1,8-Naphthalaldehydic acid may be used in the synthesis of fused bicyclic lactams, such as:2,3,5,11b-tetrahydrobenz[de][1,3]oxazolo[3,2-a]isoquinolin-5-one2,3,4,12b-tetrahydro-6H-benz[de][1,3]oxazino[3,2-a]isoquinolin-6-one2,3,4,5,7,13b-hexahydrobenz[de][1,3]oxazepino[3,2-a]isoquinolin-7-one1,2,3,11b-tetrahydro-5H-benz[de]imidazo[3,2-a]isoquinolin-5-one1,2,3,4,6,12b-hexahydrobenzo[de]pyrimido[3,2-a]isoquinolin-7-one1,2,3,4,5,13b-hexahydro-7H-benzo[de]1,3-diazepino[3,2-a]isoquinolin-7-one7H-benzo[de]benzimidazo[3,2-a]isoquinolin-7-one2,3,5,11b-tetrahydrobenzo[de]thiazolo[3,2-a]isoquinolin-5-one(9S,9R)-methyl 5-oxo[2,3,5,11b]-tetrahydrobenz[de]oxazolo[3,2-a]isoquinoline-3-carboxylate(3R,11bS)-3-phenyl-2,3,5,11b-tetrahydrobenz[de][1,3]oxazolo[2,3-a]isoquinolin-5-one
