Synthesis and cytotoxicity of 2-methyl-1-substituted-imidazo [4,5-g]quinoline-4,9-dione and 7,8-dihydro-10H-[1,4]oxazino[3',4':2,3]imidazo[4,5-g]quinoline-5,12-dio ne derivatives

2-Methyl-1-substituted-imidazo[4,5-g]quinoline-4,9-diones and 7,8-dihydro-10H-[1,4]oxazino-[3',4':2,3]imidazo[4,5-g]quinoline-5, 12-dione (19) derivatives have been synthesized from 6,7-dichloro-5,8-quinolinedione for developing the new anticancer drugs. Our study on the cytotoxicity of imidazoquinolinedione derivatives has revealed that 7,8-dihydro-10H-[1,4]oxazino-[3',4':2,3]imidazo[4,5-g]quinoline-5, 12-dione (19), a tetracyclic heteroquinone analogue, exhibited high cytotoxicity on human colon tumor cell (HCT 15) in vitro SRB assay. The IC50 value of this compound was 0.026 microg/mL whereas those of doxorubicin and cisplatin were 0.023 microg/mL and 1.482 microg/mL, respectively. Meanwhile compounds 5-7 and 12 in the series of 1-substituted-imidazoquinolinediones showed relatively good activity on human brain tumor cell lines (XF 498).     

Synthesis of functionalized benzo[<Emphasis Type="Italic">f</Emphasis>]2<Emphasis Type="Italic">H</Emphasis>-chromenes and evaluation of their antimicrobial activities

Knoevenagel cyclocondensations of α-hydroxy naphthaldehyde with β-oxodithioesters and ketene dithioacetals yielded 2H-benzo[f]chromene-2-thiones and 2H-benzo[f]chromen-2-ones, respectively, in high yields. The newly synthesized compounds were evaluated for antifungal and antibacterial activities. Among them, compounds (2-furyl)(3-thioxo-3H-benzo[f]chromen-2-yl)methanone and phenyl(3-oxo-3H-benzo[f]chromen-2-yl)methanone exhibited excellent antifungal activity against tested fungi Curvularia lunata and Fusarium moniliforme. The highest antibacterial activity against the tested bacteria Escherichia coli and Staphylococcus aureus was observed for (4-chlorophenyl)(3-oxo-3H-benzo[f]chromen-2-yl)methanone. The results of antimicrobial screening demonstrate that (2-furyl)(3-thioxo-3H-benzo[f]chromen-2-yl)methanone, phenyl(3-oxo-3H-benzo[f]chromen-2-yl)methanone, and (4-chlorophenyl)(3-oxo-3H-benzo[f]chromen-2-yl)methanone are promising as antimicrobial drugs.     

A microwave-assisted facile regioselective Fischer indole synthesis and antitubercular evaluation of novel 2-aryl-3,4-dihydro-2H-thieno[3,2-b]indoles

A series of novel 2-aryl-3,4-dihydro-2H-thieno[3,2-b]indoles has been synthesised regioselectively in good yields from the reaction of 5-aryldihydro-3(2H)-thiophenones and arylhydrazine hydrochloride. This reaction is found to be assisted by microwaves. The thieno[3,2-b]indoles were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv (MTB) and multi-drug resistant M. tuberculosis (MDR-TB). Among 22 compounds screened, [2-(2,4-dichlorophenyl)-7-fluoro-3,4-dihydro-2H-thieno[3,2-b]indole] (6t) was found to the most active compound with MIC of 0.4 μg/mL against MTB and MDR-TB.     

Synthesis and antibacterial activity of some new benzo[5,6]chromeno[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidines

The synthesis and antibacterial activity of some new benzo[5,6]chromeno[2,3-d]pyrimidine derivatives are described. The title compounds were obtained by the reaction of 1H-benzo[f]chromenes with aliphatic and aromatic amines. The structures of all newly synthesized compounds were confirmed by IR, ¹HNMR, ¹³C NMR, and NOESY experiments. The compounds exhibited potent antibacterial activity against gram-positive and gram-negative bacterial species. 10-Methyl-12-(4-hydroxyphenyl)-10,12-dihydro-11H-benzo[5,6]chromeno[2,3-d] pyrimidin-11-imine displayed greater antibacterial activity against gramnegative bacterial species than did ciprofloxacinandamoxicillin.     

