title: Novel synthesis of the ortho ester derivative of 4,5-epoxymorphinan.
abstract: [reaction: see text]. A method was found for the novel synthesis of ortho ester derivatives that are potentially useful as selective epsilon opioid receptor ligands. An unexpected 17-(cyclopropylmethyl)-4,5alpha-epoxy-6alpha-hydroxy-3,7,7-trimethoxy-8-oxa-6,14-endoethanomorphinan was produced when 17-(cyclopropylmethyl)-4,5alpha-epoxy-3-methoxy-6alpha,14-dihydroxy-6beta-(1,3-dithia-2-yl)-morphinan was treated in methanol with trimethyl orthoformate and CuO/CuCl2. This ortho ester derivative was then converted to an ester with acid. The structure of the ortho ester was determined by 2D NMR (HMBC) and mass spectra.
authors.affiliation: School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Watanabe
authors.forename: Toshitsugu
authors.initials: T
authors.lastname: Kai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nagase
mesh_terms: D004952:Esters; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009019:Morphinans / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: C496139:4,5-epoxymorphinan; D004952:Esters; D009019:Morphinans