Studies of C-Nor-D-homosteroids. II. The Synthesis of C-Nor-D-homopregnane Derivatives from Steroidal Sapogenins.
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چکیده
منابع مشابه
D-nor steroids: anomalous conformation and reactivity of C-D-cis D-norandrostanes.
The C/D-cisD-norandrostanes 1a, 1b, 1c, 2a, 2b, and 2c were prepared and their reactivity studied. Whereas carbonium ion reactions of 1b and 1c are readily interpreted on the basis of their assigned stereochemistry, reactions of 2b and 2c suggest that these compounds react via conformations in which the 16beta-substituents are pseudoequatorial, requiring a ring C boat conformation as shown in f...
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The first total synthesis of (±)-pallambins C and D has been accomplished in a linear 38 step reaction from (±)-Wieland-Miescher ketone. The key conversions are featured as follows: a Grob fragmentation-intramolecular aldol cyclization and a thiourea/palladium-catalyzed carbonylative annulation.
متن کاملSynthesis of nor-C-linked neuraminic acid disaccharide: a versatile precursor of C-analogs of oligosialic acids and gangliosides.
The Neu5Acalpha(2,8)Neu5Ac disaccharide is an important constituent of tumor related antigen, however, the O-linkage is catabolically unstable. Vaccination with a catabolically stable sialic acid C-glycoside analog might enhance immunogenicity. The synthesis of Neu5Ac nor-C-disaccharide 20R/S, corresponding to versatile precursors of C-analogs of oligosialic acid and gangliosides, is reported. ...
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ژورنال
عنوان ژورنال: Chemical and Pharmaceutical Bulletin
سال: 1964
ISSN: 0009-2363,1347-5223
DOI: 10.1248/cpb.12.1