e Chemie der Cellulose," 665 pages, Berlin, 1911.

CHAPTER VI

GLUCOSIDES

Strictly speaking, the term _glucoside_ should be applied only to such
compounds as contain glucose as the characteristic basic group. But in
common usage, it refers to any compound which, when hydrolyzed, yields a
sugar as one of the products of the hydrolysis. In all the natural
glucosides which occur in plant tissues, the other organic constituent,
which is represented by the R in the formula for glucosides
(R.C_{6}H_{11}O_{5}, or R.(CHOH)_{5}CHO) is some aromatic group, or
closed-ring benzene derivative.[3] The different organic constituents of
glucosides are of a great variety of types, such as phenols, alcohols,
aldehydes, acids, oxyflavone derivatives, mustard oils, etc. It is
noteworthy, however, that no nitrogenous groups of the protein type have
been found combined with sugars in glucosides.

Some glucosides contain more than one saccharide group, possibly as di- or
trisaccharides. Under proper conditions of hydrolysis, one or more of the
saccharide groups can be removed from such compounds, resulting in
glucosides of simpler structure.

Most of the common glucosides are derived from _d_-glucose. Some are known,
however, which are derivatives of galactose or rhamnose; while in some
cases the exact nature of the sugar which is present has not yet been
determined.

FOOTNOTES:

[3]

HC
// \
HC CH
The structural formula for benzene, C_{6}H_{6}, | | is one which it is
HC CH
\\ /
CH

difficult and inconvenient to reproduce in type. On that account, it is

/\
customary to indicate this formula by a plane hexagon, thus | |.
\/

It is understood, in all such cases, that the figure represents six carbon
atoms arranged in a closed ring, with alternate double and single bonds,
and with a hydrogen atom attached to each carbon. The printing of some
other group as OH, CH_{3}, adjacent to an angle of the hexagon means that
this group replaces the H atom in the