title: Zwitterionic borane adducts of N-heterocyclic carbenes from mesomeric betaines of uracil.
abstract: We prepared a series of imidazolium-substituted uracil-anions which are members of the class of cross-conjugated heterocyclic mesomeric betaines. They are in tautomeric equilibrium with their N-heterocyclic carbenes, uracil-6-yl-imidazol-2-ylidenes. These carbenes can be trapped by reaction with sulfur, selenium, as well as by triethylborane and triphenylborane, respectively. The latter trapping reaction yielded the first representatives of a new heterocyclic zwitterionic ring system, imidazo[2',1':3,4][1,4,2]diazaborolo[1,5-c]pyrimidinium-10-ide. Results of two single crystal X-ray structure analyses are presented.
authors.affiliation: Clausthal University of Technology, Institute of Organic Chemistry, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, Germany. schmidt@ioc.tu-clausthal.de.
authors.forename: Jiaxi
authors.initials: J
authors.lastname: Zhang
authors.forename: Nazar
authors.initials: N
authors.lastname: Pidlypnyi
authors.forename: Martin
authors.initials: M
authors.lastname: Nieger
authors.forename: Jan C
authors.initials: JC
authors.lastname: Namyslo
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmidt
mesh_terms: D000838:Anions; D001622:Betaine / Q000737:chemistry*; D001880:Boranes / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D014498:Uracil / Q000737:chemistry*
chemical_list: D000838:Anions; D001880:Boranes; D006571:Heterocyclic Compounds; C030011:carbene; D001622:Betaine; D014498:Uracil; D008697:Methane; C079756:triethylborane