Investigation on the reactivity of α-azidochalcones with carboxylic acids: Formation of α-amido-1,3-diketones and highly substituted 2-(trifluoromethyl)oxazoles
نویسندگان
چکیده
The reaction of α-azidochalcones with carboxylic acids has been investigated resulting in the formation of α-amido-1,3-diketones under microwave irradiation via in situ formation of 2H-azirine intermediates. An interesting reaction is described wherein, with trifluoroacetic acid at lower temperature, it affords highly substituted 2-(trifluoromethyl)oxazoles. These flexible transformations proceed under solvent free conditions in good to excellent yields without any catalyst.
منابع مشابه
Prediction of accurate pKa values of some α-substituted carboxylic acids with low cost of computational methods
The acidity constants (pKa) of thirty four (34) ;-substituted carboxylic acids in aqueous solution havebeen calculated using conductor-like polarizable continuum (C-PCM) solvation model. The gasphaseenergies at the Density Functional Theory (DFT-MPW1PW91) and solvation energies atHartree Fock (HF) are combined to estimate the pKa values which are very close to the experimentalvalues where, and ...
متن کاملInvestigation on the effect of trifluoromethyl group on the [3+2] cycloadditions of thiocarbonyl S-methanides with α, β-unsaturated ketones: A theoretical study using DFT
A [3+2] cycloaddition (32CA) reaction among a thiocarbonyl ylide (TCY 2) with (E)-4,4,4-trifluoro-4-phenylbut-3-en-2-one (TFB 4) as an electron-deficient enone in tetrahydrofuran (THF) were studied within the Molecular Electron Density Theory (MEDT), at the DFT-B3LYP/6-31G(d) computational level to analysis energetics, selectivities, and mechanistic aspects. The reaction can progress in four co...
متن کاملAn efficient and practical entry to 2-amido-dienes and 3-amido-trienes from allenamides through stereoselective 1,3-hydrogen shifts
Preparations of de novo acyclic 2-amido-dienes and 3-amido-trienes through 1,3-hydrogen shifts from allenamides are described. These 1,3-hydrogen shifts could be achieved thermally or they could be promoted by the use of Brønsted acids. Under either condition, these processes are highly regioselective in favour of the α-position, and highly stereoselective in favour of the E-configuration. In a...
متن کاملThe stereoselective formation of highly substituted CF3-dihydropyrans as versatile building blocks.
The highly enantioselective dienamine-mediated formation of 5-bromo-6-(trifluoromethyl)-3,4-dihydro-2H-pyrans from α,β-unsaturated aldehydes and α-bromo-(trifluoromethyl)-enones employing a C2-symmetric aminocatalyst is described. The products are demonstrated to be applicable in coupling reactions directly onto the ring, thereby granting access to a broad scope of highly substituted 6-(trifluo...
متن کاملA Highly Diastereoselective and Enantioselective Phase-Transfer Catalyzed Epoxidation of β-Trifluoromethyl-β,β-disubstituted Enones with H2O2
Trifluoromethylated organic compounds, especially chiral quaternary alcohols bearing trifluoromethyl group are of important intermediates in drugs, agrochemicals and etc.An efficient epoxidation of β-CF3-β,β-disubstituted unsaturated ketones (6) has been developed with environmental benign hydrogen peroxide as the oxidant and F5-substituted chiral qua...
متن کامل