title: Intramolecular hydrogen bond strength and pK(a) determination of N,N'-disubstituted imidazole-4,5-dicarboxamides.
abstract: N,N'-Disubstituted imidazole-4,5-dicarboxamides (I45DCs) form an intramolecular hydrogen bond worth an estimated 14 +/- 1 kcal/mol, as measured with a model structure in DMSO-d6 at 3 mM, thereby predisposing the molecular conformation to a folded rather than extended form. The I45DCs also show evidence of aggregation in both CDCl3 (>1 mM) and DMSO-d6 (>10 mM) solutions. These compounds are uncharacteristically weak bases in comparison with imidazoles bearing similar electron-withdrawing groups.
authors.affiliation: Department of Chemistry, 111 Willard Hall, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Rush
authors.forename: Stacey L
authors.initials: SL
authors.lastname: Sandstrom
authors.forename: Jianqing
authors.initials: J
authors.lastname: Yang
authors.forename: Rebecca
authors.initials: R
authors.lastname: Davis
authors.forename: Om
authors.initials: O
authors.lastname: Prakash
authors.forename: Paul W
authors.initials: PW
authors.lastname: Baures
mesh_terms: D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013816:Thermodynamics
chemical_list: D007093:Imidazoles