Arene oxides of quinoline: epoxidation, N-oxidation and N-methylation reactions

Abstract

trans- 5,6,7,8- Diepoxy-5,6,7,8-tetrahydroquinoline 5, 5,6-epoxy-5,6-dihydroquinoline 1-oxide 3, 7,8-epoxy-7,8-dihydroquinoline 1 -oxide 4 and trans- 5,6,7,8 -diepoxy - 5,6,7,8 -tetrahydroquinoline1-oxide 6 have been formed by oxidation of the corresponding arene oxides of quinoline, 5,6-epoxy5,6-dihydroquinoline 1 and 7,8-epoxy-7,8-dihydroquinoline 2. The cis-diepoxides, cis-5,6,7,8-diepoxy-5,6,7,8-tetrahydroquinoline 8 and cis-5,6,7,8-diepoxy-5,6,7,8-tetrahydroquinoline 1-oxide 9 were both obtained by a stepwise synthesis from 7,8-epoxy-7,8-dihydroquinoline 2via the bromohydrin 7. N-Methylation of 5,6-epoxy-5,6-dihydroquinoline 1 and 7,8-epoxy-7,8-dihydroquinoline 2 with methyl trifIuoromethanesulphonate yielded the corresponding N-methylquinolinium arene oxide salts 10 and 11.