Novel synthesis of 1,6- and 1,4-dialkyl glycolurils and their supramolecular organization

New regioselective reaction of 1-alkyl-5-hydroxy-4,5-diphenyl-1H-imidazol-2(5H)-one with alkylureas gives predominantly 1,6-dialkyl-3a,6a-diphenylglycolurils along with minor quantities of the 1,4-isomers. In case of propyl homologues, co-crystal of 1,6/1,4-dipropyl glycolurils would precipitate. Based on the analysis of the crystal packing of the products, new type of supramolecular chains for 1,4-disubstituted glycolurils has been identified.