Streptonigrin関連化合物の合成研究 : (第3報)4-フェニルピリジン誘導体の合成(複素環式化合物の合成研究 第148報)

抄録

Synthesis of streptonigrin (I) and its derivative (II) was attempted. The demethyl derivative of the A/B ring of I and A/B ring of II have already been synthesized and, in the present series of work, synthesis of C/D ring of these compounds was examined. At the same time, pharmacological activities of the compounds formed during the syntheses were examined. For this purpose, attempt was made to extend the synthetic reactions used by Eby and Hauser in which benzoylacetonitrile was treated with polyphosphoric acid to obtain the amide which, without its isolation, was treated with acetone to obtain 6-methyl-4-phenyl-2-pyridone. In order to increase one methyl group in 5-position and to obtain the pyridone compound which can be derived to the C/D ring of streptonigrin, a preliminary experiment was carried out with benzoylacetonitrile and methyl ethyl ketone which were treated with polyphosphoric acid. The product thereby obtained was found to have a methyl group in the 5-position, as was expected, by examination of its NMR spectrum. Therefore, 2, 3, 4, -trimethoxybenzoylacetonitrile was prepared and this was treated as above and 4-(2, 3, 4-trimethoxyphenyl)-5, 6-dimethyl-2-pyridone (VIIIb) was obtained. In order to introduce an amino group into the 3-position of this compound, nitration and bromination were attempted but no satisfactory result was obtained.