title: A new synthesis of 2,3-di- or 2,3,3-trisubstituted 2,3-dihydro-4-pyridones by reaction of 3-ethoxycyclobutanones and N-p-toluenesulfonyl imines using titanium(IV) chloride: synthesis of (+/-)-bremazocine.
abstract: N-p-Toluenesulfonyl (Ts) aldimines reacted with 3-ethoxycyclobutanones by catalysis of titanium(IV) chloride to afford 2,3-di- or 2,3,3-trisubstituted N-Ts-2,3-dihydro-4-pyridones. Synthesis of (+/-)-bremazocine was efficiently accomplished by using this method.
authors.affiliation: School of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan. jimatsuo@p.kanazawa-u.ac.jp
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Matsuo
authors.forename: Ryohei
authors.initials: R
authors.lastname: Okado
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ishibashi
mesh_terms: D001575:Benzomorphans / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D003503:Cyclobutanes / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D011728:Pyridones / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D014025:Titanium / Q000737:chemistry*
chemical_list: D001575:Benzomorphans; D003503:Cyclobutanes; D007097:Imines; D011728:Pyridones; D014025:Titanium; C039460:titanium trichloride; C027248:bremazocine