312
D. J. BELL
CHoOH
CH 2 OH
Sucrose
CH 2 OH
Trehalose
α-D-Glucopyranosyl-jS-D-fructofuranoside
a-D-Glucopyranosyl-a-D-glucopyranoside
or
/3-D-Fructofuranosyl-a-D-glucopyranoside
Symbol: GaßFi
Symbol: GaaG
(Ff = D-fructofuranose)
III. Nucleosides, Nucleotides, and Nucleic Acids {46)
A. DERIVATIVES OF D-RIBOSE AND 2-DEOXY-D-RIBOSE
The aglycones of glycosides which have been considered above
have been derived from hydroxy compounds. A universally distributed
group of glycosides is composed of compounds in which the pentoses
D-ribofuranose (LVIII) and 2-deoxy-D-ribofuranose (LVIX) are linked
through their reducing groups to a nitrogen atom in the ß-anomeric
configuration.
CHoOH
CH,OH
£> >—r
OH
OH
(LVIII)
<
v
kr^ Ί K
OH
(LIX)
\/
The nitrogen joined to the glycosyl radical in these compounds is usually that occupying position 9 in purines or position 3 in pyrimidines.
Such compounds are classed as nucleosides, more specifically as ribonucleosides and deoxyribonucleosides. When an actual compound is
considered, e.g., the derivative formed between adenine and D-ribose,
the purine (or pyrimidine) base is numbered as usual and the numbers