The cycloaddition-ring transformation reaction sequence of pyrido[1,2-a]pyrazines with substituted naphthoquinones furnished a series of new highly substituted azaanthraquinones. Whereas monosubstituted naphthoquinones were normally leading to two regioisomeric products, in some cases a preference for only one regioisomer was observed. The amino derivative 3b which was isolated as the main product proved to be suitable for further modifications at the primary amino group. The derivatives obtained possess groups capable of connecting the molecule with other substructures for applications as functional dyes. The newly synthesized azaquinones show strong and very broad absorptions between 400 and 600 nm in their UV/Vis spectra
吡啶并[1,2-a]吡嗪与取代萘醌的环加成-环转化反应序列产生了一系列新的高度取代的氮杂蒽醌。虽然单取代的萘醌通常会导致两种位置异构体产物,但在某些情况下观察到对只有一个位置异构体的偏好。作为主要产物分离出的氨基衍生物3b被证明适合进一步在主要氨基团上进行修饰。所得到的衍生物具有能够将分子与其他亚结构连接起来以应用为功能染料的基团。新合成的氮杂蒽醌在其紫外/可见光谱中显示出强烈且非常宽的吸收峰,在400至600纳米之间。