Naphtholactam

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.

Naphtholactam

Names
Preferred IUPAC name Benzo[cd]indol-2(1H)-one
Other names 1,8-naphtholactam
Identifiers
CAS Number	130-00-7
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL217045
ChemSpider	60558
ECHA InfoCard	100.004.523
EC Number	204-973-4
PubChem CID	67222
CompTox Dashboard (EPA)	DTXSID5059610
InChI InChI=1S/C11H7NO/c13-11-8-5-1-3-7-4-2-6-9(12-11)10(7)8/h1-6H,(H,12,13) Key: GPYLCFQEKPUWLD-UHFFFAOYSA-N
SMILES C1=CC2=C3C(=C1)C(=O)NC3=CC=C2
Properties
Chemical formula	C11H7NO
Molar mass	169.183 g·mol−1
Appearance	white solid
Melting point	181 °C (358 °F; 454 K)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302
Precautionary statements	P264, P270, P301+P312, P330, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Dye precursor

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.^[1] Naphthostyrils can be produced by metal-catalyzed cyclization of 1-naphthylamides.^[2]

Chemical structure of typical naphtholactam dye.

N-Ethylnaphtholactam and related derivatives are precursors to many dyes. The lactam condenses with anilines in the presence of phosphorus oxychloride.^[3]