The solution of 3,6-dichlorophthalic anhydride in 300 ml of N,Ndimethylformamide
are heated to the boiling point over 15 min with tbutylcarbazate.
Subsequent to evaporation of the solvent, N-(tbutyloxycarbonylamino)-
3,6-dichlorophthalimide is obtained from ethanol.
The solution of N-(t-butyloxycarbonylamino)-3,6-dichlorophthalimide in 400 ml
of absolute tetrahydrofuran are slowly dripped into a suspension of aluminum
lithium hydride in absolute tetrahydrofuran. The mixture is heated to the
boiling point. Conventional processing yields N-(t-butyloxycarbonylamino)-4,7-
dichloroisoindoline.
N-(t-Butyloxycarbonylamino)-4,7-dichloroisoindoline are introduced into
concentrated hydrochloric acid and stirred at room temperature. The
hydrochloride of 2-amino-4,7-dichloroisoindoline precipitates in the form of
crystals is obtained, melting point 230°-232°C.
2-Amino-4,7-dichloroisoindoline hydrochloride and cyanamide are heated over
2 h to the boiling point in n-amyl alcohol. The solvent is evaporated off and
the residue recrystallized from isopropyl alcohol and ethyl ether, yielding the
(4,7-dichloroisoindolin-2-yl)guanidine in the form of hydrochloride, melting
point 235°-237°C.
To obtained the base (4,7-dichloroisoindolin-2-yl)guanidine the salt (4,7-
dichloroisoindolin-2-yl)guanidine hydrochloride is treated with sodium
bicarbonicum.
