Ravibabu Velpula

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 in vitro cytotoxic activity of novel coumarinylimidazo[2,1-b]thiazole derivatives

A series of novel coumarinylimidazo[2,1-b]thiazole derivatives were synthesized by the treatment of 3-(2-aminothiazol-4-yl)-2H-chromen-2-one with phenacyl bromides followed by Vilsmeier–Haack and Knoevenagel condensation reactions. Structures of all the newly synthesized compounds were confirmed by their spectral and analytical studies. All the synthesized compounds were screened for their in vitro cytotoxic activity against Breast cancer cell line (MCF-7), Hepatocellular liver carcinoma cell line (HepG2), Cervical carcinoma cell line (HeLa) and Lung cancer cell line (NCI-H460). Cytotoxic activity results revealed that, the compound 4d has shown broad spectrum activity against MCF-7, HepG2 & HeLa with IC50 values 16.99 ± 0.7, 13.92 ± 0.2 & 5.18 ± 0.1 μM respectively. Compound 6 against MCF-7 (IC50 10.83 ± 0.5 μM) and HeLa (IC50 6.77 ± 0.2 μM), 4a, 4c & 5a against HeLa and 5c against NCI-H460 with IC50 values 7.13 ± 0.4, 14.21 ± 0.6, 17.87 ± 0.5 & 16.27 ± 0.5 μM respectively have shown good activity. Remaining compounds have shown moderate activity against all the tested cell lines.

Brønsted acidic ionic liquid catalysis: An efficient and eco-friendly synthesis of novel fused pyrano pyrimidinones and their antimicrobial activity

AbstractA series of novel fused pyrano pyrimidinones were synthesized by the condensation of 2-amino-4-aryl-4H-benzo[h]chromene-3-carbonitriles with 2-oxo-2H-chromene-3-carboxylic acid under neat conditions employing an efficient, eco-friendly and reusable Brønsted acidic ionic liquid, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulphate as catalyst. All the synthesized compounds were characterized by their analytical and spectroscopic data and they were screened for in vitro antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis as Gram- positive, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia as Gram-negative bacterial strains and antifungal activity against Aspergillus flavus, Saccharomyces cerevisiae, Candida rugosa and Candida albicans. Compounds 2c and 2d have shown good antibacterial activity against Escherichia coli while 2g has shown marked antifungal activity against Candida rugosa. Graphical AbstractPyrano pyrimidinones were synthesized by the condensation of 2-amino-4-aryl-4H-benzo[h]chromene-3-carbonitriles with 2-oxo-2H-chromene-3-carboxylic acid in the presence of Brønsted acidic ionic liquid, (4-sulphobutyl)tris(4-sulphophenyl)phosphonium hydrogen sulphate as catalyst. All the synthesized compounds were screened for in vitro antimicrobial activity.

One-pot multicomponent synthesis of novel 1-thiazolyl-5-coumarin-3-yl-pyrazole derivatives and evaluation of their cytotoxic activity

A series of novel 1-thiazolyl-5-coumarin-3-yl-pyrazole derivatives (4a–l) were synthesized via one-pot multicomponent reaction of 5-substituted salicylaldehydes (1a–c), 4-hydroxy-6-methyl-2H-pyran-2-one (2) and 2-hydrazinyl-4-arylthiazoles (3a–d) in acetonitrile using a catalytic amount of piperidine under reflux conditions. This multicomponent approach has advantages such as reduced reaction time and a high product yield percentage when compared with corresponding multistep approaches. All the synthesized compounds were evaluated for their cytotoxic activity against Hep G2 (hepatocellular liver carcinoma) and MCF-7 (breast cancer) cell lines and compared with the standard drug Doxorubicin. Among all the compounds, compounds 4d against Hep G2, 4k against MCF-7 and 4e against both Hep G2 & MCF-7 showed excellent cytotoxic activity.

Synthesis and Antibacterial Evaluation of Novel 3,6-Disubstituted Coumarin Derivatives

Abstract A novel series of 3,6-disubstituted coumarin derivatives were synthesized by the reaction of ethyl-2-(3-acetyl-2-oxo-2H-chromen-6-yl)-4-methylthiazole-5-carboxylate with thiosemicarbazide and various phenacyl bromides / 3-(2-bromoacetyl)-2H-chromen-2-ones / 2-(2-bromoacetyl)-3H-benzo[f]chromen-3-one in ethanol having catalytic amount of acetic acid under reflux conditions with good yields. All the synthesized compounds were fully characterized by spectral studies and evaluated for their in vitro antibacterial activity against Pseudomonas aeruginosa, Bacillus subtilis (Gram positive), Escherichia coli, and Azatobacter (Gram negative) bacterial strains. Activity results revealed that the compound 6h against Escherichia coli and compound 6i against Pseudomonas aeruginosa and Escherichia coli have shown maximum zones of inhibition. Remaining compounds showed moderate to good activity against all the tested bacterial strains compared with the standard drug cefotaxime. GRAPHICAL ABSTRACT

An Eco-Friendly Improved Protocol for the Synthesis of Bis(3-indolyl)methanes Using Poly(4-vinylpyridinium)hydrogen Sulfate as Efficient, Heterogeneous, and Recyclable Solid Acid Catalyst

Highly efficient and eco-friendly protocol for the synthesis of bis(3-indolyl)methanes by the electrophilic substitution reaction of indole with aldehydes catalyzed by poly(4-vinylpyridinium)hydrogen sulfate was described. Excellent yields, shorter reaction times, simple work-up procedure, avoiding hazardous organic solvents, and reusability of the catalyst are the most obvious advantages of this method.