Kamma, Koteswara Rao Cho, Joungmo Won, Hyo Jun Nam, So-Yeon Le, Ngan Hong Jung, Je Hyeong Lee, Kee-In 2024-02-13T04:30:04Z 2024-02-13T04:30:04Z 2024-02-13 2024-01 https://pubs.kist.re.kr/handle/201004/148596 During the synthetic studies toward 5,6,7,3 ',4 '-monomethoxytetrahydroxyflavones, a concise pedalitin synthesis procedure was achieved. As previously reported, 6-hydroxy-2,3,4-trimethoxyacetophenone was prepared by Friedel-Crafts acylation of 1,4-dihydroxy-2,6-dimethoxybenzene with boron trifluoride diethyl etherate in acetic acid. When aldol condensation of 6-hydroxy-2,3,4-trimethoxyacetophenone 2b with vanillin was performed in basic conditions, it produced 2 '-hydroxychalcone 3b, and, surprisingly, along with 3-hydroxyflavone 4 in a considerable amount. We propose that this oxidative cyclization is presumably due to the contribution of a quinone methide, likely to be subjected to aerobic oxidation. The chalcone was then subjected to oxidative cyclization with iodine in dimethyl sulfoxide to afford flavone 5 in good yield. To our delight, serial demethylation of the three methoxy groups at the 5-, 6-, and 3 '-positions of 5 proceeded smoothly to produce pedalitin 1, under hydrogen bromide solution (30% in acetic acid). The crystal structures of 3-hydroxyflavone 4 and pedalitin tetraacetate 6 were unambiguously determined by X-ray crystallography. English Multidisciplinary Digital Publishing Institute (MDPI) Synthetic Studies toward 5,6,7,3′,4′-Monomethoxytetrahydroxyflavones: Synthesis of Pedalitin Article 10.3390/molecules29020513 1 Molecules, v.29, no.2 Molecules 29 2 Y scie scopus 001153109800001 2-s2.0-85183392809 Biochemistry & Molecular Biology Chemistry, Multidisciplinary Biochemistry & Molecular Biology Chemistry Article HYDROXYLATED POLYMETHOXYFLAVONES FLAVONOIDS INHIBITORS DEMETHYLATION ANALOGS 5,6,7,3 &apos ,4 &apos --monomethoxytetrahydroxyflavone pedalitin 2&apos -hydroxychalcone 3-hydroxyflavone aerobic oxidation demethylation X-ray crystal structure