title: Synthesis of orthogonally protected L-threo-beta-ethoxyasparagine.
abstract: Orthogonally protected L-threo-beta-ethoxyasparagine (Fmoc-EtOAsn(Trt)-OH, 1) was synthesized from diethyl (2S,3S)-2-azido-3-hydroxysuccinate 2 in eight steps as a building block for solid-phase peptide synthesis. The starting material is easily available in multi-gram scale from D-diethyltartrate. The transformation steps reported here are robust and scalable. Thus, a significant amount of 1 (1.8 g) was obtained in 21% overall yield. The synthesis reported is also expected to be useful for the preparation of other O-substituted L-threo-beta-hydroxyasparagine derivatives.
authors.affiliation: Institute for Research in Biomedicine, Barcelona Science Park, Baldiri Reixac 10, 08028, Barcelona, Spain. jan.spengler@irbbarcelona.org
authors.forename: Jan
authors.initials: J
authors.lastname: Spengler
authors.forename: Marta
authors.initials: M
authors.lastname: Pelay
authors.forename: Judit
authors.initials: J
authors.lastname: Tulla-Puche
authors.forename: Fernando
authors.initials: F
authors.lastname: Albericio
mesh_terms: D001216:Asparagine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D003500:Cyclization; D005449:Fluorenes / Q000138:chemical synthesis* / Q000737:chemistry; D006020:Glycopeptides / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: C552027:2-(9H-fluoren-9-yl)methoxycarbonylamino-3-ethoxy-N-tritylsuccinamic acid; D005449:Fluorenes; D006020:Glycopeptides; D001216:Asparagine