4,5-Dihydroxyimidazolidin-2-ones in the α-ureidoalkylation reaction of N-(carboxyalkyl)-, N-(hydroxyalkyl)-, and N-(aminoalkyl)ureas 1. α-Ureidoalkylation of N-(carboxyalkyl)ureas

The alpha-ureidoalkylation of N-(carboxyalkyl)ureas (ureido acids) with 1,3-H-2 (s-), 1,3-Me (2) (s-), and 1,3-Et-2 (s-)4,5-dihydroxyimidazolidin-2-ones was systematically studied. The yields of glycolurils were shown to decrease both in going from 1,3-H-2 (s-) to 1,3-Me-2 (s-) and 1,3-Et-2 (s-) 4,5- dihydroxyimidazolidin-2-ones and with elongation and branching of the carboxyalkyl chain in the ureido acids under study. The optimal reaction time for most of ureido acids is 3 h. The reaction mechanism was proposed. This mechanism was partially confirmed by quantum chemical methods and H-1 NMR spectroscopy. Crystals of a number of the newly synthesized compounds were studied by X-ray diffraction, and two new conglomerates were found. A method was developed for the enantiomeric analysis of some racemic N-(carboxyalkyl)-glycolurils by chiral-phase HPLC.