Synthesis and anticancer activities of new Benzothiadiazinyl Hydrazinecarboxamides and Anilino[1,2,4]triazolo[1,5-b][1,2,4]thiadiazine 5,5-diones.

Two series of compounds (5-14 and 15-23) based on the scaffolds of 2-(1,1-dioxido-4-phenyl-4Hbenzo[e][1,2,4]thiadiazin-3-yl)-N-(4-methoxyphenyl)hydrazinecarboxamide (5) and 2-((4-methoxyphenyl)amino)-10-phenyl-10H-benzo[e][1,2,4]triazolo[1,5-b][1,2,4]thiadiazine 5,5-dioxide (15) respectively, were designed and synthesized. These compounds were tested for anticancer activity against various cancer cell lines including lung, ovary, prostate, breast and colon cancers. They exhibited moderate to good inhibitory activity against the above cell lines and compound 9 was found to be the most active one from these two series. Further studies showed that cancer cell growth inhibition by compounds 22 and 23 could be in part due to the inhibition of tubulin polymerization, with the IC50 values of 4.70 and 5.25 µM, respectively.

Anti-tubercular agents. Part 6: synthesis and antimycobacterial activity of novel arylsulfonamido conjugated oxazolidinones.

As a part of investigation of new anti-tubercular agents in this laboratory, herein we describe the synthesis of a new class of arylsulfonamido conjugated oxazolidinones. The in vitro activity of these conjugated (6a-f, 7a-d, 9a-c and 11a-c) molecules against Mycobacterium tuberculosis H(37)Rv by using rifampicin and linezolide as positive controls is discussed, compounds 7c and 9a-c are found to be the most active members in this series. Further, cytotoxicity of the potent conjugates of the series (7c, and 9a-c) was evaluated on human foreskin fibroblast (HFF) cells by using MTT assay. Finally, these studies suggest that compounds 7c and 9a may serve as promising lead scaffolds for further generation of new as anti-TB agents.

Synthesis of 3,3-diindolyl oxyindoles efficiently catalysed by FeCl3 and their in vitro evaluation for anticancer activity.

A simple and highly efficient method has been developed for the synthesis of 3,3-diindolyl oxyindoles by the reaction of indoles with isatin or 5-fluoro isatin using a catalytic amount (5 mol%) of FeCl(3) at room temperature in a short reaction time in high yields. All these compounds were evaluated against a panel of five human cancer lines and most of them showed potent cytotoxicity. Compound 4b showed IC(50) of 4.7 and 5 microM against SK-N-SH and DU-145 cell lines, respectively, whereas 4c, 4d, 4f and 4k showed IC(50) of 2.2, 1.2, 3.6 and 3.6 microM, respectively, against DU-145 cell line. Interestingly, some of the compounds are selectively potent in prostate cancer (DU-145) with IC(50) values of 1.2-19.6 microM.

Synthesis, DNA-binding ability and anticancer activity of benzothiazole/benzoxazole-pyrrolo[2,1-c][1,4]benzodiazepine conjugates.

A series of benzothiazole and benzoxazole linked pyrrolobenzodiazepine conjugates attached through different alkane or alkylamide spacers was prepared. Their anticancer activity, DNA thermal denaturation studies, restriction endonuclease digestion assay and flow cytometric analysis in human melanoma cell line (A375) were investigated. One of the compounds of the series 17d showed significant anticancer activity with promising DNA-binding ability and apoptosis caused G0/G1 phase arrest at sub-micromolar concentrations. To ascertain the binding mode and understand the structural requirement of DNA binding interaction, molecular docking studies using GOLD program and more rigorous 2 ns molecular dynamic simulations using Molecular Mechanics-Poisson-Boltzman Surface Area (MM-PBSA) approach including the explicit solvent were carried out. Further, the compound 17d was evaluated for in vivo efficacy studies in human colon cancer HT29 xenograft mice.

An efficient synthesis of bis(indolyl)methanes and evaluation of their antimicrobial activities.

A versatile and efficient method has been developed for the synthesis of bis(indolyl)methanes by using aluminium triflate (0.5 mol%) as a novel catalyst. Further, some of the synthesized compounds were evaluated for their efficacy as antibacterial and antifungal activities. Most of the compounds have shown moderate to good inhibitory activity.

Synthesis, DNA-binding ability and evaluation of antitumour activity of triazolo[1,2,4]benzothiadiazine linked pyrrolo[2,1-c][1,4]benzodiazepine conjugates.

