1.4- diene-3-ones

Finally the chemical aromatization of Ring A which occurs in nature in the biosynthesis of estrogens must be mentioned. It can be done by thermal cleavage of the C-19 methyl group in 1,4-dien-3-ones (H.H. Inhoffen, 1940 C. Djerassi, 1950) and was later achieved at lower temperatures with lithium — biphenyl in THF (H.L. Dryden, Jr., 1964). 

The 17-ethylene ketal of androsta-l,4-diene-3,17-dione is reduced to the 17-ethylene ketal of androst-4-en-3,17-dione in about 75% yield (66% if the product is recrystallized) under the conditions of Procedure 8a (section V). However, metal-ammonia reduction probably is no longer the method of choice for converting 1,4-dien-3-ones to 4-en-3-ones or for preparing 5-en-3-ones (from 4,6-dien-3-ones). The reduction of 1,4-dien-3-ones to 4-en-3-ones appears to be effected most conveniently by hydrogenation in the presence of triphenylphosphine rhodium halide catalysts. Steroidal 5-en-3-ones are best prepared by base catalyzed deconjugation of 4-en-3-ones. ... 

Therapeutic Function Androgen anabolic Chemical Name 17/J-Hydroxy-l 7-methylandrosta-1,4-dien-3-one Common Name Methandienone Structural Formula ... 

The second example is an intermolecular crystal-state reaction. Cross-conjugated 1,5-disubstituted 1,4-dien-3-ones in solution undergo both cis-trans photoisomerization and photodimerization, yielding complex mixtures of products, including die all-trans-substituted cyclobutane 2 in the case of 1,5-diphenyl-1,4-pentadien-3-one. In contrast, dienones such as 3a in whose crystals adjacent molecules lie parallel and strongly overlapped react in the solid to give 3b as the sole photoproduct. This isomerically pure tricyclic diketone results, formally, from an eight-center dimerization. It is not formed in the reaction in solution, and could be prepared by other methods only with considerable difficulty (4). 

When estra-l,3,5(10)-trien-3-ols are treated with Wfluorobis rifluoromethylsulfonyljamine (Id) in chloroform the ortho and para fluorination products 18-20 are formed. In contrast, when acetic acid is used as a solvent, fluorination in the para position occurs selectively and 10/ -fluoroestra-1,4-dien-3-one derivatives 20 are formed in high yield.147... 

Soladulcidine (solasodanol) (196) Nocardia restrictus Solasoda-1,4-diene-3-one (198) — 188... 

Steroidal 1,4-dien-3-ones react with phosphorus pentasulphide in an inert solvent to give the purple-blue l,4-diene-3-thiones (235) (Amax330 and 565—580nm).204 The thiones are remarkably stable, but can be oxidized to give syn- and anti-S-oxides, which are separable but are interconverted on standing. Diphenyl-diazomethane reacts with the dienethione at room temperature to give the 3-(diphenylmethylene)-1,4-diene (236) directly.204... 

Aromatization of Rings.—Phosphorylation of prednisolone (269) at C-21 with pyrophosphoryl chloride is accompanied by a novel fragmentation with rearrangement to give the highly toxic 9,10-seco-c-nor-aldehyde (270) as its 3,21-diphosphate. Simpler analogues, including either the 11 (3 - or the 11 a -hydroxy-1,4-dien-3-one structure, suffered the same reaction.221... 

The transformation of 1,4-dien-3-ones such as 295 (Scheme 2.111) into cyclopentenone 296 represents an example of the preparative utilization of carbocationic chemistry for cyclopentenones. This reaction, known as Nazarov s cyclization, was discovered almost half a century ago. While the initial... 

Androsta-1,4-dien-17(i-ol-3-one 17-(cyclopent-l -enyl) ether. The 17-ether function instead of the 17a-methyl group in this derivative (Quin-bolin, S-147) [14] is present in order to assure protection against metabolic inactivation of the 17-hydroxyl group [12]. The compound is orally applied and shows androgenic and anabolic activities similar to those of 17o -methyl-17/3-hydroxyandrost-1,4-dien-3-one. 

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