Cyclization of 4,5‐Diamino Pyrazole Derivatives and Their Antibacterial Activities

A convenient synthesis of intermediate 4,5‐diamino‐3‐aryl‐1‐phenylpyrazoles 4a – 4c was reported. The different cyclization reactions were carried out with chalcone, 2‐mercaptoacetic acid and p‐anisialdehyde, ethyl chloroformate, glyoxal and thiourea to afford different N and S containing heterocycles. The reaction conditions were compared by conventional heating and microwave irradiation. The structures of the cyclization products were determined by analytical and spectroscopic data. All the synthesized compounds were screened for antibacterial activities in vitro.     

Studies on Synthesis of Novel Triazole Tagged Pyrazole Fused Naphthalene 5‐Thiazine‐5,5‐dioxide Derivatives,Their Antimicrobial,and Antioxidant Activity

A series of novel triazole tagged pyrazole fused naphthalene‐5‐thiazine‐5,5‐dioxide derivatives 8 and 9 were synthesized starting from sodium salt of saccharin 1 . The structure of each intermediate and products was established on the basis of spectroscopy data. All the synthesized compounds 8 and 9 were screened against various bacterial and fungal strains but found to show no activity up to 150‐µg/mL concentration. Further screening for antioxidant property resulted promising compounds.     

Green Synthesis,Antibacterial, and Antifungal Activities of 1,3,4‐Oxadiazines

1,3,4‐Oxadiazine derivatives were prepared via green and more sustainable procedure employing Grinding Chemistry. The green context of the procedure was evaluated by comparing its components with that of the conventional one. The antibacterial and antifungal activities of all the synthesized compounds were evaluated against some bacterial and fungal strains and showed promising results. The structures of the resulted compounds were identified and confirmed by elemental analysis and mass, ¹H‐NMR, and ¹³C‐NMR spectroscopies.     

Microwave Assisted Synthesis of Flavonoid Based 1,2,3-Triazole and Isoxazole Derivatives,Their Antibacterial,Antioxidant, and Anticancer Activities

Russian Journal of General Chemistry - New flavonoid based 1,2,3-triazole and isoxazole derivatives have been synthesized under microwave irradiation and conventional heating methods. Structures of...     

新型吡唑Schiff碱及金属配合物的合成和抑菌活性

以3-氨基-4-氰基吡唑和芳醛为原料合成了10个新型吡唑Schiff碱及铜(II)、镍(II)、锌(II)、钴(II) 4个金属配合物. 用元素分析, IR, 1H NMR及单晶解析表征了Schiff碱及金属配合物的结构. 测定了Schiff碱及金属配合物对金黄色葡萄球菌、大肠杆菌、枯草杆菌和绿脓杆菌的抑菌活性. 生物活性研究表明, Schiff碱及金属配合物对金黄色葡萄球菌、大肠杆菌和绿脓杆菌都有较好的抑菌效果, 其中铜(II)和锌(II)配合物对金黄色葡萄球菌和大肠杆菌的抑菌活性最好.     

Synthesis of 3-Substituted Pyrazole Derivatives by Mixed Anhydride Method and Study of Their Antibacterial Activities

A convenient synthesis of 3-substituted pyrazole derivatives by a mixed anhydride method using i-butylchloroformate and N-methylmorpholine at ?20 °C in tetrahydrofuran and study of in vitro antibacterial activities of the prepared compounds against Staphylococcus epidermidis, Bacillus subtilis, Pseudomonas aeruginosa, and Proteus valguris by agar-diffusion method were carried out. The results suggested that the products 4a, 4b, and 4c exhibited moderate to feeble inhibition against all test bacteria at greater concentration but 4d was best against Staphylococcus epidermidis (22 mm) and worst against Pseudomonas aeruginosa (16 mm) at the greatest concentration (2.5 mg/ml), and the activities decreased with decrease in concentration.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis and Herbicidal Activity of 1,2,4‐Triazole Derivatives Containing a Pyrazole Moiety

A series of triazole derivatives containing a pyrazole moiety were synthesized and characterized by ¹H NMR, ¹³C NMR, and HRMS. The herbicidal activities of these compounds were tested against lettuce and bentgrass. Most of the tested compounds were moderately herbicidal activity against lettuce and bentgrass. Among them, compounds 6f and 6g had the highest herbicidal activity (80% inhibitory) against lettuce and bentgrass.     

