Browsing by Author "Singh, Praval Pratap"

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    Caesium carbonate promoted regioselective O-functionalization of 4,6-diphenylpyrimidin-2(1H)-ones under mild conditions and mechanistic insight
    (Royal Society of Chemistry, 2023-06-05T00:00:00) Kumar, Vijay; Singh, Praval Pratap; Dwivedi, Ashish Ranjan; Kumar, Naveen; Rakesh kumar, None; Chandra Sahoo, Subash; Chakraborty, Sudip; Kumar, Vinod
    A facile one-step catalyst free methodology has been developed for the regioselective functionalization of 4,6-diphenylpyrimidin-2(1H)-ones under mild conditions. Selectivity towards the O-regioisomer was achieved by using Cs2CO3 in DMF without use of any coupling reagents. A total of 14 regioselective O-alkylated 4,6-diphenylpyrimidines were synthesized in 81-91% yield. In the DFT studies it was observed that the transition state for the formation of the O-regioisomer is more favourable with Cs2CO3 as compared to K2CO3. Furthermore, this methodology was extended to increase the O/N ratio for the alkylation of 2-phenylquinazolin-4(3H)-one derivatives. � 2023 The Royal Society of Chemistry.
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    Identification of 1,3,4-oxadiazoles as tubulin-targeted anticancer agents: a combined field-based 3D-QSAR, pharmacophore model-based virtual screening, molecular docking, molecular dynamics simulation, and density functional theory calculation approach
    (Taylor and Francis Ltd., 2023-09-11T00:00:00) Das, Agnidipta; Sarangi, Manaswini; Jangid, Kailash; Kumar, Vijay; Kumar, Amit; Singh, Praval Pratap; Kaur, Kamalpreet; Kumar, Vinod; Chakraborty, Sudip; Jaitak, Vikas
    Cancer is one of the most prominent causes of death worldwide and tubulin is a crucial protein of cytoskeleton that maintains essential cellular functions including cell division as well as cell signalling, that makes an attractive drug target for cancer drug development. 1,3,4-oxadiazoles disrupt microtubule causing G2-M phase cell cycle arrest and provide anti-proliferative effect. In this study, field-based 3D-QSAR models were developed using 62 bioactive anti-tubulin 1,3,4-oxadiazoles. The best model characterized by PLS factor 7 was rigorously validated using various statistical parameters. Generated 3D-QSAR model having high degree of confidence showed favourable and unfavourable contours around 1,3,4-oxadiazole core that assisted in defining proper spatial positioning of desired functional groups for better bioactivity. A five featured pharmacophore model (AAHHR_1) was developed using same ligand library and validated through enrichment analysis (BEDROC160.9 value = 0.59, Average EF 1% = 27.05, and AUC = 0.74). Total 30,212 derivatives of 1,3,4-oxadiazole obtained from PubChem database was prefiltered through validated pharmacophore model and docked in XP mode on binding cavity of tubulin protein (PDB code: 1SA0) which led into the identification of 11 HITs having docking scores between ?7.530 and ?9.719 kcal/mol while the reference compound Colchicine exerted docking score of ?7.046 kcal/mol. Following the analysis of MM-GBSA and ADME studies, HIT1 and HIT4 emerged as the two promising hits. To verify their thermodynamic stability at the target site, molecular dynamic simulations were carried out. Both HITs were further subjected to DFT analysis to determine their HOMO-LUMO energy gap for ensuring their biological feasibility. Finally, molecular docking based structural exploration for 1,3,4-oxadiazoles to set up a lead of Formula I for further advancements of tubulin polymerization inhibitors as anti-cancer agents. Communicated by Ramaswamy H. Sarma. � 2023 Informa UK Limited, trading as Taylor & Francis Group.