2-Carb-21

Continued from 2-Carb-20

Contents

• 2-Carb-21. Ketoaldonic acids
  • 21.1. Naming
  • 21.2. Derivatives

2-Carb-21.1. Naming

Names of individual ketoaldonic acids are formed by replacing the ending '-ulose' of the corresponding ketose by '-ulosonic acid', preceded by the locant of the ketonic carbonyl group. The anion takes the ending '-ulosonate'. The numbering starts at the carboxy group.

In glycosides derived from ketoaldonic acids, the ending is '-ulosidonic acid', with appropriate ring-size infix, e.g. '-ulopyranosidonic acid'.

Examples:

D-erythro-Pent-2-ulosonic acid

D-arabino-Hex-5-ulosonic acid

α-D-arabino-Hex-2-ulopyranosonic acid

3-Deoxy-α-D-manno-oct-2-ulopyranosonic acid

Note. The last of the above examples is one of the possible forms of the compound referred to by the three-letter symbol Kdo (formerly the abbreviation KDO, from the previously allowed trivial name ketodeoxyoctonic acid). Similarly the symbol Kdn for the C9 sugar 3-deoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid is widely used.

2-Carb-21.2. Derivatives

Esters, lactones, lactams, acyl halides etc. are named by modifying the ending '-ic acid' as described for aldonic acids (2-Carb-20.2).

Examples:

Ethyl (methyl α-D-arabino-hex-2-ulopyranosid)onate

Note. The parentheses are inserted to distinguish between the ester alkyl group (cited first) and the glycosidic O-alkyl group.

β-D-arabino-Hex-2-ulopyranosono-1,5-lactone

Indol-3-yl D-xylo-hex-5-ulofuranosonate; trivial name isatan B

L-xylo-Hex-2-ulosono-1,4-lactone   L-threo-Hex-2-enono-1,4-lactone   L-lyxo-Hex-2-ulosono-1,4-lactone
(L-Ascorbic acid is the equilibrium mixture of all three isomers)

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