104873-63-4Relevant articles and documents
Stereoselective Synthesis of 20-(Hydrofuryl)steroids via the Isoxazole Derivatives
Khripach,Zhabinskii,Ol'khovik,Zavadskaya,Drachenova,Khripach
, p. 805 - 809 (2007/10/03)
The reaction of 1,3-dipolar cycloaddition of steroid acetylenic alcohols to acetonitrile oxide is studied. The possibility is shown for stereoselective transformation of the obtained adducts, 3,5-disubstituted isoxazoles, via their derivatives with an open functionalized side chain into 20-(hydrofuryl)steroids, in particular, into one of the eight possible isomeric tetrahydrofuranoles.
Synthesis of Crinosterol, a Synthetic Intermediate of Brassinolide and Castasterone
Takatsuto, Suguru,Ikekawa, Nobuo
, p. 591 - 594 (2007/10/02)
Stereoselective synthesis of crinosterol, -(22E,24S)-ergosta-5,22-dien-3β-ol (4), was achieved in ca. 50percent overall yield from (20S)-20-formyl-6β-methoxy-3α,5-cyclo-5α-pregnane (5).Coupling of (5) with lithium acetylide gave a 2:1 mixture of separable products (6) and (7), whose configurations at C-22 were determined by chemical correlation with the known compounds (8) and (9), respectively.The triethylsilyl ether of the 22R isomer (6) was lithiated and then treated with iodomethane, to provide, after desylilation, the acetylenic alcohol (10).Partial hydrogenation of (10) with Lindlar catalyst followed by orthoester Claisen rearrangement yielded the ester (12), whose ester group was reduced to a trideuteriomethyl group.Acid treatment of the resulting ether (13) afforded crinosterol (4), the deuterium content of which was 98percent.
