The cyclization reaction of ortho-ethynylbenzaldehyde derivatives into isoquinoline derivatives.
In order to elucidate the reaction mechanism of the cyclization between an ethynyl group and an imino group at the ortho-position on an aromatic ring to afford isoquinolines, reaction of 2-ethynylbenzaldehydes under various conditions was examined. It is concluded that reaction proceeds via an ionic process and the isoquinoline 4-hydrogen atom derives from the solvent. In addition, it was found that 2-ethynylbenzaldehyde O-methyloximes underwent cyclization in the presence of primary and secondary alcohols to give 3-substituted isoquinolines.
Sakamoto
T
T
Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan. Sakamoto@mail.pharm.tohoku.ac.jp
Numata
A
A
Kondo
Y
Y
D001547:Benzaldehydes / Q000737:chemistry*; D003500:Cyclization; D007202:Indicators and Reagents; D007546:Isoquinolines / Q000737:chemistry*; D010165:Palladium
D001547:Benzaldehydes; D007202:Indicators and Reagents; D007546:Isoquinolines; C413250:ethynylbenzaldehyde; D010165:Palladium