Synthesis and In Vitro Antibacterial Activities of Novel 2‐Aryl‐3‐(phenylamino)‐2,3‐dihydroquinazolin‐4(1H)‐one Derivatives

An efficient synthesis of novel 2‐aryl‐3‐(phenylamino)‐2,3‐dihydroquinazolin‐4(1H)‐one derivatives using KAl(SO₄)₂.12H₂O (Alum) as a catalyst from an aldehyde and 2‐amino‐N‐phenylbenzohydrazine in ethanol is described. All synthesized derivatives were screened for anti‐bacterial activity. Some compounds exhibited promising anti‐bacterial activity with reference to standard antibiotics.     

Synthesis and Antibacterial Activities of Novel Biphenyltetrazole Derivatives Bearing 1,3,4‐Oxadiazole

Several new 5‐[4′‐(5‐phenyl‐1,3,4‐oxadiazol‐2‐ylsulfanylmethyl)‐biphenyl‐2‐yl]‐tetrazoles derivatives have been synthesized. The structures of these new compounds were confirmed by elementary analyses and spectral data. The antibacterial activities of the compounds were also evaluated.     

含噻唑和1,2,3-三唑环的硫代磷酸肟酯的合成与生物活性

为了寻找高效、低毒的新型农用化学品,以2-氯-5-(氯甲基)噻唑为起始原料,设计合成了一系列新型含1,2,3-三唑和噻唑杂环的肟醚硫代磷酸酯衍生物,采用IR, 1H NMR, 31P NMR, MS和元素分析对其进行了结构表征。初步生物活性测试结果表明：该系列化合物具有中等程度的杀虫和杀菌活性。     

Green and Efficient Synthesis of 4‐Heteryl‐Quinolines and Their Antibacterial Evaluations

A green and efficient synthesis of 4‐heteryl‐quinolines ( 9a , 9b , 9c , 9d ), ( 10a , 10b , 10c , 10d ) and ( 11a , 11b , 11c , 11d ) has been described using PEG‐600 as a green solvent. Initially, 4‐chloro‐2‐methylquinolines ( 5a , 5b , 5c , 5d ) on reaction with aromatic heterocyclic thiols ( 6 ), ( 7 ), and ( 8 ) using PEG‐600 at 100°C for 30–40 min resulted in ( 9 ), ( 10 ), and ( 11 ) in good yields. Alternatively, ( 9 ), ( 10 ), and ( 11 ) could also be prepared in dimethylformamide using K2CO3 as base and tetrabutylammonium bromide as phase transfer catalyst at 100°C for 1–2 h. All the compounds were synthesized and characterized by IR, NMR, mass spectroscopy, and 13C NMR analysis. All synthesized compounds were screened for their antibacterial activity against clinical strains that include Gram‐positive (Bacillus subtilis MTCC 121, staphylococcus aureus MLS‐16 MTCC 2940, Micrococcus lutes MTCC 2470, and Staphylococcus aureus MTCC 96) and Gram‐negative bacteria (Candida albicans MTCC 3017, Klebsiella planticola MTCC 530, Escherichia coli MTCC 739, and Pseudomonas aeruginosa MTCC 2453). The results revealed that compounds ( 9a , 9d , 10a , 10c , 11b , and 11d ) exhibited significant antibacterial activity almost equal to the standard drug, that is, Ciprofloxacin.     

Synthesis,Reactions and Antimicrobial Activity of Some New Indolyl‐1,3,4‐Oxadiazole,Triazole and Pyrazole Derivatives

Indole‐3‐carboxylic acid hydrazide 3 was prepared and was treated with aromatic aldehydes in ethanol to give the corresponding hydrazone derivatives 4–7 in good yields. The indole carbohydrazide was incorporated into the 3‐indolyloxadiazoles 8–11 and 18 , 3‐indolyltriazoles 13–17 and 35 , 3‐indolylpyrazole derivatives 19–23 and carbamate derivatives 26–27 . Furthermore, interaction of the carboazide 24 with hydrazine hydrate in refluxing toluene afforded the corresponding semicarbazide derivative 30 . The thiadiazine derivative 34 was also prepared. Some of these compounds were screened in vitro for their antibacterial and antifungal activity.     

新型席夫碱的合成及其抑菌活性

以2,6-二甲基吡啶为原料合成了关键中间体2,6-吡啶二甲酰肼(3);3分别与醛或酮反应制得了一系列新型席夫碱(la～lf),产率50%～97qo,其结构经UV,NMR,IR和MS表征.初步生物活性测试结果表明,1对金黄色葡萄球菌、变形杆菌,大肠杆菌和芽孢杆菌均具有一定的抑菌活性,其中1d的抑菌活性最高.     

