Malonamides have a diamide structure that allows for potential applications in ligands for metals, nuclear waste sequestration and fluorescent chemosensors. Our lab has developed a multicomponent reaction catalyzed by rare earth salts La(OTf)<sub>3</sub> and Sc(OTf)<sub>3</sub> to access indolylmalonamides, a new class of malonamides (Figure 1). These compounds show interesting properties that are affected by their chemical structure, including photophysical properties. Of specific interest is the phenol moiety of these malonamides. To assess the involvement of the phenol structure on fluorescence, a series of new indolylmalonamides was synthesized that vary the electronic effects to study the structure activity relationship (SAR). The indolylmalonamides were synthesized from 8-methoxycoumarin-3-carboxylate, 6-fluorocoumarin-3-carboxylate, coumarin-3-carboxylate and diethyl benzylidene malonate to afford the electron-withdrawing, electron-donating, neutral and phenyl indolylmalonamide derivatives, respectively. The absorbance, excitation and emission spectra were analyzed in order to assess the quantum yields, Stokes shifts and molar absorptivity values of the compounds. The electronic effects of the phenol component were determined to not contribute significantly to fluorescence efficiency as per the value of the quantum yields of the indolylmalonamides.

Analysis of the structure activity relationship between novel malonamides and their fluorescence characteristics

253rd National Meeting (2017)

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