3988-51-0Relevant academic research and scientific papers
Synthesis and evaluation of photophysical properties of Series of π-conjugated oxazole dyes
Mahuteau-Betzer, Florence,Piguel, Sandrine
, p. 3188 - 3193 (2013/06/27)
Incorporation of π-conjugated spacers at the 2 or 5 position of a 2,5-disubstitutedaryloxazole led to new series of fluorescent dyes. They show emissions from visible to 700 nm along with significant Stokes shift up to 208 nm and a strong solvatochromic fluorescence. These compounds are easily accessible in one step through direct C-H bond functionalization.
Room temperature copper(II)-catalyzed oxidative cyclization of enamides to 2,5-disubstituted oxazoles via vinylic C-H functionalization
Cheung, Chi Wai,Buchwald, Stephen L.
, p. 7526 - 7537 (2012/10/30)
A copper(II)-catalyzed oxidative cyclization of enamides to oxazoles via vinylic C-H bond functionalization at room temperature is described. Various 2,5-disubstituted oxazoles bearing aryl, vinyl, alkyl, and heteroaryl substituents could be synthesized in moderate to high yields. This reaction protocol is complementary to our previously reported iodine-mediated cyclization of enamides to afford 2,4,5-trisubstituted oxazoles.
Simple and efficient preparation of 2,5-disubstituted oxazoles via a metal-free-catalyzed cascade cyclization
Wan, Changfeng,Gao, Linfeng,Wang, Qiang,Zhang, Jintang,Wang, Zhiyong
supporting information; experimental part, p. 3902 - 3905 (2010/11/04)
A practical and simple synthesis of 2,5-disubstituted oxazoles was developed via an iodine-catalyzed tandem oxidative cyclization. A wide range of common commercial aromatic aldehydes can be used as reaction substrates, which displayed excellent functional group compatibility in this reaction.
Stereoselective direct copper-catalyzed alkenylation of oxazoles with bromoalkenes
Besselievre, Francois,Piguel, Sandrine,Mahuteau-Betzer, Florence,Grierson, David S.
supporting information; experimental part, p. 4029 - 4032 (2009/06/18)
(Chemical Equation Presented) A copper-catalyzed direct alkenylation of oxazoles with bromoalkenes has been developed. The method is both regio- and stereoselective and tolerates a variety of functional groups. A wide range of 2-E-vinyl-substituted oxazoles were obtained in high yields including the highly fluorescent alkaloid annuloline.
Iminophosphorane-Mediated Synthesis Of Oxazole Alkaloids: One-Step Preparation Of O-Methylhalfordinol And Annuloline
Molina, Pedro,Fresneda, Pilar M.,Almendros, Pedro
, p. 2255 - 2258 (2007/10/02)
The three-component reaction between triphenylphosphine, 4-methoxyphenacyl azide and nicotinoyl chloride or 3,4-dimethoxycinnamoyl chloride leads directly in good yields to O-methylhalfordinol or annuloline respectively.
Lewis Acid Promoted Reactions of Diazocarbonyl Compounds. 3. Synthesis of Oxazoles from Nitriles through Intermediate β-Imidatoalkenediazonium Salts
Doyle, Michael P.,Buhro, William E.,Davidson, James G.,Elliott, Robert C.,Hoekstra, James W.,Oppenhuizen, Mark
, p. 3657 - 3664 (2007/10/02)
Lewis acid promoted reactions of α-diazocarbonyl compounds with nitriles provide a general method for the production of oxazoles in high isolated yields.The generality of this method is evaluated by the effectiveness of oxazole formation in surveys of Lewis acids, diazocarbonyl compounds, and nitriles.Because of the relative absence of α-halogenation products in reactions performed with BF3*Et2O, this Lewis acid is preferred when the nitrile is employed as the reaction solvent.Reactions of diazo ketones in nitrile solvents generally result in higher oxazole yields(70-99percent) than do reactions of ethyl diazoacetate (26-31percent).When these transformations are performed at or below room temperature, at least 1 equiv of the Lewis acid is required, although catalytic activity is observed in reactions performed at 65 deg C.In BF3*Et2O promoted reactions, a minimum tenfold molar excess of nitrile is required for optimum oxazole production, although use of SbF5 results in high yields of oxazoles even when only a threefold excess of the nitrile is employed.The mechanism for oxazole formation is established as involving initial activation of the nitrile through association with the Lewis acid, followed by attack of the nitrilium complex at the carbonyl oxygen of the diazocarbonyl compound and internal displacement of nitrogen.Although Lewis acid association with the diazocarbonyl compound is the more favorable process in reactions performed with equivalent amounts of nitrile and diazocarbonyl compound, only equilibrium association of the Lewis acid with the nitrile effectively leads to oxazole formation.
