D-glycero-D-gluco-Heptose
not D-gluco-D-glycero-heptose
Continued from 2-Carb-6 and 2-Carb-7
Contents
The aldoses with three to six carbon atoms have trivial names which are given, together with the formulae in the Fischer projection, in Chart I (2-Carb-2.2). (See also the alphabetical listing of trivial names in the Appendix.)
The trivial names form the basis of the configurational prefixes (see 2-Carb-4.3).
Systematic names are formed from a stem name and a configurational prefix or prefixes. The stem names for the aldoses with three to ten carbon atoms are triose, tetrose, pentose, hexose, heptose, octose, nonose, decose. The chain is numbered so that the carbonyl group is at position 1.
The configuration of the CHOH groups of the sugar is designated by the appropriate configurational prefix(es) from Chart I. When used in systematic names, these prefixes are always to be in lower case letters (with no initial capital), and italicized in print. Each prefix is qualified by D or L (Chart I shows only the D structures).
Examples:
D-ribo-Pentose for D-ribose
D-manno-Hexose for D-mannose.
The trivial names are preferred for the parent sugars and for those derivatives where all stereocentres are unmodified.
2-Carb-8.3. Multiple configurational prefixes
An aldose containing more than four chiral centres is named by adding two or more configurational prefixes to the stem name. Prefixes are assigned in order to the chiral centres in groups of four, beginning with the group proximal to C-1. The prefix relating to the group of carbon atom(s) farthest from C-1 (which may contain less than four atoms) is cited first.
Examples:
2-Carb-8.4. Multiple sets of chiral centres
If sequences of chiral centres are separated by non-chiral centres, the non-chiral centres are ignored, and the remaining set of chiral centres is assigned the appropriate configurational prefix (for four centres or less) or prefixes (for more than four centres).
Example:
Note 1. This convention is not needed for parent aldoses, only for deoxy aldoses, ketoses and similar compounds (see 2-Carb-10.4 and 2-Carb-11.2).
Note 2. Since all aldoses up to the hexoses have trivial names that are preferred, the systematic names apply only to the higher aldoses. However, the configurational prefixes are also used to name ketoses (see below) and other monosaccharides.
2-Carb-8.5. Anomeric configuration in cyclic forms
For the specification of α and β in cyclic forms see 2-Carb-6.
Systematic names for individual dialdoses are formed from the systematic stem name for the corresponding aldose (see 2-Carb-8.2), but with the ending 'odialdose' instead of 'ose', and the appropriate configurational prefix (Chart I). A choice between the two possible aldose parent names is made on the basis of 2-Carb-2.2.2.
Examples:
galacto-Hexodialdose
Note. The prefix 'meso-' could be included in the latter case, but it is not needed to define the structure.
If a cyclic form is to be named, the locants of the anomeric centre and of the carbon atom bearing the ring oxygen atom must be given (in that order) (cf. 2-Carb-6.4). If there is more than one ring size designator, they are placed in alphabetical order (e.g. furanose before pyranose).
Examples:
(6R)-D-gluco-Hexodialdo-6,2-pyranose
Methyl α-D-gluco-hexodialdo-6,3-furanose-1,5-pyranoside
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