no decrease in plasma levels. [ edit ] Synthesis Clonidine, 2-(2,6-dichlorophenylamino)imidazoline, is synthesized from 2,6-dichloroaniline, the reaction of which with ammonium thiocyanate gives N-(2,6- dichlorophenyl)thiourea. Methylation of this product, followed by the subsequent reaction with ethylene diamine gives clonidine. K. Zeile, H. Staehle, K. H. Hauotman, DE 1303141   (1961). H.