title: A general method for the solid-phase synthesis of unsymmetrical tri- and tetrasubstituted ureas.
abstract: A general method for the preparation of unsymmetrical di, tri-, and tetrasubstituted ureas on polymer supports is presented. Polymer-bound primary and secondary amines react with imidazolium salts (urea donors), which are generated from the reaction of N,N'-carbonyldiimidazole (CDI) with primary and secondary amines followed by alkylation with MeI to give tri- and tetrasubstituted ureas in excellent yields (76-98%) and purities (80-99%).
authors.affiliation: Chemical and Physical Sciences, DuPont Pharmaceuticals Company, Experimental Station, P.O. Box 80500, Wilmington, Delaware 19880-0500, USA. changsheng.zheng@dupontpharma.com
authors.forename: Changsheng
authors.initials: C
authors.lastname: Zheng
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Combs
mesh_terms: D000588:Amines / Q000737:chemistry; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D011108:Polymers / Q000737:chemistry; D014508:Urea / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D000588:Amines; D011108:Polymers; D014508:Urea