title: Verpacamides A-D, a sequence of C11N5 diketopiperazines relating cyclo(Pro-Pro) to cyclo(Pro-Arg), from the marine sponge Axinella vaceleti: possible biogenetic precursors of pyrrole-2-aminoimidazole alkaloids.
abstract: [reaction: see text] Four C(11)N(5) diketopiperazine metabolites named verpacamides A (6), B (7), C (8), and D (9) consisting of a proline-arginine dipeptide skeleton have been isolated from the marine sponge Axinella vaceleti. Verpacamides A-D are a sequence of metabolites showing the transformation of proline and arginine into the oxidized guanidinyl-cyclo(Pro-Pro) 8 and 9. Compounds 6-9 are structurally and chemically related to C(11)N(5) pyrrole-2-aminoimidazole metabolites also isolated from the Axinellidae and Agelasidae families of sponges and exemplified by dispacamide A (4) and dibromophakellin (10).
authors.affiliation: Institut de Chimie des Substances Naturelles du CNRS, Gif-sur-Yvette, France.
authors.forename: Carine
authors.initials: C
authors.lastname: Vergne
authors.forename: Nicole
authors.initials: N
authors.lastname: Boury-Esnault
authors.forename: Thierry
authors.initials: T
authors.lastname: Perez
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Martin
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Adeline
authors.forename: Elise
authors.initials: E
authors.lastname: Tran Huu Dau
authors.forename: Ali
authors.initials: A
authors.lastname: Al-Mourabit
mesh_terms: D000470:Alkaloids / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D047089:Axinella / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010456:Peptides, Cyclic / Q000737:chemistry*; D010879:Piperazines / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D000470:Alkaloids; D010456:Peptides, Cyclic; D010879:Piperazines; C518054:cyclo(prolylarginyl); C518053:cyclo(prolylprolyl); C465248:phakellin