Mechanistic studies of the rearrangements of steroidal 16,17-ketols and syntheses of 20→16-cis-γ-carbolactones

Utilization of 17-keto-androstanes as starting materials for the synthesis of α- or β-oriented steroidal 20→16-γ-carbolactones has been explored following two different strategies. A highly efficient, stereospecific protocol has been developed for the β-oriented cis-γ-lactone. A different approach,...

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Detalles Bibliográficos
Autores principales: Bruttomesso, A.C., Doller, D., Gros, E.G.
Formato: JOUR
Materias:
Biosynthesis
Natural products
NMR
Stereospecificity
Steroids and sterols
carbonyl derivative
hydroxyl group
ketol
lactone derivative
steroid
tomatine
article
carbon nuclear magnetic resonance
reaction analysis
synthesis
Androstanols
Lactones
Magnetic Resonance Spectroscopy
Models, Chemical
Models, Molecular
Spironolactone
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09680896_v7_n5_p943_Bruttomesso
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:Utilization of 17-keto-androstanes as starting materials for the synthesis of α- or β-oriented steroidal 20→16-γ-carbolactones has been explored following two different strategies. A highly efficient, stereospecific protocol has been developed for the β-oriented cis-γ-lactone. A different approach, involving prior attachment of a 3-carbon side chain on C-17 of a 17-oxo-16β-acetoxy-androstane led to the epimeric, α-oriented lactone. The mechanism of the rearrangement of epimeric 16β- or 16α-hydroxy-17-keto-androstanes to 17β-hydroxy-16-keto-androstanes was studied by 13C NMR spectroscopy. The former occurs through a 1,2-sigmatropic H-shift, while the latter is likely to take place by simple enolization-reprotonation. Copyright (C) 1999 Elsevier Science Ltd.

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