title: A quadruply hydrogen bonded heterocomplex displaying high-fidelity recognition.
abstract: An exceptionally strong quadruply hydrogen-bonded complex is formed between 2,7-diamido-1,8-naphthyridine 3 (DAN) and the butylurea of guanosine 6 (UG) in chloroform. The UG unit can be prepared in four steps from guanosine on a 10 g scale in excellent yields without chromatographic purification. The association constant (Kassoc approximately 5 x 10(7) M(-1)) for the UG.DAN complex determined by fluorescence energy transfer from the naphthyridine unit of 3 to coumarin 343 covalently linked UG (18) is among the highest reported for a neutral DNA base-pair analogue. The weak self-association of DAN (Kdimer < 10 M(-1)) and UG (Kdimer ca. 200-300 M(-1)) means that the UG.DAN complex forms with unparalleled fidelity.
authors.affiliation: Department of Chemistry, Roger Adams Laboratory, 600 South Mathews Avenue, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Taiho
authors.initials: T
authors.lastname: Park
authors.forename: Eric M
authors.initials: EM
authors.lastname: Todd
authors.forename: Shoji
authors.initials: S
authors.lastname: Nakashima
authors.forename: Steven C
authors.initials: SC
authors.lastname: Zimmerman
mesh_terms: D018360:Crystallography, X-Ray; D006151:Guanosine / Q000031:analogs & derivatives* / Q000737:chemistry; D006860:Hydrogen Bonding; D007700:Kinetics; D009287:Naphthyridines / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014508:Urea / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D009287:Naphthyridines; D006151:Guanosine; D014508:Urea; C006865:butylurea