- Compound, preparation method and applications thereof, and glycosidase inhibitor
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The invention relates to the field of enzyme inhibitors, and discloses a compound, a preparation method and applications thereof, and a glycosidase inhibitor, wherein the compound has a structure represented by a formula (I), R is any one selected from hy
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- Reversal of Stereoselectivity in Cycloadditions of Five-Membered Cyclic Nitrones Derived from Hexoses
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Two five-membered cyclic nitrones derived from hexoses, a newly synthesized d-allo-configured nitrone and an already known d-talo-configured nitrone, have been examined in 1,3-dipolar cycloaddition reactions with vinyl acetate, allyl benzoate, methyl acrylate, acrylonitrile, and vinylene carbonate. The reactions of the d-allo-configured nitrone proceeded preferentially through the expected exo-anti transition state, but all the cycloadditions of the d-talo-configured nitrone surprisingly showed high exo-syn selectivity. This reversal of stereoselectivity has been explained by 3D analysis of the preferred conformations of the nitrones, obtained from X-ray data. The structures were further inspected using CONFLEX, PM5, and DFT calculations. All these methods revealed that the dioxolane substituents attached to C-5 of both nitrones had opposite spatial locations.
- Malatinsky, Tomá?,Spi?áková, Mária,Babjak, Matej,Doháňo?ová, Jana,Marek, Jaromír,Moncol, Ján,Fischer, Róbert
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p. 1086 - 1098
(2017/02/23)
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- Enantioselective, chromatography-free synthesis of β3-Amino acids with natural and unnatural side chains
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β3-Amino acids are key components of some pharmaceuticals, excellent surrogates for metabolically labile α-amino acids, and building blocks for chiral heterocycles. Unfortunately they are not easily accessible in enantiomerically pure form, especially when possessing unnatural side chains. A flexible, chromatography-free process for the synthesis of enantiopure β3-amino acids possessing natural and unnatural side chains is described. The procedure uses inexpensive starting materials and reagents and offers a good alternative to the hazardous and expensive Arndt-Eistert homologation of enantiopure α-amino acids. Its utility has been demonstrated with the preparative scale synthesis of two valuable β3-amino acids possessing unnatural side chains.
- Gerfaud, Thibaud,Chiang, Ying-Ling,Kreituss, Imants,Russak, Justin A.,Bode, Jeffrey W.
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experimental part
p. 687 - 696
(2012/07/13)
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- Spirocyclopropyl pyrrolidines as a new series of α-l-fucosidase inhibitors
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Polyhydroxy 4-azaspiro[2.4]heptane derivatives (spirocyclopropyl iminosugars) were prepared in four to six steps from readily available protected aldoses. The key step of the reaction sequence involves a titanium-mediated aminocyclopropanation of glyconon
- Laroche, Christophe,Behr, Jean-Bernard,Szymoniak, Jan,Bertus, Philippe,Schuetz, Catherine,Vogel, Pierre,Plantier-Royon, Richard
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p. 4047 - 4054
(2007/10/03)
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- Enantioselective Synthesis of 5-LO Inhibitor Hydroxyureas. Tandem Nucleophilic Addition-Intramolecular Cyclization of Chiral Nitrones
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An enantioselective synthesis of chiral hydroxyurea based 5-lipoxygenase inhibitors is reported via a five-step sequence in about 30% overall yield. The synthesis is based on a novel tandem nucleophilic addition-intramolecular cyclization reaction in which a chiral nitrone functions as the electrophilic acceptor species. A mannose-based chiral auxiliary controls the diastereoselectivity of the reaction in an 8:1 ratio. After the auxiliary removal and appropriate functionalization, a single recrystallization afforded the target structures in >99% ee.
- Lantos, Ivan,Flisak, Joseph,Liu, Li,Matsuoka, Richard,Mendelson, Wilf,Stevenson, David,Tubman, Ken,Tucker, Lynn,Zhang, Wei-Yuan,Adams, Jerry,Sorenson, Margaret,Garigipati, Ravi,Erhardt, Karl,Ross, Steve
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p. 5385 - 5391
(2007/10/03)
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- Enantioselective Synthesis of 5-LO Inhibitors Using a Gulofuranose Auxiliary
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The pure R-(+)-enantiomer of 5-lipoxygenase inhibitor Zileuton was prepared by diastereoselective methyl Grignard addition to an aldonitrone bearing a D-gulofuranose-derived chiral auxiliary.Addition of the Lewis acid trimethylaluminum leads to a reversal of the alkylation stereochemistry and the potent pyrido analogue, R-(+)-RS-27871 was prepared in this way from an L-gulofuranose-derived nitrone.
- Rohloff, John C.,Alfredson, Thomas V.,Schwartz, Martin A.
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p. 1011 - 1014
(2007/10/02)
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