2-Hydrazinopyridine → 4-Hydroxy-3-[2-(2-pyridinyl)diazenyl]-1-naphthalenesulfonic acid

Participants

Reaction Steps

1,2-Naphthoquinone-4-sulfonic acid sodium salt (26 g) was dissolved in a mixture of water (500 ml) and concentrated hydrochloric acid (250 ml). To this solution was added 2-pyridylhydrazine (11 g) in water (100 ml). The reaction mixture became warm and the product started to precipitate. After 30 minutes of cooling, the product was filtered off and washed with a small volume of water, acetone and ether. Yield 32 g (96 percent).

Provenance & Evidence