“…It is noteworthy that the ready solubility of cardo polyimides has led to the possibility of their synthesis by different procedures: by the two-stage polycyclisation of tetracarboxylic acid dianhydrides and diamines 2~4 -4ft 146 -174 ~1 77 -2m -210 ~ 213> 218 " 22°-223> 228 ' 25Qi 258 ' 262> 263 -26S with thermal and catalytic imidisation of polyamidoacids, by a single-stage polycyclisation in solution both in the presence of catalysts and without them (see, for example, 49,146,[171][172][173][178][179][180][181][182][183][211][212][213][214]217,222,223,225,250,258,261,263), by the reaction of tetracarboxylic acid dichloride diesters and diamines, 2 -4 ' 49 .' 83 -i85.2oo,2ii,26i and by the polycyclisation of tetracarboxylic acid dianhydrides and trimethylsilyl derivatives of diamines.…”