Naphtholactam is an organic compound derived from naphthalene. It is a tricyclic species consisting of a naphthalene core fused with a lactam (NH-CO-) at the 1,8-positions. The N-alkyl derivatives are commercially important.
It is a precursor to the dye anthanthrone via ring-opening to the amino carboxylic acid, which can be converted to the diazonium salt. Naphthostyril derivatives are also of interest in medicinal chemistry. Naphthostyrils can be produced by metal-catalyzed cyclization of 1-naphthylamides.
N-Ethylnaphtholactam and related derivatives are precursors to many dyes. The lactam condenses with anilines in the presence of phosphorus oxychloride.