SYNTHESIS OF -DIKETONE AS AN INTERMEDIATE FOR 3-PRENYLFLAVONE
Flavonoids are a group of polyphenolic natural products characterized with their C6–C3–C6 carbon skeleton. They have been reported to exhibit a wide range of bioactivities, such as antibacterial, antiviral, anti-inflammatory, antiallergic, and vasodillator (expanding blood vessels). Flavonoid deriv...
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| Format: | Theses |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/35394 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Flavonoids are a group of polyphenolic natural products characterized with their C6–C3–C6 carbon skeleton. They have been reported to exhibit a wide range of bioactivities, such as antibacterial, antiviral, anti-inflammatory, antiallergic, and vasodillator (expanding blood vessels). Flavonoid derivatives commonly found in plants from Moraceae family, particularly from Artocarpus and Morus generas, are 3-prenylflavones. It has been reported that they are bioactive as anticancer and antiplasmodium, and their activities have been attributed to prenylation at C-3 and B-ring trioxygenation pattern at C-2’, C-4’, and C-5’. To further study the bioactivities, 3-prenylflavone needs to be synthesized via prenylation and subsequent cyclization from -diketone. In this research, a -diketone, 1-(2- hydroxyphenyl)-3-phenylpropane-1,3-dione, had been synthesized as a precursor for the simplest 3-prenylflavone. The synthesis was carried out in four-step involving Baker-Venkataraman rearrangement reaction from phenol as starting material, with an overall yield up to 6.6%. Acetylation of fenol with glacial acetic acid and concentrated sulfuric acid as catalyst produced 25–52% of phenyl acetate. Aluminum chloride-catalyzed Fries rearrangement converted phenyl acetate into o-hydroxyacetophenone (o-HAP) in 34% yield. Benzoylation of o- HAP and rearrangement of the ester product in presence of potassium hydroxide in pyridine afforded -diketone. The yield of these two latter steps were 27–44% and 82–85%, respectively. Claisen condensation between acetophenone and methyl o-t-butyldimethylsilylsalicylate was failed. However, protection of methyl
salicylate resulted in 49–72% yield. All products synthesized in this research had been characterized spectroscopically and, for solid products, the melting point were characterized as well.
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