Search results for "Nitrone"
showing 10 items of 31 documents
Oxidation of N,N-Benzylalkylamines to Nitrones by Mo(VI) and W(VI) Polyperoxo Complexes
1996
Abstract Oxidation of N,N-benzylalkylamines in chloroform by Mo(VI) and W(VI) polyperoxo complexes (PPC) of general formula Q+3{PO4[MO(O2)2]4}3− (Q+ = onium ion) yield the corresponding nitrones as oxidized products quantitatively. Only in the case of N,N-benzylmethylamine the formation of nitrone is accompanied by 25% of benzaldoxime. Oxidation of N,N-benzyltertbutylamine and N,N-benzylisopropylamine follows second order kinetics. This finding does not disqualify the hypothesis that the reaction might occur by a rate determining nucleophilic attack of the amine onto the peroxide oxygens leading, through a Bartlett-type transition state, to the probable formation of the corresponding hydrox…
The role of the trifluoromethyl group in reactivity and selectivity in polar cycloaddition reactions. A DFT study
2012
Abstract The role of the trifluoromethyl group in reactivity, regio-, and stereoselectivity in cycloaddition reactions has been analyzed by studying the 1,3-dipolar cycloaddition (13DC) reactions of nitrone 4 with 3,3,3-trifluoro-1-nitropropene 7b and 3,3,3-trifluoro-2-nitropropene 14 using density functional theory (DFT) methods at the B3LYP/6-311G(d) level. The recent M06-2X functional has also been evaluated but, although the thermodynamic performance is improved, the kinetic data are not necessarily better than those obtained by the popular B3LYP functional for cycloaddition reactions. Four reactive channels associated with the meta and ortho regio- and endo and exo stereoselective appr…
Heterocyclic rearrangements. Synthesis of 1,2,4-oxadiazolo[2,3-a]pyrimidinium systems and their ring opening into pyrimidineN-oxides
1986
Reaction des methyl- et phenyl-5 amino-3 oxadiazoles-1,2,4 avec l'acetylacetone ou la benzoylacetone en presence d'acide perchlorique: obtention de methyl- et phenyl-2 methyl- et phenyl-5 methyl-7 oxadiazolo [2,3-a] pyrimidiniums-4 qui se decyclisent ensuite en oxydes-1 d'acylamino-2- et amino-2 methyl-4 methyl- et phenyl-6 pyrimidines
Synthesis, molecular structure, spectroscopic properties and stability of (Z)-N-methyl-C-2,4,6-trimethylphenylnitrone.
2015
Abstract New N-methyl-C-2,4,6-trimethylphenylnitrone 1 has been synthesized starting from N-methylhydroxylamine and mesitaldehyde. The product was fully characterized using different spectroscopic techniques; FTIR, NMR, UV–Vis, high resolution mass spectrometry and X-ray diffraction. The relative stability and percent of population of its two possible isomers (E and Z) were calculated using the B3LYP/6-311++G(d,p) method in gas phase and in solution. In agreement with the X-ray results, it was found that Z-isomer is the most stable one in both gas phase and solution. The molecular geometry, vibrational frequencies, gauge-including atomic orbital (GIAO), and chemical shift values were also c…
Organocatalytic enantioselective synthesis of trifluoromethyl-containing tetralin derivatives by sequential (hetero)Michael reaction–intramolecular n…
2017
The enantioselective synthesis of tetralin derivatives bearing a trifluoromethylated all‐carbon quaternary stereocenter has been accomplished through a synthetic sequence comprising an organocatalytic β‐functionalization of ortho‐1‐trifluoromethylvinyl‐(hetero)aromatic conjugated aldehydes followed by the intramolecular nitrone 1,3‐cycloaddition reaction (INCR). Both nitromethane and N‐Cbz‐hydroxylamine were employed as nucleophiles in the initial organocatalytic conjugate addition step, which provided the chiral information required for the subsequent diastereoselective INCR. Although diastereoselectivity was moderate, good yields and enantioselectivities were, in general, obtained. Intere…
Crystal structure of C-2-benzo-thia-zole-N-methyl-nitrone.
2015
The molecule of the title compound {systematic name:N-[(benzothiazol-2-yl)methylidene]methylamineN-oxide}, C9H8N2OS, is close to planar [maximum deviation from the mean plane = 0.081 (2) Å], its conformation being stabilized by a strong intramolecular attractive S...O interaction [2.6977 (16) Å]. In the crystal, molecules are linked into centrosymmetric dimers by pairs of weak C—H...O hydrogen bonds.
Crystal structure oftrans-dichloridobis[N-(5,5-dimethyl-4,5-dihydro-3H-pyrrol-2-yl-κN)acetamide]palladium(II) dihydrate
2017
The title complex, [PdCl2(C8H14N2O)2]·2H2O, was obtained by N–O bond cleavage of the oxadiazoline rings of thetrans-[dichlorido-bis(2,5,5-trimethyl-5,6,7,7a-tetrahydropyrrolo[1,2-b][1,2,4]oxadiazole-N1)]palladium(II) complex. The palladium(II) atom exhibits an almost square-planar coordination provided by twotrans-arranged chloride anions and a nitrogen atom from each of the two neutral organic ligands. In the crystal, N—H...O, O—H...O and O—H...Cl hydrogen bonds link complex molecules into double layers parallel to thebcplane.
Crystal structure of (2R*,3aR*)-2-phenylsulfonyl-2,3,3a,4,5,6-hexahydropyrrolo[1,2-b]isoxazole
2017
The title compound, C12H15NO3S, was prepared by 1,3-dipolar cycloaddition of 3,4-dihydro-2H-pyrrole 1-oxide and phenyl vinyl sulfone. In the molecule, both fused five-membered rings display a twisted conformation. In the crystal, C—H...O hydrogen bonds link neighbouring molecules, forming chains running parallel to thebaxis.
Crystal structure of trans-dichloridobis[N-(5,5-dimethyl-4,5-dihydro-3H-pyrrol-2-yl-κN)acetamide]palladium(II) dihydrate
2017
The title complex, [PdCl2(C8H14N2O)2]2H2O, was obtained by N–O bond cleavage of the oxadiazoline rings of the trans-[dichlorido-bis(2,5,5-trimethyl- 5,6,7,7a-tetrahydropyrrolo[1,2-b][1,2,4]oxadiazole-N1 )]palladium(II) complex. The palladium(II) atom exhibits an almost square-planar coordination provided by two trans-arranged chloride anions and a nitrogen atom from each of the two neutral organic ligands. In the crystal, N—HO, O—HO and O—HCl hydrogen bonds link complex molecules into double layers parallel to the bc plane. peerReviewed
Crystal structure of
2017
The synthesis and crystal structure of the complex trans-[dichlorido-bis(N-(4,5-dihydro-5,5-dimethyl-3H-pyrrol-2-yl)acetamide)]palladium(II) dihydrate is described.