Skip to content
Licensed Unlicensed Requires Authentication Published by De Gruyter 2016 (Print 1979)

21-Hydroxy- and 17,21 -Dihydroxy-20-Ketosteroids (Colorimetry)

From: Colorimetric and Fluorimetric Determination of Steroids

  • Jaroslav Bartos and Maurice Pesez

Abstract

This report is devoted to two classes of reactions. 1. Methods of colorimetric determination of ketosteroids which make use of the reaction of a carbonyl group with a hydrazine, a hydrazone or a hydrazide. Three of these methods use p-nitro- or 2,4-dinitrophenylhydrazine, thus allowing the determination of steroids bearing a carbonyl group at position 3, 17 or 20. Isoniazid gives colored hydrazones only with Δ4-or Δ1,4-3-ketosteroids, whereas salicyloylhydrazide allows the fluorimetric determination of 17-ketosteroids. Under suitable conditions, phenylhydrazine gives a colored species only with 17,21-dihydroxy-20-ketosteroids (Porter-Silber reaction). These compounds can also be determined with 2-hydrazinobenzothiazole or with 3-methylbenzothiazolin-2-one hydrazone in the presence of an oxidant. 2. Other methods of determination of 21-hydroxy-20-ketosteroids: The three reactions cited above give positive results only when the steroid bears a hydroxy group at position 17. More generally, 21-hydroxy-20-ketosteroids can be determined through their reducing properties, using sodium molybdate, a tetrazolium salt or p-nitroso-N,N-dimethylaniline as reagent. The 21-hydroxy-20-keto group can be oxidized either with cupric acetate, to give the corresponding glyoxal derivative which is developed as a quinoxaline absorbing in the UV range, or with periodic acid to give formaldehyde which can be determined either colorimetrically or fluorimetrically.

QuelleSource

Downloaded on 28.3.2024 from https://www.degruyter.com/database/IUPAC/entry/iupac.51.0515/html
Scroll to top button