49707-52-0Relevant academic research and scientific papers
Manganese-Catalyzed Selective Hydrogenative Cross-Coupling of Nitriles and Amines to Form Secondary Imines
Li, Xiao-Gen,Zhou, Qi-Lin
supporting information, p. 3471 - 3475 (2021/04/29)
Manganese complexes with tridentate PNN ligands have been synthesized as catalysts for hydrogenative cross-coupling reaction of nitriles and amines to form secondary imines. This reaction afforded a variety of unsymmetrical secondary imines in good yields with excellent selectivity. Investigation of catalyst intermediates indicated that an amido manganese complex may be the active catalyst species for this reaction. (Figure presented.).
Vanadium-and chromium-catalyzed dehydrogenative synthesis of imines from alcohols and amines
Madsen, Robert,Miao, Yulong,Samuelsen, Simone V.
supporting information, p. 1328 - 1335 (2021/05/29)
Vanadium(IV) tetraphenylporphyrin dichloride and chromium(III) tetraphenylporphyrin chloride have been developed as catalysts for the acceptorless dehydrogenation of alcohols. The catalysts have been applied to the direct synthesis of imines in overall good yields from a variety of alcohols and amines. The transformations are proposed to proceed by metal?ligand bifunctional pathways with an outer-sphere transfer of two hydrogen atoms from the alcohol to the metal porphyrin complexes. The results show that vanadium and chromium catalysts can also be employed for the dehydrogenation of alcohols with the release of hydrogen gas, and they may represent valuable alternatives to other catalysts based on Earth-abundant metals.
Dehydrogenative synthesis of imines from alcohols and amines catalyzed by a ruthenium N-heterocyclic carbene complex
Maggi, Agnese,Madsen, Robert
experimental part, p. 451 - 455 (2012/04/23)
A new method for the direct synthesis of imines from alcohols and amines is described where hydrogen gas is liberated. The reaction is catalyzed by the ruthenium N-heterocyclic carbene complex [RuCl2(IiPr)(p-cymene)] in the presence of the ligand DABCO and molecular sieves. The imination can be applied to a variety of primary alcohols and amines and can be combined with a subsequent addition reaction. A deuterium labeling experiment indicates that the catalytically active species is a ruthenium dihydride. The reaction is believed to proceed by initial dehydrogenation of the alcohol to the aldehyde, which stays coordinated to ruthenium. Nucleophilic attack of the amine affords the hemiaminal, which is released from ruthenium and converted into the imine.
Spin trapping chemistry of iminyl free radicals
Janzen, Edward G.,Nutter, Dale E.
, p. 131 - 140 (2007/10/03)
The iminyl radicals formed from hydrogen atom abstraction between tert-butoxyl radicals and benzylidene-N-alkyl-or N-arylamines were trapped by 2-methyl-2-nitrosopropane and investigated by EPR spectroscopy. The compounds investigated were benzylidene N-methyl, ethyl, 1-propyl, 1-butyl, 2-methylpropyl, 1-methylethyl, 1-methylpropyl, 1-ethylpropyl, 1-methylbutyl and cyclohexyl derivative and also benzylidene N-phenyl, 4-tolyl, 4-fluorophenyl, 4-methoxyphenyl, 4-chlorophenyl, 4-nitrophenyl and 4-trifluoromethylphenyl derivatives. In every case the iminyl nitroxide (aminoxyl) was produced in benzene at room temperature. The nitrogen hyperfine splitting constants were in the ranges 3.39-3.56 and 9.68-9.77 G for the iminyl and nitroxyl nitrogens, respectively, for the benzylidene-N-alkylamines and 3.60-3.77 and 8.45-9.15 G for the iminyl and nitroxyl nitrogens, respectively, for the benzylidene-N-arylamines. Very little evidence was found for hydrogen atom abstraction from the alkyl groups attached to the imine function. The absolute rate constant for hydrogen atom abstraction of the iminyl hydrogen was estimated to be 1.2 × 104 M-1 s-1 based on competitive experiments with addition of tert-butoxyl radicals to 2-methyl-2-nitrosopropane (1.5 × 106 M-1 s-1). This value is considerably slower than that for benzaldehyde (2.4 × 107 M-1 s-1).
