DIGITALIS GROUP. 
§§ 542-544-] 
441 
If digitalein is dissolved in 1^ parts alcohol and f part of water added, and the 
mixture shaken, the whole solution sets in a mass of hydrate, C 28 H 48 O 10 , rosettes of 
needles, m.p. 75°. The hydrate is not easily soluble in water, alcohol, or petroleum 
ether, but dissolves in chloroform. 
§ 542. Digitonin [C 27 H 46 0 14 +5H 2 0 2 ], colourless needles, decomposing at about 225°. 
It is soluble in 57 parts of absolute alcohol, in 120 parts at 50°. Turns a ray of polarised 
light to the left. If the glucoside is dissolved in acetic acid, a trace of ferric chloride 
added, and then Kiliani’s solution (0-5 grm. ferrous sulphate dissolved in 1 c.c. water 
and mixed with 100 c.c. of concentrated sulphuric acid) added so as to form two layers, 
a rose-red ring forms, which soon disappears. It dissolves in concentrated sulphuric 
acid with a red colour. On hydrolysis it decomposes into digitogenin, glucose, and 
galactose. 
Digitonin is familiar in laboratories as a precipitant of cholesterin, but does not 
appear to be a simple substance, according to the researches of A. Windaus and A. 
Scheckenburger ( Ber ., 1913). A solution of digitonin in 95 per cent, alcohol gradually 
deposits a new glucoside, which also forms an additive compound with cholesterin, to 
which they give the name of Gitonin, soluble in 85 per cent, alcohol. It occurs in the 
form of white amorphous granules, decomposing at 272°, is lsevo-rotatory, [a]"^ —50-69°, 
and gives a rose-red coloration on boiling with concentrated hydrochloric acid. 
An alcoholic solution of digitonin, added to an alcoholic solution of cholesterin, 
gives rise to a colourless crystalline precipitate in fine needles of digitonin cholesteride, 
which can be acetylated, and cholesterol acetate obtained and separated. Digitonin 
also combines with amyl alcohol and other alcohols, such as linaluol, geraniol, and 
sabinol (A. Windaus, Ber., 1909). Hence an alcoholic solution of cholesterol is a valu¬ 
able reagent in attempting to identify this glucoside or mixture of glucosides. 
Digitogenin, C 31 H 50 O 6 , is insoluble in water and aqueous alkalies ; it 
is somewhat soluble in alcohol, chloroform, and glacial acetic acid ; it 
forms a crystalline compound with alcoholic potash, which is strongly 
alkaline, and not very soluble in alcohol. Oxidation converts it into 
digitogenic acid, [a] D —67-1°. In aqueous KHO it forms a magnesium 
salt, C 28 H 42 0 8 Mg7H 2 0, small hard nodules of minute needles. 
§ 543. Digitalin, C 35 H 56 0 14 , when perfectly pure, forms fine, white, 
glittering, hygroscopic needles, or groups of crystalline tufts; it is 
without smell, but possesses a bitter taste, which is at once of slow 
development and of long endurance. On warming, it becomes soft 
under 100°, and, above that temperature, is readily decomposed with 
evolution of white vapours. It is insoluble in water, in dilute soda 
solution, in ether, and in benzene. It is soluble in chloroform, especially 
in chloroform and alcohol, and dissolves easily in warm acetic acid ; 
12 parts of cold and 6 of boiling alcohol of 90 per cent, dissolve 
one of digitalin. On hydrolysis it yields digitalose, 1 C 7 H 14 0 5 . Con¬ 
centrated sulphuric acid dissolves it with the production of a green 
colour, which by bromine passes into violet-red, but on the addition 
of water becomes green again. Hydrochloric acid dissolves it with the 
production of a greyish-yellow colour, passing gradually into emerald- 
green ; water precipitates from this solution a resinous mass. 
§ 544. Digitaletin. —A substance obtained by Walz on treating his digitalin by 
dilute acids. It is crystalline, and its watery solution tastes bitter. It melts at 
175°, and decomposes, evolving an acid vapour at about 206°. It dissolves in 848 
1 H. Kiliani, Ber., 1898, xxxi. 
