Synthesis, spectral characteristics and supramolecular organization of new non-symmetrically 1,6- and 1,4-dialkyl- 3а,6а-diphenylglycolurils

The two approaches for the preparation of non-symmetrically 1,6- and 1,4-dialkyl-3a,6a-diphenylglycolurils were developed as a result of studying new regioselective reactions of 1-alkyl-5-hydroxy-4,5-diphenyl-1 H -imidazole-2(5 H )-ones with 1-alkylureas. A selectivity of the formation of 1,6-dialkyl isomers was detected. The 1,6- and 1,4-dialkyl-3а,6а-diphenylglycolurils were isolated in 55–77% and 11–29% yields respectively, and characterized by ¹ H NMR and ¹³ C NMR spectroscopy. The mechanism for the formation of 1,6- and 1,4-isomers was proposed. Self-organization of 1-ethyl-6-methyl-3a,6a-diphenylglycoluril and its crystallosolvates with HCOOH, dioxane and a mixture of Py and H ₂ O (in a 1:1 ratio), 1-butyl-3a,6a-dipheny-4-propylglycoluril, crystallosolvate of 1-ethyl-3a,6a-diphenyl-6-propylglycoluril with MeCN was studied by X-ray diffraction analysis. Based on the analysis of the crystal packing of structures, it was found that the self-organization of studied molecules in crystals of 1,4- and 1,6-disubstituted 3a,6a-diphenylglycolurils demonstrates new examples of supramolecular synthons with \(\:{R}_{2}^{2}\left(8\right)\) motif based on an N-H…O=С hydrogen bond.