     

香草醛葡萄糖苷希夫碱衍生物Ⅳ的合成与结构表征

目的合成一种兼有香草醛活性和希夫碱功效的化合物,筛选具有镇静、抗癫疒间、抗癌的药物。方法用葡萄糖、香草醛为原料,经过乙酰化、溴代等步骤合成了中间体四乙酰葡萄糖香草醛苷,然后与对氯苯胺反应。结果合成了目标化合物Ⅳ。对目标化合物Ⅳ用IR、1HNMR、MS进行结构表征,分析证实所合成的化合物与预期结构一致。结论依据药物拼合原理,可以对香草醛进行结构改造和修饰,合成其希夫碱类化合物。     

Absorption and fluorescence study of the interaction between (2-hydroxy-benzimido)ethyl-n-hexylselenide and bovine serum albumin

The binding of Schiff base selenide, (2-hydroxy-benzimido)ethyl-n-hexylselenide, to bovine serum albumin (BSA) was studied using fluorescence spectroscopy. The measurement was performed in Tris-HCl buffer aqueous medium at pH 7.4. Stern-Volmer graphs were plotted and quenching constants were estimated. The quenching constant at 303 K was (1.639 +/- 0.046) x 10(13) L mol(-1) s(-1). Decreased quenching was observed as temperature increased, but at the temperature range of 303-313 K, the association of Schiff base selenide to BSA was not significantly different. The static quenching presented in the system of Schiff base selenide and BSA. A complex was possibly formed between Schiff base selenide and BSA, which was responsible for the quenching of the fluorescence of BSA. This fact was also confirmed by differences in the absorption spectra of BSA before and after Schiff base selenide addition. The hydrophobic interaction was found to play a main role in the binding according to the thermodynamic parameters, enthalpy change (DeltaH) and entropy change (DeltaS) of reaction. Schiff base selenide most likely binds to the hydrophobic pockets within sub domain IIA of BSA, which can be proved by competition experiments for sodium dodecyl sulfate. By constant-wavelength synchronous fluorescence spectra, the influence of (2-hydroxy-benzimido)ethyl-n-hexylselenide on the surrounding environment of tyrosine and tryptophan residues in BSA was also investigated. The red shift of the fluorescence peak of tryptophan residues indicated that the hydrophobic amino acid structure surrounding tryptophan residues in BSA collapsed slightly after the addition of (2-hydroxy-benzimido)ethyl-n-hexylselenide.     

Gramicidin S: a peptide model for protein glycation and reversal of glycation using nucleophilic amines

Abstract: Nonenzymatic glycation of proteins has been implicated in various diabetic complications and age‐related disorders. Proteins undergo glycation at the N‐terminus or at the ε‐amino group of lysine residues. Glycation of proteins proceeds through the stages of Schiff base formation, conversion to ketoamine product and advanced glycation end products. Gramicidin S, which has two ornithine residues, was used as a model system to study the various stages of glycation of proteins using electrospray ionization mass spectrometry. The proximity of two ornithine residues in the peptide favors the glycation reaction. Formation of advanced glycation end products and diglycation on ornithine residues in gramicidin S were observed. The formation of Schiff base adduct is reversible, whereas the Amadori rearrangement to the ketoamine product is irreversible. Nucleophilic amines and hydrazines can deglycate the Schiff base adduct of glucose with peptides and proteins. Hydroxylamine, isonicotinic acid hydrazide and aminoguanidine effectively removed glucose from the Schiff base adduct of gramicidin S. Hydroxylamine is more effective in deglycating the adduct compared with isonicotinic acid hydrazide and aminoguanidine. The observation that the hydrazines are effective in deglycating the Schiff base adduct even in the presence of high concentrations of glucose, may have a possible therapeutic application in preventing complications of diabetes mellitus. Hydrazines may be used to distinguish between the Schiff base and the ketoamine products formed at the initial stages of glycation.     

Synthesis,characterization and biological applications of novel Schiff bases of 2-(trifluoromethoxy) aniline

A series of five new Schiff bases (1–5) were synthesized by reacting 2-(trifluoromethoxy) aniline with different aromatic aldehydes. The Schiff base compounds were characterized by spectroscopic and analytical methods. Crystal structure of one new compound was also reported. The pharmacological properties, including antibacterial (14 bacterial species), antifungal (7 strains),antimalarial, anti-trypanosomal and anti-HIV activities of the compounds, were investigated. Cytotoxicity of the tested compounds was evaluated against human cervix adernocarcinoma cells (HeLa). Bacterial minimum inhibitory concentration (MIC) results by broth microdilution method showed that Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Proteus vulgaris, Klebsiella oxytoc and Klebsiella pneumonia were more sensitive in the presence of tested compounds with an MIC value of 15.6 µg/mL. All the tested compounds showed good to moderate activity against fungi. The sensitivity of Aspergillus fumigatus was higher than other strains with aminimum cell death concentration (MFC) of 15.6 µg/mL. Compound 1 showed greater antimalarial and anti-trypanosomal properties with very low to no cytotoxic effects against HeLa cells as compared with compound 5, while other compounds exhibited poor activity. Compounds 1–5 demonstrated good activity against HIV type-1. These Schiff base compounds could be used as good antimicrobial agents.     

酚取代双膦酸酯Schiff碱的合成及抗癌活性研究

设计合成了１１个含有Ｓｃｈｉｆｆ碱双键的酚取代双膦酸酯类化合物。对小鼠白血病细胞Ｐ３８８、人肺腺癌细胞Ａ－５４９的体抗癌活性实验表明：目标分子中酚羟基的位置对化合物的活性有着重要影响,当酚羟基位于Ｓｃｈｉｆｆ碱双键的邻位时,其活性高于其他化合物。     

苯并咪唑Schiff碱的合成及其杀菌活性

以邻苯二胺、乳酸、芳香胺为原料合成了５种未见文献报道的苯并咪唑Ｓｃｈｉｆｆ碱类化合物（３ａ～３ｅ）。所有化合物均经元素分析、红外光谱、紫外光谱、核磁共振谱确证。抑菌活性测试表明它们具有比较好的抑菌能力。