title: Synthesis of Tertiary and Quaternary Amine Derivatives from Wood Resin as Chiral NMR Solvating Agents.
abstract: Chiral tertiary and quaternary amine solvating agents for NMR spectroscopy were synthesized from the wood resin derivative (+)-dehydroabietylamine (2). The resolution of enantiomers of model compounds [Mosher's acid (3) and its n-Bu₄N salt (4)] (guests) by (+)-dehydroabietyl-N,N-dimethylmethanamine (5) and its ten different ammonium salts (hosts) was studied. The best results with 3 were obtained using 5 while with 4 the best enantiomeric resolution was obtained using (+)-dehydroabietyl-N,N-dimethylmethanaminium bis(trifluoromethane-sulfonimide) (6). The compounds 5 and 6 showed a 1:1 complexation behaviour between the host and guest. The capability of 5 and 6 to recognize the enantiomers of various α-substituted carboxylic acids and their n-Bu₄N salts in enantiomeric excess (ee) determinations was demonstrated. A modification of the RES-TOCSY NMR pulse sequence is described, allowing the enhancement of enantiomeric discrimination when the resolution of multiplets is insufficient.
authors.affiliation: Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1, P. O. Box 55, FI-00014, Helsinki 00100, Finland. tiina.laaksonen@helsinki.fi.
authors.forename: Tiina
authors.initials: T
authors.lastname: Laaksonen
authors.affiliation: Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1, P. O. Box 55, FI-00014, Helsinki 00100, Finland. sami.heikkinen@helsinki.fi.
authors.forename: Sami
authors.initials: S
authors.lastname: Heikkinen
authors.affiliation: Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1, P. O. Box 55, FI-00014, Helsinki 00100, Finland. kristiina.wahala@helsinki.fi.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Wähälä
mesh_terms: D000588:Amines / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D019906:Nuclear Magnetic Resonance, Biomolecular; D012116:Resins, Plant / Q000737:chemistry*; D012997:Solvents / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D014934:Wood / Q000737:chemistry*
chemical_list: D000588:Amines; D012116:Resins, Plant; D012997:Solvents
keywords: (+)-dehydroabietylamine; NMR spectroscopy; chiral resolution; chiral solvating agent