695809-23-5Relevant academic research and scientific papers
Determination of the conformations and relative configurations of exocyclic amines
Montalvo-gonzlez, J. Ascencin,Iniestra-galindo, Maria Guadalupe,Ariza-castolo, Armando
, p. 938 - 944 (2011/07/30)
The conformations and relative configurations of 20 amines, classified according to the following labeling scheme, were analyzed. Series a comprised compounds derived from N-(1-phenylethyl)cyclohexanamine, b comprised derivatives of N-[1-(naphthalen-2-yl)ethyl]cyclohexanamine, c comprised derivatives of N-(diphenylmethyl)cyclohexanamine, and d comprised derivatives of N-(propan-2-yl)cyclohexanamine. The compounds were labeled as follows: 1 indicates cyclohexanamine, 2 indicates 2-methylcyclohexanamines, 3 indicates 3-methylcyclohexanamines, 4 indicates 4-methylcyclohexanamines, and 5 indicates 4-tert-butylcyclohexanamines. These compounds were prepared without the use of stereoselective induction and, therefore, all expected stereoisomers were observed. Structural assignments were established by 1H, 13C, and 15N NMR.
Differentiation of Diastereomeric 2-substituted Cyclohexanamines with Three Chirality Centres by 13C NMR Spectroscopy
Knupp, Gerd,Frahm, August W.
, p. 37 - 41 (2007/10/02)
The 13C NMR spectra of optically active primary and secondary 2-substituted cyclohexanamines were measured and the chemical shifts were unequivocally assigned.Similar studies were made with four diastereomeric 2-methyl-N-(1-phenylethyl)cyclohexanamines with three chirality centres.KEY WORDS: 13C NMR; optically active cyclohexanamines; diastereomeric 2-methyl-N-(1-phenylethyl)cyclohexanamines.
Asymmetric Reductive Amination of Cycloalkanones, 2. Synthesis and Absolute Configuration of 2-Substituted Cyclohexanamines
Knupp, Gerd,Frahm, August W.
, p. 2076 - 2098 (2007/10/02)
Asymmetric synthesis of 2-substituted cyclohexanamines from racemic cyclohexanones by means of reductive amination in a three-step procedure is described.Condensation of the ketones 5 with the optically active auxiliary amines 6 leads to the imines 7, which are hydrogenated to the secondary amines 8 with Raney nickel.Hydrogenolysis with palladium-on-charcoal yields the primary amines 9.With Raney nickel as catalyst the synthesis of the amines 8 and 9 runs with high chemical yield under complete diastereomeric and high grade enantiomeric control, respectively.Enantiomeric excess is determined via the diastereomeric acylamines 10 by means of HPLC.Stereochemical analysis including the absolute configuration of 8 and 9 is performed with 1H, 13C NMR spectroscopy, via the CD of the salicylidenes 11 and the X-ray spectrum of the amine 9c. - Reaction mechanism is investigated via the partially deuterated amine 13 to come up as a kinetically controlled asymmetric hydrogenation combined with a thermodynamically controlled transformation.
