The Reaction of Diketene With Steroid Alcohols and Steroids Derived From Hecogenin

Logan, Robert Thomas (1962) The Reaction of Diketene With Steroid Alcohols and Steroids Derived From Hecogenin. PhD thesis, University of Glasgow.

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Part I of this thesis describes the preparation of the aceto-acetates of steroid alcohols by reaction with diketene, and the examination of their pyrolysis products. Acetoacetates of 3-alcohols were very stable, little or no decomposition to the original alcohol being noticeable. The same was true of other secondary and tertiary alcohols studied. Alcohols in the 17-position having an adjacent 20-ketone gave alphabeta-unsaturated lactones having an acetyl side-chain. Attempts were made to remove this side-chain and thus obtain a lactone ring similar to that found in the carbenolides. Hydrolysis using acid and alkali, and the Haloform Reaction were unsuccessful. The 23-oxime was prepared with the intention of carrying out Beckmann Rearrangement to the amide, followed by hydrolysis and rearrangement to the required product. This was also unsuccessful. The oxime, on treatment with acid or base gave an interesting compound, formulated as 4-(3'beta,17'alpha-dihydroxy-11'-oxe-20'pregnenylidene)-3-methyl-5-isoxazolone. At the other end of the molecule the 3-acetate was hydrolysed, oxidised, and a 1,4-diene system inserted by reaction of the saturated 3-ketone with 2,3-dichloro-5,6-dicyanoquinone. The second part of the thesis deals with an attempted preparation of an 18-oxygenated steroid from hecogenin acetate cyanhydrin. The latter compound on treatment with thionyl chloride gave 3beta-acetoxy-13 beta-cyano-17a-methylene-C-nor-D-homo-5alpha,25D-sp irostane which gave the 17a-ketone on ozonolysis. Hydrolysis of the nitrile group did not give the beta-keto acid expected. 3beta-Acetoxy-17a-oxo-C-nor-D-homo-5alpha,25D-spirostane was prepared, and its cyanhydrin, when treated with thionyl chloride, gave an elimination and not the rearrangement expected. The 17a-methylene compound obtained above was reduced to the 13beta-aminomethyl steroid with lithium aluminium hydride. Nitrous acid treatment of the amine gave the alcohol and not the ring enlarged compound. C-Homohecogenin was obtained by reduction of hecogenin acetate cyanhydrin with lithium aluminium hydride and treatment of the crude product with nitrous acid. Separation of the ketonic fraction with Girard Reagent T gave the required product. The amine from the reduction was characterised as the acetate. This acetate, on treatment with nitrous acid gave a ketone, thought to be the isomeric C-homo ketone.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Organic chemistry
Date of Award: 1962
Depositing User: Enlighten Team
Unique ID: glathesis:1962-79462
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 05 Mar 2020 09:29
Last Modified: 05 Mar 2020 09:29

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