Sorbose thin-layer chromatography

Similar results were reported two years later by Patil and Bose. They investigated the acetonation of L-sorbose in acetone containing 4% of concentrated sulfuric acid, and showed by thin-layer chromatography that the 1,2-monoacetal 11 and the diacetal 3 are formed early in the reaction, whereas the 2,3-monoacetal 4 appears much later. Treatment of pure 3 or pure 4 under these acetonating conditions was reported to produce an equilibrium mixture of the two, but no 11 was detected in either experiment. They concluded that the conversion of 11 into 3 is irreversible, and that 4 is formed by subsequent hydrolysis of the more labile 1,3-dioxolane ring involving C-4 and C-6 of 3. 

In 1967, Maeda published a detailed paper on the reaction of L-sorbose with 2,2-dimethoxypropane. Using thin-layer chromatography for isolation, and infrared and proton magnetic resonance spectroscopy for characterization, he reported four major products [3, 17, l,3 4,6-di-0-isopropylidene-j3-L-sorbofuranose (18), and 1,2 -4,6-di-0-isopropylidene-)8-L-sorbofuranose (20)] and six minor products (15, 19, 21, 22-24) from the reaction, after 4 hours at 45° with p-toluenesulfonic acid as the catalyst. 

An apparatus for descending, thin-layer chromatography of iso-propylidene acetals of L-sorbose has been described. 

E. lllner. Purity testing of sorbose and sorbitol by thin-layer chromatography on Silufol ready-prepared plates, Pharmazie 39 689-690 (1984). 

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