Lactam and amide acetals. 69. Synthesis and properties of 3-(aminomethylene)-2-indolinone derivatives

Oxindole derivatives reacted with the diethyl acetals of dimethylformamide and dimethylacetamide to give the corresponding derivatives of 3-(aminomethylene)-, (aminoethylidene)-, and (ethoxyethylidene)-2-indolinone. These products were then easily converted to N-aryl- and N-alkylaminomethyleneoxindoles upon treatment with aryl or alkyl amines. The alkylation of N,N-dimethylaminomethylene-2-indolinones by dimethyl sulfate and triethyloxonium tetrafluoroborate, and the reactions of the resulting methyl sulfates and tetrafluoroborates with nucleophilic reagents were studied. The configuration of the 3-(aminomethylene)-2-indolinone derivatives prepared at the enamine C=C double bond was investigated by NMR. The free energies of activation for the cis—trans isomerization were determined in a number of cases.For Communication 68, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1190–1198, September, 1991.