title: A Metal-Free Regioselective Multicomponent Approach for the Synthesis of Free Radical Scavenging Pyrimido-Fused Indazoles and Their Fluorescence Studies.
abstract: This study deals with a new and efficient metal-free regioselective synthesis of pyrimido-fused indazoles with nitrogen ring junction motifs. We have developed a metal-free domino type reaction between 3-aminoindazole, aryl aldehydes and aceotophenones in the presence of KOH/DMF that leads to pyrimido[1,2-b]indazole analogues. Response Surface Methodology (RSM) coupled with a Box-Behnken design (BBD) were utilized for exploring the effect of base used (A), temperature of reaction (B) and (C), reaction time. This approach can allow access to a variety of pyrimidoindazole fluorophores and related compounds. The compoundN,N-dimethyl-4-(2-phenylpyrimido[1,2-b]indazol-4-yl)aniline (4e) displays the maximum fluorescence intensity at 518 nm and shows a fluorescence quantum yield of 0.068. The synthesized pyramido-fused indazoles have been evaluated for their free radical scavenging activity and compound4fshowed good antioxidant activity.
authors.affiliation: Chemistry of Heterocycles & Natural Product Research Laboratory, Department of Chemistry, School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu, India. myne.palani@gmail.com.
authors.forename: Jeyakannu
authors.initials: J
authors.lastname: Palaniraja
authors.affiliation: Chemistry of Heterocycles & Natural Product Research Laboratory, Department of Chemistry, School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu, India. selvarajmohanaroopan@gmail.com.
authors.forename: Selvaraj
authors.initials: S
authors.lastname: Mohana Roopan
authors.affiliation: G Mokesh Rayalu, Department of mathematics, School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu, India. mokesh.g@gmail.com.
authors.forename: G
authors.initials: G
authors.lastname: Mokesh Rayalu
authors.affiliation: Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia. naldhabi@ksu.edu.sa.
authors.forename: Naif
authors.initials: N
authors.lastname: Abdullah Al-Dhabi
authors.affiliation: Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia. mvalanarasu@gmail.com.
authors.forename: Mariadhas
authors.initials: M
authors.lastname: Valan Arasu
mesh_terms: D016166:Free Radical Scavengers / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D007191:Indazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry; D018384:Oxidative Stress / Q000187:drug effects; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D016166:Free Radical Scavengers; D007191:Indazoles; D011743:Pyrimidines; D009584:Nitrogen
keywords: A3 coupling; Box-Behnken design (BBD); N-fused pyrimidine; Strecker synthesis; fluorescence