in hexane soln. of educts was refluxed for 32 h; mixt. was filtd., washed with hexane, solvent was evaporated under reduced pressure, vac. distn., product distd. at 158-162° (1 Torr), elem. anal.;

in diethyl ether mixt. was heated for 16 h to 70-80°C; volatile material was distd. off, viscous product under reduced pressure, NMR, MS;