1-Naphthol → 1-[4-(4-(Dimethylamino)naphthylazo)phenylazo]-4-hydroxy-naphtalene

Participants

Reaction Conditions

Reaction Steps

2.9 g of 1-(4-amino-phenylazo)-4-(dimethylamino)naphtalene were dissolved in a mixture of 2.5 ml of HCl 37% and 5 ml of water. The obtained solution was cooled to 0° C., followed by dropwise addition of 0.69 g of sodium nitrite in 3 ml of water, while keeping the reaction temperature below 4° C. After complete addition, stirring was continued for 45 min at about 4° C. and the obtained mixture was then added to an ice-cooled solution of 1.44 g of 1-naphtol in NaOH/water (1.1 g/11 ml, while keeping the reaction temperature below 5° C. After complete addition, the reaction mixture was further stirred for 1 h at about 5° C. and then poured into 100 ml of water. The resulting brownish precipitate was filtered off, washed with water (100 ml) and methanol (50 ml). Crystallisation in methanol gave 3.3 g of the desired product.

Provenance & Evidence