Browsing by Author "Heo, Myunghoe"

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    Enantioselective Synthesis of Homoisoflavanones by Asymmetric Transfer Hydrogenation and Their Biological Evaluation for Antiangiogenic Activity
    (ACS Publications, 2019-08-05) Heo, Myunghoe; Lee, Bit; Sishtla, Kamakshi; Fei, Xiang; Lee, Sanha; Park, Soojun; Yuan, Yue; Lee, Seul; Kwon, Sangil; Lee, Jungeun; Kim, Sanghee; Corson, Timothy W.; Seo, Seung-Yong; Ophthalmology, School of Medicine
    Neovascular eye diseases are a major cause of blindness. Excessive angiogenesis is a feature of several conditions, including wet age-related macular degeneration, proliferative diabetic retinopathy, and retinopathy of prematurity. Development of novel anti-angiogenic small molecules for the treatment of neovascular eye disease is essential to provide new therapeutic leads for these diseases. We have previously reported the therapeutic potential of anti-angiogenic homoisoflavanone derivatives with efficacy in retinal and choroidal neovascularization models, although these are racemic compounds due to the C3-stereogenic center in the molecules. This work presents asymmetric synthesis and structural determination of anti-angiogenic homoisoflavanones and pharmacological characterization of the stereoisomers. We describe an enantioselective synthesis of homoisoflavanones by virtue of ruthenium-catalyzed asymmetric transfer hydrogenation accompanying dynamic kinetic resolution, providing a basis for the further development of these compounds into novel experimental therapeutics for neovascular eye diseases.
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    Total Synthesis of Naturally Occurring 5,7,8-Trioxygenated Homoisoflavonoids
    (American Chemical Society, 2020-05-06) Kwon, Sangil; Lee, Sanha; Heo, Myunghoe; Lee, Bit; Fei, Xiang; Corson, Timothy W.; Seo, Seung-Yong; Ophthalmology, School of Medicine
    Homoisoflavonoids are in the subclass of the larger family of flavonoids but have one more alkyl carbon than flavonoids. Among them, 5,7,8-trioxygenated homoisoflavonoids have not been extensively studied for synthesis and biological evaluation. Our current objective is to synthesize 2 5,7,8-trioxygenated chroman-4-ones and 12 5,7,8-trioxygenated homoisoflavonoids that have been isolated from the plants Bellevalia eigii, Drimiopsis maculata, Ledebouria graminifolia, Eucomis autumnalis, Eucomis punctata, Eucomis pallidiflora, Chionodoxa luciliae, Muscari comosum, and Dracaena cochinchinensis. For this purpose, 1,3,4,5-tetramethoxybenzene and 4'-benzyloxy-2',3'-dimethoxy-6'-hydroxyacetophenone were used as starting materials. Asymmetric transfer hydrogenation using Noyori's Ru catalyst provided 5,7,8-trioxygenated-3-benzylchroman-4-ones with R-configuration in high yield and enantiomeric excess. By selective deprotection of homoisoflavonoids using BCl3, the total synthesis of natural products including 10 first syntheses and three asymmetric syntheses has been completed, and three isomers of the reported dracaeconolide B could be provided. Our research on 5,7,8-trioxygenated homoisoflavonoids would be useful for the synthesis of related natural products and pharmacological applications.