Studies on Quinoline and Isoquinoline Derivatives. I. Condensation of Quinoline and Isoquinoline N-Oxides with Isoxazoles

In order to introduce a carbon function to the 2-position of quinoline, the reaction of quinoline 1-oxide with some isoxazole derivatives whose 4-positions are free, was investigated. The products, such as 2-(5-amino-3-methyl-4-isoxazolyl)-, 2-(5-ethylamino-3-methyl-4-isoxazolyl)-, 2-(5-hydroxy-3-methyl-4-isoxazolyl)-, and 2-(5-ethoxy-3-methyl-4-isoxazolyl)-quinolines were hydrogenated in the presence of Raney nickel catalyst to give the quinoline derivatives possessing the desired side chains. Treatment of 2-(5-hydroxy-3-methyl-4-isoxazolyl) quinoline with excess phosphoryl chloride afforded 2-(5-chloro-3-methyl-4-isoxazolyl) quinoline whose chlorine atom could be substituted by diethylamine and ethoxide ion. These reactions were equally applied to isoquinoline 2-oxide yielding the corresponding products.