Treatment of 3-chloro-5-cyanoaniline (I) with thiophosgene afforded the corresponding aryl isothiocyanate (II). Ritter reaction of 3-ethyl-3-pentanol (III) using NaCN and H2SO4 produced formamide (IV), which was hydrolyzed to amine (V) with NaOH. Then, condensation of isothiocyanate (II) with amine (V) yielded thiourea (VI). Subsequent removal of H2S in (VI) by treatment with PPh3, CCl4 and Et3N gave carbodiimide (VII). Finally, addition of cyanamide to (VII) in the presence of i-Pr2NEt furnished the required cyanoguanidine.
Treatment of 3,5-dichloroaniline (I) with thiophosgene afforded the corresponding aryl isothiocyanate (II). Ritter reaction of 3-ethyl-3-pentanol (III) using NaCN and H2SO4 produced formamide (IV), which was hydrolyzed to amine (V) with NaOH. Then, condensation of isothiocyanate (II) with amine (V) yielded thiourea (VI). Subsequent removal of H2S in (VI) by treatment with PPh3, CCl4 and Et3N gave carbodiimide (VII). Finally, addition of cyanamide to (VII) in the presence of i-Pr2NEt furnished the required cyanoguanidine.