Paolo Sanna

Novel substituted quinoxaline 1,4-dioxides with in vitro antimycobacterial and anticandida activity.

Thirty-six 6(7)-substituted-3-methyl- or 3-halogenomethyl-2-phenylthio-phenylsulphonyl-chloro-quinoxaline 1,4-dioxides belonging to series 3-6 were synthesised and submitted to a preliminary in vitro evaluation for antimycobacterial, anticandida and antibacterial activities. Antitubercular screening showed a generally good activity of 3-methyl-2-phenylthioquinoxaline 1,4-dioxides (3d,e,h-j) against Mycobacterium tuberculosis, and exhibited MIC between 0.39 and 0.78 microg mL(-1) (rifampicin MIC=0.25 microg mL(-1)), whereas in compounds 4d,e, 5a,b,d,e,l and 6b-e,j,l MIC ranged between 1.56 and 6.25 microg mL(-1). Results of the antibacterial and anticandida screening showed that 6e and 6l exhibited MIC=0.4 and 1.9 microg mL(-1), respectively, against Candida krusei (miconazole MIC=0.9 microg mL(-1)), and 4i, 5b,d, 6e, MIC=3.9 microg mL(-1) against Candida glabrata (miconazole MIC=0.4 microg mL(-1)), while compounds 3d,l, 5e,l, and 6b,d,e,l showed MIC=15.6 microg mL(-1) against Vibrio alginolyticus.

Synthesis and antitubercular activity of 3-aryl substituted-2-(1H(2H)benzotriazol-1(2)-yl)acrylonitriles

A series of 22 3-aryl substituted-2-(1H(2H)-benzotriazol-1(2)-yl)acrylonitriles was synthesized for a preliminary in vitro evaluation of antitubercular activity according to an international program with the Tuberculosis Antimicrobial Acquisition & Coordinating Facility (TAACF). This work reports the synthetic approach and analytical and spectroscopic characterization (UV, IR, 1H- and 13C-NMR) of all compounds synthesized. Several compounds showed an interesting activity in the preliminary screening with a percent growth inhibition of the virulent Mycobacterium tuberculosis between 40 and 99% at the concentration of 12.5 microg/mL. The most effective derivatives E-5a and E-5e were also tested against M. avium in vitro.

Novel functionalized pyrido[2,3-g]quinoxalinones as antibacterial, antifungal and anticancer agents

A series of twelve novel pyrido[2,3-g]quinoxalinones (3-14), variously substituted at the C-3 position, was synthesized, structurally determined and submitted to a preliminary in vitro evaluation for antibacterial, anticandida and anticancer activities. Results of the antimicrobial screening showed that all compounds, with the exception of 6, 11 and 12, exhibited interesting activity against all strains tested; while compound 10 was found to have encouraging in vitro anticancer activity at a concentration of l0(-4) M.

Synthesis of substituted 2-ethoxycarbonyl- and 2-carboxyquinoxalin-3-ones for evaluation of antimicrobial and anticancer activity

A series of variously substituted quinoxalin-3-ones bearing an ethoxycarbonyl or carboxy group in the C-2 position has been prepared and their structures proved by 1H NMR spectroscopy. The obtained compounds were investigated in vitro for antimicrobial and anticancer activities. Preliminary results showed a moderate activity against a few strains of bacteria but no significant anticancer and anti-HIV activity.

Preparation and biological evaluation of 6/7-trifluoromethyl(nitro)-, 6,7-difluoro-3-alkyl (aryl)-substituted-quinoxalin-2-ones: Part 3

A new series of quinoxalinones 6/7-trifluoromethyl or nitro- and 6,7-difluoro substituted bearing various side-chains (alkyl, halogenoalkyl, benzyl and phenyl groups) at C-3 of the ring system was synthesized and submitted to preliminary in vitro evaluation for antibacterial, antifungal, antimycobacterial, anticancer and anti-HIV activities. Results of these screenings showed that compounds 23-28 exhibited a good inhibition activity against various strains of Candida. Compound 24 showed also an interesting in vitro anticancer activity.

