First total synthesis and phytotoxic activity of Streptomyces sp metabolites abenquines

摘要

The first total synthesis of abenquines A, B2, C and D has been achieved in three steps starting from commercially available 2,5-dimethoxyaniline, with overall yields of 41-61%. Four analogues bearing the amino acids a-valine (17), L-methionine (18), and glycine (19), and benzylamine (20), were also prepared in 45-72% yield. The inhibitory properties of these compounds were evaluated against the photoautotrophic growth of a model Synechococcus sp. strain. Abenquine C and its enantiomer were substantially ineffective, whereas all other abenquines significantly inhibited cell proliferation, with concentrations causing 50%-inhibition of algal growth ranging from 10(-5) to 10(-6) M. (C) 2016 Elsevier Ltd. All rights reserved.