103632-91-3Relevant articles and documents
Dehydrogenation of perfluoroalkyl ketones by using a recyclable oxoammonium salt
Hamlin, Trevor A.,Kelly, Christopher B.,Leadbeater, Nicholas E.
supporting information, p. 3658 - 3661 (2013/07/19)
A novel dehydrogenation reaction of perfluoroalkyl ketones by the oxoammonium salt 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (4-NHAc-TEMPO+BF4-, Bobbitt's salt, 1) is described. The reaction proceeds under mildly basic conditions and appears to be unique to perfluoroalkyl ketones. A proposed mechanism for this unusual transformation is given. The byproduct of the reaction, 4-acetylamino-2,2,6,6-tetramethyl-1-piperidinyloxy (1a), can easily be recovered and used to regenerate the oxoammonium salt. The dehydrogenation of perfluoroalkyl ketones by using an oxoammonium salt is reported. The reaction proceeds under mildly basic conditions and affords α,β-unsaturated products in fair to excellent yields. The reaction likely proceeds through a two-step sequence. The spent oxidant can easily be recovered and used to regenerate the oxoammonium salt. Copyright
Ligand-induced selectivity in the rhodium(II)-catalyzed reactions of α-diazo carbonyl compounds
Padwa, Albert,Austin, David J.,Hornbuckle, Susan F.
, p. 63 - 72 (2007/10/03)
3-Allyl-2,5-diazopentanedione and 3-butenyl-2,5-diazopentanedione were allowed to react with a trace amount of a rhodium(II) catalyst in methylene chloride at room temperature. The major products isolated correspond to the internal trapping of a carbonyl ylide as well as intramolecular cyclopropanation. Changing the catalyst from Rh2(OAc)4 to Rh2(cap)4 to Rh2(tfa)4 caused a significant alteration in product distribution. A rather unusual and unexpected regiochemical crossover in the cycloaddition occurred when Rh2(tfa)4 was used and is most likely due to complexation of the metal with the dipole. A computational approach to rationalize the observed product distribution was carried out. The thermodynamic stabilities of cycloaddition transition states were approximated from the computationally derived strain energies of ground state molecules using traditional force-field techniques. Globally minimized ground state energies were obtained for all possible cycloaddition products, and final strain energies were calculated. In all cases studied, the lower energy isomer corresponded to the cycloadduct actually isolated. A study of the regiochemical aspects of the Rh(II)-catalyzed reaction of 1-diazo-3-(2-oxo-2-phenylethyl)hexane-2,5-dione was also carried out. Cyclization of the initially formed rhodium carbenoid occurred exclusively across the acetyl rather than the benzoyl group. The structure of the internal cycloadduct was assigned on the basis of a proton-detected multiple-bond heteronuclear multiple-quantum coherence experiment.
Dipeptides as renin inhibitors
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, (2008/06/13)
Dipeptides are described which are represented by the formula STR1 wherein the various substituents are defined hereinbelow. These compounds have a strong inhibitory efect on human renin, and are useful as a therapeutically active agent for the treatment of hypertension, especially renin-associated hypertension.
