Crystal structures of 10alpha-gon-5-enes from the synthetic pathway to desogestrel.
X-ray crystallographic studies performed on the product of the ketalization reaction of 13beta-ethyl-11alpha-hydroxy-gon-5-ene-3,17-dione have lead to the unequivocal assignment of the 10alpha stereochemistry to C10, showing that an inversion of configuration occurred during formation of the 3,17-diketal. From the Swern oxidation of this compound, 11alpha-(methylthio)methoxy-10alpha-gonene was obtained as the major product instead of the desired 11-ketone. Modeling studies showed that the configurational instability at C10 is determined by the presence of the 11alpha-hydroxyl group.
Modica
Emilia
E
Dipartimento di Chimica, Biochimica e Biotecnologie per la Medicina, Università di Milano, 20133 Milano, Italy.
Colombo
Diego
D
Ronchetti
Fiamma
F
Scala
Antonio
A
Bombieri
Gabriella
G
Marchini
Nicoletta
N
Toma
Lucio
L
D018360:Crystallography, X-Ray; D017135:Desogestrel / Q000138:chemical synthesis*; D006067:Gonanes / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure
D006067:Gonanes; D017135:Desogestrel