Poly-Diels-Alder Addition with a Bisoxazole as Bisdiene and a Bismaleinimide as Bisdienophile

Abstract

The poly-Diels-Alder addition between the new bisdiene 1,4-bis(5-methoxy-2-oxazolyl)benzene (4) and N,N′-hexamethylene-bis[2-(2,5-dihydro-2,5-dioxo-pyrrole-1-yl) acetamide] (7) is described. The structure of the resulting polyadduct 12 was proved by ¹H NMR spectroscopy with the aid of the low-molecular-weight model compounds 1,4-bis(1,3-dihydro-7-hydroxy-1,3-dioxo-2-phenyl-pyrrolo[3,4-c] pyridine-4-yl)benzene (9) and N,N'-hexamethylene-bis[2-(1, 3-dihydro-7-hydroxy-6-methyl-1,3-dioxo-4-phenyl-pyrrolo [3,4-c]pyridine-2-yl)acetamide] (11). The reaction proceeds via the aromatization of the primarily formed cycloadducts. Polyadduct 12 shows a number average degree of polymerization P_n of about 11 – 12 (M_n = 8500 − 9200 g/mol), calculated from ¹H NMR endgroup signals.