Five-membered 2,3-dioxo heterocycles: C. Reaction of methyl 1-aryl-3-cinnamoyl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carbocylates with acyclic enamines

Methyl 1-aryl-3-cinnamoyl-4,5-dioxo-4,5-dihydro-1 H -pyrrole-2-carbocylates react with N-substituted ethyl 3-amino-3-phenylprop-2-enoates, ethyl 3-aminobut-2-enoates, 3-amino-1,3-diphenylprop-2-en-1-ones, and dimethyl 2-arylaminofumarates to give 9-ethoxycarbonyl-, 9-benzoyl-, and 8,9-bis(methoxycarbonyl)-4-cinnamoyl-1,7-diazaspiro[4.4]nona-3,8-dienes.