Synthesis and Crystal Structures of Novel Glycoluryl Carboxylic Acids Conglomerates

Abstract The two novel conglomerats were obtained by crystallization of racemic (S)-2-((3aS,6aR)- and (R)-2-((3aR,6aS)-2,5-dioxohexahydroimidazo[4,5-d]imidazole-1(2H)-yl)-3-methylbutanoic acids (racemate I), (R)-2-(3aR,6aR)- and (S)-2-((3aS,6aS)-4,6-dimethyl-2,5-dioxohexahydroimidazo[4,5-d]imidazole-1(2H)-yl)pentanoic acids (racemate II), which were synthesized by highly diastereoselective condensation of 4,5-dihydroxyimidazolidine-2-ones with racemic ureido acids for the first time. The differences in the molecular geometry of I and II are studied by X-ray diffraction that showed them to crystallize as conglomerates in non-centrosymmetric space groups Pna21 and P212121, respectively.