Dialkyl selenite

A number of reoxidants for selenium dioxide have been examined. For example, while hydrogen peroxide is sometimes successful, oxidation of cholecalciferol (27) or derivatives widi selenium dioxide alone gave poor results not improved by addition of hydrogen peroxide. In this case, use of sodium periodate or tetra-R-butylammonium periodate gave increased yields. The reaction was much improved when carried out under reflux in methanol or solvent mixtures containing methanol, and indeed selenous acid and dialkyl selenites, suggested as intermediates in die reaction, both accomplished a similar oxidation in nonalcoholic solvents in die presence of a reoxidant, A -methylmorpholine iV-oxide proving superior. 

Dialkyl selenites, on reaction with SbCls, readily gave the monoalkoxy-derivative SbCUOR, with SeOCla as the by-product, and the acceptor properties of such mono-alkoxy species, where R = Me, Et, C2H4C1, CH2Cp3, or CH2CCl3, have been investigated. 

On the other hand when diethyl selenite reacted with primary alcohols it gave dialkyl selenite by alcohol interchange but with secondary and tertiary alcohols only partial replacement was observed. ... 

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