A series of substituted 2-methylenehydrazino-4-aryl-4-oxobut-2-enoic acids and their anilides and esters were obtained using reactions of 4-aryl-2-hydroxy-4-oxobut-2-enoic acids and their amides and esters with benzophenone hydrazone, benzyl monohydrazone, and triphenylphosphazines. The methyl ester of 2-(1,2-diphenyl-2-oxoethylidenehydrazino)-4-(4-chlorophenyl)-4-oxobut-2-enoic acid was also synthesized by decyclization of 3-(1,2-diphenyl-2-oxoethylidenehydrazino)-5-(4-chlorophenyl)-3H-furan-2-one using methanol. The synthesized compounds exhibit moderate anti-inflammatory, analgesic, and antimicrobial activity.Key words: derivatives of 2-methylenehydrazino-4-aryl-4-oxobut-2-enoic acids, synthesis, biological activity. 4-Aryl-2-hydroxy-4-oxobut-2-enoic acids, aroylpyrotartaric acids (APA), and their esters and amides (general formulas Ia -k) are known to be highly reactive toward a variety of chemical transformations [1-3]. Furthermore, many of these compounds have a broad spectrum of pharmacological activity [1,4,5]. N-substituted derivatives of APA and their esters and amides also exhibit various types of activity. In particular, they exhibit antibacterial, analgesic, anti-inflammatory, and antimicrobial activity [4][5][6]. Therefore, it seemed interesting to prepare new N-substituted a-hydrazone derivatives of APA and their amides and esters and to study their biological activity.We used three methods for the synthesis of N-substituted a-hydrazine derivatives of APA and their amides and esters:A. Reactions of acids and amides and esters I with hydrazones (IIa and -b).B. Reactions of acids and amides and esters I with triphenylphosphoranylidenehydrazones (triphenylphosphazines) (IIIa -c).C. Decyclization of N-substituted 5-aryl-3-hydrazono-3H-furan-2-ones (IV) by OH-and NH-nucleophiles.2-Diphenylmethylenehydrazino-and 2-(1,2-diphenyl-2-oxoethylidenehydrazino)-4-aryl-4-oxobut-2-enoic acids (Va -i) were synthesized beforehand by reaction of 4-aryl-2-hydroxy-4-oxobut-2-enoic acids (Ia -f) with benzophenone hydrazone and benzyl monohydrazone (IIa and -b) by the literature method [7]. Reaction of ester Ik with benzyl monohdrazone produced the methyl ester of 2-(1,2-diphenyl-2-oxoethylidenehydrazino)-4-(4-chlorophenyl)-4-oxobut-2-enoic acid (Vr), which was also synthesized by method C, decyclization of 3-(1,2-diphenyl-2-oxoethylidenehydrazono)-5-(4-chlorophenyl)-3H-furan-2-one (IV) using methanol (Scheme 1).We found that the reaction of these compounds with triphenylphosphazines III occurred at the a-carbonyl gruop of the diketo form regardless of the structure of the carbonyl substrate I. Thus, reaction of triphenylphosphazines IIIa -c; which were prepared using diazomethane, diphenyldiazomethane, and benzoyldiazomethane; with acids Ib, -c, and -e, anilides Ig -i, and methyl ester Ij formed the substituted 2-methylenehydrazino-4-aryl-4-oxobut-2-enoic acids (Vc, -d, and -j -l), anilides (Vm -p), or methyl ester Vq. The reaction occurred with an equimolar ratio of reagents in inert aprotic solvent at room temperature...
