Chemistry of iminofurans: XIII. Recyclization of 4-arylamino-2- tert -butyl-5-oxo-2,5-dihydrofuran-2-yl acetates with ethyl cyanoacetate

Recyclization of 4-arylamino-2-tert-butyl-5-oxo-2,5-dihydrofuran-2-yl acetates with ethyl cyanoacetate in the presence of triethylamine afforded the corresponding ethyl 2-amino-1-aryl-5-(3,3-dimethyl-2-oxobutylidene)-4-oxo-1H-4,5-dihydropyrrole-3-carboxylates.