title: An efficient synthesis of N-tert-butoxycarbonyl-O-cyclohexyl-L-tyrosine.
abstract: A facile and efficient synthesis of N-tert-butoxycarbonyl-O-cyclohexyl-L-tyrosine [Boc-Tyr(Chx)-OH] is described. Boc-Tyr-OH was treated with NaH in dimethylformamide and then with 3-bromocyclohexene to give N-Boc-O-(cyclohex-2-enyl)-L-tyrosine [Boc-Tyr(Che)-OH] in 70% yield. Hydrogenation of Boc-Tyr(Che)-OH over PtO2 afforded Boc-Tyr(Chx)-OH in almost quantitative yield. The highest yield was achieved when a side product in the synthesis of Boc-Tyr-OH, Boc-Tyr(Boc)-OH, was not removed, because it was also converted to Boc-Tyr(Che)-OH without any additional manipulations. The new synthetic method described here is convenient for practical use, and would facilitate the widespread use of the Chx group for the hydroxy-protection of Tyr.
authors.affiliation: Department of Industrial Chemistry, Faculty of Engineering, Seikei University, Tokyo, Japan. Yasuhiro.Nishiyama@uth.tmc.edu
authors.forename: Y
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: S
authors.initials: S
authors.lastname: Ishizuka
authors.forename: S
authors.initials: S
authors.lastname: Shikama
authors.forename: K
authors.initials: K
authors.lastname: Kurita
mesh_terms: D002853:Chromatography, Liquid; D009682:Magnetic Resonance Spectroscopy; D014443:Tyrosine / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: C423028:N-tert-butoxycarbonyl-O-cyclohexyltyrosine; D014443:Tyrosine