M. S. Sinsky, R. G. Bass
1984
Citations
0
Influential Citations
20
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
The reactions of some ortho-substituted anilines with various α,β-acetylenic ketones were investigated as a route to 4-alkyl-, 4-aryl-, 4-hydroxy-, and 4-amino-3-quinolyl ketones. The anilines examined were 2-aminoacetophenone (1), 2-aminobenzophenone (2), anthranilonitrile (3), methyl anthranilate (4), and ethyl anthranilate (5). The acetylenic ketones used were 1,4-diphenyl-2-butyne-1,4-dione (6), 3-butyn-2-one (7), 1,3-diphenyl-2-propyn-1-one (8), and 4-phenyl-3-butyn-2-one (9). The acetylenic ketones typically reacted with the anilines to give enamines; however, exceptions were found. Acetylene 6 reacts with 3 to give the enamine (13) along with a small amount of 2,3-dibenzoyl-4-quinolamine (14). The reactions of 1 or 2 with 6 give the respective quinoline derivatives directly. Acetylene 8 reacts with 2 to give 3-benzoyl-2,4-diphenylquinoline (22) directly, whereas no reaction occurs between 8 and 1 or 3. Acetylene 9 does not react with 1, 2, or 3. The enamines exist as the intramolecularly hydrogen bonded isomers and usually undergo cyclization with 5 molar equivalents of methanolic sodium methoxide to give quinoline derivatives. The 4-quinolinols exist predominantly as the 4-quinolinone tautomer.