Satyajit Singh

Bio: Satyajit Singh is an academic researcher from Guru Nanak Dev University. The author has contributed to research in topics: Docking (molecular) & Topoisomerase. The author has an hindex of 3, co-authored 5 publications receiving 108 citations. Previous affiliations of Satyajit Singh include Manipal University & Khalsa College, Amritsar.

3-Formylchromone based topoisomerase IIα inhibitors: discovery of potent leads

Abstract: Substituted 3-formylchromones were synthesized and evaluated as inhibitors of the human DNA topoisomerase IIα (hTopo-IIα) enzyme. The results of the decatenation, relaxation and DNA intercalation assays revealed that the compounds (11b, 12a, 12b, 12d, 12e, 13a and 13b) exhibited potent inhibitory activity against the hTopo-IIα enzyme, and are nonintercalating agents. These compounds also possess significant in vitro cytotoxicity (LC50 ranges from 0.5–8.6 μM) against prostate (PC-3) cancerous cell line as seen in comparison to the standard drug etoposide. To further probe the plausible mode of action of 3-formylchromone derivatives, molecular docking studies have also been carried out, which showed that the compounds under investigation fitted well in the ATP binding pocket of hTopo-IIα enzyme with good docking scores and form nonbonding interactions with the crucial residues of the catalytic site.

Chromone: A Valid Scaffold in Medicinal Chemistry

Abstract: This work was supported by the Foundation for Science and Technology (FCT), Portugal (projects PTDC/QUI-QUI/113687/2009 and PEst-C/QUI/UI0081/2013). A.G. (SFRH/BD/43531/2008) and M.J.M. (SFRH/BD/61262/2009) thank FCT for grants.

Isoxazolidine: A Privileged Scaffold for Organic and Medicinal Chemistry

Abstract: The isoxazolidine ring represents one of the privileged structures in medicinal chemistry, and there have been an increasing number of studies on isoxazolidine and isoxazolidine-containing compounds. Optimization of the 1,3-dipolar cycloaddition (1,3-DC), original methods including electrophilic or palladium-mediated cyclization of unsaturated hydroxylamine, has been developed to obtain isoxazolidines. Novel reactions involving the isoxazolidine ring have been highlighted to accomplish total synthesis or to obtain bioactive compounds, one of the most significant examples being probably the thermic ring contraction applied to the total synthesis of (±)-Gelsemoxonine. The unique isoxazolidine scaffold also exhibits an impressive potential as a mimic of nucleosides, carbohydrates, PNA, amino acids, and steroid analogs. This review aims to be a comprehensive and general summary of the different isoxazolidine syntheses, their use as starting building blocks for the preparation of natural compounds, and their m...

Chromone, a privileged scaffold for the development of monoamine oxidase inhibitors.

Abstract: Two series of novel chromone derivatives were synthesized and investigated for their ability to inhibit the activity of monoamine oxidase. The SAR data indicate that chromone derivatives with substituents in position 3 of γ-pyrone nucleus act preferably as MAO-B inhibitors, with IC(50) values in the nanomolar to micromolar range. Almost all chromone 3-carboxamides display selectivity toward MAO-B. Identical substitutions on position 2 of γ-pyrone nucleus result in complete loss of activity in both isoforms (chromones 2-12 except 3 and 5). Notably, chromone (19) exhibits an MAO-B IC(50) of 63 nM, greater than 1000-fold selectivity over MAO-A, and behaves as a quasi-reversible inhibitor. Docking experiments onto the MAO binding of the most active compound highlight different interaction patterns among the isoforms A and B. The differential analysis of the solvation effects among the chromone isomers gave additional insight about the superior outline of the 3-substituted chromone derivatives.