Synthesis and antimicrobial activities of N-chloroacetyl-2,6-diarylpiperidin-4-ones

An array of new N-chloroacetyl-2,6-diarylpiperidin-4-ones has been synthesised and their antibacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Salmonella typhi, and antifungal activity against Cryptococcus neoformans, Candida albicans, Rhizopus sp., Aspergillus flavus, and Aspergillus niger examined. Compounds 14 against P. aeruginosa, 15 against S. typhi, 16 against S. aureus, and 19 against B. subtilis showed marked antibacterial activity. Similarly, compounds 15 and 19 against A. niger and 19 against A. flavus exerted significant antifungal activities.     

Synthesis of 4-aminoantipyrine Schiff bases and their antimicrobial activities

Various compounds of 4-aminoantipyrine Schiff bases (M₁–M₁₂) were synthesized via a condensation reaction of 4-aminoantipyrine with different benzaldehydes through a conventional method of refluxing the mixture for 3–4 h. The synthesizedSchiff bases were characterized by using elemental analyses, FT-IR, UV-Vis, Mass, ¹H and ¹³C NMR spectroscopy. The antimicrobial activity of the synthesized Schiff bases was investigated against 12 bacterial strains(Mycobacterium smegmatis, Bacillus cereus, Bacillus subtilis, Enterococcus faecalis, Staphylococcus epidermidis, Klebsiella pneumonia, Escherichia coli, Enterobacter cloacae,Klebsiella oxytoca, Proteus vulgaris, Enterobacter aerogenes, and Pseudomonas aeruginosa), and antifungal activities were tested against seven fungal strains (Aspergillus flavus, Aspergillus carbonarious, Aspergillus parasiticus, Aspergillus fumigatus,Aspergillus niger, Fusarium verticillioides and Fusarium proliferatum). The antimicrobial activities of the synthesized compounds were compared with standard streptomycin and nalidixicacid. The results obtained from antibacterial assay indicated that M₁–M₁₂ inhibited potential growth of Proteus vulgaris with minimum inhibitory concentrations (MICs) ranging from 15.6–250 µg/mL compared with the standard nalidixic acid with an MIC of 500 µg/mL. Moreover, we could conclude that most of the tested compounds experienced mild to low activities at 15.6 µg/mL. Their activities could be attributed to their low concentrations.The antifungal analysis showed that the tested fungi were not sensitive to the prepared Schiff bases at the prepared concentration of 500 µg/mL. Therefore, we recommended further analysis on both cytotoxicity and minimum bactericidal concentration (MBC) to ascertain their potential effects against human cells.     

Synthesis and antimicrobial activity of [2-[2-(N,N-disubstituted thiocarbamoyl-sulfanyl)-acylamino] thiazol-4-yl]acetic acid ethyl esters

[2-[2-(N, N-Disubstituted thiocarbamoyl-sulfanyl)acylamino ]thiazol-4-yl]acetic acid ethyl esters (3a-x) were synthesized by the reaction of potassium salts of N, N-disubstituted dithiocarbamoic acids with [2-(2-chloroalkanoyl)amino-thiazol-4-yl]acetic acid ethyl esters. The structures of the synthesized compounds were confirmed by elemental analyses, UV, IR, (1)H-NMR, and EI mass spectral data. The antimicrobial activities of all the compounds were investigated by microbroth dilution technique using Mueller-Hinton broth and Mueller-Hinton agar. In this study, Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa AT CC 1539, Salmonella typhi, Shigella flexneri, Proteus mirabilis ATCC 14153 and Candida albicans ATCC10231 were used as test microorganisms. Among the tested compounds 3a, d, e, f, h, k, w activity against S. epidermidis ATCC 12228 (MIC: 156 mg/L, 78 mg/L, 62.5 mg/L, 78 mg/L, 62.5 mg/L, 312 mg/L, 250 mg/L, respectively), compound 3d had some activity against S. aureus ATCC 6538 (MIC: 156 mg/L) and C. albicans ATCC 10231(MIC: 156 mg/L). Compounds 3l, 3x also evaluated for antituberculosis activity against Mycobacterium tuberculosis H37Rv using the BACTEC 460 radiometric system and BACTEC 12B medium. The preliminary results indicated that all of the tested compounds were inactive against the test organism.     

Synthesis and screening of analgesic and anti-inflammatory activity of 6-acyl-3-(4-substituted benzoylmethyl)-2(3H)-benzoxazolones

In this study, the synthesis and analgesic and anti-inflammatory activities of some new 6-acyl-3-(4-substituted benzoylmethyl)-2(3H)-benzoxazolone derivatives are reported. Their structures were confirmed by microanalysis, IR and NMR spectral analysis. Their analgesic activities were determined by using modified Koster method, and antiinflammatory activities were determined by using Peacock Dial Thickness Gauge Ozaki.     

