36.8 g (0.1 mol) of N-benzoyl-DL-tyrosil-di-n-propylamide are suspended in
350 cc of toluene; there are then added, under agitation, 5.4 g (0.1 mol) of
sodium methylate and 50 cc (0.1 mol) of a titrated toluenic solution of 2-diethylamino-ethyl-chloride. The temperature is taken up to 105°C and the
solution is left at this temperature, in agitation, for 12 hours. The toluenic
solution is extracted with HCl 2 N; the aqueous acid phase is alkalized, cold,
with sodium carbonate, and then reextracted with successive portions of ethyl
acetate.
The reunited organic phases are anhydrified upon anhydrous Na2SO4,filtered
and dried off. The oily residue which is obtained crumbles after a few hours of
rest. Amount obtained 39.2 g. Yield 84%. Melting point 65°C to 67°C
(crystallizes with petroleum ether).
The free base can be salified so as to render it hydrosoluble. For this purpose,
for example, it is dissolved in acetone and precipitated as an oxalate by the
addition of a solution of oxalic acid in ethanol. Recrystallizes with ethanol.
Melting point (oxalate): 159°C to 162°C. Alternatively it can be dissolved in
acetone and precipitated with an acetone solution of HCl. Recrystallizes with
acetone-ethanol. Melting point (chlorhydrated): 181°C to 183°C.