Identification of the 5,5-dioxo-7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine derivatives as highly selective PDE4B inhibitors

A PDE4B subtype selective inhibitor is expected to have a wider therapeutic window than non-selective PDE4 inhibitors. In this Letter, two series of 7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine derivatives and 5,5-dioxo-7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine derivatives were evaluated for their PDE4B subtype selectivity using human PDE4B2 and PDE4D2 full length enzymes. To improve their PDE4B selectivity over PDE4D, we optimized the substituents on the pyrimidine ring and the side chain phenyl ring, resulting in several derivatives with more than 100-fold selectivity for PDE4B. Consequently, we identified 2-(3-chloro-4-methoxy-phenyl)-5,5-dioxo-7,8-dihydro-6H-thiopyrano[3,2-d]pyrimidine derivative 54 as a highly selective PDE4B inhibitor, which had potent hPDE4B inhibitory activity with an IC₅₀ value of 3.0 nM and 433-fold PDE4B selectivity over PDE4D.     

Synthesis of novel bis(pyrimido[5,4-c]quinoline-2,4(1H,3H)-dione) and its derivatives: Evaluation of their antioxidant properties

One pot cyclocondensation reaction of barbituric/thiobarbituric acid with aromatic aldehydes and p-phenylenediamine/2,6-diaminopyridine by refluxing in glacial acetic acid afforded novel bis(pyrimido[5,4-c]quinoline-2,4(1H,3H)-diones)/pyrido bis(pyrimido[5,4-c]quinoline-2,4(1H,3H)-diones. All the synthesized compounds were screened for their antioxidant activities using FRAP and DPPH methods. Compounds with chloro substituents showed relatively good antioxidant properties.     

2-Substituted-1-(2-morpholinoethyl)-1H-naphtho[2,3-d]imidazole-4,9-diones: Design,synthesis and antiproliferative activity

Thirty-six of novel compounds 2-substituted-1-(2-morpholinoethyl)-1H-naphtho[2,3-d]imidazole-4,9-diones, bearing a N-(2-morpholinoethyl) group and a 2-substituted imidazole segment on a naphthoquinone skeleton, were designed, synthesized and tested as anticancer agents. Cytotoxicity was evaluated in vitro against three human cancer cell lines: human breast carcinoma cell line (MCF-7), human cervical carcinoma cell line (Hela), and human lung carcinoma cell line (A549); and one normal cell line: mouse fibroblast cell line (L929). Among them, the compound 2-(3-chloro-4-methoxyphenyl)-1-(2-morpholinoethyl)-1H-naphtho[2,3-d]imidazole-4,9-dione showed good antiproliferative activity against MCF-7, Hela and A549 (IC₅₀ values are equal to 10.6?μM, 8.3?μM and 4.3?μM respectively) and low cytotoxicity to L929 (IC₅₀ value is equal to 67.3?μM).     

Synthesis and antifungal activity of benzo[d]oxazole-4,7-diones

Benzo[d]oxazole-4,7-diones were synthesized and tested for in vitro antifungal activity against fungi. Among them tested, many compounds showed good antifungal activity. The results suggest that benzo[d]oxazole-4,7-diones would be potent antifungal agents.     

Synthesis and antifungal activity of furo[2,3-f]quinolin-5-ols

Furo[2,3-f]quinolin-5-ol derivatives were synthesized and tested for in vitro antifungal activity against Candida,Aspergillus species, and Cryptococcus neoformans. Among them tested, many furo[2,3-f]quinolin-5-ols showed good antifungal activity. The results suggest that furo[2,3-f]quinolin-5-ols would be promising antifungal agents.     

