SYNTHESIS OF ISOMERIC (<i>E</i>)-[4-(DIMETHYLAMINO)PHENYL]VINYLQUINOXALINES – PRECURSORS FOR A NEW CLASS OF NONLINEAR OPTICAL CHROMOPHORES

Abstract

Methods are presented for the preparation of isomeric (Е)-3-, (Е)-6-, (Е)-7-[4-(dimethylamino)phenylethenyl]quinoxalin-2-ones and 2-phenylquinoxalines – compounds of ''donor–π-bridge'' type, which serve as precursors for new nonlinear optical chromophores with potentially high first hyperpolarizability values. The introduction of dimethylanilinoethenyl moiety at the position 3 of the quinoxaline system was achieved in good yields by fusion of 3-methyl derivatives with 4-(dimethylamino)benzaldehyde at 220°С in the presence of catalytic amounts of acetic anhydride and pyridine during the synthesis of 3-(dimethylaminophenylethenyl)quinoxalin-2-ones or as a result of condensation of these reactants by the action of 20 М sodium hydroxide solution in the presence of Aliquat 336 during the synthesis of 3-(dimethylaminophenylethenyl)-2-phenylquinoxalines. The introduction of dimethylanilinoethenyl moiety at the positions 6 and 7 was achieved by Heck reaction of p-dimethylaminovinylbenzene with 6- or 7-bromoquinoxalines in the presence of palladium acetate. The structures of isomeric 6-bromo- and 7-bromo-3-methyl derivatives of quinoxalines were confirmed by X-ray structural analysis.

Authors: Sirina M. Sharipova, Alina A. Gilmutdinova, Dmitry B. Krivolapov, Zilya R. Khisametdinova, Olga N. Kataeva, Aleksey A. Kalinin