title: Solid-phase synthesis of 5-noranagrelide derivatives.
abstract: Solid-phase synthesis of 1H-benzo[d]imidazo[1,2-a]imidazol-2(3H)-one derivatives employing Fmoc-α-amino acids and nitroaryl fluorides as key building blocks has been developed. The Fmoc-α-amino acids immobilized on Wang resin, equipped with a piperazine carbamate linker, were transformed to o-nitroanilines in two steps. After reduction of the nitro group, the corresponding o-phenylenediamines gave the 2-aminobenzimidazole scaffold by reaction either with cyanogen bromide or with Fmoc-NCS. Cleavage from the polymer support and further cyclization afforded the target compounds. The developed methodology represents a versatile and simple approach for the preparation of various corresponding 1H-benzo[d]imidazo[1,2-a]imidazol-2(3H)-ones from a large number of commercially available building blocks.
authors.affiliation: Department of Organic Chemistry, Institute of Molecular and Translational Medicine, Faculty of Science, Palacky University , 771 46 Olomouc, Czech Republic.
authors.forename: Ivano
authors.initials: I
authors.lastname: Messina
authors.forename: Igor
authors.initials: I
authors.lastname: Popa
authors.forename: Vítězslav
authors.initials: V
authors.lastname: Maier
authors.forename: Miroslav
authors.initials: M
authors.lastname: Soural
mesh_terms: D001562:Benzimidazoles / Q000138:chemical synthesis* / Q000737:chemistry; D020650:Combinatorial Chemistry Techniques; D015394:Molecular Structure; D011744:Pyrimidinones / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D001562:Benzimidazoles; D011744:Pyrimidinones