Reaction of naphthoquinones with substituted nitromethanes. Facile synthesis and antifungal activity of naphtho[2,3-d]isoxazole-4,9-diones

We report here a simple entry into naphtho[2,3-d]isoxazole-4,9-dione system containing a EWG in position 3 using the readily available 2,3-dichloro-1,4-naphthoquinone and nitromethyl derivatives in the presence of base. Antifungal activity of synthesised naphthoquinones was evaluated against ATCC and PYCC reference strains of Candida. The results suggest that the naphtho[2,3-d]isoxazole-4,9-dione scaffold has the potential to be developed into novel and safe therapeutic antifungal agents.     

Indolylmethylene benzo[h]thiazolo[2,3-b]quinazolinones: Synthesis,characterization and evaluation of anticancer and antimicrobial activities

A series of novel 10-((1H-indol-3-yl)methylene)-7-aryl-7,10-dihydro-5H-benzo[h]thiazolo[2,3-b]quinazolin-9(6H)-ones (8a–t) have been synthesized in good yields by the reaction of benzo[h]quinazoline-2(1H)-thiones (4a–f) with 2-chloro-N-phenylacetamide (5) followed by Knoevenagel condensation with various indole-3-carbaldehydes (7a–d) under conventional method. All the synthesized compounds were characterized by spectral studies and screened for their in vitro anticancer and antimicrobial activities. Compound 8c has exhibited excellent activity against MCF-7 (breast cancer cell line) than the standard drug Doxorubicin. Compound 8d against both the cancer cell lines, 8q against MCF-7 and 8c, 8h against HepG2 have also shown good activity. Remaining compounds have shown moderate activity against both the cell lines. Antimicrobial activity revealed that, the compound 8q and 8t against Staphylococcus aureus and 8i, 8k, 8l, 8q & 8t against Klebsiella pneumoniae have shown equipotent activity on comparing with the standard drug Streptomycin. Remaining compounds have shown significant antibacterial and comparable antifungal activities against all the tested microorganisms.     

Synthesis and antitubercular evaluation of amidoalkyl dibenzofuranols and 1H-benzo[2,3]benzofuro[4,5-e][1,3]oxazin-3(2H)-ones

A new class of amidoalkyl dibenzofuranols and 1H-benzo[2,3]benzofuro[4,5-e][1,3]oxazin-3(2H)-ones was synthesized in very good yields through polyphosphoric acid supported on silica (PPA-SiO₂) catalyzed one-pot three component condensation of 2-dibenzofuranol; aromatic aldehydes and acetamide or benzamide or urea under solvent free conditions. At 125 °C the reaction led to the formation of amidoalkyl dibenzofuranols 5a-k where as at 160 °C cyclization take place to give oxazin-3(2H)-one analogues 6a-e. Screening all the 16 compounds for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB) resulted 1-((4-chlorophenyl)(2-hydroxydibenzo[b,d]furanyl)methyl)urea 5h; 1-((4-bromophenyl)(2-hydroxydibenzo[b,d]furanyl)methyl)urea 5i; 1-phenyl-1H-benzo[2,3]benzo furo[4,5-e][1,3]oxazin-3(2H)-one 6a (MIC 3.13 μg/mL) and 1-(4-chlorophenyl)-1H-benzo[2,3]benzofuro[4,5-e][1,3]oxazin-3(2H)-one 6b; 1-(4-bromophenyl)-1H-benzo[2,3]benzofuro [4,5-e][1,3]oxazin-3(2H)-one 6c (MIC 1.56 μg/mL) as most active antitubercular agents.     

Synthesis and cytotoxicity of thieno[2,3-b]quinoline-2-carboxamide and cycloalkyl[b]thieno[3,2-e]pyridine-2-carboxamide derivatives

Seventy nine derivatives of thieno[2,3-b]quinolines, tetrahydrothieno[2,3-b]quinoline, dihydrocyclopenta[b]thieno[3,2-e]pyridine, cyclohepta[b]thieno[3,2-e]pyridine and hexahydrocycloocta[b]thieno[3,2-e]pyridine were either synthesized or obtained commercially and tested for their antiproliferative activity against HCT116, MDA-MB-468 and MDA-MB-231 human cancer cell lines. The most potent eight compounds were active against all cell lines with IC₅₀ values in the 80–250 nM range. In general hexahydrocycloocta[b]thieno[3,2-e]pyridines were most active with increasing activity observed as larger cycloalkyl rings were fused to the pyridine ring.     

