Synthesis and antitumor evaluation of fluoroquinolone C3 fused heterocycles(Ⅱ):From triazolothiadiazines to pyrazolotriazoles

To further expand an effective modified route for the shift from an antibacterial fluoroquinolone（FQ） to an antitumor FQ,two series of title compounds based on an isostere of the FQ C3 carboxylic group with two fused heterocyclic rings,[1,2,4]triazolo[3,4- b][1,3,4]thiadiazine and pyrazolo[5,1-c][1,2,4]triazole,respectively,were designed and synthesized starting from the current antibacterial FQs,and their in vitro antitumor activity against L1210,CHO cell lines were evaluated via their respective IC₅₀ values.     

Synthesis and antibacterial activity of novel [1,2,4]triazolo [3,4-h][1,8]naphthyridine-7-carboxylic acid derivatives

Novel tricyclic fluoroquinolones,[1,2,4]triazolo[3,4-h][1,8]naphthyridine-8-one-7-carboxylic acid derivatives 4a-4h bearing carrying a functional Mannich-base moiety at the C-8 position,were synthesized and evaluated for their antimicrobial activity.The results showed that some compounds with a piperazine side chain exhibited comparable or better antibacterial activity than comparator cirprofloxacin.Furthermore,the targeted compounds also displayed a broad spectrum of activity against resistant strains including both Gram-negative and Gram-positive bacteria.In particular,compound 4h showed an MIC of 0.25 μg/mL in antibacterial assay against multiple drug-resistant Escherichia coli,which represents an about 30-fold increase of potency compared to ciprofloxacin.Thus,their excellent antibacterial activity against resistant strains suggests that triazole-fused fluoroquinolones warrant further optimization as novel anti-infective chemotherapies.     

Design,synthesis and biological evaluation of new rhodacyanine analogues as potential antitumor agents

In an attempt to develop potent antitumor agents,new rhodacyanine analogues containing the pyridinium ring（5a-5h）,the isoquinolinium ring（6a-6c） and the quinolinium ring（7a-7e） linked to the rhodanine ring via N-N covalent bond were designed, synthesized and evaluated for antitumor activity against human lung cancer cell line（H460） by MTT assay in vitro.Most of the tested compounds showed enhanced antitumor activity with IC₅₀ values ranging from 0.006 to 9.2 u,mol/L as compared to the lead compound MKT-077.Among them,the most promising compound 7d(IC₅₀ = 0.006μmol/L) was 216.7 times more active than MKT-077(IC₅₀ = 1.3μmol/L).The preliminary structure-activity relationship of the target compounds was discussed.     

Synthesis and Antibacterial Activities of Erythromycin Derivatives

Ten new erythromycin antibacterial agents containing amidino group were designed and synthesized from erythromycin via oximation, reduction and condensation. Their structures were confirmed by MS and ^13C NMR; the synthetic condition(reaction medium)was explored; and their in vtiro antibacterial activities were tested. Compound HMA-3 showed antibacterial activity against staphylococcus aureus, which is equivalent to that of erythromycin A. Compounds HMA-8 and HMA-4 also showed an antibacterial activitiy. But no compound showed bactericidal activity.     

Study on the synthesis and antimicrobial activity of novel cationic porphyrins

A novel series of quaternary ammonium cationic derivatives based on tetrapyridyl-porphyrin was synthesized.All the compounds were evaluated for their in vitro antibacterial activities against S.aureus,E.coli and P.aeruginosa,and antifungal activities against C.albicans,where microorganisms were exposed and unexposed to the irradiation.The results revealed that some of these compounds,especially,3a and 4a displayed satisfactory antibacterial activity against Gram-positive bacteria S.aureus and moderate an...     

Synthesis and structure-activity relationship of rhodomyrtone derivatives as antibacterial agent

To study structure-activity relationship of rhodomyrtone against Gram-positive bacteria,structural modification of rhodo-myrtone was carried out to afford its 10 analogues.All compounds were assayed for their antibacterial potency using broth microdilution method.The results indicated that rhodomyrtone exhibited higher antibacterial activity against all Gram-positive bacteria than its analogues,with the exception of rhodomyrtone 6,8-diacetate(3) and oxime analogues 6 and 7 which demonstrated similar activity as the parent compound against Bacillus subtilis and Staphylococcus epidermidis with minimum inhibitory concentration and minimum bactericidal concentration ranged from 1 to 4μg/mL and 2 to 4μg/mL,respectively.In contrast,all analogues displayed no activity against Acinetobacter baumannii.Hydroxyl and ketone groups of rhodomyrtone were elucidated to be essential for the antibacterial property.     

