1-Amino-4,5-8-naphthalenetricarboxylic acid-1,8-lactam-4,5-imide-containing macrocycles: Synthesis, molecular modeling and polymerization - Polyimides and Other High Temperature Polymers - page 192

be seen from the comparison of the molecular weights of synthesized products
(Table 1) and the mass spectra obtained (Figs. 1, 2). Additional confirmation of
the molecular structure comes from the analysis of 1 H-NMR spectra (Figs. 3 and
4), where all signals can be assigned to the protons of the corresponding cyclic
structure. The yields of individual macrocycles (not a mixture of cycles) are high
(up to 60% in case of cycle). It seems that this phenomenon is due to fa-

vorable conformation adopted by a dimer on cyclization. Scheme 2 shows the cy-
clization reaction. The dimer formed by reaction of one equivalent of diol with

LI2Bph

Scheme 2. Macrocyclization and side reactions.