AMIDE-BASED [12]-, [12.12]- AND [12.12.12.12]PARACYCLOPHANES - NONPLANARITY OF AMIDE AND PHENYL GROUPS IN THE [12]CYCLOPHANE

A reaction between ethylenediaminetetraacetic dianhydride and p-xylene -alpha,alpha'-diamine has given three amide-based cyclophanes with dif ferent ring sizes; the(1 : 1)-reaction product is arboxymethyl)-2,5,8, 11-tetraaza[12]paracyclophane, the (2:2)-product is oxo-5,8,23,26-tetr akis(carboxymethyl)-2,5,8,11,20, 23,26,29-octaaza[12. 12]paracyclophan e, and the (4:4)-product is 3,10,21,28,39,46,57,64-octaoxo-5,8,23,26,4 4, 59,62-octakis(carboxymethyl)-2,5,8, 6,59,62,65-hexadecaaza[12.12.12 .12]paracyclophane. These amide paracyclophanes have been characterize d by NMR. infrared, absorption and electrospray mass spectroscopies. A b initio calculations have shown that the amide and phenyl groups in t he(1:1)-product, ie., amide[12]paracyclophane, are distorted from the planar structures owing to the strain of the small cyclophane ring. Th is unusual structure results in physical properties different from tho se of the other cyclophanes having larger ring sizes: for example, (1) a low acidity of the amide hydrogen and (2) a low basicity of the ami no nitrogen.