title: Synthesis, anti-tuberculosis activity, and 3D-QSAR study of 4-(adamantan-1-yl)-2-substituted quinolines.
abstract: Structural optimization of the previously identified 4-(adamantan-1-yl)-2-quinolinecarbohydrazide (AQCH, MIC=6.25 microg/mL, 99% inhibition, Mycobacterium tuberculosis H37Rv) has led to two series of 4-(adamantan-1-yl)-2-substituted quinolines (Series 1-2). All new derivatives were evaluated in vitro for antimycobacterial activities against drug-sensitive M. tuberculosis H37Rv strain. Several 4-adamantan-1-yl-quinoline-2-carboxylic acid N'-alkylhydrazides (Series 1) described herein showed promising inhibitory activity. In particular, analogs 7, 9, 20, and 21 displayed MIC of 3.125 microg/mL. Further investigation of AQCH by its reaction with various aliphatic, aromatic, and heteroaromatic aldehydes led to the synthesis of 4-adamantan-1-yl-quinoline-2-carboxylic acid alkylidene hydrazides (Series 2). Analogs 42-44 and 48 have produced promising antimycobacterial activities (99% inhibition) at 3.125 microg/mL against drug-sensitive M. tuberculosis H37Rv strain. The most potent analog 35 of the series produced 99% inhibition at 1.00 microg/mL against drug-sensitive strain, and MIC of 3.125 microg/mL against isoniazid-resistant TB strain. To understand the relationship between structure and activity, a 3D-QSAR analysis has been carried out by three methods-comparative molecular field analysis (CoMFA), CoMFA with inclusion of a hydropathy field (HINT), and comparative molecular similarity indices analysis (CoMSIA). Several statistically significant CoMFA, CoMFA with HINT, and CoMSIA models were generated. Prediction of the activity of a test set of molecules was the best for the CoMFA model generated with database alignment. Based on the CoMFA contours, we have tried to explain the structure-activity relationships of the compounds reported herein.
authors.affiliation: Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar, Punjab 160 062, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Nayyar
authors.forename: Vikramdeep
authors.initials: V
authors.lastname: Monga
authors.forename: Alpeshkumar
authors.initials: A
authors.lastname: Malde
authors.forename: Evans
authors.initials: E
authors.lastname: Coutinho
authors.forename: Rahul
authors.initials: R
authors.lastname: Jain
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000494:pharmacology; D000995:Antitubercular Agents / Q000138:chemical synthesis* / Q000494:pharmacology*; D002855:Chromatography, Thin Layer; D003198:Computer Simulation; D007538:Isoniazid / Q000494:pharmacology; D016018:Least-Squares Analysis; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D021281:Quantitative Structure-Activity Relationship; D011804:Quinolines / Q000138:chemical synthesis* / Q000494:pharmacology; D012293:Rifampin / Q000494:pharmacology; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000995:Antitubercular Agents; D008024:Ligands; D011804:Quinolines; D000218:Adamantane; D007538:Isoniazid; D012293:Rifampin