A series of triazolobenzothiadiazine-pyrrolobenzodiazepine conjugates linked through different alkane spacers have been prepared. These compounds have exhibited significant cytotoxicity against most of the cell lines examined. Compound 5a displays GI(50) values from 1.83 to 2.38 microM against seven human tumour cell lines, and is identified as a promising lead compound from this series. Their DNA thermal denaturation studies have also been carried out, and one of the compounds 5c elevates the DNA helix melting temperature of the CT-DNA by 2.6 degrees C after incubation for 36 h.

Synthesis, structural characterization and biological evaluation of novel [1,2,4]triazolo [1,5-b][1,2,4]benzothiadiazine-benzothiazole conjugates as potential anticancer agents.

Two series of 10-substituted 5,5-dioxo-5,10-dihydro[1,2,4]triazolo[1,5-b][1,2,4]benzothiadiazine 2-methyl/ethyl sulfanyl benzothiazole derivatives (5a-d) and 10-substituted 5,5-dioxo-5,10-dihydro[1,2,4]triazolo[1,5-b][1,2,4] benzothiadiazine 2-phenoxy benzothiazole derivatives (16a-c) were synthesized and their structures confirmed by NMR, MS, IR and X-ray crystallography. These compounds were evaluated for their cytotoxicity against 60 human tumour cell lines. One of the synthesized compounds (5b) exhibited significant inhibitory activity against most of the cell lines and has been further evaluated for the five-dose screening.

Synthesis, structure analysis, and antibacterial activity of some novel 10-substituted 2-(4-piperidyl/phenyl)-5,5-dioxo[1,2,4]triazolo[1,5-b][1,2,4]benzothiadiazine derivatives.

A new series of 10-substituted 5,5-dioxo-5,10-dihydro[1,2,4]triazolo[1,5-b]-[1,2,4]benzothiadiazine arylsulfonamide derivatives (10a-j and 13a-f) was synthesized. The structures of these compounds were confirmed on the basis of spectral data, elemental analysis, X-ray analysis, and quantum chemical calculations. These compounds were evaluated for their efficacy as antibacterial agents against various Gram-positive and Gram-negative strains of bacteria. Amongst these compounds 10f and 10i were the most active compounds against Escherichia coli and 13e against E. coli as well as Bacillus subtilis. Moreover, other compounds also showed potent inhibitory activity in comparison to the standard drugs.

Anti-tubercular agents. Part IV: Synthesis and antimycobacterial evaluation of nitroheterocyclic-based 1,2,4-benzothiadiazines.

In continuation of our earlier work on benzothiadiazines, we have prepared a series of nitrofuran, nitrothiophene and arylfuran coupled benzothiadiazines and evaluated them for antimycobacterial and antibacterial activities. One of the compounds 2f has shown good in vitro antimycobacterial activity. All the synthesized compounds have shown moderate to good antibacterial activity.

1,2,4-benzothiadiazine linked pyrrolo[2,1-c][1,4]benzodiazepine conjugates: synthesis, DNA-binding affinity and cytotoxicity.

Benzothiadiazine-pyrrolobenzodiazepine conjugates linked through different alkane spacers have been prepared. These new classes of hybrid molecules exhibit cytotoxicity against many cancer cell lines. Their DNA thermal denaturation studies have been carried out and one of the compounds (4b) elevates the DNA helix melting temperature of the CT-DNA by 6.7 degrees C after incubation for 36 h.

Synthesis of a new class of 2-anilino substituted nicotinyl arylsulfonylhydrazides as potential anticancer and antibacterial agents.

A series of N'-1-[2-anilino-3-pyridyl]carbonyl-1-benzenesulfonohydrazide derivatives (7a-i) was synthesized and five of them were selected by the National Cancer Institute (NCI) and evaluated for their in vitro anticancer activity. Three of the investigated compounds 7d, 7f and 7g exhibited significant anticancer activity in the primary assay and further tested against a panel of 60 human tumour cell lines. Compound 7g showed 50% growth inhibitory activity in leukaemia, melanoma, lung cancer, colon cancer, renal cancer and breast cancer cells with GI(50) value of 3.2-9.6 microM. The synthesized compounds (7a-i) were also evaluated for their antibacterial activity against various Gram-positive and Gram-negative strains of bacteria. Most of these compounds showed better inhibitory activity in comparison to the standard drugs.

Anti-tubercular agents. Part 3. Benzothiadiazine as a novel scaffold for anti-Mycobacterium activity.

In an effort to develop new and more effective therapies to treat tuberculosis, a series of benzothiadiazine 1,1-dioxide derivatives were synthesized and their in vitro activity against Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium intracellulare was evaluated. One of the compounds, 8c, exhibited potent anti-tubercular activity, particularly for the resistant strains and thus prompted us to investigate its in vivo profile. However, the in vivo testing in a mouse model of tuberculosis infection did not show significant anti-tubercular activity, probably because of its poor bioavailability.