Ethyl formate → 1-(3'-Aminophenyl)-2-formylamino-propane

A mixture of 1-(3'-amino-phenyl)-2-amino-propane and 12.5 ml of ethyl formate was boiled for 10 hours, and then the reaction mixture was evaporated, leaving 1-(3'-aminophenyl)-2-(formyl-amino)-propane. 4.45 gm of this amide were dissolved in 25 ml of pyridine, 2.6 ml of chlorothioformic acid-S-ethyl ester were added to the solution at 10°-20° C., and the mixture was allowed to stand for a few hours. Thereafter, the reaction solution was poured into ice water, and the aqueous mixture was extracted with ether. The ethereal extract was washed five times with water and once briefly with 1/10 N hydrochloric acid, and was then evaporated, leaving as a residue 1-[3'-(ethylthiocarbonyl-amino)-phenyl]-2-(formyl-amino)-propane. The residue was added to a mixture of 75 ml of methanol and 5 ml of concentrated hydrochloric acid, and the mixture was allowed to stand for three days at room temperature. Thereafter, the resulting solution was evaporated, the residue was triturated with acetonitrile, and the crystalline product formed thereby was recrystallized from acetonitrile and a little water, yielding the hydrochloride of the formula ##STR21## which had a melting point of 185°-186° C.