in acetonitrile absence of air; stirring (room temp., 24 h); collection (filtration), washing (MeCN), crystn. (MeCN/CH2Cl2, -30°C); elem. anal.;

in dichloromethane absence of air; stirring (0°C, 2 h); filtration, evapn. of filtrate, crystn. (CH3CN, -25°C, several days); elem. anal.;

in dichloromethane absence of air; stirring (0°C, 2 h); filtration, evapn. of filtrate, crystn. (CH3CN, -25°C, several days); elem. anal.;