title: Synthesis of renieramycins: construction of the core ring system of cribrostatin 4 through modified Pictet-Spengler cyclization of 3,6-bisarylpiperazine-2,5-dione with diethoxyethyl benzoate.
abstract: A nine-step synthesis of pentacyclic key intermediate 11 of cribrostatin 4 (2) along with renieramycin I (1i) from 3,6-bisarylpiperazine-2,5-dione derivative 3 is described. The key step of this synthesis is the stereoselective cyclization of lactam nitrogen with diethoxyethyl benzoate, followed by the stereoselective hydrogenation to generate ABC ring system 6.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Yokoya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.forename: Naoki
authors.initials: N
authors.lastname: Saito
mesh_terms: D001565:Benzoates / Q000737:chemistry*; D003500:Cyclization; D006865:Hydrogenation; D007546:Isoquinolines / Q000737:chemistry*; D008968:Molecular Conformation; D010879:Piperazines / Q000737:chemistry*; D044005:Tetrahydroisoquinolines / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D001565:Benzoates; D007546:Isoquinolines; D010879:Piperazines; D044005:Tetrahydroisoquinolines; C412688:cribrostatin 4; C561143:renieramycin I; C003905:3,6-bis(5-chloro-2-piperidyl)-2,5-piperazinedione