第3級アミンオキシドに関する研究(第46報)塩化トシルの存在下におけるキノリンN-オキシド亜硝酸ソーダとの反応

抄録

Quinoline 1-oxide (I) reacted with sodium nitrite and tosyl chloride in cold ethanol (-10- -20°) to afford, besides carbostyril (II), 2-nitro- (III) and 4-nitro-quinoline (IV), although in a poor yield. When carried out in anhydrous and cold dimethylformamide (DMF), the reaction followed another path and 3-nitroquinoline 1-oxide (V) was formed, accompanied by the recovery of unchanged I, small amounts of by-products being detected in some cases. After various examinations, it was found that V is obtained in 60-80% yield by the repeated treatment of I with an excess reagent under similar conditions. The formation of V seems to involve nitrosation of a dihydroquinoline intermediate followed by oxidation to a nitro compound.