By reducing flavanthrone (II), 8,16-diazapyranthrene (V) (denoted as flavanthrene) was obtained. On the other hand, leucoflavanthrone dibenzoate was also prepared. Since these two substanses give nearly identical absorption spectra, the leucobenzoate is considered to have the VI formula (5,13-dibenzoyloxy-8,16-diazapyranthrene) and to belong to the same conjugated system as flavanthrene. Consequently, it may be considered that the leuco-form of flavanthrone corresponds to the IV formula (5,13-dihydroxy-8,16-diazapyranthrene) in which two carbonyl groups are reduced, but not the III formula (8-hydro-13-hydroxy-5-oxo-8,16-diazapyranthrene) previously presented. In addition, the leucobenzoate can also be synthesized by boiling the quinone with zinc dust and benzoyl chloride in o-dichlorobenzene containing pyridine. This method, devised by the author, is easy to perform and gives a good yield.
通过还原二
萘嵌苯酮(II),得到了8,16-二氮杂
芘烷(V)(记作二
萘嵌苯烷)。另一方面,也合成了二
萘嵌苯酮二
苯甲酸酯的还原型。由于这两种物质具有几乎相同的吸收光谱,因此二
苯甲酸酯还原型被认为是具有VI式(5,13-二苯甲酰氧基-8,16-二氮杂
芘烷),并且属于与二
萘嵌苯烷相同的共轭体系。因此,可以认为二
萘嵌苯酮的还原型对应于IV式(5,13-二羟基-8,16-二氮杂
芘烷),其中两个羰基被还原,而非先前呈现的III式(8-羟基-13-羟基-5-氧代-8,16-二氮杂
芘烷)。此外,二
苯甲酸酯还原型也可以通过在含有
吡啶的
邻二氯苯中,用
锌粉和
苯甲酰氯煮沸醌来合成。这一方法由作者设计,操作简便且产率高。