Originator
Valpin,Endo (Du Pont),US,1963
Manufacturing Process
Preparation of Di-n-propyl acetyl tropine hydrochloride: Tropine (11.12 grams)
was dissolved in 100 ml of anhydrous pyridine and to this solution was added
15.64 grams of di-n-propyl acetyl chloride. The mixture was refluxed for 6
hours. This solution was then cooled and the pyridine removed in vacuum.
The residue was dissolved in chloroform. The chloroform solution was washed
with 10% hydrochloric acid to remove the residual trace of pyridine. The
hydrochloride of the product ester is soluble in chloroform and is not extracted
from chloroform by hydrochloric acid. This is an unexpected property.
The chloroform solution of the hydrochloride was dried over anhydrous
calcium sulfate, and evaporated to dryness, leaving a semisolid residue of
product ester hydrochloride. This was recrystallized from chloroform-hexane
mixture, MP 186°C.
Preparation of the Anisotropine Methyl Bromide: To the acetone solution of the
free base was added an acetone solution, containing an excess of methyl
bromide. Within a few minutes the methobromide started to crystallize. The
mixture was allowed to stand for several hours. The crystallized solid was
filtered, and additional product was obtained by evaporation of the filtrate.
The yield was nearly quantitative. After recrystallization from acetone, the
product melted at 329°C.
