title: Molybdenum oxides as highly effective dehydrative cyclization catalysts for the synthesis of oxazolines and thiazolines.
abstract: In the presence of molybdenum oxide the dehydrative cyclization of N-acylserines, N-acylthreonines, and N-acylcysteines can be carried out under Dean-Stark conditions in toluene to give oxazolines and thiazolines. The ammonium salts (NH(4))(6)Mo(7)O(24).4H(2)O and (NH(4))(2)MoO(4) have excellent catalytic activities for the dehydrative cyclization of serine and threonine derivatives, and the acetylacetonate complex MoO(2)(acac)(2) has a remarkable catalytic activity for the dehydrative cyclization of cysteine derivatives. In addition, polyaniline-supported MoO(2)(acac)(2) can easily be recovered and reused.
authors.affiliation: Graduate School of Engineering, Nagoya University, Chikusa, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sakakura
authors.forename: Rei
authors.initials: R
authors.lastname: Kondo
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Ishihara
mesh_terms: D002384:Catalysis; D003500:Cyclization; D003545:Cysteine / Q000031:analogs & derivatives* / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry*; D010080:Oxazoles / Q000138:chemical synthesis*; D012694:Serine / Q000031:analogs & derivatives* / Q000737:chemistry*; D013844:Thiazoles / Q000138:chemical synthesis*; D013912:Threonine / Q000031:analogs & derivatives* / Q000737:chemistry*
chemical_list: D010080:Oxazoles; D013844:Thiazoles; D013912:Threonine; D012694:Serine; D008982:Molybdenum; D003545:Cysteine