1,2,4-噁二唑类化合物的合成及抗菌活性研究

以对溴苯腈为原料,通过多步反应合成了一系列3-(吗啉苯基)-5-取代-1,2,4-异噁唑类化合物和3-(吗啉苯基)-5-取代-4,5-二氢-1,2,4-噁二唑类化合物,并用1HNMR、13C NMR和MS进行了结构确证。这些化合物对测试的部分革兰氏阳性菌,如金黄色葡萄球菌、耐甲氧西林金黄色葡萄球菌、表皮葡萄球菌、粪肠球菌显示出一定的抗菌活性,但与噁唑烷酮类上市药物利奈唑胺相比,抗菌活性有明显下降。这一结果表明对于化合物的抗菌活性,1,2,4-噁二唑杂环不如噁唑烷酮结构有效。     

Alga-mediated facile green synthesis of silver nanoparticles: Photophysical,catalytic and antibacterial activity

A facile, convenient and green method has been employed for the synthesis of silver nanoparticles (AgNPs) using dried biomass of a green alga, Chlorella ellipsoidea. The phytochemicals from the alga, as a mild and non-toxic source, are believed to serve as both reducing and stabilizing agents. The formation of silver nanoparticles was confirmed from the appearance of a surface plasmon resonance band at 436 nm and energy dispersive X-ray spectroscopy. The transmission electron microscopy images showed the nanoparticles to be nearly spherical in shape with different sizes. A dynamic light scattering study revealed the average particle size to be 220.8 ± 31.3 nm. Fourier transform infrared spectroscopy revealed the occurrence of alga-derived phytochemicals attached to the outer surface of biogenically accessed silver nanoparticles. The powder X-ray diffraction study revealed the face-centred cubic crystalline structure of the nanoparticles. The as-synthesized biomatrix-loaded AgNPs exhibited a high photocatalytic activity for the degradation of the hazardous pollutant dyes methylene blue and methyl orange. The catalytic efficiency was sustained even after three reduction cycles. A kinetic study indicated the degradation rates to be pseudo-first order with the degradation rate being 4.72 × 10⁻² min⁻¹ for methylene blue and 3.24 × 10⁻² min⁻¹ for methyl orange. The AgNPs also exhibited significant antibacterial activity against four selected pathogenic bacterial strains.     

Durian waste mediated green synthesis of zinc oxide nanoparticles and evaluation of their antibacterial,antioxidant, cytotoxicity and photocatalytic activity

ABSTRACT

The synthesized ZnO NPs using durian rind in solution has shown maximum absorption at 355.5?nm with the bandgap of 3.33?eV, spectrophotometrically. SEM and TEM studies revealed that the shape of the synthesized ZnO NPs was spherical with an average size of 280 and 283?nm, respectively. However, DLS analysis of ZnO NPs revealed the average particle size of 456?d.nm. The presence of [100], [002], [101], [102], [110], [103], [200], [112] and [201] planes in XRD corroborate the formation of pure wurtzite structure of ZnO NPs. Synthesized ZnO NPs showed remarkable photocatalytic activity on degradation of methylene blue and sulfanilamide, antioxidant activity, considerable antimicrobial activity against Escherichia coli and Staphylococcus aureus, and considerable cytotoxic activity against brine shrimp. The sulfanilamide degradation was found to be 96.70%, under natural sunlight and in the presence of 0.1% ZnO NPs at pH 10 with a time of 3?h. The dye degradation was found to be 84% under sunlight in the presence of 0.01% ZnO NPs at pH 10 with a time of 40?min. The synthesized ZnO NPs may be explored furthermore in the fields of wastewater treatment, biomedicine, biosensor, and nanotechnology.     

Synthesis and antibacterial activity of hydroxylated 2-arylbenzothiazole derivatives

Abstract

N-acyliminium reagents formed in situ from benzothiazole and alkyl chloroformates react with hydroxyarenes in a Friedel-Crafts manner, providing access to 2-(hydroxyaryl)-benzothiazolines with antibacterial properties.     

Waste-grass-mediated green synthesis of silver nanoparticles and evaluation of their anticancer,antifungal and antibacterial activity

Grass waste was used for transform an inexpensive waste into health. Silver nanoparticles (AgNPs) have been synthesized using waste material (dried grass). The average size of silver nanoparticles observed in transmission electron images was estimated to be about 15?nm. The anticancer, antifungal and antibacterial effect of AgNPs were studied in vitro. The minimum inhibitory concentration of AgNPs against Pseudomonas aeruginosa and Acinetobacter baumannii was calculated about 3?µg/ml. The highest level of inhibitory effect of AgNPs against Fusarium solani was close to 90% at a concentration of 20?μg/ml of AgNPs. An inhibitory effect on the cancer cell growth is reach, by increasing the concentration of AgNPs to 5?µg/ml; the cancer cells’ survival decreases about 30%. Western results showed that the expression of Cyclin D1 protein of MCF-7 cell line decreased after treatment with the effective concentration of AgNPs.     

