複素環式化合物の合成研究(第515報)Streptonigrin関連化合物の合成研究(第11報)2-Chloro-5,6,8-trimethoxyquinolineの合成について

抄録

For the synthesis of streptonigrin skeleton by the Ullmann reaction, 2-chloroquinoline derivative was obtained from p-anisidine as the starting material. p-Anisidine was converted to 6-methoxy-5-nitroquinoline 1-oxide (V) by a three-step procedure. Treatment of V with phosphoryl chloride gave 2-chloroquinoline derivative (VI). Reduction of the nitro group with stannous chloride in ethanol solution saturated with hydrogen chloride gas afforded an amino compound (VIIa), which was submited to the oxidation using Fremy's salt. Further, p-quinolinedione (VIII) was reduced to IXa, which was methylated with diazomethane to afford 2-chloro-5, 6, 8-trimethoxyquinoline (IXc).