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Simple Synthesis of Dialkyl 2-(3-Oxo-3H-indol-2-yl)-but-2-enedioates

Yavari I., Dehghan S., Alborzi A., Mohtat B.

Polish Journal of Chemistry

2005

Vol. 79 / nr 5

845-850

Triphenylphosphine undergoes a smooth addition reaction with dialkyl acetylenedicarboxylates in the presence of isatin or 5-bromoisatin to produce stable crystalline phosphorus ylides. These products exist as a mixture of two geometrical isomers. Dynamic NMR effects have been observed in the 1H NMR spectra of dimethyl 2-(2,3-dioxo-2,3-dihydro-1H-indol-1-yl)-3-(1,1,1-triphenyl-_5-phosphanylidene)-succinate. These ylides are converted to dialkyl 2-(3-oxo-3H-indol-2-yl)-but-2-enedioates in boiling toluene.

Synthesis of Fluorinated Dialkyl 1-Aryl-4-alkoxy-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates

Yavari I., Nasiri F., Djahaniani H.

Polish Journal of Chemistry

2004

Vol. 78 / nr 10

1871-1876

Alkyl 2-(2-fluoro-anilino)-2-oxo-acetates or ethyl 2-oxo-2-(trifluoromethylanilino)-acetate undergo a multistep reaction with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine to produce dialkyl l-(2-fluorophenyl)-4-alkoxy-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates or dialkyl 4-ethoxy-5-oxo-1-[2-(trifluoromethyl)-phenyl]-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates in good yields. Dynamic NMR study of dimethyl 4-ethoxy-5-oxo-1-[2-(trifluoromethyl)-phenyl]-2,5-dihydro-1H-pyrrole- 2,3-dicarboxylate shows a fairly high energy barrier (DeltaG _ = 60.9 kJ mol-1) for rotation around the N-aryl single bond, which leads to an observable atropisomerism.