Depending on the reaction conditions N-arylsulfonyl-1,4-quinone imines with enamines led to the formation of the products of 1,4-addition, derivatives of benzo-and naphthofuran, indole, and benzindole.A multitude of publications describe the reactions of p-benzoquinone with enamines resulting in heterocyclic compounds: benzofuran (I) [1][2][3][4] or indole (II) [2, 3, 5-9] derivatives which are mostly biologically active substances [4,10,11]. The structure of the reaction products depends on the structure of initial compounds (it is the most strongly affected by the substituent at the nitrogen atom of the enamine) [2, 6, 8] and the conditions of the reaction [2,8,12].Several papers consider the reactions of N-arylsulfonyl-1,4-quinone imines with enamines, in particular, with imines of acetylacetone and ethyl 3-arylaminocrotonates [13][14][15][16]. The reaction of N-tosyl-1,4-benzoquinone imine with acetylacetone imine in methanol or acetic acid resulted in a heterocyclic derivative (I, X = TsNH, R 1 = COMe, R 2 = Me) [15,16], in acetone another structure was obtained (II, X = TsNH, R 1 = COMe, R 2 = Me, Y = 4-MeC 6 H 4 ) [16]. In reactions of N-tosyl-1,4-benzoquinone imine with esters of 3-arylaminocrotonic X O R 2 R 1 X N R 2 R 1 Y I II acid in chloroform or acetone only indole derivatives were obtained (II, X = TsNH, R 1 = COOEt, R 2 = Me, Y = 4-MeC 6 H 4 , Ph, 4-MeOC 6 H 4 ) [13, 14, 16], N-tosyl-1,4-naphthoquinone imine in acetone formed only the open-chain product of 1,4-addition [17]. The formation of indole derivatives is favored by the presence of an aryl substituent at the nitrogen atom of the enamine [13].Benzofuran derivatives were obtained at the hydrolysis of the addition products of the esters of 3-alkyl-and 3-arylaminocrotonic acids [18,19] to N-tosyl-1,4-benzoquinone monoimine. No research concerned the effect on the direction of this reaction of the substituents in the quinoid ring of the N-arylsulfonyl-1,4-quinone imines. It was formerly established that in the reactions of p-benzoquinone with enamines the substituents in the quinoid ring govern the direction of this reaction [4,6,7,9]. The goal of this study was the establishment of the effect of the reaction condition and the structure of Narylsulfonyl-1,4-quinone imines, in particular, of the position and the character of the substituent in the quinoid ring, on the direction of their reactions with the acetylacetone imine and the esters of 3-arylaminocrotonic acid .The reaction of N-arylsulfonyl-1,4-benzoquinone monoimines IIIа-IIIo with p-tolylaminopent-3-en-2-one (IVа) and esters of 3-arylaminocrotonic acid IVb, IVc was carried out in acetone, acetic acid, dichloroethane,
