Five-membered 2,3-dioxo heterocycles: XCVII. Reaction of 3-aroylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones with Fischer’s base

Abstract

Abstract —3-Aroylpyrrolo[1,2- a ]quinoxaline-1,2,4(5 H )-triones reacted with 1,3,3-trimethyl-2-methylidene-2,3-dihydro-1 H -indole (Fischer’s base) to give (2 Z )-1-aryl-2-[3-oxo-3,4-dihydroquinoxalin-2(1 H )-ylidene]-5-(1,3,3-trimethyl-2,3-dihydro-1 H -indol-2-ylidene)pentane-1,3,4-triones. * For communication XCVI, see [1]. Substituted 4-acyl-1 H -pyrrole-2,3-diones, including those fused by the [ e ] side to aza heterocycles, readily react with binucleophiles to produce a variety of fused heterocyclic and spiro-heterocyclic systems [2–4]. We previously studied reactions of 4-acyl-1 H -pyrrole-2,3-diones fused to quinoxalin-2-one fragment, 3-aroylpyr-rolo[1,2- a ]quinoxaline-1,2,4(5 H )-triones, with primary enamines. The reactions of pyrroloquinoxalinetriones with N -alkyl-substituted dimedone imines involved successive addition of the β-CH and NH groups in the enamine fragment of the latter (enamine tautomer) to the C 3a and C 2 atoms of pyrroloquinoxalinetrione, respectively, to give bridged 3,10,13-triazapentacyclo-[10.7.1.0