Reeves' conformational formulas of aldopyranoses can be described by combinations o f letters and numbers. This system may be especially useful when many conformational formulas would have to be printed. The CI conformation of sugars in the series is to be visualized with the C , atom on the right, below, and the C , atom on the left, above in the chair f o r m = 4C,, and the ring members must be numbered clockwise. Applying these conventions, both in the D-and series the axial substituents attached to the C,, C, and C, atoms in the C1 conformation are directed downwards, while those affixed to the C, and C, atoms point upwards relative to the plane o f the ring. The C,-substituent in pyranoses of CI conformation is axial in the case of ~-sugars, and equatorial in ~-sugars. The axial position is designated in the formula by its location written in parentheses and the substituents other than -H and -OH are indicated behind the parentheses. 4C1 means an aldopyranose ring o f C l conformation. 4C,(-)fi-CH,0H means /h-glucopyranose, 4C1(I,2)fi-CH,0H denotes a-D-mannopyranose. If the figure "fi" also occurs in parentheses, the symbol represents an L-sugar, e.g., 4C1(1,2,5)J-CH,0H means P-L-gulose, or 4C,(1,2,5)5-COOH,3deoxy is 3-deoxy-~-~-guluronic acid in CI conformation. The 1C conformation is designated as ,C4, Bl as 4B1, B2 as sBz, etc. The ring members are numbered in the "alternative" conformations ( l C , IB, 2B, 3B) counter-clockwise.
(Zusamrnenfassung siehe Seite 84; RCsumC 2 la page 84) ':-= angle between the -OH groups.