[chemical substances]
   compounds
     Class carbohydrates [Cn(H2O)n, etc.]
       Class saccharides
         Class monosaccharides - sugars
           01.02 Class aldoses [H[CH(OH)]nC(=O)H (n>=2), etc.]
           01.02 Class ketoses [H[CHOH]nC(=O)[CHOH]mH, etc.]
           01.05 Class ketoaldoses
           01.07 Class amino sugars
           01.09 Class aldonic acids [HOCH2[CH(OH)]nC(=O)OH]
           01.10 Class ketoaldonic acids
           01.11 Class uronic acids
           01.12 Class aldaric acids [HOC(=O)[CH(OH)]nC(=O)OH]
           05.1 Class furanoses
           05.1 Class pyranoses
           17 Class enoses