In connection with our studies of biologically active
1,2,3,4-tetrahydroisoquinoline
marine natural products, we describe herein a useful intramolecular
photoredox transformation of 7-methoxy-6-methyl-1,2,3,4-tetrahydroisoquinoline-5,8-dione
tricyclic models into 5-hydroxy-tetrahydroisoquinol[1,3]dioxoles in
excellent yields. We applied this methodology to the transformation
of renieramycin M into renieramycins T and S and the transformation
of saframycin A. The results of cytotoxicity studies are also presented.
Nakijinols A, B and analogues E through G, which are structurally unique and biologically significant sesquiterpenoid benzoxazoles, can be efficiently obtained in a highly unified manner from the sesquiterpenoid quinone, smenospongine. The starting material is accessible from the (+)-5-methyl Wieland-Miescher ketone. The synthetic method features strategic construction of the requisite dihydroxylated benzoxazole substructure via the ring closure of the N-(2-hydroxyphenyl)-formamide or -acetamide moiety. The synthesis of nakijinols is reported here for the first time. The absolute configurations of nakijinols A and E were also established.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.