in benzene warmed in sealed tube at 130-140°C for 2 h; evapd. in vac. dissolved in benzene/hexane (2:1), chromd. (Kieselgel), evapd.; elem. anal.;

in benzene warmed in sealed tube at 160-180°C for 2 h; evapd. in vac. dissolved in benzene/hexane (2:1), chromd. (Kieselgel), evapd.; elem. anal.;