Reduction of steroidal tosylhydrazones

Reduction of Steroidal Tosylhydrazones with Sodium B orodeuteride... 

Reduction of steroid tosylhydrazones Steroid tosylhydrazones can be reduced to the corresponding methylene compounds in 55-75% yield by NaBFLt in HOAc without reduction of alkoxycarbonyl substituents. 

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... 

A new selective and very mild method for the reduction of ketone tosylhydrazones to hydrocarbons offers promise for steroid chemistry reduction with catechol-borane and buffered hydrolysis gives the hydrocarbon in good yield.193 2,4-Dinitrobenzenesulphonylhydrazine is superior to toluene-p-sulphonylhydrazine for... 

Reduction of a unsaturated tosylhydrazones. Hutchins et al. reported briefly that reduction of tosylhydrazones of aliphatic a,/8-unsaturaled ketones produces alkenes resulting from migration of the double bond to the carbon originally bearing the carbonyl group. Taylor and Djerassi have since examined this reduction in detail with steroidal substrates and found that the situation is more complex. Thus reduction of the tosylhydrazone of A -cholestenone gives the four products shown in equation (I). Reduction of the tosylhydrazone of A - -cholestadienone-3 is even more complex (equation II). 

The reduction of tosylhydrazones by complex metal hydrides has been used very effectively to prepare saturated steroid hydrocarbons in high yields. ... 

In keto steroids the reductions were also achieved by electrolysis in 10% sulfuric acid and dioxane using a divided cell with lead electrodes (yields 85-97%) [862], hy specially activated zinc dust in anhydrous solvent (ether or acetic anhydride saturated with hydrogen chloride) (yields 50-87%) [155, 86J], and by the above mentioned reduction of tosylhydrazones with sodium borohydride (yields 60-75%) [811]. 

The reduction of tosylhydrazones by complex metal hydrides has been used very effectively to prepare saturated steroid hydrocarbons in high yields.317 In certain cases this reduction (with lithium aluminum hydride) takes a different course, and olefins are formed.318 The effect is dependent on both the reagent concentration and the steric environment of the hydrazone.319 Dilute reagent and hindered hydrazone favor olefins borohydride gives the saturated hydrocarbon. The hydrogen picked up in olefin formation comes from solvent, and in full reduction one comes from hydride and the other from solvent. This was shown by deuteriation experiments with the hydrazone (150) 319... 

Tosylhydrazones on reaction with alkylithium reagents give olefins in high yield. This new synthesis allowed for exas le the preparation of 16-androstene from androstan-17-one in quantitative yield.Reduction of carbonyl functions to methylene c ui be effected electrochemically or by treatment of the steroid ketones with powdered zinc in acetic anhydride saturated with hydrogen chloride at room temperature." ... 

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