title: New easy approach to the synthesis of 2,5-disubstituted and 2,4,5-trisubstituted 1,3-oxazoles. The reaction of 1-(methylthio)acetone with nitriles.
abstract: The reaction of 1-(methylthio)acetone with different nitriles in the presence of triflic anhydride led to the one-pot formation of 2-substituted 5-methyl-4-methylthio-1,3-oxazoles in good yield. 1,2- and 1,4-Bisozaxolyl-substituted benzenes were obtained when the reaction was carried out using aromatic dinitriles. The methylthio group at the C4 position of the oxazole ring was easily removed with Raney nickel to form 2-substituted 5-methyl-1,3-oxazoles in good yields. 4-Methylsulfonyl derivatives were prepared by the oxidation of the MeS group with m-CPBA. The proposed mechanism for the formation of oxazoles involves an unstable 1-(methylthio)-2-oxopropyl triflate, which was detected from the low-temperature NMR spectra.
authors.affiliation: Departamento de Química Organica, Facultad de Ciencias Químicas, Universidad Complutense, E-28040 Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Herrera
authors.forename: Roberto
authors.initials: R
authors.lastname: Martínez-Alvarez
authors.forename: Pedro
authors.initials: P
authors.lastname: Ramiro
authors.forename: Dolores
authors.initials: D
authors.lastname: Molero
authors.forename: John
authors.initials: J
authors.lastname: Almy
mesh_terms: D000096:Acetone / Q000031:analogs & derivatives* / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D010080:Oxazoles / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D013440:Sulfides / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry; D013696:Temperature
chemical_list: C519210:1-(methylthio)acetone; D007659:Ketones; D009570:Nitriles; D010080:Oxazoles; D013440:Sulfides; D000096:Acetone; D013455:Sulfur