i.e. The unsubstituted monomer. Besides the oxidation of pyrrole which gives a very low yield, is there any advanced method for an improved conversion?
Taherpour, Avat and Kheradmand, Khojasteh claimed one-pot microwave-assisted solid phase synthesis of cyclic imides (yield 70-75%) from cyclic anhydrides using potassium bromide solid phase and urea or thiourea. See
---Asian Journal of Chemistry, 20(5), 3341-3344; 2008
Here is another one by Taherpour, Avat et al who claimed One-pot synthesis of imides (yield 75%) from anhydrides in solid phase using thioacetamide (CH3CSNH2) in NaCl solid phase at 100 C. See
---Asian Journal of Chemistry, 18(3), 2401-2403; 2006