Nomenclature of Carbohydrates (Recommendations 1996)

2-Carb-23

Continued from 2-Carb-22

Contents

2-Carb-23. Aldaric acids

2-Carb-23.1. Naming

Names of individual aldaric acids are formed by replacing the ending '-ose' of the systematic or trivial name of the parent aldose by '-aric acid'. Choice between possible names is based on 2-Carb-2.2.2.

Examples:


L-Altraric acid
not L-talaric acid


D-Glucaric acid
not L-gularic acid


L-glycero-D-galacto-Heptaric acid
not L-glycero-D-gluco-heptaric acid

2-Carb-23.2. meso Forms

To the names of aldaric acids that are symmetrical, which therefore have no D- or L- prefix, the prefix 'meso-' may be added for the sake of clarity. Examples: meso-erythraric acid, meso-ribaric acid, meso-xylaric acid, meso-allaric acid, meso-galactaric acid.

The D or L prefix must however be used when a meso-aldaric acid has become asymmetric as a result of substitution.

Examples:


meso-Xylaric acid


meso-Galactaric acid


4-O-Methyl-D-galactaric acid
not 3-O-methyl-L-galactaric acid

2-Carb-23.3. Trivial names

For the tetraric acids, the trivial name tartaric acid remains in use, with the stereochemistry given using the R,S system. Esters are referred to as 'tartrates' (the second 'a' is elided).

Examples:


(2R,3R)- or (+)-Tartaric acid
or L-threaric acid


(2S,3S)- or (-)-Tartaric acid
or D-threaric acid


(2R,3S)- or meso-Tartaric acid
or erythraric acid

Note. In the older literature, there is confusion about the use of D and L in the case of tartaric acids. It is therefore recommended to use the R,S system in this case.

2-Carb-23.4. Derivatives

Derivatives formed by modifying the carboxy group (salts, esters, lactones, lactams, acyl halides, amides, nitriles etc.) are named by the methods of 2-Carb-20.2. Dilactones, half-esters, amic acids etc. are named by the methods of [13, 14]. In cases of ambiguity, locants should be specified.

Examples:


1-Methyl hydrogen D-galactarate


6-Methyl hydrogen D-galactarate


D-Glucar-1-amic acid


Methyl D-glucar-6-amate


D-Mannaro-1,4:6,3-dilactone error details

References

13. IUPAC Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F and H, 1979 Edition, Pergamon Press, Oxford, U.K. Sections E and F are reprinted in ref. 2, pp. 1-18 and 19-26, respectively.

14. Guide to IUPAC Nomenclature of Organic Compounds, Recommendations 1993, Blackwell Scientific Publications, Oxford (1993).

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