Studies on tertiary amine oxides. LXI. Some reactions of 2-phenylquinoline 1-oxide and its derivatives.

Abstract

The orientation of nitration of 2-phenylquinoline 1-oxide (1) with potassium nitrate and sulfuric acid was found to be principally governed by the concentration of sulfuric acid independently of the reaction temperature. Thus, whereas the reaction in concentrated sulfuric acid gave 3'-nitro derivative (3) as the main product, the use of 70-75% sulfuric acid was favorable for the formation of 4-nitro derivative (2). Further nitration of 2 and 3 readily produced 3', 4-dinitro compound (4). The Reissert-Henze reaction of 2-(4-methoxyphenyl) quinoline 1-oxide (7) afforded 1-benzoyloxy-4-cyano-1, 4-dihydroquinoline (12) besides 4-cyano (9), 6-benzoyloxy- (10) and 8-benzoyloxy-quinolines (11). From the reaction of 2-(4-nitrophenyl) quinoline 1-oxide (8), the corresponding 1, 4-dihydroquinoline (15) was also isolated together with 6-and 3-benzoyloxyquinolines (13 and 14). The mechanism of the formation of benzoyloxy derivatives was discussed.