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Title: Chemical transformations of steroids towards the preparation of steroidal drug and drug intermediates hormones and some ansasecosteroids
Researcher: Borah, Parinita
Guide(s): Chowdhury, P K
Keywords: Chlorination
University: Gauhati University
Completed Date: 31/12/1997
Abstract: In the first chapter of the thesis, the Manganese mediated stereospecific chlorination of steroidal olefins and ketones using the system MnO2-TMSCl or MnO2-AcCl in acetic acid medium has been explored. The method has been utilised towards the preparation of various steroidal trans-dichlorides, 3B-acetoxy-17a-chloropregnan-20-one and 17a-chloroprogesterone in excellent yield under mild reaction conditions. The system has also been utilised towards the chlorination of various 20-ketopregnanes leading to the construction of the corticosteroid side chain which finds an important place in steroid field. Besides these, some reactions on chlorinated products have been carried out which appeared to be chemically interesting. In the second chapter a mild and chemoselective deoxygenation of steroidal ketones with Zinc and Hydrogen chloride generated in situ using the system Zinc-AlCl3.6H2O-THF-H2O has been described. The utility of the method towards the preparation of various 3-deoxy-steroids having potential biological activity (aromatase inhibitors) has been put forwarded. The third chapter of the thesis describes the experiments aimed at transformation of readily available 20-ketopregnanes into 17-ketoandrostanes (C-19 steroids) of male sex hormones using a Tin-mediated selective Bayer-Villiger oxidation process. A number of 17-ketosteroids of commercial value have been prepared using this selective Bayer-Villiger oxidation technique from various 20-ketopregnanes. The preparation of 4-hydroxyandrostene-3, 17-dione - a potent aromatase inhibitor has also been described using this reaction as a key step. The fourth chapter deals with the Magnesium lodide or Chlorotrimetylsilane induced catalytic isomerization of isospirostanes to furstenols. A simplified method for the synthesis of 16-Dehydropregnenolone acetate (16-DPA) and its analogue which are the key intermediates for almost all the steroidal drugs and hormones have been described starting from isospirostanic compounds diosgenin and its relative. The last chapter of
Appears in Departments:Department of Chemistry

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02_certificate.pdf57.36 kBAdobe PDFView/Open
03_content.pdf40.96 kBAdobe PDFView/Open
04_abstract.pdf28.26 kBAdobe PDFView/Open
05_chapter 1.pdf1.07 MBAdobe PDFView/Open
06_chapter 2.pdf1.83 MBAdobe PDFView/Open
07_chapter 3.pdf782.15 kBAdobe PDFView/Open
08_chapter 4.pdf882.54 kBAdobe PDFView/Open
09_chapter 5.pdf558.58 kBAdobe PDFView/Open
10_chapter 6.pdf363.17 kBAdobe PDFView/Open
11_list of publications and patents filed on the work done.pdf26.65 kBAdobe PDFView/Open

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