Mechanistic Pathways in Amide Activation: Flexible Synthesis of Oxazoles and Imidazoles
نویسندگان
چکیده
The preparation of substituted aminooxazoles and aminoimidazoles from α-arylamides and α-aminoamides through triflic anhydride-mediated amide activation is reported. These reactions proceed via the intermediacy of nitrilium adducts and feature N-oxide-promoted umpolung of the α-position of amides as well as a mechanistically intriguing sequence that results in sulfonyl migration from nitrogen to carbon. Quantum-chemical mechanistic analysis sheds light on the intricacies of the process.
منابع مشابه
Converting oxazoles into imidazoles: new opportunities for diversity-oriented synthesis.
We report the optimization of a neglected reaction for the rapid and direct conversion of oxazoles into N-substituted imidazoles. The utility of this microwave-promoted reaction for diversity-oriented synthesis is demonstrated in the preparation of >40 N-substituted imidazoles, including α-imidazolyl esters.
متن کاملOrganocatalytic strategies for the construction of optically active imidazoles, oxazoles, and thiazoles.
This study demonstrates the first enantioselective synthesis of hydroxyalkyl- and aminoalkyl-substituted imidazoles, oxazoles, and thiazoles. The approach developed utilizes a highly effective one-pot reaction cascade that consists of either an organocatalytic epoxidation or aziridination of α,β-unsaturated aldehydes coupled with a [3+2]-annulation, in which amidines, ureas, or thioureas act as...
متن کاملOne-Pot solvent-free synthesis of Highly Substituted Imidazoles catalyzed by zeolite
A series of tri- and tetra- substituted imidazoles were synthesized from benzyl, aldehyde and ammonium acetate in the presence of zeolite as an ecofriendly reusable catalyst under microwave irradiation in the absence of solvent. The yields are high to excellent and the use of microwave irradiation reduces reaction times to few minute.
متن کاملMechanism of imidazole and oxazole formation in [C-2]-labelled glycine and alanine model systems
Studies with C-2-labelled glycine and alanine in model systems containing 2,3-butanedione, glyceraldehyde or glyoxal have indicated that imidazoles and oxazoles can be formed from a-dicarbonyl compounds through Strecker reaction and subsequent formation of a-amino carbonyl reactive intermediates. These intermediates can react with any aldehyde in the reaction mixture to form an imine which in t...
متن کاملMagnetic Fe3O4 nanoparticles as a highly efficient catalyst for the synthesis of imidazoles under ultrasound irradiation
To be fairly general and catalyst is easily separated by magnetic devices and can be reused without any apparent loss of activity for the reaction. Fe3O4 nanoparticles were prepared by chemical coprecipitation method and was found to be a mild and effective catalyst for the efficient, one-pot, three-component synthesis of 2,4,5-trisubstituted imidazoles at room temperature under ultrasound irra...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 19 شماره
صفحات -
تاریخ انتشار 2017