magnesium in diethyl ether Grignard reagent made from NpBr and Mg in Et2O and C6H6, cooled at 0°C, PhMeSnCl2 in Et2O added dropwise, reaction completed after 16 h; obtained yellow oil solidified upon addn. of methanol, solid recrystd. from MeOH and benzene; elem. anal.;