PROCESS FOR PREPARING 3,5:4,6- PROTECTED DERIVATIVES OF L- OR D- GULONIC ACID, THEIR USE IN PREPARING 2- KETO-L- OR D- GULONIC ACID OR THEIR ESTERS OR L- OR D- ASCORBIC ACID, AND CERTAIN NOVEL 2-NITRATO-GULONATE INTERMEDIATES

摘要

The invention relates to a process in which a 3,5:4,6-protected derivative of L- or D-glulonic acid is prepared by contecting L- or D-gulono-1,4-lactone with an aldehyde dialkyl acetal, or with an aldehyde and an alcohol, in the presence of an acid having a pKa of less than 3. This protected derivative may be oxidised and hydrolysed to 2-keto-L- or D-gulonic acid or ester thereof, which in turn may be hydrolysed to L- or D-ascorbic acid. L-ascorbic acid is of course Vitamin C. The invention also relates to the novel intermediates produced by the above processes.