Intramolecular hydrogen bond strength and pK(a) determination of N,N'-disubstituted imidazole-4,5-dicarboxamides.
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.
Rush
Jeremy R
JR
Department of Chemistry, 111 Willard Hall, Kansas State University, Manhattan, Kansas 66506, USA.
Sandstrom
Stacey L
SL
Yang
Jianqing
J
Davis
Rebecca
R
Prakash
Om
O
Baures
Paul W
PW
D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013816:Thermodynamics
D007093:Imidazoles