Synthesis and Antimicrobial Activity of Racemic 1,5‐Diols: 2‐(1,3‐Diaryl‐3‐hydroxypropyl)cyclohexan‐1‐ol Derivatives

A series of novel racemic 2‐(1,3‐diaryl‐3‐hydroxypropyl)cyclohexan‐1‐ol derivatives were synthesized from 1,5‐diketones. All the synthesized compounds were characterized by spectroscopic methods. The antibacterial activities of obtained chiral 1,5‐diols were investigated against four Gram‐positive and three Gram‐negative bacteria by determining of minimum inhibitory concentrations (MICs) in vitro. Compounds 3b , 3c , and 3d were found to be active against Enterococcus faecalis and Escherichia coli. In addition, compound 3j were found to be moderately active against all tested bacterial strains.     

Synthesis and Antimicrobial Activity of Novel Quinoxaline Derivatives

In this study, certain 3‐substituted styrylquinoxalin‐2(1H)‐ones ( 2a‐d ) and their 2‐chloro ( 3a‐d ) and 2‐piperazinyl derivatives ( 4a‐g ) were synthesized from 3‐methylquinoxalin‐2(1H)‐one ( 1 ). In addition, a series of 1‐alkyl‐3‐substituted styrylquinoxalin‐2(1H)‐ones ( 5a‐d ) was also prepared. Moreover, 3‐(N²‐arylidenehydrazinocarbonyl)quinoxalin‐2(1H)‐ones ( 8a‐c ) as well as their cyclized oxadiazolinyl derivatives ( 9a‐c ) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one ( 7 ). Furthermore, 3‐(5‐substituted thio‐1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐ones ( 11a‐c ) and ( 12a‐c ) were obtained from the intermediate compound ( 10 ) ‐ previously obtained via cyclization of ( 7 ) with CS₂. Likewise, 3‐(5‐oxo‐4,5‐dihydro‐(1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐one ( 13 ), 3‐[5‐(4‐nitrophenyl)‐1,3,4‐oxadiazol‐2‐yl]‐quinoxalin‐2(1H)‐one ( 14 ) and its 2‐chloro derivative ( 15 ) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one ( 7 ). Some of these derivatives were evaluated for antimicrobial activity in vitro and some of the tested compounds showed antibacterial or antifungal activity.     

A Facile Synthesis of New 4,6‐Dichloropyridine Derivatives,Their Biological Evaluation for Antimicrobial and Antioxidant Activity,and Docking Studies

A facile synthesis of new 4,6‐dichloropyridine derivatives 5 ( a–f ), 6 ( a–c ), and 7 ( a–c ) were synthesized using both conventional heating and solvent‐free microwave irradiation techniques. The results revealed that the latter method is superior to the conventional heating method. The easy work‐up of the products, rapid reaction, and mild conditions are noticeable features of this protocol. Structural elucidation of the synthesized compounds was made on the basis of various spectroscopic methods. The synthesized compounds were evaluated for their in vitro antimicrobial activity (minimum inhibitory concentration; MIC) against various microbial strains using the agar well‐diffusion method. Among the compounds, 5c showed best antimicrobial activity against most of the employed strains, especially against Staphylococcus aureus, Escherichia coli, Rhizopus arrhizus, and Candida albicans. Compounds 5a , 6a , 6c , 7a , and 7c showed significant antioxidant activity when compared to the other compounds. In addition to this, theoretical docking studies were performed for the highly potent compounds 5a , 6a , 6c , 7a , and 7c against three different drug targets belonging to the oxidoreductase family, and the results were found to be highly satisfactory.     

Liquid‐Phase Synthesis of 2‐Methyl‐2‐Aryloxypropanoic Acid Derivatives from Polyethylene Glycol) Supported 2‐Bromo‐2‐Methylpropanoate

An efficient liquid‐phase synthesis of 2‐methyl‐2‐aryloxypropanoic acid derivatives with good yields and high purity on soluble polyethylene glycol (PEG) has been developed by treatment of PEG‐bound 2‐bromo‐2‐methylpropanoate with phenoxides in the presence of a catalytic amount of NBu₄I and KI, and subsequent cleavage from the PEG.     