Synthesis,Docking and Biological Evaluation of Isoquinolonic Acid Derivatives

A series of isoquinolonic acid derivatives（4a-4o） was synthesized via one-pot synthesis for their anti-tumor activity. The structures of all the targeted compounds were confirmed by IH nuclear magnetic resonance （IH NMR） spectrometry and mass spectrometry（MS）. The anti-tumor activities of compounds 4a-4o against MG63（human osteosarcoma cells） and B16-F10（mouse melanoma cells） were examined. To evaluate the antitumor effect of the as-synthesized compounds, we compared the half maximal inhibitory concentration（1C50） of compounds 4a--4o to that of camptothecin（CPT） which appeared to be active against a broad range of human cancers. Among all the compounds, compound 41 shows the most potent biological activity against MG63 cells[IC50=（2.16i0.26） μmol/L] and B16-F10 cells[IC50=（6.95±0.24）μmol/L], thus providing useful information for the antitumor activity and potential practical use of isoquinolonic acid compounds. In addition, we screened out an efficient compound（41） that shows potential inhibit activity against Topoisomerase 1（Topo 1） by docking simulation.     

Synthesis and antibacterial activity of Schiff bases of 5-substituted isatins

Based on the existing reports on the bioactive isatin derivatives, a number of Schiff bases were synthesized by reacting 5-substituted isatins with bioactive amines/hydrazides and their structures were confirmed using spectroscopic methods such as NMR, IR and mass spectrometry. Furthermore, Nbenzylation of isatin followed by the Schiff base formation furnished a new series of compounds(11a–13c) which allowed the analysis of the effect of isatin N-substitution on the bioactivity of the resulting compounds. The antibacterial activity of the synthesized derivatives was evaluated using a microtiter plate method on a series of gram positive and gram negative bacterial strains. Compounds 2d, 3b, 5c and 6a were among the most potent derivatives against Pseudomonas aeruginosa(MIC = 6.25 μg/m L).Analysis of the structure–activity relationship showed that the incorporation of(thio)urea-based Schiff bases lead to more potent derivatives with a broader spectrum of antibacterial activity. In addition,highly lipophilic compounds such as 11a–12c did not show any measurable antibacterial activity, which implies that an optimal lipophilicity might be an important requirement for the antibacterial activity of the studied isatins. Finally, the finding that hydantoin derivatives of N-benzylisatins(13a–13c) still exhibit some antibacterial activity prompted us to consider exploring the bioactivity of more diverse derivatives of isatin-aminohydantoin Schiff bases(compounds 1a–1d) in our future studies.     

Synthesis and antitumor evaluation of C3/C3 fluoroquinolone dimers(Ⅰ):Tethered with a fused heterocyclic s-triazolo[2,1-b][1,3,4]thiadiazole

<正>Five C3/C3 fluoroquinolone dimers tethered with a fused heterocyclic ring of s-triazolo[2,1-b][1,3,4]thiadiazole derived from antibacterial quinoiones were synthesized and characterized,and their in vitro antitumor activity against L1210,CHO cell lines was evaluated via the respective IC_(50) values.     

Synthesis of Some N-Alkoxycarbonyl-N″-benzoyl-benzamidrazones（p-toluamidrazones） and 1,3,5-Trisubstituted 1,2,4-Triazole Derivatives from N-Benzoylimidates and their Antimicrobial and Anticancer Screening Studies

Some new N-alkoxycarbonyl-N″-benzoyl-benzamidrazones （p-toluamidrazones） 3a-3d, and 1,3,5-trisubstituted 1,2,4-triazole 4a-4h derivatives by starting from N-benzoylbenzimidates or N-benzoyl-p-toluimidates. The structures of compounds 3 and 4 were established on the basis of elemental analyses, IR, ^1H NMR, ^13C NMR and UV data. Antimicrobial experiments of the compounds performed by using agar-well diffusion and broth microdilution methods revealed that only compounds 3a-3d, 4a and 4b showed inhibitory effect only on Candida albicans ATCC 60193. However, compound 4b had also specific antibacterial activity against Staphylococcus aureus ATCC 25923. The other compounds showed neither antifungal nor antibacterial activities. Compounds 3a, 4a and 4b have been screened on three human tumor cell lines, breast cancer （MCF7）, non small cell lung cancer （NCI-H460）, and CNS cancer （SF-268） at the National Cancer Institute （NCI）, USA, which were found to exhibit low antiproliferative activity.     

