Gluconic acid periodate oxidation

As a corollary to this work, oxidation with periodate constitutes the basis of analytical procedures for the determination of 6-deoxyhexoses ( methylpentoses ),88 calcium gluconate89 and gluconic acid,90 hexitols,91 94... 

Proof of the location of the methoxyl group at C3 was established by application of periodate oxidation to methyl 2-acetamido-2-deoxy-3-0-methyl-a-D-glucopyranoside and to 2-amino-2-deoxy-3-0-methyl-D-gluconic acid. The first compound was resistant to oxidation, whereas the second consumed two equivalents of periodate per mole and released one mole of formaldehyde and one mole of formic acid per mole, but afforded no ammonia. ... 

The structure of the second di-O-isopropyl idene-D-fructose has been defined (181). It is known that carbon 1 in this isomer is open since, on oxidation with alkaline permanganate, an acid was obtained, without acetone removal, which on acid hydrolysis yielded 1-C-carboxy-D-arabinose (2-keto-D-gluconic acid) (182). Acid hydrolysis yielded a mono-O-isopropylidene-D-fructose characterized as a crystalline triacetate. Deacetylation of this nonreducing compound yielded a product consuming one mole of periodate per mole of substance. Only two possible nonreducing mono-O-isopropyli-dene derivatives are compatible with this analysis 1,2-0-isopropylidene-D-fructofuranose and 2,3-0-isopropylidene-D-fructopyranose. The former is eliminated by the formation of a carboxyl group at carbon 1. Since hydrolysis by aqueous acid will not shift the position of an attached isopropylidene group, the structure of this mono-O-isopropylidene-D-fructose is therefore established as 2,3-0-isopropylidene-D-fructopyranose and the second diiso-propylidene derivative is established as 2,3 4,5-di-0-isopropylidene-D-fructose (II). 

---