A new synthesis of 1,5-dihydropyridazino[3,4-<i>b</i>]quinoxalines and 2-(pyrazol-4-yl)quinoxalines
作者:Yoshihisa Kurasawa、Akiko Takano、Kyoko Kato、Atsushi Takada、Ho Sik Kim、Yoshihisa Okamoto
DOI:10.1002/jhet.5570330339
日期:1996.5
The reaction of 6-chloro-2-(l-methylhydrazino)quinoxaline 1-oxide 3 with acetylenedicarboxylates gave the 8-chloro-1-memyl-1,5-dihydropyridazino[3,4-b]quinoxaline-3,4-dicarboxylates 4a,b and 2-(pyrazol-4-yl)quinoxaline 1-oxides 5a,b. The formation of compounds 4a,b would follow the 1,3-dipolar cycloaddition reaction, subsequent 1,2-hydrazino migration, and then dehydrative cyclization, while the production
6-氯-2-(1-甲基肼基)喹喔啉1-氧化物3与炔二羧酸酯的反应得到8-氯-1-甲酰基-1,5-二氢吡啶并嗪[3,4- b ]喹喔啉-3,4-二羧酸酯4a,b和2-(吡唑-4-基)喹喔啉1-氧化物5a,b。化合物4a,b的形成将遵循1,3-偶极环加成反应,随后的1,2-肼基迁移,然后脱水环化,而化合物5a,b的生成将通过将肼基加至乙炔而进行-二羧酸酯导致吡唑环的构建,随后吡唑环的重排。化合物5a,b将其用磷酰氯/ N,N-二甲基甲酰胺脱氧以变成4-(喹喔啉-2-基)吡唑-3-羧酸酯8a,b。