Synthesis and evaluation of anticonvulsant and antimicrobial activities of 3-hydroxy-6-methyl-2-substituted 4h-pyran-4-one derivatives

In this study, thirteen 3-hydroxy-6-methyl-2-substituted 4H-pyran-4-one derivatives were synthesized for the evaluation of their potential anticonvulsant activity. Mannich bases were prepared by the reaction of substituted piperazine derivatives with allomaltol and formaline. The structures of the synthesized compounds were confirmed by IR, (1)H-NMR and elemental analysis. Their anticonvulsant activities were determined in vivo by maximal electroshock (MES), sub-cutaneous Metrazol (scMet), and rotorod toxicity tests for neurological deficits. The antimicrobial activities of the synthesized compounds were investigated in vitro against some bacteria and fungi using the microdilution broth method. Ac-cording to the activity studies, 3-hydroxy-6-methyl-2-[4-(2-trifluoromethyl-phenyl)-piperazin-1-ylmethyl]-4H-pyran-4-one (3i) was the compound determined to be most active in the scMet test for all doses at four hours and for the 300 mg/kg dose at half an hour. 2-[4-(4-Chloro-phenyl)-piperazin-1-ylmethyl]-3-hydroxy-6-methyl-4H-pyran-4-one (3f) was found to be protective against MES whereas 2-chlorophenyl derivative (3e) was not. Looking at the antifungal activity results, compounds 3b, 3h, and 3i were determined to have activity against all fungi.     

Synthesis and biological activity of ethyl 2-(substituted benzylthio)-4-(3'-(ethoxycarbonyl)biphenyl-4-yl)-6-methyl-1,4-dihydropyrimidine-5-carboxylate derivatives

In the present study, a new series of ethyl 2-(substituted benzylthio)-4-(3'-(ethoxycarbonyl)-biphenyl-4-yl)-6-methyl-1,4-dihydropyrimidine-5-carboxylate derivatives was synthesized. The newly synthesized compounds were characterized by (1) H-NMR, mass and C, H, N analyses. All newly synthesized compounds were screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes and Klebsiella pneumoniae) and antifungal (Aspergillus flavus, Aspergillus fumigatus, Candida albicans, Penicillium marneffei and Trichophyton mentagrophytes) activity. The results revealed that all synthesized compounds have a significant biological activity against the tested microorganisms. Compounds 8a, 8b, 8c, 8e, 8f, 8i, and 8j exhibited good antimicrobial activity.     

Synthesis, antibacterial, and antifungal activities of biolabile (E)-1-(4-morpholinophenyl)-3-aryl-prop-2-en-1-ones

Abstract  A collection of biolabile (E)-1-(4-morpholinophenyl)-3-aryl-prop-2-en-1-ones 8–13 are synthesized, characterized by melting point, elemental analysis, mass spectroscopy (MS), Fourier-transform infrared (FT-IR), and ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopic data and evaluated for their in vitro antibacterial and antifungal activities. Compounds 8–13 exerted a wide range of antibacterial activities against all tested Gram-positive and Gram-negative bacterial strains. All the compounds 8–13 were more active against Pseudomonas. Of the synthesized compounds, compounds 9 and 11 exhibited a wide range of antibacterial activities against Staphylococcus aureus, β-Heamolytic streptococcus, Escherichia coli, Klebsiella pneumonia, and Pseudomonas. Compounds 10, 12, and 13 exerted strong antifungal activities against all tested fungal strains, namely Aspergillus flavus, Mucor, Rhizopus, and Microsporum gypsuem. Graphical Abstract        

Synthesis of new 3-(substituted phenacyl)-5-[3'-(4H-4-oxo-1-benzopyran-2-yl)-benzylidene]-2,4-thiazolidinediones and their antimicrobial activity

Synthesis of 3-(3-nitrophenacyl)thiazolidine-2,4-dione 2g and 3-(substituted phenacyl)-5-[3'-(4H-4-oxo-1-benzopyran-2-yl)-benzylidene]-2,4-thiazolidinediones 4a-g are reported in this paper. These compounds 4a-g were prepared from 3'-flavone carboxaldehyde and 3-substituted phenacyl-2,4-thiazolidinediones using Knoevenagel reaction. The structures of all compounds were confirmed by IR, 1H-NMR, mass spectral data, and elemental analyses. The molecules 4a-g were evaluated for in-vitro antimicrobial activity against Staphylococcus aureus, Candida albicans, Candida krusei, Candida glabrata, and Candida parapsilosis. Compounds 4c and 4f showed better inhibitory activity when compared to fluconazole against Candida krusei and Candida glabrata.     

