title: Synthesis of echinamines A and B, the first aminated hydroxynaphthazarins produced by the sea urchin Scaphechinus mirabilis and its analogues.
abstract: The first total synthesis of two marine aminated hydroxynaphthazarins, echinamines A (3-amino-7-ethyl-2,5,6,8-tetrahydroxy-1,4-naphthoquinone) and B (2-amino-7-ethyl-3,5,6,8-tetrahydroxy-1,4-naphthoquinone), produced by the sea urchin Scaphechinus mirabilis is described. This was achieved from 1,2,4-triacetoxybenzene (13) through a sequence involving double Fries rearrangement of 13, reduction of 3,5-diacetyl-1,2,4-trihydroxybenzene (14), methylation of 3,5-diethyl-1,2,4-trihydroxybenzene (15), simultaneous double acylation of 3,5-diethyl-1,2,4-trimethoxybenzene (16) with a dichloromaleic anhydride-ethyl radical elimination process, methylation of 6,7-dichloro-3-ethyl-2-hydroxynaphthazarin (17), nucleophilic substitution of a chlorine atom by the methoxy group in 6,7-dichloro-3-ethyl-2-methoxynaphthazarin (18), introduction of an amino group via direct substitution of a chlorine atom in 7-chloro-3-ethyl-2,6-dimethoxy- (11) and 7-chloro-2-ethyl-3,6-dimethoxynaphthazarins (12) by an azido group, and functional group deprotection. The synthesis of amino analogues of spinazarin and spinochrome D is also described.
authors.affiliation: Pacific Institute of Bioorganic Chemistry, Russian Academy of Sciences, 159, Prospect 100 let Vladivostoku, Vladivostok 690022, Russian Federation.
authors.forename: Nataly D
authors.initials: ND
authors.lastname: Pokhilo
authors.forename: Maria I
authors.initials: MI
authors.lastname: Shuvalova
authors.forename: Maxim V
authors.initials: MV
authors.lastname: Lebedko
authors.forename: Galina I
authors.initials: GI
authors.lastname: Sopelnyak
authors.forename: Alla Ya
authors.initials: AY
authors.lastname: Yakubovskaya
authors.forename: Natalia P
authors.initials: NP
authors.lastname: Mischenko
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Fedoreyev
authors.forename: Victor Ph
authors.initials: VP
authors.lastname: Anufriev
mesh_terms: D000818:Animals; D015394:Molecular Structure; D009285:Naphthoquinones / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification; D012617:Sea Urchins / Q000737:chemistry*
chemical_list: D009285:Naphthoquinones; C505310:echinamine A; C505311:echinamine B