Title:
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Expedient organocatalytic syntheses of 4-substituted pyrazolidines and isoxazolidines
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Author:
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Yousfi, Tarek; Elliott, Alysha; Hanane, Messiad; Merdes, Rashid; Moyano i Baldoire, Albert
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Other authors:
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Universitat de Barcelona |
Abstract:
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The efficient organocatalytic synthesis of heterocyclic systems of biological relevance is a subject of growing interest. We have found that the pyrrolidine/benzoic acid-catalyzed reaction of α-substituted propenals such as methacrolein, 2-benzylpropenal and 2-(n-hexyl)propenal with activated hydrazines takes place in very good yields (83%-99.6%) under very mild conditions to afford 4-substituted pyrazolidin-3-ols (as diastereomer mixtures); subsequent oxidation with PCC affords the corresponding-4-substituted-3-pyrazolidinones in essentially quantitative yields. In a similar way, 4-substituted isoxazolidinones are obtained with N-Cbz-hydroxylamine as a reagent. The use of chiral diarylprolinol trimethylsilyl ethers as catalysts allows the synthesis of several of these compounds in optically active form, in some cases with excellent enantioselectivity (up to 96:4 er). A preliminary evaluation of the biological activity shows that some of these compounds exhibit interesting antibacterial and antifungal activities. |
Subject(s):
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-Catàlisi asimètrica -Enantioselective catalysis |
Rights:
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cc-by (c) Yousfi, Tarek et al., 2016
http://creativecommons.org/licenses/by/3.0/es |
Document type:
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Article Article - Published version |
Published by:
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MDPI
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