SPECTROSCOPIC STUDIES ON SOME NEW AZO DYES DERIVED FROM 4-METHYLESCULETIN AND THEIR BIOLOGICAL-ACTIVITY

Some new mono azo dyes derived from 6,7-dihydroxy-4-methylcoumarin hav e been prepared and their electronic absorption spectra have been inve stigated in organic solvents of varying polarities. The spectra, in et hanol, display mainly five absorption bands which are assigned to thei r appropriate electronic transitions, The effect of substituents on th e absorption spectra have been investigated. The important ir bands an d H-1 nmr signals are assigned and discussed in relation to molecular structure, The presence of intramolecular hydrogen bonding and quinone -hydrazone tautomerism within the molecules have been demonstrated fro m the ir spectra. The biological activities of the azo compounds towar ds some filamentous microscopic fungi, yeasts and bacteria have also b een studied.