title: Long-range 1H-15N heteronuclear shift correlation across wide F1 spectral windows.
abstract: Long-range (1)H-(15)N heteronuclear shift correlation experiments at natural abundance are becoming more routinely utilized in the characterization of unknown chemical structures from a diverse range of sources including natural products and pharmaceuticals. Apart from the inherent challenges of the low gyromagnetic ratio and natural abundance of (15)N, investigators are also occasionally hampered by having to deal with the wide spectral range inherent to various nitrogen functional groups, which can exceed 500 ppm. Earlier triple resonance cryoprobe designs typically provided 90° (15)N pulses in the range of 35-40 µs, which did not allow the uniform excitation of wide F(1) spectral ranges for (1)H-(15)N GHMBC spectra. We report the results obtained with a newly designed Bruker 600 MHz triple resonance TCI Micro CryoProbe™ using methyl orange as a model compound, in which the (15)N resonances are separated by >450 ppm.
authors.affiliation: Merck Research Laboratories, Discovery and Preclinical Sciences, Process Chemistry-Rapid Structure Characterization Laboratory, Summit, NJ 07901, USA. gary.martin2@merck.com
authors.forename: Gary E
authors.initials: GE
authors.lastname: Martin
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Hilton
authors.forename: Detlef
authors.initials: D
authors.lastname: Moskau
authors.forename: Nicolas
authors.initials: N
authors.lastname: Freytag
authors.forename: Klemens
authors.initials: K
authors.lastname: Kessler
authors.forename: Kim
authors.initials: K
authors.lastname: Colson
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D009584:Nitrogen / Q000737:chemistry*; D009587:Nitrogen Isotopes
chemical_list: D001391:Azo Compounds; D009587:Nitrogen Isotopes; C100258:methyl orange; D006859:Hydrogen; D009584:Nitrogen