Sulfides, organic, periodate oxidation

The oxidation of the a-amino acids has not been completely studied, but it appears to be slow in most cases.8-9 The organic sulfide linkage is oxidized by periodate to a sulfone, with the concomitant liberation of iodine,48 but the oxidation of a 1-deoxy-l-thioglycoside, without occurrence of this side reaction, has been carried out at least once (in very dilute solution).44... 

SAFETY PROFILE Very toxic. Fire hazard by chemical reaction with easily oxidized materials. Explodes at 300°. Mixtures with sulfur are unstable storage hazards igniting immediately at 91 °C and after a 2-11 day delay period at room temperature. Incompatible with Al, As, C, Cu, metal sulfides, organic matter, P, and reducing materials. When heated to decomposition it emits toxic fumes of Br . See also BARIUM COMPOUNDS (soluble) and BROMINE. 

Although periodates also oxidize polycyclic aromatic hydrocarbons, phenols, hydrazines, active methylene compounds and sulfides, chemoselectivity can usually be achieved and glycol cleavage oxidation takes precedence. For example, the diol moiety in the diethyl dithioacetal derivative of o-glucose can be selectively oxidized in good yield (equation 6). In contrast, LTA is less selective than periodate and oxidizes a far greater variety of organic compounds. Consequently, in order to minimize undesired reactions, it is customary to add LTA slowly to avoid contact of the initially formed products with an excess of the oxidant (equation 7). ... 

In anaerobic soils, the individual chemistry of the ions is more distinctive. The transition metal ions in the middle of each period of the periodic table—chromium, manganese, iron, nickel, cobalt, and copper—can reduce to lower oxidation states, while the end members—scandium, titanium, and zinc—have only one oxidation state. The lower oxidation states are more water soluble but still tend to precipitate as carbonates and sulfides, or associate with organic matter, thus reducing their movement but increasing then plant availability. 

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