- Synthesis and glycosidase inhibition of: N-substituted derivatives of 1,4-dideoxy-1,4-imino-d-mannitol (DIM)
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N-Substituted derivatives of 1,4-dideoxy-1,4-imino-d-mannitol (DIM), the pyrrolidine core of swainsonine, have been synthesized efficiently and stereoselectively from d-mannose with 2,3:5,6-di-O-isopropylidene DIM (10) as a key intermediate. These N-substituted derivatives include N-alkylated, N-alkenylated, N-hydroxyalkylated and N-aralkylated DIMs with the carbon number of the alkyl chain ranging from one to nine. The obtained 33 N-substituted DIM derivatives were assayed against various glycosidases, which allowed a systematic evaluation of their glycosidase inhibition profiles. Though N-substitution of DIM decreased their α-mannosidase inhibitory activities, some of the derivatives showed significant inhibition of other glycosidases.
- Yang, Lin-Feng,Shimadate, Yuna,Kato, Atsushi,Li, Yi-Xian,Jia, Yue-Mei,Fleet, George W. J.,Yu, Chu-Yi
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- Total synthesis of seco-plakortolide e and (-)-ent-plakortolide I: Absolute configurational revision of natural plakortolide i
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A first total synthesis of (-)-ent-plakortolide I and seco-plakortolide E was accomplished from (S)-2-methylglycidol. The relevant key reactions involve a diastereoselective Mukaiyama aldol reaction, a regioselective hydroperoxysilylation, and elaboration of the 1,2-dioxane ring by intramolecular Michael addition of a hydroperoxide group to a butenolide. This synthesis allowed the revision of the absolute configuration of plakortolide I and structural revision of plakortolide E.
- Barnych, Bogdan,Vatele, Jean-Michel
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supporting information; experimental part
p. 564 - 567
(2012/03/26)
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- Zwitterionic sulfobetaine inhibitors of squalene synthase
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A substantial number of sulfobetaines (e.g., 10) have been synthesized and evaluated as inhibitors of squalene synthase (SS) on the basis of the idea that their zwitterionic structure would have properties conducive both to binding in the active site and to passage through cell membranes. When the simple sulfobetaine moiety is incorporated into compounds containing hydrophobic portions like those in farnesyl diphosphate (1) or presqualene diphosphate (2), inhibition of SS in a rat liver microsomal assay was indeed observed. For example, farnesylated sulfobetaine 10 has IC50 = 10 μM and aromatic derivative 35 has IC50 = 2 μM for SS inhibition. A wide variety of structural modifications, exemplified by compounds 43, 52, 76, 85, 91, 99, 111, and 115, was investigated. Unfortunately, no inhibitors in the submicromolar range were discovered, and exploration of a different type of zwitterion seems necessary if this appealing approach to inhibition of SS is going to provide a potential antihypercholesterolemic agent.
- Spencer, Thomas A.,Onofrey, Thomas J.,Cann, Reginald O.,Russel, Jonathon S.,Lee, Laura E.,Blanchard, Daniel E.,Castro, Alfredo,Gu, Peide,Jiang, Guojian,Shechter, Ishaiahu
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p. 807 - 818
(2007/10/03)
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- Syntheses of (-)-(2R,3R,6S)-irnigaine and (+)-(2R,3R,6S)-N- methylirnigaine
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Syntheses of irnigaine 1 and the N-methyl derivative 10 were performed starting from chiral building block 2. Synthetic and spectroscopic data are given including the absolute structure of I by an X-ray structure of the hydrochloride.
- Pahl, Axel,Wartchow, Rudolf,Meyer, Hartmut H.
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p. 2095 - 2096
(2007/10/03)
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- Enantioselective total synthesis of Irniine and Bgugaine, bioactive 2-alkylpyrrolidine alkaloids
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An asymmetric total synthesis of the 2-(R)-alkylpyrrolidines, (-)-irniine (1a) and (-)-bgugaine (1b), toxic and antibiotic components of the tubers of Arisarum vulgare, and (+)-(S)-irniine (1c), was carried out by condensation of the corresponding 4-oxoalkanoic acid (9) with chiral phenylglycinol. Acids (9) were prepared from a hetero-organocuprate (I) complex, generated by reaction of methylcopper (I) with alkylmagnesium bromides and methyl chlorocarbonylpropionate. Alkaloids (1a, 1b and 1c) displayed anti Gram(+) bacterial (MIC 12.5 - 50 μg/ml) and antifungal (MIC 6.25 - 50 μg/ml) activities.
- Jossang, Akino,Melhaoui, Ahmed,Bodo, Bernard
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p. 755 - 766
(2007/10/03)
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- Anti-inflammatory furanones
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New 5-hydroxy-2-furanone compounds having anti-inflammatory, immunosuppressive and anti-proliferative activity and are useful in treating psoriasis and modifying calcium homeostasis.
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- 100. Synthesis of Chiral 12-Phenyl(2H)dodecanoic Acids: Useful Metabolic Probes for the Biosynthesis of 1-Alkenes from Fatty Acids
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The synthesis of chiral 12-phenyl(2H)dodecanoic acids as metabolic probes for the evaluation of the stereochemical course of the biosynthesis of 1-alkenes from fatty acids in plants and insects is described.The diastereoisomeric (2R,3R)- or (2S,3S)-12-phenyl(2,3-(2)H2)dodecanoic acids 11 are obtained in high chemical and optical yield (">" 97percent e.e.) from the readily available (E)-12-phenyl(2,3-(2)H2)dodec-2-enoic acid (10) or (E)-12-phenyldodec-2-enoic acid (10a) by microbial reduction with wet packed cells of Clostridium tyrobutyricum in either (2)H2O or H2O buffer. (2R)- and (2S)-12-phenyl(2-(2)H)dodecanoic acids 9 (">" 97percent e.e.) are accessible from the allylic alcohol 6 via Sharpless epoxidation with (+)-L- or (-)-D-diethyl tartrate.Synthetic routes to the (E)- and (Z)-11-phenyl(1-(2)H) undec-1-enes 16 and 16a as reference compounds are also included.
- Goergen, Guenther,Boland, Wilhelm,Preiss, Ute,Simon, Helmut
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p. 917 - 928
(2007/10/02)
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- Synthesis and Identification of ω-Phenylalkylcatechols in Burmese Lac
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The presence of 3-(10'-phenyldecyl)- (2) (2percent), 3-(12'-phenyldodecyl)- (3) (6percent), 4-(10'-phenyldecyl)- (4) (0.3percent) and 4-(12'-phenyldodecyl)-benzene-1,2-diol (5) (0.3percent) in Burmese lac, the sap of Melanorrhoea usitata Wall has been confirmed by the synthesis of these compounds and a comparison of the gas chromatographic retention times and the mass spectral characteristic of their bis-O-(trimethylsilyl) derivatives with the derivatives of the natural products.Typically, 3,4-bis(benzyloxy)benzaldehyde (7) on Wittig reaction with triphenyl(11-phenylundecyl)phosphonium bromide (20) and subsequent catalytic hydrogenation of the resultant olefin gave compound (5) in 59percent overall yield.
- Jefferson, Alan,Sargent, Melvyn V.,Wangchareontrakul, Sirichai
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