ATROPINE. 
§ 451-1 
387 
the alkaloidal content is from 1-6 to 1-8 per cent. There is also a 
tincture which contains about 0-06 per cent, of alkaloid. 
§ 451. Properties of Atropine, C 17 H 23 N0 3 .—Atropine, hyoscyamine, and 
hyoscine have all the same formula, but differ in their molecular constitu¬ 
tion. Atropine on hydrolysis, either by heating it with hydrochloric acid 
or baryta water, is decomposed into tropine and inactive tropic acid :— 
c 17 h 23 no 3 +h 2 o=c 8 h 15 no+C 9 H 10 O 3 
Atropine. Tropine. Tropic 
acid. 
On the other hand, by heating tropic acid and tropine together, 
atropine is regenerated. 
Tropic acid crystallises in prisms which melt at 117°-118° (127°-128°, 
Miilliken, p. 60). Dehydrating agents convert it into atropic acid 
(a-phenyl-acrylic acid), 
/CH 2 OH ,,ch 2 
C 6 H 5 -CH< -> C 6 H 5 -C< “ +H 2 0 
n cooh n cooh 
Tropic acid. Atropic acid. 
Atropic acid is an isomer of cinnamic acid ; it crystallises in tablets 
which melt at 106-5°. 
Tropine is a white, crystalline, strongly alkaline substance, melting 
at 63°, and boiling at 233°. It is sublimable and optically inactive. It 
is soluble in water, alcohol, and ether, and gives precipitates with tannic 
acid, iodised hydriodic acid, Mayer’s reagent, gold chloride, and mer¬ 
curic chloride. To identify it, add a drop of 30 per cent, soda lye, sublime, 
add a drop of HC1 to sublimate, dry, then take up with water ; add a 
crystal of KI, and needles of tropine hydriodide form. 
As a result of the researches of Ladenburg, Merling, and Willstatter, 
tropine has been found to contain the piperidine, pyrrolidine, and hepta- 
methylene nuclei united thus :— 
H 2 C 
h 2 c 
H 
—C- 
/ 
N-CH 3 
\ 
—C- 
H 
Tropine. 
h 2 
-c 
^>CHOH 
-C 
H 2 
Thus the constitutional formulae of atropine (as well as hyoscyamine) 
may be represented as follows :— 
H 2 C- 
H 
-C- 
N—CH a 
H a 
-c 
ch 2 oh 
h 2 c- 
H 
Atropine. 
-C 
H, 
/ 
CH—O—CO—CH 
I 
c 5 h 6 
