“…A mixture of PMA 28 (5.4 g, 2.0 mmol) and CH 3 N(CH 2 CH 2 CN) 2 (2.9 g, 20 mmol) [19] in 1,2-dichloroethane (75 mL) was heated at 90°C for 72 h. After removal of solvents, the residue was dissolved in a small amount of methanol. Upon slow addition of ether, the brown solid precipitated out from the solution, which was the desired cross linked polymer c-PMA 28 (5 g, 71%): 1 15 and c-PMA 50 were prepared in a similar manner.…”