Hydrogen bond formation between aliphatic alcohols and tertiary amines

Hydrogen bond formation between tertiary amines and long chain and branched chain alcohols has been studied in order to understand the influence of chain length and the steric effect on the complex formation between tertiary amines and alcohols. On the addition of the amine to the alcohol the intensity of the monomeric OH band decreases and the new band appears corresponding to the alcohol—amine complex. The equilibrium constants of the complex formation are correlated by a two parameter equation. The three correlation equations obtained for three tertiary amines are: log K = 3.41 + 10.01σ* + 0.02χ (for triethylamine-alcohol) log K = 0.97 + 2.54σ* + 0.21χ (for tributylamine-alcohol) log K = 1.01 + 1.81σ* + 0.26χ (for trioctylamine-alcohol), where σ* is Taft's polar constant and χ the molecular connectivity index of the R skeleton of the alcohol.     

A facile one-pot process for the formation of hindered tertiary amines

A simple and convenient method was developed for the preparation of hindered tertiary amines via direct reductive amination of ketones with secondary aryl amines, using trichlorosilane as reducing agent and tetramethylethylenediamine (TMEDA) as organic Lewis base activator. A broad range of ketones were reacted with N-methylaniline to afford the corresponding tertiary amine products in high yield. An open transition model was proposed for the reductive step.     

Isolation by high-performance liquid chromatography and quantitation by radioimmunoassay of therapeutic concentrations of digoxin and metabolites

A method combining high-performance liquid chromatography for separation of digoxin from three of its metabolites with subsequent quantitation of each compound by radioimmunoassay is described. The metabolites are shown to interfere with the radioimmunoassay procedure thus providing the need for separation prior to assay.     

Ruthenium catalyzed synthesis of secondary or tertiary amines from amines and alcohols

Unsymmetrical secondary and tertiary amines are prepared by the ruthenium catalyzed reaction of alcohols with amines, which provides highly efficient method for synthesis of cyclic amines.     

A one-pot synthesis of tertiary amines from amines,lactams and urethanes

A one-pot synthesis of unsymmetrical tertiary amines from amides, lactams and urethanes has been developed. The reaction is general for all cases examined with the exception of N-aryl containing examples, which are not accessible by this method.     

An efficient conversion of nitroaromatics and aromatic amines to tertiary amines in one-pot way

Reductive alkylation and reductive methylation of aromatic primary amines with carbonyls and 37% formaldehyde using decaborane in one-pot way gave the corresponding tertiary amines in high yields. The reaction condition was extended for the reduction of nitroaromatic using decaborane and Pd/C followed by the reductive alkylation and reductive methylation using decaborane to give the corresponding tertiary amines in high yields.     

Low-temperature polyesterification in the presence of tertiary amines

Several variations of catalysis (nucleophilic and general basic) responsible for the lowtemperature polyesterification in solution have been investigated. The type of catalysis which predominates depends on the chemical structure of the initial reagents and the reaction conditions. Increasing basicity of the tertiary amine and increasing acidity of the bisphenol promote the general base catalysis.     

Regio- and stereospecific synthesis of allylic tertiary amines

E and Z allylic amines have been synthesised by stereo-specific elimination of Ph₂PO₂^? from pure diastereoisomers (3) and (4).     

Thermal analysis of calix[4]resorcinarene complexes with secondary and tertiary amines

Tetra-n-undecylcalix[4]resorcinarene forms solid adducts with secondary and tertiary amines. Thermal decomposition of these complexes was investigated by means of thermogravimetry (TG) and differential scanning calorimetry (DSC). It was found that deamination of complexes occurs as multi-step process. The stoichiometry of complexes was evaluated on the basis of TG studies and total heats of deamination were calculated from DSC measurements.Presented at the CCTA9 31.08-05.09 2003, Zakopane PolandThis work was supported by Grant No. 3T09A 02419 from The Polish Committee for Scientific Research. The authors thank to prof. W. Zielenkiewicz for helpful discussion during realisation of this project and prof. T. Borowiak for X-ray structure of the tetra-n-undecylcalix[4]resorcinarene. tetra-n-undecylcalix[4]resorcinarene.     