Synthesis and Structural Characterisation of Derivatives of Tricyclo[5.2.1.02,6]Dec‐8‐Ene‐3,5‐Dione with an Expected Antimicrobial Activity

Anhydrides, imides, N‐ethylimides, N‐hydroxyimides and N‐aminoimides of 1,4,5,6‐tetramethyl‐bicyclo[5.2.1.0^2,6]hept‐5‐ene‐2,3‐dicarboxylic acid, 1,4,5,6,7‐pentamethyl‐bicyclo[5.2.1.0^2,6]hept‐5‐ene‐2,3‐dicarboxylic acid and 7‐ethyl‐1,4,5,6‐tetramethyl‐bicyclo[5.2.1.0^2,6]hept‐5‐ene‐2,3‐dicarboxylic acid were obtained. Antimicrobial activity of the newly obtained derivatives was tested against selected Gram‐positive and Gram‐negative bacteria and fungi of the Candida species. The structures of obtained compounds and their antimicrobial activity were compared. Structure of 1b, 2b and 1e were determined by an X‐ray analysis.     

Antimicrobial Activity of Some Novel Thiourea,Hydrazine, Fused Pyrimidine and 2‐(4‐Substituted)anilinobenzoazole Derivatives Containing Sulfonamido Moieties

Thiophosgenation of sulfonamides 1a‐c in the presence of dilute HCl at room temperature furnished the isothiocyanatosulfonamides 2a‐c and treatment with aromatic amines gave 1,3‐disubstituted thioureas 3a,b . Also, interaction of two molecules of 2c with 1,4‐phenylenediamine yielded the novel bisthiourea 4 . Cyclocondensation of 2 with ortho amino carboxylic acid compounds such as anthranilic acids 8 , 5‐amino‐1‐phenyl‐pyrazol‐4‐carboxylic acid 9 and 4,5,6,7‐tetrahydro‐2‐amino‐benzo[b]thiophene‐3‐carboxylic acid 10 furnished the fused thiopyrimidines 11a‐d, 12 and 13 , respectively. 2‐Anilinobenzoazole derivatives 15a‐c, 16a, b and 17a,b were obtained through cyclocondensation of 2 with 1,2‐dinucleophiles.     

Synthesis,Antimicrobial and Anti‐HIV Activity of Some Novel Benzenesulfonamides Bearing 2,5‐Disubstituted‐1,3,4‐Oxadiazole Moiety

Twelve novel primary ( 4a‐c , 5a‐c ) and secondary ( 4d‐f, 5d‐f ) benzenesulfonamides bearing 2,5‐disubstituted‐1,3,4‐oxadiazole moiety have successfully been prepared by direct chlorosulfonation of phenyl substitutent present on the 2‐position of 5‐mercapto‐1,3,4‐oxadiazoles 2a‐c and their methylhio derivatives 3a‐c using chlorosulfonic acid under anhydrous conditions. Structures of the synthesized compounds were established by their physical and spectral data. Some of the synthesized compounds have been screened in vitro for their antimicrobial and anti‐HIV activity; the results were in accordance with SAR.     

Synthesis and Antimicrobial Activity of New 2,5‐Disubstituted 1,3,4‐Oxadiazoles and 1,2,4‐Triazoles and Their Sugar Derivatives

A series of new 2,5‐disubstituted‐1,3,4‐oxadiazole and 1,2,4‐triazole derivatives were synthesized by heterocyclization of acid hydrazide 1 and thiosemicarbazide derivative 2 . Furthermore, the acyclic C‐nucleoside analogs were prepared by cyclization of their corresponding sugar hydrazones by reaction with acetic anhydride. The antimicrobial activity of the prepared compounds was evaluated and some of the synthesized compounds revealed good activities against fungi.     

Synthesis,in vitro Antimicrobial,and Cytotoxic Activities of New 1,3,4‐Oxadiazin‐5(6H)‐one Derivatives from Dehydroabietic Acid

