In continuing our research on the interaction of 2-dialkylaminobenzaldehydes with unsymmetrical CHactive compounds we have carried out the reaction of 2-piperazinobenzaldehyde 1 with cyanothioacetamide 2a and cyanoacetamide 2b. It was shown that the reaction of 2-piperazinobenzaldehyde 1 with cyanothioacetamide 2a in butanol for 2 h the product of tandem reactions [2], the Knoevenagel condensation and cyclization by the "tert-amino effect" mechanism [3-6], 2,3,4,41,5,6-hexahydro-1H-pyrazin[1,2-a]quinoline 3 was formed, while reaction of benzaldehyde 1 with cyanoacetamide 2b stopped at the stage of formation of the Knoevenagel N N CHO OMe CXNH 2 NC N N OMe H NH 2 X N N N OMe NH 2 S N 1 2a,b 4a,b 3 for Х = S -toluene, for Х = О -butanol butanol Х = S butanol a X = S, b X = O + 4a

Pyrazine derivatives R 0550Interaction of 2-Piperazinobenzaldehyde with Cyanoacet(thio)amide: Stereoselective Cyclization by the "tert-Amino Effect" Mechanism. -Under conditions A the thioamide (IIIa) cyclizes to give product (IV) whereas the amide (IIIb) does not cyclize at all. -(GLUKHAREV, T. V.; KLIMOVA, E. P.; PLATONOVA, A. Y.; MORZHERIN*, Y. Y.; Chem. Heterocycl. Compd. (N. Y.) 44 (2008) 6, 759-761; Ural State Tech. Univ., Ekaterinburg 620002, Russia; Eng.) -M. Bohle 24-168