tailieunhanh - Some factors which could induce the imine-enamine tautomerism of schiff’ bases adducts of gossypol

Gossypol, a yellow pigment, isolated from cotton seeds, exhibits many interesting biological activities: antitumor, antimalarial, anti-HIV [1]. But gossypol is toxic and this toxicity may be related to the two-functional aldehyde groups [2]. Many authors prepared the Schiff’s’ base adducts of gossypol from 1985 to 2002, but these authors did not pay attention to the factor that these adducts may present under or the imine form or the enamine one. | Journal of Chemistry Vol. 42 3 P. 366 - 370 2004 SOME FACTORS WHICH COULD INDUCE THE IMINE-ENAMINE TAUTOMERISM OF SCHIFF BASES ADDUCTS OF GOSSYPOL Received 14-4-2003 NGUyEN KIM PHI PHUNG1 TON THAT QUANG1 NGUyEN THANH BINH1 GINETTE JAUReGuiBERRy2 1University of Natural Sciences National University of Ho Chi Minh City 2Museum National d Histoire Naturelle 61 Buffon 75005 Paris SUMMARy Gossypol a yellow pigment isolated from cotton seeds exhibits many interesting biological activities antitumor antimalarial anti-HIV 1 . But gossypol is toxic and this toxicity may be related to the two-functional aldehyde groups 2 . Many authors prepared the Schiff s base adducts of gossypol from 1985 to 2002 but these authors did not pay attention to the factor that these adducts may present under or the imine form or the enamine one. In this study the technique of 1H-NMR was used to determine the imine or the enamine form of Schiff s base adducts of gossypol. This technique was also applied to study some factors which could induce the imine-enamine form of adducts. The factor was used aliphatic amine of from 3 to 8 carbons or aromatic amine that has different substituent at the position para that used to condense with gossypol. The factor used solid alumine. The reagents of gossypol and amine were separately impregnated on alumine then these two reagents were mixed to react together at room temperature under visible light and without solvent. The factor VIS and UV254. I - INTRODUCTION From 1985 to 2002 many authors had synthesized the Schiff bases adducts of gossypol. These authors did not pay attention on the fact that the Shiff bases adduct of gossypol might tautomerizeto change from the imine form to the enamine one. It was showed that only the technique of 1H-NMR could be the useful tool to well determine whether the adducts were under the imine form or the enamine one. This technique was also used to study some factors which could induce the imine-enamine tautomerism in the .