A series of new 1,3,4‐oxadiazin‐5(6H)‐one derivatives ( 6a–n ) of dehydroabietic acid were designed and synthesized as potential antimicrobial and antitumor agents. Their structures were characterized by IR, ¹H NMR, ¹³C NMR, MS, and elemental analyses. All the title compounds were evaluated for their antimicrobial activity against four bacterial and three fungal strains using the serial dilution method. Among them, compound 6e showed the highest antibacterial activity against Bacillus subtilis with a minimum inhibitory concentration (MIC) value of 1.9 μg/mL. In addition, the in vitro cytotoxic activities of the title compounds were also assayed against three human carcinoma cell lines (MCF‐7, SMMC‐7721, and HeLa) through the MTT colorimetric method. As a result, compounds 6b , 6g , 6k, and 6m exhibited significant inhibition against at least one cell line with IC₅₀ values below 10 μM. Compound 6m was especially found to be the most potent derivative with IC₅₀ values of 2.26 ± 0.23, 0.97 ± 0.11, and 1.89 ± 0.31 μM against MCF‐7, SMMC‐7721, and HeLa cells, respectively, comparable to positive control etoposide.     

Syntheses of Hitherto Unknown Thiazole,Ylidene and Pyridinethione Derivatives Having a Piperidin‐1‐yl Moiety and Their Use as Antimicrobial Agents

The novel hydrazone derivatives 2a‐c were prepared by treatment of aldehydes 1a,b with some hydrazines. Thiocarbamoyl functional group in compound 2a was subjected to cyclization reactions with some α‐halocarbonyl reagents and furnished the novel thiazoles 4‐6 , 8 and 9 . Enaminonitrile 10 and pyridinone 13 derivatives were synthesized by interaction of active methylene compound 2b with N,N‐dimethylformamide‐dimethylacetal and ketene dithioacetal 11 , respectively. Aliphatic, aromatic and heteroaromatic active methylene compounds were condensed with aldehydes 1a,b to afford the new ylidenes 15a‐d , 19a,b , 20 and 21 . Substituted pyridinethiones 22 and 23 were prepared in high yields by cyclocondensation of 15c with malononitrile and ethyl cyanoacetate, respectively. Indeno[1,2‐b]pyridines 26a,b were obtained by the reaction of ylidenes 19a,b with cyanothioacetamide in ethanol and in the presence of sodium ethoxide under reflux. The structures of the synthesized compounds were established from their analytical and spectral data. The prepared compounds were also screened for their antimicrobial activity.     

Synthesis and Antimicrobial Activity of Some Annelated Quinazoline Derivatives

A highly efficient and versatile synthetic approach to the synthesis of annelated quinazoline derivatives viz 1,2,4‐triazino[4,3‐c]quinazoline 5–7 , 11 , thiazolidinylquinazoline 9 , quinazolino[4,3‐b]quin‐azolin‐8‐one 12 and imidazoquinazolines 14a,b,15 is presented. Also, a variety of pyrazolylquinazolines 19–21 and pyrimidinylquinazolines 22a,b were obtained via a sequence of heterocyclization reactions of 4‐methyl‐N‐[4‐(4‐oxo‐3,4‐dihydroquinazolin‐2‐yl)phenyl]benzene‐sulfonamide ( 2 ) with different reagents. The new compounds were synthesized with the objective of studying their antimicrobial activity.     

Synthesis,Configuration, and Antimicrobial Properties of Novel Substituted and Cyclized ‘2′,3″‐Thiazachalcones’

Nine new thiazachalcone‐based drugs, compounds 1 – 9 , were prepared and fully characterized. The configurations of the photochemical‐dimerization products 7 – 9 were rationalized by semi‐empirical calculations. Both the experimental data and the theoretical calculations showed that the δ‐truxinic acid type dimer is the most stable isomer of all. All compounds were tested for their antibacterial and antifungal activities. The N‐alkylated congeners 4 – 6 showed strong antimicrobial activities against various bacteria and a yeast‐like fungus. The MIC and MBC values were as low as 0.1 μg/ml. All the compounds were active against the Gram‐positive bacterium Staphylococcus aureus.     

