An easy route to a new class of n-azapara[2"] cyclophane-n-ones, Nsubstiiuted poriented cyclic aromatic amide (cycloaramid) oligomers, is described. The bulky diamine. N,N'-di-sec-butyl-pphenylenediamine is condensed with terephthaloyl dchloride at elevated temperature in o-dichlorobenzene to provide a high yield of N,N-di-sec-butyl-pphenyleneterephthalamide cyclic oligomers (from dimer to tridecamer). The cyclization is favored by the cis conformation of the Nsubstituted amide bonds present in the growing chain. Ring opening polymerization of these new cycloaramids to high molecular weight linear polymers can be effected in the melt phase with highly nucleophilic catalysts, such as 1,3-dialkylimidazole-2thiones especially when an acid cocatalyst is employed. The N-substituted polymers yield crystalline films and fibers with an axial repeat length which can only be explained by an unexpected trans conformation of the amide bonds. The facile synthesis of other macrocyclic amides by the steric control of macrocyclizatiin by N-substitution of the amide bond is also described. lntroductlonIn the course of extending our work on the preparation of aromatic polyamide (aramid) foams via the pyrolysis of N-alkyl substituted aromatic polyamides. (ref.

Linear very high molecular weight polyamides, such as nylons 6, 7 and 66, have been prepared via the rapid ring-opening polymerization (ROP) of their respective lactams catalyzed by super nonionic poly(aminophosphazene) and protophosphatrane bases. The super nonionic poly(aminophosphazene) bases appear to mimic catalysis by conventional anionic catalysts, but with the added advantage of the toleration of some degree of moisture. Multinuclear liquid and solid-state NMR experiments were used to probe the structure and proton transfer chemistry of P4-t-Bu, one of the most effective lactam ROP poly(aminophosphazene) bases. 31P magic-angle spinning (MAS) results showed the room-temperature structure of P4-t-Bu to be asymmetric and nonprotonated. Variable-temperature 31P MAS NMR experiments on mixtures of P4-t-Bu and ε-caprolactam demonstrated the proton transfer chemistry relevant for ROP at elevated temperature. This was confirmed by 13C MAS NMR observation of the ε-caprolactam anion in a cross-polarization experiment.

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