1. Department of Chemistry, Moscow State Lomonosov University, Russian Federation
119992, Moscow, Lenin Hills 1, Russia
2. Institute of Physiologically Active Compounds, Russian Academy of Sciences, 142432,
Chernogolovka, Moscow region, Russia
3. Organisch-Chemisches Institut der Universitaet Heidelberg, Im Neuenheimer
Feld 270 D-69120 Heidelberg, Germany