Synthesis of 4,6‐Dimethyldibenzothiophene and 1,2,3,4‐Tetrahydro‐4,6‐dimethyldibenzothiophene via Tilak Annulation

1,2,3,4‐Tetrahydro‐4,6‐dimethyldibenzothiophene was prepared by coupling 2‐bromo‐3‐methylcyclohexanone with 2‐methylbenzenethiol and annulating the product with the aid of polyphosphoric acid. A mixture of 1,2,3,4‐tetrahydro‐4,6‐dimethyldibenzothiophene and 4,6‐dimethyldibenzothiophene was prepared by coupling 2‐bromo‐3‐methylcyclohex‐2‐en‐1‐one with 2‐methylbenzenethiol and annulating the product with the aid of polyphosphoric acid. 2‐Bromo‐3‐methylcyclohexanone was synthesized by conjugate addition of Me₃Al to 2‐bromocyclohex‐2‐en‐1‐one with CuBr as catalyst and 2‐bromo‐3‐methylcyclohex‐2‐en‐1‐one by bromination? elimination of 3‐methylcyclohex‐2‐en‐1‐one. 1,2,3,4,4a,9b‐Hexahydro‐4,6‐dimethyldibenzothiophene was prepared by reduction of 1,2,3,4‐tetrahydro‐4,6‐dimethyldibenzothiophene with Zn and CF₃COOH.     

Synthesis and Antimicrobial Activity of Some Condensed [4‐(2,4,6‐Trimethylphenyl)‐1(2H)‐oxo‐phthalazin‐2‐yl]acetic Acid Hydrazide

Some new 1,2,4‐triazolo‐, 1,3,4‐oxadiazolo‐, 1,3,4‐thiadiazol‐, and pyrazolo‐2,4,6‐trimethylphenyl‐1(2H)‐oxo‐phthalazine derivatives were synthesized and identified by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. The new compounds were synthesized with the objective of studying their antimicrobial activity.     

新型N-（4，6-双取代嘧啶-2-基）-N’-（三氟甲基苯基）胍的合成，结构及生物活性研究

设计,合成了10种新型的胍衍生物,结构经FTIR, MS, 1H NMR 和元素分析确证,并且采用X-射线衍射分析方法确证了具有较好生物活性的化合物11a的结构。并且对这些化合物进行了除草活性测试,结果表明化合物11a,11b,11c在100µg·mL-1 对油菜具有较好的抑制作用,初步的KARI活性结果表明这些化合物对KARI的活性很弱。     

Synthesis,Spectral Characterization and Antimicrobial Activity of Some Transition Metal Complexes of 1,3‐Bis(1H‐benzimidazol‐2‐yl)‐2‐oxapropane

1,3‐Bis(1H‐benzimidazol‐2‐yl)‐2‐oxapropane ( L ) complexes with Fe(NO₃)₃, CoCl₂, Co(NO₃)₂, Ni(NO₃)₂, CuCl₂, Cu(ClO₄)₂, PdCl₂, CdI₂, Hg(NO₃)₂ were synthesized and characterized by elemental analysis, molar conductivity, magnetic moment, TGA, FT‐IR, NMR, ESI‐MS, fluorescence spectroscopy. Also, the crystal structure of 1,3‐bis(1H‐benzimidazol‐2‐yl)‐2‐oxapropane]dichlorocobalt(II), [Co( L )Cl₂], complex is reported that it has distorted trigonal bipyramidal geometry. Antibacterial activities of the compounds were evaluated using the disk diffusion method against six bacteria and Candida albicans. The Hg(II) complex shows superior activity toward S. epidermidis and E. coli whereas the other complexes are ineffective except the Co(NO₃)₂ complex: it showed weak activity toward all of the microorganisms.     

Synthesis of （S）-2-Ethoxy-3-Phenylpropanoic Acid Derivatives and Their Insulin-Sensitizing Activity

A series of （S）-2-ethoxy-3-phenylpropanoic acid derivatives were synthesized and their insulin-sensitizing activities were evaluated in 3T3-L1 cells. Compounds 1b, 1d, 1e and 1f exhibited more potent insulin-sensitizing activity than rosiglitazone.     

Synthesis and Antiproliferative Activities of OSW‐1 Analogues Bearing 2”‐O‐p‐Acylaminobenzoyl Residues†

OSW‐1 is a well‐known natural saponin with potent antitumor activities. We have designed and prepared a small library of 22 OSW‐1 analogues with a variety of p‐acylamino‐benzoyl groups installed at C2” of the xylose residue, wherein a regioselective (1→3)‐glycosylation of arabinoside 3,4‐diol has been achieved by manipulation of the protecting groups on the imidate donors. Bioassays lead to new structure‐activity relationships as well as two applicable fluorescent probes, which are found to localize to lysosomes in HeLa cells and could be used in further antitumor mechanism studies of OSW‐1 in living cells.