Estudo da síntese de cumarinas-flavonas e de neoflavonóides

Abstract

This work describes the synthesis of the 5,7-dihydroxy-4'-methoxy-6-(2- carboxyvinyl)-flavanone, precursor of the coumarin-flavone isolated from Croton adamantinus. The flavanone was obtained by condensation of the 8-acetil-5,7-dihydroxycoumarin with anysaldehide in presence of sodium hydroxide. The following neoflavanones were also synthesized: 7-hydroxy-5-methyl-4-( 4'- methoxyphenyl)-3,4-dihydrocoumarin, 5-hydroxy-7 -methyl-4-( 4' -methoxyphenyl)-3, 4- dihydrocoumarin, 5-methyl-7 -0-( 4-methoxycinnamoyl)-4-( 4' -methoxyphenyl)-3, 4- dihydrocoumarin, 5-hydroxy-4-( 4' -methoxyphenyl)-a-pirano-( 6" ,5": 7,8)-3,4- dihydrocoumarin and 5-pentadecyl-4-( 4' -methoxyphenyl)-3, 4-dihydrocoumarin. These compounds have been synthesized via AlCh-catalyzed condensation of 4-methoxycinnamic acid chloride with orcinol, 5,7-dihydroxycoumarin and hydrogenated cardanol. Other phenols such as resorcinol, phloroglucinol, pyrogallol, eugenol and hydrogenated cardol, do not yield condensation products with 4-methoxycinnamic acid çhloride, nevertheless led to the formation of cinnamoyl esters. The synthesized compounds were characterized based on their 1H and 13C NMR Spectroscopic experiment, including nOe difference spectroscopy, infrared and mass spectroscopies.