| 摘要 |
NEW MATERIAL:The compound of formula [R is CnH2n+1 (n is 5-8)]. EXAMPLE:2-Pentylamino-5,8-dihydroxynaphthoquinone. USE:Vat dye for fiber and dye for human hair. PREPARATION:The objective compound can be prepared by reducing 2-(alkyl)- amino-5,8-dihydroxynaphthoquinone with a reducing agent such as sodium dithionate in the presence of an alkali such as KOH, NaOH, Na2CO3, etc., in water, alcohol or a mixture of water and alcohol, or in an aqueous solution of hydrochloric acid in the presence of zinc, preferably at room temperature - refluxing temperature for 1-5hr. |