Synthesis, biological assessment and molecular modeling of 14-aryl-10,11,12,14-tetrahydro-9H-benzo[5,6]chromeno[2,3-b]quinolin-13-amines

The synthesis and pharmacological evaluation of racemic 14-aryl-10,11,12,14-tetrahydro-9H-benzo[5,6]chromeno[2,3-b]quinolin-13-amines (19-28), prepared by Friedländer reaction of 3-amino-1-aryl-1H-benzo[f]chromene-2-carbonitriles (10-18) with suitable cycloalkanones is described. These molecules are potent, in the nanomolar range [IC₅₀ (EeAChE) = 7-101 nM], and selective inhibitors of acetylcholinesterase (AChE). The most potent inhibitor, 4-(13-amino-10,11,12,14-tetrahydro-9H-benzo[5,6]chromeno[2,3-b]quinolin-14-yl)phenol (20) [IC₅₀ (EeAChE) = 7 ± 2 nM] is four-fold more active than tacrine. Kinetic studies on compound 20 showed that this is a mixed-type inhibitor of EeAChE with a K_i of 5.00 nM. However, racemic 20 was unable to displace propidium iodide, suggesting that the inhibitor does not strongly bind to the peripheral anionic site (PAS) of AChE. Docking, molecular dynamics stimulations, and MM-GBSA calculations agree well with this behavior.     

Design,synthesis and in vitro anti-tuberculosis activity of benzo[6,7]cyclohepta[1,2-b]pyridine-1,2,3-triazole derivatives

A series of novel benzo[6,7]cyclohepta[1,2-b]pyridine-1,2,3-triazole hybrids (7a–j & 8a–j) have been designed and synthesized in excellent yields by Huisgen’s [3+2] cyclo addition reaction of 3-(azidomethyl)-2-methyl-6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-b]pyridine (5) with various alkynes 6 in presence of copper sulphate and sodium ascorbate and their structures were confirmed by IR, ¹H NMR, ¹³C NMR and HRMS. The newly synthesized compounds 7a–j & 8a–j were evaluated for their in vitro anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC 27294). Among the compounds tested, the compounds 7i and 8g displayed most potent activity with MIC value of 1.56?µg/mL with low cytotoxicity.     

Photorelease of amino acids from novel thioxobenzo[f]benzopyran ester conjugates

Aiming at the enhancement of the performance of (9-methoxy-3-oxo-3H-benzo[f]benzopyran-1-yl) methyl ester as photocleavable protecting group for the carboxylic acid function at long-wavelengths, 9-methoxy-3-thioxo-3H-benzo[f]benzopyran-l-valine and l-phenylalanine model conjugates were prepared through a thionation reaction of the corresponding oxo-benzobenzopyrans. These thioxobenzobenzopyran derivatives were subjected to photocleavage reactions in the same conditions as the parent oxo-benzobenzopyrans at different wavelengths of irradiation, and photocleavage data were obtained. It was found that the exchange of the carbonyl by a thiocarbonyl group enhanced the performance of the heterocyclic protecting group at 419?nm by improving the photolysis rates, making it an appropriate group for practical applications at long wavelengths.     

Cytotoxicity and DNA Topoisomerase Inhibitory Activity of Benz[f]indole-4,9-dione Analogs

