title: Conformational state of β-hydroxynaphthylamides: Barriers for the rotation of the amide group around CN bond and dynamics of the morpholine ring.
abstract: Three β-hydroxynaphthylamides (morpholine, pyrrolidine and dimethylamine derivatives) have been synthesized and their conformational state was analyzed by NMR, X-ray and DFT calculations. In aprotic solution the molecules contain intramolecular OHO hydrogen bonds, which change into intermolecular ones in solid state. The energy barriers for the amide group rotation around the CN bond were estimated from the line shape analysis of (1)H and (13)C NMR signals. A tentative correlation between the barrier height and the strength of OHO bond was proposed. Calculations of the potential energy profiles for the rotations around CC and CN bonds were done. In case of morpholine derivative experimental indications of additional dynamics: chair-chair 'ring flip' in combination with the twisting around CC bond were obtained and confirmed by quantum chemistry calculations.
authors.affiliation: Wroclaw University of Technology, Faculty of Chemistry, Division of Chemical Engineering, 50-373 Wrocław, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Kozlecki
authors.affiliation: St. Petersburg State University, Center for Magnetic Resonance, 198504 St. Petersburg, Russia. Electronic address: peter.tolstoy@spbu.ru.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Tolstoy
authors.affiliation: Faculty of Chemistry, University of Wrocław, 50-383 Wrocław, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kwocz
authors.affiliation: St. Petersburg State University, Center for Magnetic Resonance, 198504 St. Petersburg, Russia.
authors.forename: Mikhail A
authors.initials: MA
authors.lastname: Vovk
authors.affiliation: Faculty of Chemistry, University of Wrocław, 50-383 Wrocław, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Kochel
authors.affiliation: Wroclaw University of Technology, Faculty of Chemistry, Division of Chemical Engineering, 50-373 Wrocław, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Polowczyk
authors.affiliation: University of Architecture and Civil Engineering, 625001 Tyumen, Russia.
authors.forename: Peter Yu
authors.initials: PY
authors.lastname: Tretyakov
authors.affiliation: Faculty of Chemistry, University of Wrocław, 50-383 Wrocław, Poland; The Joint Institute for Nuclear Research, Frank Laboratory of Neutron Physics, 141980 Dubna, Russia. Electronic address: aleksander.filarowski@chem.uni.wroc.pl.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Filarowski
keywords: Amide group rotation; Conformational isomerism; DNMR; Intramolecular hydrogen bond; Solvent effects; β-Hydroxynaphthylamides