Two polymorphs of 5‐cyclohexyl‐5‐ethylbarbituric acid and their packing relationships with other barbiturates. Issue 3 (17th February 2015)

• Record Type: Journal Article
• Authors: Gelbrich, Thomas; Meischberger, Isabella; Griesser, Ulrich J.
• Is Part Of: Acta crystallographica. Volume 71:Issue 3(2015:Mar.)
• Page Start: 204
• Page End: 210
• Publication Date: 2015-02-17
• Subjects: Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229615002880
• Languages: English
• ISSNs: 2053-2296

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Polymorph (I<italic>a</italic>) (m.p. 474 K) of the title compound, C₁₂H₁₈N₂O₃, displays an N—H...O=C hydrogen‐bonded layer structure which contains <italic>R</italic>₆⁶(28) rings connecting six molecules, as well as <italic>R</italic>₂²(8) rings linking two molecules. The 3‐connected hydrogen‐bonded net resulting from these interactions has the <bold>hcb</bold> topology. Form (I<italic>b</italic>) (m.p. 471 K) displays N—H...O=C hydrogen‐bonded looped chains in which neighbouring molecules are linked to one another by two different <italic>R</italic>₂²(8) rings. Polymorph (I<italic>a</italic>) is isostructural with the previously reported form II of 5‐(2‐bromoallyl)‐5‐isopropylbarbituric acid (noctal) and polymorph (I<italic>b</italic>) is isostructural with the known crystal structures of four other barbiturates.</p> </abstract>