The reaction of steroid 2,4-dienes with acetylenes

Abstract

. Can. J. Chem. 54, 3508 (1976).Reaction of 2,4-cholestadiene. 2,4-androstadien-17-one, or 3-trirnethylsiloxy-2,4-cholestadiene with dimethyl acetjlenedicarboxylate or methyl propiolate in boiling xylene results in the cleavage of rings A and B and the formation of 4-(2-arjlethyl)-5-isoprope1iyl-7a-methyltetrahydroindane derivatives. They are considered to be formed via Diels-Alder addition of the acetylene to the steroid diene followed by a retro-Dieis-Alder cleavage of the resulting bicyclo-[2.2.2]octadiene system. Attempts to isolate the Diels-Alder adducts by carrying out the additions at lower temperature were unsuccessful, since no reaction occurred. However, when 2,4-androstadien-17-one was treated with dicyanoacetylene in boiling benzene, it was possible to isolate a mixture of two stereoisomeric Diels-Alder adducts containing the bicjclo[2.2.2]-octadiene system in ring A : this was converted in boiling xylene to a retro-Diels-Alder product analogous to the products obtained with the other acetylenic dienophiles.

Antitumor Profile of Carbon-Bridged Steroids (CBS) and Triterpenoids

“…Several steroids , containing an additional 5-or 6-membered ring (s) in the steroid molecule, have been synthesized in various laboratories and demonstrate a wide range of biological activities [18,160,161,164,167,168,210,[227][228][229][230][231][232], and their structures are shown in Figures 18 and 19. Their pharmacological profile is presented in Tables 16 and 17.…”

Waxes, Triterpenes, Steroids, and Free and Bound Acids in Leaves and Stems of Centaurea aspera

“…They may be considered as missing links in the biogenetic route to alkanoic acids (6). Triterpenols are free in the plant, and to separate their individual components, the whole group was transformed in triterpenyl acetates, which were separated on silica gel-AgN03 (100:25) column (7) with hexane-Et20 (94:6). Interesting amounts of pure acetates (gc) were separated and identified not only by the properties of acetates (mp, [a], 'H-nmr, ir, ms) but by the properties of the triterpenols obtained from hydrolysis (mp, mmp, [a], 'H-nmr, ir, ms).…”

Conversion of a 3-desoxysteroid to 3-desoxyestrogen by human placental aromatase.

“…Some of the theories demonstrated to be unlikely include 2f-hydroxylation (17), Baeyer-Villiger oxygen insertion (13), 4,5-epoxidation (18,19), and 1Of-hydroxyestr-4-ene-3,17-dione formation (20). One of the remaining viable hypotheses, proposed by Akhtar et al (21) drosta-2,4-diene-17-one (11) was synthesized according to a published procedure (27). Twice-washed placental microsomes were obtained by using minor modifications of previously described methods (28 (2 ml) and partitioned between CH2C12 (60 ml) and aqueous saturated Na2SO3 (40 ml …”