Sintesis Monobenzil Krisin dari Floroglusinol melalui Zat Antara Kalkon Pinosembrin Sebagai Prekursor Krisin

Abstract

In this experiment, monobenzyl chrysin (7-benzyloxy5-hydroxyflavone) was synthesized from phloroglucinol as its starting material through oxidative cyclization route of pinocembrin chalcone. The synthesis was started with acetylation of phloroglucinol and benzylation of phloroacetophenone using 2 equivalents of benzyl bromide for 24 hours. The yield of those two steps were 70% and 21%, respectively. The condensation of 4’,6’-benzyloxy-2’- hydroxyacetophenone obtained with benzaldehyde produced a benzyl-protected chalcone which is then cyclisized oxidatively with 1 equivalent of I2 in dimethyl sulfoxide. About 9% of the product of this reaction was a monobenzyl chrysin according to characterization using proton nuclear magnetic resonance spectrum. The overall yield of this product was 1% with respect to phloroglucinol. The optimization of benzylation time of reaction and amount of added I2 should be studied further in order to increase the yield before the benzyl deprotection process conducted