Methyl esters silver salt method

Attempts to use a Lewis acid to anomerize the ester linkage at C-l from /3 to a have thus far been mostly unsuccessful however, application of Bonner s249 procedure, involving anomerization of acetylated aldoses in an acid anhydride containing an acid catalyst, was found246 to be applicable to the acetylated D-glucopyranuronate series also. Thus, /3 —> a anomerization of methyl tri-0-acetyl-l-0-propanoyl-/3-D-glucopyranuronate (prepared by the silver salt method) was achieved... 

Diacyloxy compounds are intermediates in the conversion of olefins and 1,2-dihalides to glycols (method 95). Although the diesters are seldom isolated, yields are good where their isolation has been attempted. The well-known reaction of an alkyl halide with a silver salt of an acid is used infrequently. It is sometimes valuable in making esters from acids which isomerize during direct esterification. Thus, the labile double bond of 3 niethyl-3-butenoic acid is unaffected by conversion to the methyl ester by this method. ... 

This method with some slight modihcations is applied in the synthesis of to-bromo esters from Cs to Cn. Methyl 5-bromovalerate has been prepared by treating the silver salt of methyl hydrogen adipate with bromine. The ethyl ester has been prepared from the acid by esterification or through the acid chloride. ... 

Methyl pyruvate has been prepared from the silver salt of pyruvic acid and methyl iodide,3 and from the free acid by the alcohol-vapor method without a catalyst.4 Pyruvic esters have also been prepared by the dehydrogenation of lactic acid esters.5... 

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