2—（2，4—二氟苯基）—3—（N—甲基—N—取代磺酰胺基）—1—（1H—1，2，4—三唑—1—基）—2—丙醇的合成和抗真菌活性的研究

本文设计合成了10个新的具有3－取代磺酰胺基－2－芳基－1－三唑基结构特征的三氮唑类化合物作为真菌细菌色素P450 14α－去甲基化酶的抑制剂。体外抗真菌活性试验表明化合物1b,1c,和1g对白色念珠菌,近平滑念珠菌和裴氏着色菌具有较强的抑菌活性,但总体来说活性不如酮康唑。与标准对照品氟康唑相比,化合物1b,1c和1g对近平滑念珠菌的作用分别比氟康唑强32倍,16倍和4倍;对裴氏着色菌的抑制作用分别双氟康唑强4倍,8倍和8倍。     

Synthesis of certain substituted quinoxalines as antimicrobial agents (part II)

Several fused triazolo and ditriazoloquinoxaline derivatives such as 1-aryl-4-chloro-[1,2,4]triazolo[4,3-a]quinoxalines (3a-d), 4-alkoxy[1,2,4]triazolo[4,3-a]quinoxalines (4a,b), 4-substituted-amino-[1,2,4] triazolo[4,3-a]quinoxalines (5a-h), 1-(aryl)-[1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-thione (6), 4-(arylidenehydrazino)1-phenyl-[1,2,4]triazolo[4,3-a]quinoxalines (10a-e) and [1,2,4]ditriazolo[4,3-a:3',4'-c]quinoxaline derivatives (11-13) have been synthesized and some of these derivatives were evaluated for antimicrobial and antifungal activity in vitro. It was found that compounds 3a and 9b possess potent antibacterial activity compared to the standard tetracycline.     

Synthesis and antibacterial evaluation of 1beta-methyl-2-(5-substituted heterocyclic carbamoyl)pyrrolidin-3-ylthio)carbapenem derivatives

The synthesis of a new series of 1beta-methylcarbapenems having a substituted heterocyclic carbamoyl pyrrolidine moiety is described. Their in vitro antibacterial activity against both gram-positive and gram-negative bacteria was tested, and the effect of heterocyclic substituents on the pyrrolidine was investigated. One particular compound (III(d)) having a substituted oxadiazole moiety showed the most potent antibacterial activity.     

Synthesis and antibacterial activity of 1 beta-methyl-2-(5-substituted imidazolino pyrrolidin-3-ylthio)carbapenem derivatives

The synthesis of a new series of 1 beta-methylcarbapenems containing a substituted imidazolino pyrrolidine moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of the substituent on the imidazoline ring was investigated. Compound 13 g which has a N-sulfonylmethyl substituted imidazoline moiety showed the most potent antibacterial activity.     

Synthesis, antiviral, antituberculostic, and antibacterial activities of some novel, 4-(4-substituted phenyl)-6-(4-nitrophenyl)-2-(substituted imino)pyrimidines

A variety of novel 4-(4-substituted phenyl)-6-(4-nitrophenyl)-2-substituted imino) pyrimidines were synthesized by reacting 4-(4-substituted phenyl)-6-(4-nitrophenyl)-2-amino pyrimidines with different substituted aromatic aldehydes, coumarin chloroisatin. The 4-(4-substituted phenyl)-6-(4-nitrophenyl)-2-amino pyrimidines were synthesized by reacting 3-(4'-substituted phenyl)-1-(4-nitrophenyl)-2-propen-1-ones with guanine hydrochloride. 3-(4-Substituted phenyl)-1-(4-nitrophenyl)-2-propen-1-ones were synthesized by reacting 4-nitroacetophenone with different para-substituted aromatic aldehydes. Spectral data (IR, NMR, and mass spectra) confirmed the structures of the synthesized compounds. The synthesized compounds were investigated for their antiviral, antituberculostic, and antibacterial activities. The results of antiviral, antituberculostic, and antibacterial activities indicated that the synthesized compounds exhibited mild to potent activities compared to the respective reference standards.     

