Pentoses sentence example
- Four active tetroses are possible, and three have been obtained by Ruff and Wohl from the pentoses.
- The first term includes simple sugars containing two to nine atoms of carbon, which are known severally as bioses, trioses, tetroses, pentoses, hexoses, &c.; whilst those of the second group have the formula C12H22011 and are characterized by yielding two monosaccharose molecules on hydrolysis.
- We may notice that the pentoses differ from other sugars by yielding furfurol when boiled with hydrochloric acid.
- Rhamnose or isodulcite, a component of certain glucosides, fucose, found combined in seaweeds and chinovose, present as its ethyl ester, chinovite, in varieties of quina-bark, are methyl pentoses.
- To settle this point it is necessary to consider the configuration of the isomeric pentoses - arabinose and xylosefrom which they may be prepared.Advertisement
- If the asymmetric system adjoining the COH group, which is that introduced in synthesizing the hexose from the pentose, be eliminated, the formulae at disposal for the two pentoses are CH 2 (OH) - - - COH CH 2 (OH)+-- COH.
- Hence it follows that the " optical " formulae of the acids derived from two pentoses having the configuration given above will be C02H - 0 - C02H CO 2 H + 0 - C02H, and that consequently only one of the acids will be optically active.