Ketoses trivial names

The basis for the name is the structure of the parent monosaccharide in the acyclic form. Charts I and IV (2-Carb-10) give trivial names for parent aldoses and ketoses with up to six carbon atoms. 2-Carb-8.2 and 2-Carb-10.3 describe systematic naming procedures. 

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. 

Ketoses with three to six carbon atoms are shown in Chart IV, with trivial names (and three-letter abbreviations) in parentheses. (See also the alphabetical listing of trivial names in the Appendix.)... 

Chart IV. Structures, with systematic and trivial names, of the 2-ketoses with three to six carbon atoms... 

Replacement of a hydroxy oxygen atom of an aldose or ketose, or of the oxygen atom of the carbonyl group of the acyclic form of an aldose or ketose, by sulfur is indicated by placing the prefix thio , preceded by the appropriate locant, before the systematic or trivial name of the aldose or ketose. 

General class Number of carbon atoms Formula Trivial name Aldose Ketose... 

S, 113 (1948)]. Some writers have used the name allulose instead of psicose, but there appears to be no good reason for changing the historical trivial name that was originally suggested by Ohle and Just. The name ribohexulose has been proposed by Wolfrom, Thompson and Evans as a systematic name for this ketose. 

Fructose (shown in Example 2.7) was named long before its structure was known. The same is true for most aldoses. Names like glucose, mannose, ribose, and fructose are called trivial names i.e., they are nonsystematic. However, ketoses, which are isomers of aldoses, were isolated or synthesized after the corresponding aldoses and were given names based on the names of the isomeric aldoses. Such names are misleading because they do not reflect the structural elements present in the ketoses. 

The trivial names of the aldoses can be used as prefixes to determine the stereochemistry for other chiral compounds. However, in this case, the -ose suffix is omitted and the prefix is written in italics (Figure 2.8). In this respect, it should be mentioned that the chiral centers can be separated by one or more nonchiral centers. If the number of chiral centers exceeds four (e.g., in heptose, octose, nonose, etc. derivatives), a multiple configurational prefix is added to the stem name (Figure 2.9). In this case, the first four chiral centers are selected, followed by the remaining ones. However, the name of the compound starts with the prefix of the chiral center with the highest location. In the case of ketoses, if the carbonyl group is not at C-2, then its location should also be given in the name. 

Ribulose is the ketose corresponding to ribose. In general, the ketoses are designated by the ending -ulose (unless they have trivial names, such as fructose). Xylulose is an epimer to ribulose at C-3. Ribulose phosphate and diphosphate play a role in biologic intereonversions of the sugars and in photosynthesis (Chapt. XVI-4). 

In the case of ketoses too trivial names are still frequently preferred for the fundamental types although systematic... ulose names can easily be generated in a manner similar to that used for the systematic names of aldoses (see Table 16). 

Table 16. Trivial names with three-letter-short forms and, in round brackets, systematic names for ketoses...

FIGURE 1.4 The family tree of D-ketoses with the trivial and derived names. 

FIGURE 2.7 Trivial and systematic names of ketoses drawn as their Fischer projections. 

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