Synthesis and crystal structures of novel glycoluril carboxylic acids conglomerates

The two novel conglomerates were obtained by crystallization of racemic (2 'S ,3a S ,6a R )/(2 'R ,3a R ,6a S ) (glycoluril-1-yl)-3-methylbutanoic acid and (2 'R ,3a R ,6a R )/(2 'S ,3a S ,6a S ) (4,6-dimethylglycoluril-1-yl)pentanoic acid synthesized by highly diastereoselective condensation of 4,5-dihydroxy- imidazolidin-2-ones with racemic ureido acids. The differences in the molecular geometry of synthesized racemates were studied by X-ray diffraction that showed them to crystallize as conglomerates in non-centrosymmetric space groups Pna2 1 and P2 1 2 1 2 1 , respectively