Manganese dioxide oxidation sensitivity

The sensitivity can be increased by treating the resultant precipitate with an acetic acid solution of benzidine whereupon the manganese dioxide oxidizes the benzidine to a blue oxidation product. (DANGER THE REAGENT IS CARCINOGENIC). 

Kubota and co-workers describe a novel oxidative rearrangement of the diosphenol (58) of 17iS-hydroxyandrost-4-ene-2,3-dione to the A-nor-A -1,2-diketone (59) in 33 % yield by the action of specially prep d manganese dioxide in boiling acetone. The rate of ring contraction is very sensitive to the source of the oxidant, and a trace of dilute sulfuric acid in the reaction mixture causes oxidative fission of ring A. 

Oxidation of sensitive divinyl alcohol 20 to dienone 4 is achieved by treatment with activated manganese dioxide. Commercially available active Mn02 21 is a synthetic nonstoichiometric hydrated material. This reagent provides mild conditions for oxidation of allylic, propargylic, and benzylic alcohols.10... 

Much effort has been expended in developing mild routes for the oxidation of the sensitive allylic alcohols, such as retronecine (127) to the corresponding carbonyl compounds. Mattocks has recently converted retronecine into the aldehyde (145) in 30% yield using specially prepared manganese dioxide under controlled conditions. This aldehyde (145) is probably an intermediate in the formation of the dihydropyrrolizines (see Section V,D). 

POTASSIUM lODATE (7758-05-6) KIO, Noncombustible solid but many chemical reactions can cause fire and explosions. A strong oxidizer. Reacts violently with many materials, including reducing agents, hydrides, nitrides, and sulfides combustible materials, organic substances, manganese dioxide, arsenic, finely divided metals or carbon materials, hydrides of alkali or alkaline earth metalss, metal cyanides, metal thiocyanates, phosphonium iodide, red phosphorus, sulfides, sulfur, xenon tetrafluoride. Forms explosive compounds with solid organic matter. Mixture of powdered aluminum forms heat-, friction-, and shock-sensitive explosive. Attacks chemically active metals (e.g, aluminum, copper, zinc, etc.). Thermal deconposition, at temperatures above 1040°F/560°C, releases toxic iodine fumes. 

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