caa a22 4500 605546088 CHVBK 20210128100939.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s00723-015-0644-9 doi (NATIONALLICENCE)springer-10.1007/s00723-015-0644-9 Influence of Substituents on the Lappaconitine Acetylenic Derivatives Photodegradation [Elektronische Daten] [A. Schlotgauer, V. Klimentiev, V. Kornievskaya, N. Polyakov, A. Stepanov, S. Vasilevsky, T. Leshina] The natural alkaloid lappaconitine, the anthranilic acid ester, is used against arrhythmias in medical practice, but it undergoes significant photodegradation. The latter may be the cause of the drugs phototoxicity. Furthermore, other esters of anthranilic acid are also widely used in practice, for example, as UV filters; so their photostability is an important characteristic. Thus, the improvement of these compounds resistance against light irradiation is the issue of the day. This work has shown that the appending of a substituent through the acetylene bridge into the anthranilic acid aromatic ring can significantly decrease the lappaconine derivatives photodegradation degree. The photodegradation process, according to the chemically induced dynamic nuclear polarization (CIDNP) analysis, begins with intramolecular or intermolecular reversible electron transfer (ET) with subsequent cleavage of the ester bond. The main product of the photolysis is the quaternary ammonium salt of 20-ethyl-1-α,14-α,16-β-trimethoxyaconitane-4,8,9-triol (lappaconine) of substituted anthranilic acid. It was demonstrated that the photodegradation of the lappaconitine acetylenic derivatives occurs from their triplet excited states and the substitution influences primarily the triplet reactive state formation effectivity. Graphical Abstract: Springer-Verlag Wien, 2015 Schlotgauer A. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut Klimentiev V. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut Kornievskaya V. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut Polyakov N. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut Stepanov A. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut Vasilevsky S. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut Leshina T. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut Applied Magnetic Resonance Springer Vienna 46/5(2015-05-01), 559-573 0937-9347 46:5<559 2015 46 723 https://doi.org/10.1007/s00723-015-0644-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00723-015-0644-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Schlotgauer A. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut NATIONALLICENCE 700 1- Klimentiev V. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut NATIONALLICENCE 700 1- Kornievskaya V. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut NATIONALLICENCE 700 1- Polyakov N. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut NATIONALLICENCE 700 1- Stepanov A. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut NATIONALLICENCE 700 1- Vasilevsky S. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut NATIONALLICENCE 700 1- Leshina T. Institute of Chemical Kinetics and Combustion, 630090, Novosibirsk, Russia aut NATIONALLICENCE 773 0- Applied Magnetic Resonance Springer Vienna 46/5(2015-05-01), 559-573 0937-9347 46:5<559 2015 46 723