Regiospecificity in the reaction of 2,3-dichloronaphthazarins with azide anions.Synthesis of echinamine A-a metabolite produced by the sea urchin Scaphechinus mirabilis

摘要

It was found that 6-hydroxy- and 6-alkoxy-2,3-dichloronaphthazarins react smoothly with sodium azide in methanol to produce the corresponding 2-azido derivatives as single regioisomers.We have explored the utility of this reaction for the synthesis of echinamine A (3-amino-7-ethyl-2,5,6,8-tetrahydroxy-l,4-naphthoquinone)-the first marine aminated hydroxynaphthazarin,a metabolite of the sea urchin Scaphechinus mirabilis (Agassiz).