- Synthesis of a 3,4,5-trimethoxybenzoyl ester analogue of epigallocatechin-3-gallate (EGCG): A potential route to the natural product green tea catechin, EGCG
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matrix presented The synthesis of a trimethoxybenzoyl ester (D-ring) analogue of epigallocatechin-3-gallate (EGCG) is described. The versatile synthesis route can be used to synthesize A, B, and D ring analogues of EGCG and involves a key cyclization of t
- Zaveri, Nurulain T.
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- Enantioselective synthesis of flavan-3-ols using a mitsunobu cyclization
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The synthesis of four flavan-3-ols with different substitution patterns and electron densities has been achieved in high stereo- and regioselectivity by a one-step Mitsunobu reaction from the corresponding diols, which were prepared by enantioselective Sharpless dihydroxylation of suitable olefins. The six-membered flavan-3-ols were the only cyclization products and the theoretically possible formation of five-membered rings during the Mitsunobu cyclization was not observed. The flavanols are important starting materials for the synthesis of dimers such as the procyanidins or other coupling products such as the flavan part of the potent DNA polymerase β inhibitor myristinin A. The enantioselectivities of both the Sharpless dihydroxylation and the Mitsunobu cyclization steps were monitored by chiral HPLC. Georg Thieme Verlag Stuttgart New York.
- Krohn, Karsten,Ahmed, Ishtiaq,John, Markus
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experimental part
p. 779 - 786
(2009/09/06)
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- A structure-activity study for the inhibition of metalloproteinase-9 activity and gene expression by analogues of gallocatechin-3-gallate
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Catechins are able to modulate the gelatinolytic activity of matrix metalloproteinase-9 (MMP-9) by reducing its release from macrophages. Gallocatechins decrease MMP-9 secretion by lowering MMP-9 promoter activity and mRNA levels. The effect appears to be dependent on some structural and stereochemical requirements. In this study, the relationship between chemical structure and activity was studied by testing the effect of analogues of (±)-gallocatechin-3-gallate (±)-GCG, selectively deprived of hydroxyl groups, on MMP-9 activity, transcription, and secretion. Our results indicate that (±)-GCG and (±)-catechin-3-gallate are characterized by a substitution pattern compatible with direct inhibition of MMP-9 activity. Conversely, when transcription was the target, (±)-trans-3-flavanol-3- benzoate, lacking all the hydroxyl groups, was the most effective both in lowering MMP-9 promoter activity and consequently protein secretion, and in inhibiting nuclear-factor-κB-driven transcription. Our results suggest that the structural requirements for enzyme inhibition are different from those necessary for targeting gene expression. Birkhaeuser Verlag, 2005.
- Dell'Agli,Bellosta,Rizzi,Galli,Canavesi,Rota,Parente,Bosisio,Romeo
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p. 2896 - 2903
(2007/10/03)
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- Analogs of green tea polyphenols as chemotherapeutic and chemopreventive agents
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Novel compounds useful as chemotherapeutic and chemopreventive agents are provided. The compounds are analogs of polyphenol catechins that occur in green tea, such as epigallocatichin-3-gallate (EGCG), and have the structure of formula (I) wherein R1 through R11 are defined herein. Preferred R4 moieties are selected from O, S, NH and CH2, and in exemplary compounds, R4 is O and R5 is a tri-substituted aroyloxy substituent, such as a 3,4,5-substituted benzoyloxy group. Pharmaceutical compositions are provided as well, as are methods of chemotherapy and chemoprevention.
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