新型香豆素类衍生物的合成及其抗菌活性

以水杨醛及其衍生物为原料,通过缩合、水解、酰化、酯化四步反应合成了4个新的香豆素类衍生物-取代香豆素-3-酰水杨酸(4a～4d),其结构经uv,1H NMR,IR和元素分析表征.初步抗菌活性测试结果表明,4a-4d均有一定程度的抗真菌活性.     

Microwave‐Assisted Synthesis and Characterization of Novel Sulfonamide‐β‐Lactam Conjugates

New sulfonamide‐β‐lactam molecular conjugates 3 ( a – l ) have been generated through microwave‐assisted synthesis. β‐Lactams 1 ( a – e ) reacted with selected sulfonamides under microwave irradiation in the presence of KI and mediated by K₂CO₃ to afford conjugates 3 ( a – l ). All new compounds were structurally authenticated by spectroscopic and elemental analyses.     

Synthesis and Antibacterial Activity of Novel 1H‐indol‐2‐ol Derivatives

A series of novel 1H‐indol‐2‐ol derivatives were synthesized and evaluated their antibacterial activities against rice bacterial leaf blight, tobacco bacterial wilt, and citrus canker caused by Xanthomonas oryzae pv. oryzae (Xoo), Ralstonia solanacearum, and Xanthomonas axonopodis pv. citri via the turbidimeter test in vitro. Antibacterial bioassay indicated that most compounds demonstrated good inhibitory effect against Xoo and Ralstonia solanacearum. Especially, compound 4k demonstrated the best inhibitory effect against Xoo with half‐maximal effective concentration (EC₅₀) value of 8.27 μg/mL, which was even better than those of commercial agents Bismerthiazol and Thiodiazole copper.     

姜黄素-N-取代吡唑类衍生物合成及抑菌活性

为了寻求杀菌剂的新的先导化合物,用姜黄素与取代酰肼反应得到13个新的姜黄素-N-取代吡唑类衍生物,其结构经IR,1H NMR,13C NMR,MS和元素分析所表征,初步抑菌实验结果表明,在1×10-4mol/L浓度下,所有衍生物与姜黄素对比,对枯草杆菌、金黄色葡萄球菌、大肠杆菌、青霉、黑霉有较好的抑菌效果.其中,3,5-二(4-羟基-3-甲氧基苯基乙烯基)-N-脒基吡唑(3c),3,5-二(4-羟基-3-甲氧基苯基乙烯基)-N-(苯并噻唑-2-硫基乙酰基)吡唑(3k),3,5-二(4-羟基-3-甲氧基苯基乙烯基)-N-(香豆素-3-甲酰基)吡唑(3m)有优异的抑菌效果(抑菌圈16.34～23.81 mm).这些结果表明含有噻唑环、脒基、香豆素环取代基可能有助于提高姜黄素-N-取代吡唑类衍生物的活性.     

Synthesis of Some Novel Class of Peptides from α‐Amino Nitrones and Their Potential Biological Activities

α‐amino nitrones are found to have a great significance in the synthesis of peptides. Simple reaction methodology, high yield, and atom efficiency in these reactions have made this protocol highly attractive. The synthetic route may be extended to the synthesis of dipeptides in enantiomerically pure form. Potential biological activity of the newly synthesized peptides is the major application in this new methodology.     

An Efficient Synthesis of Novel 2‐(5‐indolyl)‐1H‐benzimidazole Derivatives and Evaluation of Their Antimicrobial Activities

In this paper, we report the synthesis of novel 2‐(5‐indolyl)‐1H‐benzimidazole derivatives. The methodology involves the Sonogashira reaction of 4‐(1H‐benzimidazol‐2‐yl)‐2‐bromo‐N,N‐dimethylaniline ( 3 ) with variety of terminal alkynes to get corresponding novel 4‐(1H‐benzimidazol‐2‐yl)‐2‐alkynyl‐N,N‐dimethylaniline derivatives ( 4 ). These compounds on iodocyclization afforded novel iodoindolylbenzimidazole derivatives ( 5 ). The resulting compounds were functionalized further via palladium‐mediated carbon–carbon bond formation for generating novel structurally diversified heterocyclic compounds. All these newly synthesized compounds were evaluated for antimicrobial activity.