Synthesis and antibacterial activity of 1beta-methyl-2-(5-substituted oxadiazolo pyrrolidin-3-yl-thio)carbapenem derivatives

Synthesis of a new series of 1beta-methylcarbapenems with a substituted oxadiazolopyrrolidine moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of the substituent on the oxadiazole ring investigated. In particular, compounds 13a and 13c with ester and carbamoyl substituted oxadiazole moieties showed the most potent antibacterial activity.     

Synthesis and antifungal activities of some aryl (3-methyl-benzofuran-2-yl) ketoximes

In this study, some aryl (3-methyl-benzofuran-2-yl) ketoximes and their ethers and esters were synthesised. The structure elucidation of the compounds was performed by IR, 1H-NMR, MASS spectroscopy and elemental analyses. Antifungal activities of the compounds were examined and moderate activity was obtained.     

7-[3-氨甲基-4-(脲亚氨基)吡咯烷-1-基]喹诺酮衍生物的合成与抗菌作用研究

目的 寻找新的喹诺酮类抗菌药.方法 设计合成7-位具有较强亲水性取代基的7个氟喹诺酮衍生物,测定其体外抗菌活性.结果 化合物10对金葡菌(包括MRSA)和表葡菌(包括MRSE)的活性(MIC:0.06～4μg/mL)与左氧氟沙星和吉米沙星基本相当.化合物11对肺炎链球菌08-2的活性(MIC:0.25μg/mL)分别是左氧氟沙星和吉米沙星的128倍和32倍,化合物12对肺炎克雷伯菌09-22和09-23的活性(MIC:1μg/mL)分别是左氧氟沙星和吉米沙星的16倍和4倍,但目标物对革兰阴性菌的活性普遍弱于对照药.结论 7-位取代基的水溶性并非决定喹诺酮抗菌活性的主要因素.     

The antimicrobial activities of some 1,4-naphthalenediones (III)

In order to evaluate the antimicrobial effect of 2,3-disubstituted-1,4-naphthalenedione derivatives, we synthesized several 2-chloro, 2-bromo and 2-hydroxy-3-(substituted)-1,4-naphthalenediones (1–25). These derivatives were tested for antifungal and antibacterial activities,in vitro, againstCandida albicans 10231 and local,Aspergillus niger KCTC 1231,Tricophyton mentagrophytes KCTC 6085,Bacillus subtilis ATCC 6633,Pseudomonas aeruginosa NCTC 10490,Staphylococcus aureus ATCC 6538p,Escherichia coli NIHJ. The MIC values were determined by the two-fold agar dilution/streak method. Among these derivatives, 4, 5 and 6 showed the potent antifungal activities. Also 5 and 6 had the antibacterial activities. 5 with (1,2,4-triazolyl)-amino moiety was the most effective in preventing the growth of fungi, such asCandida albicans, Aspergillus niger andTricophyton mentagrophytes.     

Synthesis of 2-azetidinones from 2-diazo-1, 2-diarylethanones and N-(2-thienylidene)imines as possible antimicrobial agents

An equimolar reaction of 2-diazo-1, 2-diarylethanones with N-(2-thienylidene)imines affords 1-substituted-3, 3-diaryl-4-(2-thienyl)-2-azetidinones in excellent yields. The products have been characterized on the basis of satisfactory analytical and spectral (IR, 1H and 13C NMR, MS) data. The mechanism of formation of the products is shown. The antimicrobial activity of the compounds against some Gram(+) and Gram(-) bacteria, and fungi is reported.     

2-(2-苄氧羰基氨基噻唑-4-基)-5-(3-甲基-2-丁烯氧羰基)-2-戊烯酸的合成

对头孢布烯的关键中间体2-(2-苄氧羰基氨基噻唑-4-基)-5-(3-甲基-2-丁烯氧羰基)-2-戊烯酸(1)的合成工艺进行了研究。选用国内易得的(2-氨基噻唑-4-基)乙酸甲酯(2)作为起始原料,经过氨基保护、M ichae l加成-消除和选择性酯化三步反应制得目标化合物1,反应总收率63.0%。该工艺操作简单,生产成本低,适合工业化生产。     

Synthesis and evaluation of novel E-2-(2-thienyl)- and Z-2-(3-thienyl)-3-arylacrylonitriles as antifungal and anticancer agents

A series of 3-aryl-2-(2-thienyl)acrylonitriles 7 and 3-aryl-2-(3-thienyl)acrylonitriles 8 were synthesized by the reaction of aromatic aldehydes 6 with 2- and 3-thienylacetonitriles 4 and 5, and evaluated for antifungal and cytotoxic activities against a panel of opportunistic and pathogenic fungi and three different cancer cell lines, respectively.