SYNTHESIS OF 8-HYDROXYQUINOLINE CHALCONES: TRANS CONFIGURATION, INTRAMOLECULAR HYDROGEN BONDS, BROMINATION, AND ANTIFUNGAL ACTIVITY
作者:ALONSO J MARRUGO-GONZÁLEZ、VALERIE D ORLOV、ROBERTO FERNANDEZ-MAESTRE
DOI:10.4067/s0717-97072012000300019
日期:——
Nine (8-Hydroxyquinolin-5-yl)-arylpropenones were synthesized and their structures demonstrated by IR and NMR spectroscopy. These molecules showed transconfiguration and strong intramolecular hydrogen bonding; in the IR spectra of 5-formyl-8-hydroxyguinoline, 5-acety1-8-hydroxyquinoline, 1-(8-hydroxyguinolin-5-yl)-3-phenylprop-2-en-1-one and 3-(8-hydroxyquinolin-5-yl)-1-phenylprop-2-en-1-one in CHCl3, besides the known intermolecular hydrogen band (similar to 3180 cm(-1)), we identified the intramolecular hydrogen band OH-N (3460 cm(-1)), the hydrogen bond peaks shifted to low frequency in proton-donor solutions such as phenol and acetic acid (with respect to 8-hydroxyquinoline) and the bonds were broken in trifluoroacetic acid solutions, due to OH protonation; the apolar solvent CCl4 and electrophilic substituents in position 5 in the guillotine ring, limited the formation of the intermolecular hydrogen bonds and, therefore. shifted the similar to 3460 cm(-1) intramolecular hydrogen band to lower frequencies and made it stronger and sharper. The bromination of 3-(8-hydroxyquinolin-5yl)-1-(4-tolyl) prop-2-en-1-one occurred on the activated guillotine fragment, producing monobromo and tetrabromo derivatives, instead of bromination on the aliphatic double bond. Three chalcones tested showed strong antifungal activity in vitro.