Synthesis,antimicrobial, antiquorum-sensing and cytotoxic activities of new series of benzothiazole derivatives

New series of benzothiazole derivatives were designed and synthesized. The newly synthesized compounds were screened for their antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus cereus. Compounds 6j and 6o showed the highest activity against E. coli and S. aureus. The antifungal activity of these compounds was also tested against Candida albicans and Aspergillus fumigatus293. Compounds 4c, 4g and 6j exhibited the highest activity against C. albicans. In addition, compounds4 a and 6j displayed promising activity against A. fumigatus 293. The same compounds were examined for their antiquorum-sensing activity against Chromobacterium violaceum ATCC 12472, whereas compounds4 a, 6j and 6p showed moderate activity. The in vitro cytotoxicity testing of the synthesized compounds was performed against cervical cancer(Hela) and kidney fibroblast cancer(COS-7) cell lines. Results indicated that all tested compounds have IC50 values 50 mmol/L against both cell lines. Molecular properties, toxicities, drug-likeness, and drug score profiles of compounds 4a–c, 5a, 6g,h, 6j, 6l, 6o and7 c,d were also assessed.     

Synthesis,in vitro antitumor activity and molecular modeling studies of a new series of benzothiazole Schiff bases

A new series of benzothiazole Schiff bases 3–29 was synthesized and screened for antitumor activity against cervical cancer(Hela) and kidney fibroblast cancer(COS-7) cell lines. Results indicated that compounds 3, 14, 19, 27 and 28 have promising activity against Hela cell line with IC_(50) values of 2.41,3.06, 6.46, 2.22 and 6.25 mmol/L, respectively, in comparison to doxorubicin as a reference antitumor agent(IC_(50) 2.05 mmol/L). In addition, compound 3 displayed excellent activity against COS-7 cell line with IC_(50) value of 4.31 mmol/L in comparison to doxorubicin(IC_(50)3.04 mmol/L). In the present work,structure based pharmacophore mapping, molecular docking, protein-ligand interaction, fingerprints and binding energy calculations were employed in a virtual screening strategy to identify the interaction between the compounds and the active site of the putative target, EGFR tyrosine kinase. Molecular properties, toxicity, drug-likeness, and drug score profiles of compounds 3, 14, 19, 27, 28 and 29 were also assessed.     

Syntheses of Novel Flavones Containing Schiff Base Moiety

Flavones and their derivatives existing in naturae are commonly contained in plants. The members of the flavone class show a wide variety of biological activities, such as anti-inflammatory, antimierobial and antitumor activities. Sehiff bases have been intensively investigated due to their antibacterial activity and antitumor property.     

Synthesis, characterization and antibacterial properties of multifunctional hindered amine light stabilizers

A series of novel hindered amine light stabilizers containing an N-halamine moiety were designed and synthesized. Their structures were characterized by FT-IR, 1H NMR, and MS. The compounds were tested for antibacterial activity against Candida albicans, Staphylococcus aureus, and Escherichia coll. At a concentration of 0.5 mmol/L, these compounds all exhibited satisfactory antibacterial activity against all the three types of bacteria.     

Synthesis and antitumor activity of some new pyrazolo[1,5-α]pyrimidines

New series of pyrazolo[1,5-α]pyrimidine derivatives 7a-i,11a-c and Schiff bases 13a-c were synthesized and screened for their in vitro antitumor activity against three human carcinoma cell lines,namely colorectal carcinoma(HCT116),prostate adenocarcinoma(PC-3) and liver carcinoma(HepG-2) using MTT cytotoxicity assay at 100 μg/mL.Some of the tested compounds displayed good anticancer activities against HCT-116 and PC-3 cells.Whereas,compounds 7d and 11 a showed better antitumor activity than the rest of the compounds against both cell lines.A structure-activity relationship(SAR) has been discussed and structures of the newly synthesized compounds were confirmed by different spectral data(MS,IR,~1H NMR and ~(13)C NMR) and elemental analysis.     

