Streptonigrin関連化合物の合成研究(第7報) : (Streptonigrinピリジン環の合成について 複素環式化合物の合成研究 第198報

抄録

In order to synthesize streptonigric acid (III) and streptonigrinic and (IV), an attempt was made to synthesize initially the pyridine ring (C) of streptonigrin (I). Even though our final object could not have been achieved, condensation of β-diketoester (VIa∼VIb) with cyanoacetamide was found to give pyridone of XII type preferentially. This fact was proved by the conversion of the above compound into the imide (XIII). Furthermore, 2, 3, 4-trimethoxypropiophenone (Vc) was obtained by the condensation of pyrogallol trimethyl ether with propionic anhydride in the presence of polyphosphoric acid in a comparatively better yield. Moreover, a modified synthesis of the compound (XXIV) described in a previous paper was studied and the compound (XXVI) obtained by the condensation of aromatic aldehyde with ethyl acetoacetate was reacted with quinoline derivative (XIV) to give the compound (XXIV), but the compound (XXV) synthesized by the condensation of aromatic aldehyde with XIV was found not to react with ethyl acetoacetate.