A series of benz[f]indole-4,9-diones, based on the antitumor activity of 1,4-naphthoquinone, were synthesized and evaluated for their cytotoxic activity in cultured human cancer cell lines A549 (lung cancer), Col2 (colon cancer), and SNU-638 (stomach cancer), and also for the inhibition of human DNA topoisomerases I and II activity in vitro. Several compounds including 2-amino-3-ethoxycarbonyl-N-methyl-benz[f]indole-4,9-dione showed a potential cytotoxic activity judged by IC₅₀<20.0 μg/ml in the panel of cancer cell lines. Especially, 2-hydroxy-3-ethoxycarbonyl-N-(3,4-dimethylphenyl)-benz[f]indole-4,9-dione had potential selective cytotoxicity against lung cancer cells (IC₅₀=0.4 μg/ml)) compared to colon (IC₅₀>20.0 μg/ml) and stomach (IC₅₀>20.0 μg/ml) cancer cells. To further investigate the cytotoxic mechanism, the effects of test compounds on DNA topoisomerase I and II activities were used. In a topoisomerase I-mediated relaxation assay using human placenta DNA topoisomerase I and supercoiled pHOTI plasmid DNA, 2-amino-3-ethoxycarbonyl-N-(4-fluorophenyl)-benz[f]indole-4,9-dione had the most potent inhibitory activity among the compounds tested. However, most of the compounds showed only weak inhibition of the DNA topoisomerase II-mediated KDNA (Kinetoplast DNA) decatenation assay, except for 2-amino-3-ethoxycarbonyl-N-(4-methylphenyl)-benz[f]indole-4,9-dione and 2-amino-3-ethoxycarbonyl-N-(2-bromoehtyl)-benz[f]indole-4,9-dione with a moderate inhibitory activity. These results suggest that several active compounds had relatively selective inhibitory activity against toposiomearse I compared to toposiomerase II. No obvious correlation was observed between the cytotoxicity of the individual compound and the inhibitory activity of DNA relaxation and decatenation by topoisomerase I and II, respectively, in vitro.     

Design and synthesis of 4-[3,5-dioxo-11-oxa-4,9-diazatricyclo[5.3.1.02,6]undec-4-yl]-2-trifluoromethyl-benzonitriles as androgen receptor antagonists

A novel series of 4-[3,5-dioxo-11-oxa-4,9-diazatricyclo[5.3.1.0^2,6]undec-4-yl]-2-trifluoromethyl-benzonitriles has been synthesized. The ability of these compounds to act as antagonists of the androgen receptor was investigated and several were found to have potent activity in vitro and in vivo.     

Synthesis of indole-tethered [1,3,4]thiadiazolo and [1,3,4]oxadiazolo[3,2-a]pyrimidin-5-one hybrids as anti-pancreatic cancer agents

New indole-tethered [1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one (8a-j) and [1,3,4]oxadiazolo[3,2-a]pyrimidin-5-one hybrids (9a-e) were synthesized using [4+2] cycloaddition reactions of functionalized 1,3-diazabuta-1,3-dienes with indole-ketenes. All molecular hybrids were structurally characterized by spectroscopic techniques (IR, NMR, and HRMS) and screened for their anti-pancreatic cancer activity in vitro. The [1,3,4]oxadiazolo[3,2-a]pyrimidin-5-one hybrids (9a-e) showed stronger anti-pancreatic cancer activity than the [1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one hybrids (8a-j) against the PANC-1 cell line. Compound 9d bearing an ortho-chlorophenyl moiety emerged as the most potent anti-pancreatic cancer agent with an IC₅₀ value of 7.7 ± 0.4 µM, much superior to the standard drug Gemcitabine (IC₅₀ > 500 µM). The discovery of these [1,3,4]thiadiazolo and [1,3,4]oxadiazolo[3,2-a]pyrimidin-5-one hybrids elicits their potentials as pursuable candidates for pancreatic cancer chemotherapy.     

Practical and efficient synthesis of pyrano[3,2-c]pyridone,pyrano[4,3-b]pyran and their hybrids with nucleoside as potential antiviral and antileishmanial agents

A highly practical and efficient preparation of pyrano[3,2-c]pyridone and pyrano[4,3-b]pyran derivatives was developed via an ionic liquid mediated and promoted multi-component reaction of aldehyde (1), 4-hydroxy-pyridin-2(1H)-one or 4-hydroxy-2-pyranone (2), and malononitrile (3). As an application, a series of pyrimidine nucleoside-pyrano[3,2-c]pyridone or pyrano[4,3-b]pyran hybrids were efficiently obtained. These hybrid compounds were evaluated as potential antiviral and antileishmanial agents and showed encouraging biological activities.