Studies on Pillaromycin A. III. The Structure of Pillarose

Pillarose (I), C8H12O5, gives positive Fehling's and iodoform reactions. Absorption of an isolated carbonyl is observed in the infrared and ultraviolet region. I formed methyl pillarosides (VIIa, b) and mono-, diacetylpillaroses, and reacted with sodium borohydride to yield methyl dihydropillarosides (Xa, b). I consumed 2 moles of periodate. Periodate oxidation of I in acidic solution gave acetaldehyde, formic acid (and formaldehyde), succinaldehydic acid and carbon dioxide. From these degradation schemes and physico chemical properties of the above derivatives the structure, 2, 3, 6-trideoxy-2-glycoloylhexopyranos-4-ulose, was given to pillarose (I).