Three new pseudopolymorphs of 6-aminouracil

Abstract

Since 6-aminouracil derivatives show diversified use in various fields of application, we crystallized 6-aminouracil to examine its preferred hydrogen-bonding frameworks. 6-Aminouracil shows two rigid hydrogen-bonding sites,viz.one acceptor–donor–acceptor (ADA) site and one donor–donor–acceptor (DDA) site. During various crystallization attempts, we obtained three structures, namely two dimethylacetamide monosolvates, C4H5N3O2·C4H9NO, and a 1-methylpyrrolidin-2-one monosolvate, C4H5N3O2·C5H9NO. In all three structures,R21(6) N—H...O hydrogen-bonding patterns link the molecules to their respective solvent molecules. The formation ofR22(8) N—H...O hydrogen-bond motifs between 6-aminouracil molecules can only be found in two-dimensional frameworks, whereasR33(14) N—H...O patterns are present when zigzag chzins of 6-aminouracil molecules are formed.