title: Preparation of enol-tert.-butyldimethylsilyl and mixed tert.-butyldimethylsilyl-trimethylsilyl ethers for gas chromatography--mass spectrometry of steroids and bile acids.
abstract: Conditions are described for conversion of testosterone into the 3-enol, 17-bis-tert.-butyldimethylsilyl ether derivative without formation of side products. The steroid is treated with tert.- butyldimethylsilylimidazole in heptane at 100 degrees C using sodium formate as catalyst. Derivatives are also formed at different rates of 3-keto-5 alpha, 3 alpha/beta-hydroxy-, 6 alpha/beta-hydroxy-, 7 beta-hydroxy-, 16 alpha-hydroxy-, 17 beta-hydroxy(sec.)- and 20 alpha/beta-hydroxysteroids, whereas hydroxyl groups in 1 beta, 7 alpha, 12 alpha/beta, 15 beta and 17 alpha(tert.) positions do not react to a significant extent. These positions are derivatized by subsequent addition of trimethylsilylimidazole , yielding mixed derivatives which are suitable for gas chromatography--mass spectrometry with selected ion monitoring. Conditions are given for conversion of some biologically important androgens, progestins and bile acids into a single form of derivative. The use of the method is illustrated by an analysis of steroids in a rat testis.
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D008297:Male; D017646:Organosilicon Compounds; D051381:Rats; D012825:Silicon / Q000138:chemical synthesis*; D012997:Solvents; D013256:Steroids / Q000032:analysis*; D013737:Testis / Q000032:analysis; D014297:Trimethylsilyl Compounds / Q000138:chemical synthesis*
chemical_list: D001647:Bile Acids and Salts; D017646:Organosilicon Compounds; D012997:Solvents; D013256:Steroids; D014297:Trimethylsilyl Compounds; C009660:t-butyldimethylsilyl compounds; D012825:Silicon