DABCO Catalyzed Green and Efficient Synthesis of 2-Amino-4H-Pyrans and Their Biological Evaluation as Antimicrobial and Anticancer Agents.

AIM AND OBJECTIVE: The present method is simple, green and highly efficient for the synthesis of 2-amino-4H-pyran derivatives which are achieved by a one pot three component cyclocondensation of aldehyde, malanonitrile and ethyl acetoacetate or methyl acetoacetate using DABCO under solvent free with grinding conditions at room temperature. MATERIAL AND METHODS: Some of the synthesized compounds were screened for their antimicrobial and antifungal activity. The study shows that these compounds show good antimicrobial activity. Furthermore, eight of the synthesized compounds were selected for screening of their anticancer activity against human astrocytoma-glioblastoma cell line (U373MG). Some of the compounds show good anticancer activity. RESULT: Grinding synthesis of 2-amino-4H-pyran derivatives catalyzed by DABCO with various aromatic aldehydes under solvent-free conditions at room temperature was examined. The obtained compounds (22 entries) were well synthesized in good to excellent yields. CONCLUSION: The present method is simple, rapid, and most efficient green protocol for the synthesis of 2-amino-4H-pyran derivatives using highly inexpensive and easily available DABCO as an efficient catalyst under grinding and solvent free condition at room temperature.

Synthesis and biological evaluation of imidazo[1,2-[Formula: see text]]pyridazines as inhibitors of TNF-[Formula: see text] production.

Tumor necrosis factor-alpha (TNF-[Formula: see text] is an important pro-inflammatory cytokine responsible for a diverse range of inflammatory diseases including rheumatoid arthritis. In the present manuscript, our medicinal chemistry efforts on the design, synthesis and TNF-[Formula: see text] evaluation of a series of 3, 6-disubstituted imidazo[1,2-b]pyridazine is described. The best compounds were 3-pyridyl and (4-(methylsulfonyl)phenyl) analogs 8q and 8w, showing inhibition of TNF-[Formula: see text] production with IC[Formula: see text]values of 0.9 and 0.4 [Formula: see text]M, respectively. The identified leads have potential for further development for treatment of inflammatory diseases.

Synthesis and in vitro evaluations of 6-(hetero)-aryl-imidazo[1,2-b]pyridazine-3-sulfonamide's as an inhibitor of TNF-α production.

Tumor necrosis factor-α is an important pro-inflammatory cytokine having a key role in hosts defensive process of immune systems and its over expression led to a diverse range of inflammatory diseases such as Rheumatoid arthritis, Cronh's disease, psoriasis, etc. This paper describes our medicinal chemistry efforts on imidazo[1,2-b]pyridazine scaffold: design, synthesis and biological evaluation. By the introducing sulfonamide functionality at 3 positions and substituting 6 positions with (hetero)-aryl groups', a small library of compounds was prepared. All synthesized compounds were screened for lipopolysaccharide (LPS) mediated TNF-α production inhibitory activity. Biological data revealed that the majority of the compounds of this series showed moderate to potent TNF-α production inhibitory activity. Compound 5u and 5v are the most potent compounds from the series with activity of IC50 = 0.5 µM and 0.3 µM respectively. A short SAR demonstrates that 3-sulfonyl-4-arylpiperidine-4-carbonitrile moiety on imidazo[1,2-b]pyridazine showed better activity compared to the 3-(4-aryllpiperazin-1-yl) sulfonyl) in hPBMC assay. The molecular modeling studies revealed that the potent TNF-α production inhibitory activity 5v due to the extra stability of complex because of an extra pi-pi (π-π) stacking, hydrogen-bonding interactions.

Discovery of tetrahydrocarbazoles as dual pERK and pRb inhibitors.

The extracellular signal-regulated kinase (ERK) is one of the most important molecular targets for cancer that controls diverse cellular processes such as proliferation, survival, differentiation and motility. Similarly, the Rb (retinoblastoma protein) is a tumor suppressor protein and its function is to prevent excessive cell growth by inhibiting cell cycle progression. When the cell is ready to divide, pRb is phosphorylated, becomes inactive and allows cell cycle progression. Herein, we discovered a new series of tetrahydrocarbazoles as dual inhibitors of pERK and pRb phosphorylation. The in-house small molecule library was screened for inhibition of pERK and pRb phosphorylation, which led to the discovery of tetrahydrocarbazole series of compounds as potential leads. N-(3-methylcyclopentyl)-6-nitro-2,3,4,4a,9,9a-hexahydro-1H-carbazol-2-amine (1) is the dual inhibitor lead identified through screening, displaying inhibition of pERK and pRb phosphorylation with IC50 values of 5.5 and 4.8 µM, respectively. A short structure-activity relationship (SAR) study has been performed, which identified another dual inhibitor 9-methyl-N-(4-methylbenzyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazol-2-amine (16) with IC50 values 4.4 and 3.5 µM for inhibition of pERK and pRb phosphorylation, respectively. This compound has a potential for further lead optimization to discover promising molecularly-targeted anticancer agents.

Methylsulfonyl benzothiazoles (MSBT) derivatives: Search for new potential antimicrobial and anticancer agents.

A series of novel 4 and 5-substituted methylsulfonyl benzothiazole (MSBT) compounds having amide, alkoxy, sulfonamide, nitro and amine functionality were synthesized from sequential reactions on 5-ethoxy-2-(methylsulfonyl)benzo[d]thiazole such as nitration, reduction, sulfonation, dealkylation, etc. All synthesized compounds were screened against antimicrobial and selected screened for anticancer activity. Antimicrobial activities studies reveled that among all compounds screened, out of MSBT-07, MSBT-11, MSBT-12, MSBT-14, MSBT-19, and MSBT-27 were found to have promising antimicrobial activity at MIC range of 4-50µg/ml against selected bacterial as well as fungal species. Compounds having good antimicrobial activity were screened for cervical cancer (HeLA cell lines). Of these MSBT-07 and MSBT-12 significantly reduced the cell growth. Consequently their calculated GI50 values were found to be 0.1 or <0.1µM.

Piperlongumine derived cyclic sulfonamides (sultams): Synthesis and in vitro exploration for therapeutic potential against HeLa cancer cell lines.

A novel modification of piperlongumine is designed, bearing a cyclic sulphonamide (sultam) and its synthesis is described. For the first time herein we report the synthesis and biological evaluation of the natural product derived cyclic sulfonamides using Grubbs second generation catalyst (Grubbs II) via ring closing metathesis approach. Synthesis of a series of piperlongumine derived sultams is done in a moderate to good yield using Wittig reaction, Ring-Closing Metathesis (RCM) and, amide synthesis by using mixed anhydride, approach. All synthesized compounds were evaluated for anticancer activity and some demonstrated dose dependent reduction in HeLa cell growth. Of these 7, 10 and 14 significantly reduced the cell growth. Consequently their calculated GI50 values were found to be 0.1 or <0.1 µM.