Amination of 2-Hydroxy-and 2,3-Dihydroxynaphthazarins.Synthesis of Echinamines A and B,Metabolites Produced by the Sand Dollar Scaphechinus mirabilis

摘要

2-Hydroxynaphthazarins reacted with aqueous ammonia at the C~1=O carbonyl group,following the addition-elimination pattern with formation of 8-aminojuglone derivatives.Reactions of 2,3-dihydroxynaph-thazarins with the same reagent involved the C~2=O carbonyl group of the corresponding 1,2-naphthoquinoid tautomer to produce 2-aminonaphthazarin derivatives.7-Ethyl-2,3,6-trihydroxynaphthazarin(echinochrome)reacted with aqueous ammonia to give 3(2)-amino-7-ethyl-2(3),6-dihydroxynaphthazarins(echinamines A and B)that are metabolites recently isolated from the sand dollar Scaphechinus mirabilis.