Synthesis and antibacterial activity of novel 10, 11-epoxy acylide erythromycin derivatives

A series of novel acylide derivatives have been synthesized from clarithromycin A via a facile procedure. The C-3 modifications involved replacing the natural C-3 cladinosyl group in clarithromycin core with different aryl-piperzine sidechain via chemical synthesis. Meanwhile a distinctive intermediate with 10,11-epoxy moiety was obtained. The structure and stereochemistry of this novel structure were confirmed via NMR and X-ray crystallography. Potential anti-bacterial activities against both Grampositive and Gram-negative bacteria were reported. Because of existence of C10,11-epoxide, these derivatives can be used as intermediates for further structural modification.     

Microwave-assisted synthesis of rhodamine derivatives

The microwave synthesis of 12 rhodamine-derived imines is described. The present work involves condensation of rhodamine hydrazide with various aromatic aldehydes in ethanol under microwave irradiation. The results obtained indicate that, unlike classical heating, microwave irradiation results in higher yields, shorter reaction time, mild reaction condition and simple work-up procedure. The structures of synthesized compounds were confirmed by ¹H-NMR, ¹³C-NMR, FT-IR and high-resolution mass spectra data.     

Synthesis, antibacterial and antifungal activity of some derivatives of 2-phenyl-chromen-4-one

Some derivatives of 2-phenyl-chromen-4-one (flavone ring) have been synthesized and tested for antibacterial and antifungal activities along with their chalcone precursors against four human pathogenic bacteria and five plant mould fungi. The structures of the synthesized compounds were elucidated by UV, IR and¹H NMR spectroscopic techniques, and elemental analysis. The antibacterial and antifungal screens of the synthesized compounds were performed in vitro by the filter paper disc diffusion method and the poisoned food technique.     

三芥子酸甘油酯类似物的合成及抑菌活性

以N-(2-溴乙基)邻苯二甲酰亚胺或N-(4-溴丁基)邻苯二甲酰亚胺和硫氢化钠为起始原料,通过取代、肼解、亲核加成等反应合成了10个三芥子酸甘油酯(erucin)类似物,通过核磁共振氢谱、碳谱及质谱对其结构进行了确认。采用比浊法初步测试了其对大肠杆菌、金黄色葡萄球菌、白色葡萄球菌、藤黄八叠球菌、枯草芽孢杆菌、蜡状芽孢杆菌和四联球菌等7种菌的生长抑制活性,测试结果显示,化合物对测试菌种都表现出较好的生长抑制活性,其中苄硫乙基-1-硫代异硫氰酸酯(5e)和苄硫基丁基-1-硫代异硫氰酸酯(5j)活性最高,对大肠杆菌的最低生长抑制浓度仅为7.8μg/m L,对金黄色葡萄球菌的最低生长抑制浓度也仅为15.6μg/m L和31.2μg/m L。     

吡啶联喹唑啉酮衍生物的设计、合成与抗菌活性研究

以靛红酸酐为起始原料,设计并合成了14个结构新颖的吡啶联喹唑啉酮类衍生物.所有化合物经1 H NMR、13 C NMR和高分辨质谱(HRMS)表征确证其结构.初步抗菌活性结果显示,该类化合物对水稻白叶枯病菌(Xanthomonas oryzae pv.Oryzae,Xoo)、猕猴桃溃疡病菌(Pseudomonassyr...     

Microwave-assisted green synthesis of 1, 3-benzodioxole derivatives

Abstract

2-Phenyl-substituted 1,3-benzodioxole derivatives were synthesized by microwave irradiation by reacting catechol with benzoic acid derivatives in the presence of polyphosphoric acid as a catalyst which acts as a solvent and also as a cyclizing agent. This synthesis has various advantages over other catalytic conventional synthesis because it saves time, increases yield, and is a simple, economical, and effective synthesis. Moreover, this is also an excellent green chemistry approach as it does not require additional toxic solvents or harmful chemicals, and overall it reduced energy utilization than the other methods of synthesis.

     

Synthesis,antifungal and antibacterial activity of calix[4]arene-based 1,3,4-oxadiazole derivatives

We describe the synthesis of some novel p-tert-butylcalix[4]arene-based (5-aryl-1,3,4-oxadiazol-2-yl)2-chloroethanethioate derivatives ( 4a–e ). These compounds were synthesized by the reaction of tetra-tert-butyl calix[4]arene ( 1 ) with (5-aryl-1,3,4-oxadiazol-2-yl)2-chloroethanethioate ( 3a–e ) in the presence of potassium carbonate as a weak base and dry acetone as the solvent. All the newly synthesized calix[4]arene derivatives were characterized by elemental analysis and various spectroscopic methods such as FT-IR, ¹H NMR,¹³C NMR, DEPT, and ESI-MS. The synthesized compounds were tested in vitro for their antibacterial and antifungal activities against Escherichia coli and Aspergillus fumigates in comparison with enrofloxacin and amphotericin as reference drugs, which are normally used for treating such infections. The synthesized compounds showed different inhibition zones against the tested bacteria and fungi. Compound 4c was found to be most effective against A. fumigates, whereas compound 4e was found to be equally effective against E. coli and A. fumigates.     