Synthesis and antiproliferative activity of 3-aryl-2-(1H-benzotriazol-1-yl)acrylonitriles. Part III

A new series of 30 3-aryl-2-(1H-benzotriazol-1-yl)acrylonitriles were synthesized and tested for biological activity as part of our research in the antimicrobial and antitumor fields. In particular, title compounds were evaluated in vitro against representative strains of Gram-positive and Gram-negative bacteria (S. aureus, Salmonella spp), mycobacteria (M. fortuitum, M. smegmatis ATCC 19420 and M. tuberculosis ATCC 27294), yeast and mould (C. albicans ATCC 10231 and A. fumigatus). Furthermore, their antiretroviral activity against HIV-1 was determined in MT-4 cells together with cytotoxicity. In these assays title compounds and 47 additional derivatives described previously (P. Sanna, A. Carta, M.E. Rahbar Nikookar, Eur. J. Med. Chem. 35 (2000) 535-543; P. Sanna, A. Carta, L. Gherardini, M.E. Rahbar Nikookar, Farmaco 57 (2002) 79-87) were tested for their capability to prevent MT-4 cell growth. All compounds resulted devoid of antibacterial, antifungal and anti-HIV-1 activity. In anti-mycobacterial assays several compounds resulted active (MIC(50)=6.0-70 microM) against M. tuberculosis. However, since they showed cytotoxicity against MT-4 cells at lower concentrations (CC(50)=0.05-25 microM), their anti-mycobacterial activity was not selective. For this reason, the most cytotoxic compounds were also evaluated for antiproliferative activity against a panel of human cell lines derived from both hematological and solid tumors. Compound 34 resulted the most potent compound against the above human tumor-derived cell lines.

Synthesis and antimycobacterial activity of 3-aryl-, 3-cyclohexyl- and 3-heteroaryl- substituted-2-(1H(2H)-benzotriazol-1(2)-yl)prop-2-enenitriles, prop-2-enamides and propenoic acids. II.

A series of 32 3-aryl-, 3-cyclohexyl-, and 3-heteroaryl-substituted-2-(1H(2H)-benzotriazol-1(2)-yl)-prop-2-enenitriles, prop-2-enamides and propenoic acids, was synthesized as a part of our research in the antitubercular field, according to an international program with the Tuberculosis Antimicrobial Acquisition and Coordinating Facility (TAACF). This work reports the preparation and analytical and spectroscopic characterization (MS, UV, IR, 1H NMR) of all compounds synthesized. Among these only a few compounds (E-4b,c, E-5a, E-7e and E-8d) were found to be endowed with modest growth inhibition of Mycobacterium tuberculosis. However, the obtained results allowed to acquire interesting structure-activity relationships.

Synthesis and evaluation for biological activity of 3-alkyl and 3-halogenoalkyl-quinoxalin-2-ones variously substituted. Part 4

A new series of 3-isopropyl-, 3-trifluoromethyl- and 3-bromomethylquinoxaline-2-ones variously substituted on the benzo-moiety were synthesized and submitted to a preliminary in vitro evaluation for antibacterial, antifungal and anti-HIV activities. Furthermore, all compounds were also tested for cytotoxicity. Results of the screening showed that compound 10 exhibits moderate antimicrobial activity against Staphylococcus aureus (MIC = 33 microM), and that 25 and 26 showed interesting cytotoxicity versus mock-infected MT-4 cells. All the other compounds were inactive.

Synthesis of E/Z 3-(1H-Benzotriazol-1-yl)-3-(pyridin-4-yl)acrylonitriles and E/Z 2-(3-Imino-2-benzofuran-1(3H)-ylidene)acetonitriles. An Unusual Case of Displacement of the Benzotriazole Ring

Synthesis of 3-(1H-benzotriazol-1-yl)-3-(pyridin-4-yl)acrylonitriles (E/Z 6) and 2-(3-imino-2-benzofuran-1(3H)-ylidene)acetonitriles (E/Z 20), by an unusual case of displacement of the benzotriazole ring, has been described. The X-Ray structure analysis of Z 20 and antimycobacterial activity of both E/Z 6 and E/Z 20 were also reported.

Addition reactions of 5-aminobenzotriazoles with dimethyl acetylenedicarboxylate (DMAD). Formation of (Z/E) Michael adducts, (benzotriazol-5-yl)-2-pyridones, a triazolo-9,10-dihydrobenzo[b]azepine and a triazolo-2-oxindole

5-Aminobenzotriazoles (1a-d) reacted with DMAD to give the regioselective Michael adducts (Z)-(2a-d), accompanied with (benzotriazol-5-yl)-2-pyridones (3b-d), and in one case (2c) with the triazolo-9,10-dihydrobenzo[b]azepine (4). Cyclisation of the adducts (Z)-(2b-d) in Dowtherm gave the triazolo[4,5-f]- quinolinones (6b-d), which were converted into chloro derivatives (9b-d), in turn hydrolysed and decarboxylated to 9-chloro-1(2)-methyltriazolo[4,5-f]- quinolines (11c-d). Compound (1c) in refluxing acetonitrile with DMAD undergoes unusual cyclisation into triazolo-2-oxindole (5), then converted into 2-methyltriazolo[4,5-f]carbostyril-9-carboxylate (17)