Naphthol AS-D

Naphthol AS-D is a synthetic naphthol-based coupling component widely employed in the production of azo dyes for textile and pigment applications. It reacts with diazonium salts to produce bright, high-fastness colors on cellulosic fibers such as cotton, rayon, and linen, as well as on silk and leather. Naphthol AS-D is a key intermediate and building block in the creation of other dyes. Its chemical reactivity and color-yielding properties make it a standard in dye formulations. The derivative Naphthol AS-D chloroacetate (NASDCA) is a fluorigenic substrate for granulocyte specific esterases (e.g. Proteinase 3 (PR3) and Cathepsin G). It can be hydrolyzed into Naphthol AS-D by esterases to mix with diazonium salt and form insoluble red-brown precipitate in the cytoplasm that can be visualized under a microscope. This enzyme is usually considered specific for cells of granulocytic lineage. Spectral Data: lambdaEx=430nm, lambdaEm=493nm.