title: One-pot solvent free synthesis and DNA binding studies of thieno[2,3-b]-1,8-naphthyridines.
abstract: With the aim of evaluating interaction between double-stranded calf thymus (ds)DNA and sulphur containing fused planar rings, the derivatives of 1,8-naphthyridine containing thiono groups were synthesized by the condensation of 2-mercapto-3-formyl[1,8]naphthyridines using 1-chloroacetone, 2-chloroacetamide, chloroaceticacid, and 2-chloro-1-phenylethanone in the presence of anhydrous potassium carbonate as s catalyst under solvent free microwave irradiation. The structures of the compounds were elucidated on the basis of elemental analysis, IR, (1)H NMR, and mass spectra. The interaction of thieno[2,3-b]-1,8-naphthyridine-2-carboxylic acid (TNC) (3a) with ct-DNA was studied by UV-Vis spectrophotometry, viscosity, thermal denaturation, as well as cyclic voltammetry experiments. On binding to DNA, the absorption spectrum underwent bathochromic and hypochromic shifts. Binding parameters, determined from spectrophotometric measurements indicated a binding constant of Kb=2.1 x 10(6) M(-1). The thieno[2,3-b]-1,8-naphthyridine-2-carboxylic acid (3a) increases the viscosity of sonicated rod-like DNA fragments. The binding of TNC to DNA increased the melting temperature by about 4 degrees C. The decrease in peak current heights and shifts of peak potential values are observed by the addition of calf thymus DNA in cyclic voltammetry studies.
authors: Department of Studies and Research in Industrial Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta, India.
authors: Tangali R Ravikumar
authors: TR
authors: Naik
authors: Halehatty S Bhojya
authors: HS
authors: Naik
authors: Mustur C
authors: MC
authors: Prabhakara
mesh_terms: D001665:Binding Sites; D002254:Carbonates / Q000737:chemistry; D002384:Catalysis; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004563:Electrochemistry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008872:Microwaves; D008956:Models, Chemical; D009287:Naphthyridines / Q000138:chemical synthesis* / Q000378:metabolism; D009691:Nucleic Acid Denaturation; D011188:Potassium / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D014783:Viscosity
chemical_list: D002254:Carbonates; D009287:Naphthyridines; D012997:Solvents; D004247:DNA; C427203:calf thymus DNA; C037593:potassium carbonate; D011188:Potassium