2-[N-(1,3-diamino-isopropyl)-amino]-4-phenyl-2-imidazolines and salts thereof

#This invention relates to novel 2-[1,3-diamino-isopropyl)-amino]-4-phenyl-2-imidazolines and acid addition salts thereof, as well as to a method of preparing these compounds.

#More particularly, the present invention relates to a novel class of compounds represented by the formula ##STR2## wherein R.sub.1 is chlorine, bromine, fluorine or methyl;

#R.sub.2 and R.sub.3 which may be identical to or different from each other, are each hydrogen, chlorine or methyl;

#6.5 gm (0.022 mol) of 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and 10.65 gm (0.053 mol) of N-(1,3-bis-diethylamino-isopropyl)-amine were admixed by stirring, and the mixture was slowly heated to 100.degree. C, whereupon a significant amount of methylmercaptan was given off and the temperature of the mixture spontaneously rose to 130.degree. C. The reaction mixture was maintained at this temperature for 30 minutes, was then cooled to 40.degree. C and at that temperature admixed with 15 ml of acetone. A crystalline substance separated out, which was collected and washed with a mixture of acetone and ether (1:1), yielding 4.2 gm of the hydrochloride of the formula ##STR6## After recrystallization from water, the salt had a melting point of 192.degree. C.

#A mixture consisting of 2.77 gm (0.01 mol) of 4-(2-methyl-5-chloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride, 2.0 gm (0.01 mol) of N-(1,3-bis-diethylamino-isopropyl)-amine and 70 ml of anhydrous dimethylsulfoxide was stirred and slowly heated to 130.degree. C. After 4 hours' stirring at that temperature, 600 ml of water were added to the reaction mixture. The aqueous mixture was then fractionally extracted with ether at gradually increasing pH-values which were achieved by addition of sodium hydroxide. The fractions containing the desired compound were combined, dried and evaporated, leaving as a residue 1.7 gm of raw 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(2-methyl-5-chloro-phenyl)- 2-imidazoline. The raw base was purified by chromatography on a silicagel column, using acetone:benzene:methanol:concentrated ammonia (10:10:8:2) as the eluant. The eluate fractions containing the pure product were combined and evaporated, the residue was taken up in ether, and the resulting solution was admixed with ethanolic tartaric acid. The initially amorphous precipitate formed thereby was reprecipitated from ethanol/ether and then had a melting point of 85.degree. C (decomp.); it was identified to be the tritartrate of the formula ##STR7##

#In the following examples, whenever an oxalate was prepared, it was obtained by dissolving the free base in ether, acidifying the solution with ethereal oxalic acid, and recrystallizing the salt from ethanol.