Ketoses systematic 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. 

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. 

As with ketoses, many deoxy sugars are incorrectly named. In so-called 2-deoxy-D-ribose, there are only two chiral carbon atoms and the sugar is related to D-erythrose. The systematic name is 2-deoxy-o-erythro-pentose. 

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

The ketoses are classified as 2-ketoses, 3-ketoses, etc., following the carbonyl position on the chain. The 2 of 2-ketoses, a common natural structure, can be removed. The suffix ose is replaced by ulose in the parent name. Likewise, fructose is a 2-hexulose, or more simply, a hexulose. For the complete name, it is preceded by the configuration descriptor. The systematic name of fructose 4.37 would be D-araZ>Z o-2-hexulose. In the case of 2-ketoses, there is no possible ambiguity for the configuration of pyranoses and furanoses. The nomenclature is copied from that of aldoses as, for example, /3-D-fructopyranose 4.38. Methyl glycoside 4.39 of sialic acid is called methyl 5-acetamido-3,5-dideoxy-D-gZycera-a -D-gaZacfo-2-nonulopyranosidonic acid. 

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...

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. 

Figure 1.3. Structures and names of the D-family of ketoses starting with the triose and progressing systematically to the four possible D-hexoses by adding a single asymmetric center with the two possible configurations to each structure.

---