Synthetic approaches to 2-substituted 1-oxo- and 3-oxotetrahydroisoquinolines

Article abstract of DOI:10.1002/jhet.5570320113

2-Substituted homophthalimides 2a-c were reduced regioselectively with sodium borohydride to carbinol-lactam intermediates 3a-c, which were dehydrated, followed by hydrogenation, to give 1-oxotetrahydroisoquinolines or 3,4-dihydroisoquinolin-1(2H)ones 5a-c. The isomeric 3-oxo-tetrahydroisoquinolines or 1,4-dihydroisoquinolin-3(2H)-ones 8a-i were obtained in satisfactory yields via heating 3-isochromanone (6) with the corresponding amines 7a-i in the presence of aluminum chloride.