Formation of p-aminostyrene cyclic tetramer

Two isomers (1a and 1b) of p-aminostyrene cyclic tetramer (1,9,17,25-tetram ethyl-2,10,18,26-tetraaza[2,2,2.2]paracyclophane, 1) were produced from the linear oligomer P, by passing it through a silica gel column. These are st ereochemical isomers (1a: RSRS, meso and 1b: RRSS, meso) and stable in solu tion. They include two solvent molecules in their crystalline states; 1a in cludes benzene and Ib includes ethanol.