reaction followed by a regioselective postcyclization strategy was implemented for the facilesynthesis of N,N'-disubstituted dihydroorotic acid amides under mild conditions. We obtained, for the first time, a library of 29 derivatives, encompassing 19 Nα-substituted-N4-dihydroorotyl-4-aminophenylalanine derivatives, a key residue of gonadotropin-releasing hormone antagonist Degarelix. The corresponding