Studies on condensed heterocyclic compounds II.Synthesis and antibacterial activity of 3-(4''''-pyridyl)-6-aroylamino/arylamino-S-triazolo[3,4-b]-1,3,4-thiadiazoles

3-(4′-Pyridyl)-4-amino-5-mercapto-1,2,4-triazole(1)reacted with aroyl isothiocyanates2a-1 to yield twelve novel 3-(4′-pyridyl)-6-aroylamino-S-triazolo[3,4-b]-1,3,4-thiadiazoles,4a-1.Triethylamine was necessary for the condensation of 1 with phenyl isothiocyanate(3)to give 3-(4′-pyridyl)-6-phenylamino-S-triazolo[3,4-b]-1,3,4-thiadiazole(6).The structures were confirmed bythe elemental and spectral analyses.Their antibacterial activity against B.Subtilis,E.Coli,E.aerogenes and S.aureus was observed preliminary.     

Phase Transfer Catalyzed Synthesis and Antibacterial Activity of Water-soluble S-Triazolo[3,4-b][1,3,4]thiadiazoles Containing Piperazine Group

6/3-（4-Chlorophenyl）-s-triazolo[3, 4-b][1, 3, 4]thiadiazoles （2,a-e） and （Sa-e） were synthesized respectively by intermolecular cyclization of 5-aryl / 4-chlorophenyl-4-amino-3- mercapto-1, 2, 4-triazoles （la-e） and （4） with 4-chlorobenzoic acid / aryl acids, which were condensed with piperazine under phase transfer catalyst TBAB to yield the corresponding free bases of monopiperazine derivatives and followed to form water-soluble salts （3a-e） and （6a-e） with hydrochloric acid in good yields. The in vitro biological results showed that piperazine group conjugated with the above fused heterocycles played an important role in antibacterial activity. The structures of novel compounds were confirmed by IR, ＇H NMR, MS and elemental analysis.     

Silver Chloride Loaded Mesoporous Silica Particles and Their Application in the Antibacterial Coatings on Denture Base

Thiol-functionalized MCM-41 type mesoporous silica particles（MSPs） were prepared and loaded with silver chloride to act as antibacterial agents. The antibacterial activity of the silver chloride loaded MSPs（AgCI-MSPs） was evaluated by the minimum bactericidal concentration（MBC） against Candida albieans（ATCC 10231）. The AgC1-MSPs with the highest antibacterial activity were then dispersed in hybrid coatings with different mass ratios to fabricate antibacterial coatings. The antibacterial activity of the coatings was tested against Candida albicans{ATCC 10231） and Streptococcus mutans（ATCC 25175）. The resulting antibacterial coatings exhibited high antibacterial activity, good adhesion to the substrate and high hardness.     

Synthesis and Antitumor Activity of Sorafenib Analogs Containing a Tetrazole Moiety

A novel series of diaryl biuret derivatives containing a tetrazole moiety was designed and synthesized.All the target compounds were evaluated for their in vitro antitumor activity against HT-29,HepG2,MCF-7 and A549 cells by MTT assay.Most of them exhibited obvious antitumor activity,and four of them(4a,4c,4h and 7a)were superior to sorafenib in general.Among them,Compound 4h displayed more potent activity than sorafenib in all tested cancer cells.Compound 4c exhibited the most outstanding activity in inhibition of growth of HepG2 cells(IC50=0.55 μmol/L).Further,they both revealed favorable metabolic stability in in vitro assay.Compounds 4c and 4h are promising candidates for further development.     

Synthesis and biological evaluation of new pyrrolopyrazinone compounds as potential antitumor agents

A series of pyrrolo[1,2-a]pyrazinone compounds(5a-9f) were synthesized,and their cytotoxic activity against SKOV-3,A549.HeLa cells in vitro were evaluated by the MTT method.Some of the compounds showed potential antitumor activity against three tumor cell lines.Among them,compounds 9c and 9d showed the most potent cytotoxic activity.The preliminary mechanism of action was discussed.