Design And Synthesis Of A Sulphur Containing Schiff Base Drug: Dna Binding Studies And Theoretical Calculations

The Schiff base compound MTA ((E)-5-methyl-N'-((5-methylthiophen-2-yl)methylene)-1H-pyrazole-3-carbohydrazide) derived from 2-thiophenecarboxaldehyde and 5-methylpyrazole-3-carbohydrazide has been designed to develop new sulphur containing DNA targeted molecule. The MTA has been characterized by elemental analyses, H-1-NMR, single crystal X-ray diffraction studies as well as by geometry optimization of using DFT/B3LYP. The interaction of MTA with Calf thymus DNA (CT-DNA) was studied by spectroscopic and calorimetric techniques. The synthesized compound was found to bind with CT-DNA through groove binding mode, and the binding constant was estimated to be (4.15 +/- 0.08) x 10(4) M-1. The negative Delta G(0) and positive Delta S-0 values obtained from the calorimetric technique confirmed the spontaneity of the binding of MTA with DNA. Communicated by Ramaswamy H. Sarma