ii 7 
Similar conclusions must be drawn from a comparison of the 
different melting-points of / 3 -guarinine and its derivatives, with those 
of theine or theobromine and their derivatives, as can be seen from 
the following table : — 
/ 3 -Guarinine 
Theine 
Theobromine 
Free base . 
. 217-219 0 
234 - 235 ° 
329-330° 
Acetyl derivative. 
Not known 
Not known 
Methyl . . 
. 167-168° 
1 37 —1 38 0 
119-121° 
Bromine . 
. 236-237° 
206-209° 
Not known 
A great deal of attention has been paid by other workers to the 
tannic acid, 5 the so-called gnarana-tannic acid, found in guarana, but 
I have been unable to confirm their results, viz., that guarana-tannic 
acid is identical with catechin. On the other hand, my results point 
more or less to the fact that this particular acid is identical with 
Chloro genic acid , isolated by Gorter 6 from Liberian coffee-beans. 
Gorter has recently proved that coffee-tannic acid does not exist, and 
has shown this acid to be a mixture of chlorogenic and coffalic acids. 
He 7 has also shown the so-called Heliant-tannic acid fiom 
Helianihus annuus to be chlorogenic acid. 
A quantitative estimation of the tannic acid in the guarana carried 
out by Korner's and Nierenstein’s 8 caseine method gave 4 3 per cent., 
an amount which seemed to be sufficient for an attempt at isolating it. 
The acid was accordingly isolated by the acetone-method and 
purified by formation of its lead salt. It represented an amorphous 
powder of no definite melting point. It was further purified y 
dissolving the product in ethyl acetate ; the solution, aftei filtering, 
was evaporated to dryness and re-dissolved in boiling waiter, from 
which solution it slowly separated out in small colourless nee es, 
which melted at 199 0 to 201°. 0 
For the analysis the product was dried for two hours at 1 10 . 
°‘i886 gr. gaveo'3664 gr. CO a and o'oSy? gr. H a O. 
Found, C = 5298%, FI = 5 ' 1 7 - . G/ 
^32^3 8 0 19 (Chlorogenic acid) requires: C = 5290/0, 5 2 
^uH 14 0 6 (Catechin) requires: C = 62'06%, FI — 4 $3 "• 
