Reactions of 3-Acetyltropolone and Its Methyl Ethers with 1,2-Ethanediamines

Article abstract of DOI:10.1246/bcsj.56.3358

3-Acetyltropolone reacted with 1,2-ethanediamine to give N,N-bis(3-acetyl-2-oxo-3,5,7-cycloheptatrienyl)-1,2-ethanediamine (3) and 5-acetyl-3,4-dihydro-2H-cycloheptapyrazine (4), along with a small amount of by-products, which were 8-acetyl-1,2,3,4-tetrahydro-5-quinoxalinecarbaldehyde (5), 5-acetyl-1,2,3,4-tetrahydroquinoxaline (6), and 2-methyl-5,6-dihydro-4H-pyrrolo<1,2,3-de>quinoxaline (7).The minor products (5-7) resulted from the contraction of the seven-membered ring of the compound 4. 2-Acetyl-7-methoxytropone (2a) also reacted with 1,2-ethanediamine to give the same products (3-7) in higher yields.On the other hand, the same reaction of 3-acetyl-2-methoxytropone (2b) readily gave 4-7.The reaction of 2a with N-methyl-1,2-ethanediamine gave N-(3-acetyl-2-oxo-3,5,7-cycloheptatrienyl)-N'-methyl-1,2-ethanediamine (14), 5-acetyl-1-methyl-2,3-dihydro-1H-cycloheptapyrazine (15), 8-acetyl-4-methyl-1,2,3,4-tetrahydro-5-quinoxalinecarbaldehyde (16), 5-acetyl-1-methyl-1,2,3,4-tetrahydroquinoxaline (17), and 2,6-dimethyl-5,6-dihydro-4H-pyrolo<1,2,3-de>quinoxaline (18).The same reaction of 2b also gave the products (15-18).The several reactions of these products are also described.