title: Observation of two N2-isobutyrylguanine tautomers by NMR spectroscopy.
abstract: N(2)-isobutyrylguanine was prepared by treatment of guanine with isobutyryl chloride. Two tautomers, 1,7-dihydro-2-(isobutyroyl)amino-6H-purin-6-one and 1,9-dihydro-2-(isobutyroyl)amino-6H-purin-6-one, were identified in almost 1:1 ratio in dichloromethane-dimethyl sulfoxide (1:1 v/v) by NMR spectroscopy. By using the selective-inversion experiments, enthalpy, entropy, and free energy for activation were determined. This work represents the first report of guanine tautomers observed directly by NMR spectroscopy.
authors.forename: Lijing
authors.initials: L
authors.lastname: Yang
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.forename: Razvan
authors.initials: R
authors.lastname: Simionescu
authors.forename: Hongbin
authors.initials: H
authors.lastname: Yan
mesh_terms: D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013237:Stereoisomerism
chemical_list: C105554:N(2)-isobutyrylguanine; D006147:Guanine