Telaah Reaksi Benzoilasi Resasetofenon dalam Sintesis 7- Hidroksiflavon Melalui Penataan-Ulang Baker-Venkataraman

Abstract

Dibenzoyl resacetophenone (diBz) is an important precursor in synthesis of 7-hydroxyflavone and its derivatives through Baker-Venkataraman rearrangement. In previous studies, benzoylation of resacetophenone by using benzoyl chloride (BzCl) resulted 3 different products, namely p-benzoyl resacetophenone (p-Bz), diBz, and 3-benzoyl-7-hydroxyflavone (3-Bz-7-HF). In this study, the optimum condition to synthesize diBz was studied. Benzoylation of resacetophenone in pyridine at room temperature gave optimum conversion percentage when the mmol ratio of resacetophenone:Bz was 1:2. p-Bz was the main product, but the yield of diBz increased higher mmol of resacetophenone was used. On the other hand, benzoylation of resacetophenone at reflux temperature of acetone gave 3-Bz-7-HF as the only product. Control of temperature and reaction time was concluded as the main factor affecting the amount of diBz. p-Bz was dominant at the beginning of reaction, then diBz started to be formed, being promoted by the heat of reaction as well as prolonging heating. However, if the reaction temperature was too high or the reaction time was prolonged, 3-Bz-7-HF would be formed. Further study is still needed to find the optimum reaction time and temperature to synthese diBz