Ketones steroid

LiAKOBujaH. A selective reducing agent for converting RCOCl to aldehydes and reducing steroid ketones. See aluminium hydride. 

By similar procedures diazirines were prepared not only from simple aliphatic ketones but also from hydroxyketones and )3-aminoketones (B-67MI50800), and so were a large number of diazirines from steroidal ketones (65JA2665). Permanganate, bromine, chlorine and hypochlorite were used as oxidants. A one-step preparation of diazirines from ketones like 3-nonanone, ammonia and chlorine has been claimed in a patent (66USP3290289). 3,3-Diazirinedicarboxylic acid derivatives like (286) were obtained directly from oxime tosylates by the action of two moles of O-ethoxyamine (81AG(E)200). 

The procedure described is an example of a more general synthetic method for the direct conversion of ketones into cyanides. " The reaction has been carried out successfully with acyclic and cyclic aliphatic ketones, including numerous steroidal ketones and aryl-alkyl ketones. The conversion of diaryl or highly hindered ketones such as camphor and )3,j8-dimethyl-a-tetralone requires the use of a more polar solvent. The dimethoxyethane used in the present procedure should be replaced by dimethyl sulfoxide. ... 

Steroid ketones Apply the sample solution followed by Girard s reagent (0 1% tnmethylacetyl hydrazide in 10% acetic acid) and allow to react for 15 h in an atmosphere of acetic acid Then dry at 80 °C for 10 mm and after cooling chromatograph the hydrazones that have been formed [81]... 

When saturated steroidal ketones are reduced in ammonia, an alcohol is usually present to act as a proton donor and high yields of steroidal alcohols are obtained. Under these conditions, reduction probably proceeds by protonation of the radical-anion (or ketyl) (61), which results from a one electron addition to the carbonyl group, followed by addition of a second electron and proton. Barton has proposed that reduction proceeds via protonation of the dianion (62) arising from addition of two electrons to the carbonyl group. This proposal implies that the ketyl (61) undergoes addition of a second electron in preference to undergoing protonation by the... 

The reduction of an asymmetric cyclohexanone (e.g. a steroidal ketone) can lead to two epimeric alcohols. Usually one of these products predominates. The experimental results for the reduction of steroidal ketones with metal hydrides have been well summarized by Barton and are discussed in some detail in a later section (page 76) unhindered ketones are reduced by hydrides to give mainly equatorial alcohols hindered ketones (more accurately ketones for which axial approach of the reagent is hindered " ) are reduced to give mainly axial alcohols. 

The data available on the stereochemistry of reduction of steroidal ketones have been obtained largely in the course of synthetic work, rather than in studies devoted specifically to stereochemical problems. As discussed in an earlier section, the proportion of epimers depends on the steric environment of the ketone, the reagent, the solvent and the temperature. These factors will be discussed below. 

Steroid ketones are apparently hydrogenated in the following order C-3>C-16, C-17, C-20 C-7, C-6 > C-12 > Hindered... 

Reduction of Steroidal Ketones with Lithium Aluminum Deuteride... 

As a general procedure, a mixture of the steroidal ketone (50 mg) and lithium aluminum deuteride (20 mg) in dry ether (5 ml, freshly distilled from lithium aluminum hydride) is heated under reflux until the reduction is complete according to thin layer chromatography test. The excess deuteride is then decomposed by the careful addition of a few drops of water and the reaction mixture is worked up by the usual procedure. For hindered ketones or esters the use of other solvents, such as tetrahydrofuran or dioxane, may be preferable to allow higher reaction temperatures. 

Deuteration by Electrochemical Reduction of a Steroidal Ketone in the Presence of Deuterium Oxide-10% Deuterio-sulfuric Acid... 

The following general procedure has been used for the reduction of the tosylhydrazone derivatives of various steroidal ketones. A mixture of the tosylhydrazone (50 mg) and sodium borodeuteride (50 mg) in dry dioxane (3 ml) is heated under reflux for 2 hr, and then the excess deuteride is decomposed by the addition of a few drops of acetic acid. Ether is added and the resulting solution is washed with 2 N sodium bicarbonate solution and... 

This reaction has been successfully extended to the preparation of the following labeled steroidal ketones ... 

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