Synthesis,antibacterial activity and docking studies of substituted quinolone thiosemicarbazones

Abstract

Fifteen 2-quinolone thiosemicarbazone derivatives of which eleven were new, were synthesized at room temperature. The key intermediate was the quinolone carbaldehyde, from which thiosemicarbazones were formed by the reaction of thiosemicarbazides with the aldehyde moiety. The structures of the synthesized compounds were elucidated by 1D and 2D-NMR spectroscopy and mass spectrometry. The synthesized compounds showed antibacterial activity with MBCs in the range 0.80 to 36.49?mM against Staphylococcus aureus, Staphylococcus aureus Rosenbach (MRSA), Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli and Salmonella typhimurium. The best activity was seen when a larger halogen such as chlorine and bromine were substituted at C-6 on the quinolone scaffold and when a planar phenyl group was present on the thiosemicarbazone moiety. Activity was reduced when a smaller fluorine atom was present at C-6 or when a methyl group was attached to the thiosemicarbazone. This group of compounds showed a high negative binding affinity, which suggested promising antimcrobial activity. The 6-chloro derivative with a phenyl group on the thiosemicarbazone had the greatest negative binding affinity.     

Synthesis of nitrogen-containing monoterpenoids with antibacterial activity

Abstract

Incorporation of the Beckmann rearrangement into the presented research resulted in the formation of nitrogen-containing terpenoid derivatives originating from naturally occurring compounds. Both starting monoterpenes and obtained derivatives were subjected to estimation of their antibacterial potential. In the presented study, Staphylococcus aureus was the most sensitive to examined compounds. The Minimal Inhibitory Concentration (MIC) experiments performed on S. aureus demonstrated that the (?)-menthone oxime (?)-8 and (+)-pulegone oxime (+)-13 had the best antibacterial activity among the tested derivatives and starting compounds. Their MIC₉₀ value was 100?µg/mL. The obtained derivatives were also evaluated for their inhibitory activity against bacterial urease. Among the tested compounds, three active inhibitors were found – oxime 14 and lactams (?)-15 and 16 limited the activity of Sporosarcina pasteurii urease with K_i values of 174.3?µM, 43.0?µM and 4.6?µM, respectively. To our knowledge, derivative 16 is the most active antiureolytic lactam described to date.     

Ultrasound-assisted efficient synthesis of polyfunctional 1,2,4-triazoles as novel antibacterial and antioxidant agents

Novel 4,5-diphenyl-1H-imidazol-1-yl-1H-1,2,4-triazole derivatives were synthesized using a facile and highly efficient, one-pot, four-component procedure in the presence of KHSO₄ as an acidic catalyst under ultrasonic irradiations in short reaction times (10–25 min) and good to excellent yields (70–96%). The synthesized compounds were screened for their antibacterial activities against Gram-negative (Escherichia coli, Pseudomonas aeruginosa) and Gram-positive (Bacillus subtilis, Micrococcus luteus) bacteria, and their antioxidant activity was also evaluated. Some of the products showed potential antibacterial and high antioxidant activities.     

辛酸蔗糖酯的超声合成、性能及应用

研究了超声技术促进蔗糖的酰化反应, 考察了反应温度、时间和催化剂等对反应的影响, 当蔗糖与辛酸乙酯的物质的量比为2∶1, 反应温度为70 ℃, 催化剂为(占辛酸乙酯质量分数)11%和反应压力为11 kPa的条件下, 超声反应2 h, 能高产率地获得辛酸蔗糖酯, 且产物的单酯化物含量达92%. 产物的结构经IR, 1H NMR和MS确证, 同时测定了产物的溶解性、亲水亲油平衡值(HLB)和热稳定性; 研究了辛酸蔗糖酯在织物的抗菌整理上的应用, 结果显示对金黄色葡萄球菌具有良好的抑菌效果(抑菌率为70%), 但对大肠杆菌无抑制作用.     

水杨酰肼Schiff碱的合成、表征及抑菌活性

Sehiff碱具有多个氧、氮配位原子,是一类重要的生物配体,某些Schiff碱具有抗癌、抗病毒、抑制细菌生长等生物活性。本文制备了两个水杨酰肼类Schiff碱化合物,并探讨了结构组成、波谱性能及抑菌活性。     

砷配合物的固相合成、表征及抑菌活性研究

一些砷、锑的配合物具有抗癌、杀菌等生物功能[1,2],可用于药物研究.近年来,用砷剂(主要是三氧化二砷)治疗急性早幼粒细胞白血病(APL),具有缓解率高而复发率低的优点,引起世人的关注.因砒霜中仅含氧和砷,起药物作用的实际是砷(Ⅲ).因此,选择有生物功能的配体合成新型砷配合物对治疗白血病可能有一定药物作用.由于砷的无机盐易水解,故合成砷的生物配合物很困难,对砷配合物的研究也很少报道 [3-7].本文用异烟肼、L-苯丙氨酸和三碘化砷通过室温固相反应合成了两种未见报道的砷配合物,经元素分析,紫外光谱,X-射线粉末衍射,中、远红外光谱和热重差热分析确定了配合物的化学组成,并对配合物的抑菌活性进行了研究.