1-ethyl-1H-pyrrole-2,5-dione 128-53-0 1H-pyrrole-2,5-dione, 1-ethyl- InChI=1/C6H7NO2/c1-2-7-5(8)3-4-6(7)9/h3-4H,2H2,1H N-ethylmaleimide