Advances in the field of the synthesis of amino derivatives of terpenoids
Information on the synthesis of amino derivatives of monoterpenes by the reduction of oximes by the Leuckart reaction, and by the reductive amination of ketones by amines and nitriles is generalized. The stereochemistry of the amines formed as the result of the above-mentioned reactions is discussed.
Heterogeneous Catalysis as an Efficient Tool for Selective Hydrogenation of Oximes to Amines and Hydroxylamines
The synthesis of many biologically active compounds is not complete without transforming the carbonyl group into an amino group, carried out by the reaction of nucleophilic substitution with hydroxylamine at the carbonyl carbon atom and further reduction of the C–N and N–O bonds. This method eliminates nitrating agents that exhibit oxidizing properties and may cause undesirable effects on other structural fragments of complex molecules. Selective hydrogenation of oximes over heterogeneous catalysts is still one of the most useful and challenging reactions in synthetic organic chemistry to obtain amines and hydroxylamines since the 1920s when the Adam’s catalyst was first used for this reaction. In this review, we focused on the application of heterogeneous catalysts for the hydrogenation of oximes in relation to the methods applied for pharmaceutical synthesis.
Conformational analysis by nuclear magnetic resonance—VII : The conformational free energy of the nitro group
Abstract The conformational equilibria of nitrocyclohexane and cis -4-methylnitrocyclohexane have been investigated by NMR. The equilibrium constants for both compounds have been calculated from the band widths and time averaged coupling constants of the α-proton at room temperature, whilst low temperature studies have been carried out on cis -4-methylnitrocyclohexane. From these measurements, the conformational free energy ΔG value) of the nitro group has been found to be 1·3 kcal/mole.