Selective N-alkylation of amines using nitriles under hydrogenation conditions: facile synthesis of secondary and tertiary amines

Nitriles were found to be highly effective alkylating reagents for the selective N-alkylation of amines under catalytic hydrogenation conditions. For the aromatic primary amines, the corresponding secondary amines were selectively obtained under Pd/C-catalyzed hydrogenation conditions. Although the use of electron poor aromatic amines or bulky nitriles showed a lower reactivity toward the reductive alkylation, the addition of NH(4)OAc enhanced the reactivity to give secondary aromatic amines in good to excellent yields. Under the same reaction conditions, aromatic nitro compounds instead of the aromatic primary amines could be directly transformed into secondary amines via a domino reaction involving the one-pot hydrogenation of the nitro group and the reductive alkylation of the amines. While aliphatic amines were effectively converted to the corresponding tertiary amines under Pd/C-catalyzed conditions, Rh/C was a highly effective catalyst for the N-monoalkylation of aliphatic primary amines without over-alkylation to the tertiary amines. Furthermore, the combination of the Rh/C-catalyzed N-monoalkylation of the aliphatic primary amines and additional Pd/C-catalyzed alkylation of the resulting secondary aliphatic amines could selectively prepare aliphatic tertiary amines possessing three different alkyl groups. According to the mechanistic studies, it seems reasonable to conclude that nitriles were reduced to aldimines before the nucleophilic attack of the amine during the first step of the reaction.     

Isolation, separation and analysis in neurochemistry: trace amines and acids as an illustrative example

In this brief overview various neurochemical isolation procedures that can be adopted for the analysis of several monoamine neurotransmitters/neuromodulators and their principal oxidatively deaminated metabolites are outlined. With respect to the trace amines, they can be identified and quantitated as their so-called dansyl derivatives after thin-layer chromatographic separation by mass spectrometric (MS) electron-impact (EI) ionisation followed by selected-ion monitoring (SIM) of their molecular ions. Deuterated homologues are added as internal standards at the start of the analytical procedure. The MS-EI-SIM procedure offers a tissue extract or releasate sensitivity of about 100 pg/g of tissue or fluid. In the case of tryptamine or phenylethylamine, by utilising different derivatives (N-acetylpentafluoropropionyl or N-acetylpentafluorobenzoyl), which cyclise to form perfluorinated spirocyclic compounds, it is possible using MS negative chemical ionisation techniques coupled with monitoring of the (M-HF) ions to achieve sensitivities for tissue extracts of 1 pg/g or less. Acidic and neutral metabolites (up to twelve of them can be assayed simultaneously) can be detected and quantitated in tissue extracts, releasates or biological fluids as their methylpentafluoropropionyl or trifluoroethyl-pentafluoropropionyl derivatives in the 100-1000 pg range using gas chromatographic-MS-SIM procedures.     

Spectrofluorimetric flow-injection determination of tertiary amines in non-aqueous media

The cyclic condensation of malonic acid with acetic anhydride in non-aqueous media is catalyzed selectively by tertiary amines. This derivatization reaction is adapted for flow injection analysis. A reaction pathway for the cyclization of a mixed anhydride condensate to form a fluorescent fully acylated phloroglucinol carboxylic acid is proposed. The effects of reaction parameters on the sensitivity of the reactionare described and calibration data are presented for ?2.7 mM triethylamine, tripentylamine, N,N-diethylaniline and pyridine. A secondary amine (diethylamine) gave a negligible response, but both primary and secondary amines partially quenched the fluorescence induced by a tertiary amine.     

High-performance liquid chromatographic detection and quantitation of amines in must and wine

Three fluorigenic reagents were tried in order to increase the sensitivity of the detection of various amines. The derivatives formed were then used to develop a reversed-phase high-performance liquid chromatographic (HPLC) procedure for the separation of at least five amines. Dns-C1 and fluorescamine were rejected. The chromatogram of Dns-amines from red wine was overcrowded with unidentifiable peaks. It was then postulated that ammonia or phenol derivatives or other by-products of the Dns derivatization reaction interfered with the separation of amines. Fluorescamine, although it produced highly fluorescent derivatives, had the drawback of reacting with di- and polyamines to give more than one derivative and this interfered with the resolution. o-Phthaldialdehyde (OPT) was used successfully for the derivatization of amines in red must and wine. The method involved the reaction of amines with OPT in the presence of mercaptoethanol followed by extraction of the derivatives with ethyl acetate. A reversed-phase HPLC system was developed for the separation of OPT derivatives of agmatine, cadaverine, ethanolamine, histamine, phenylethylamine, putrescine, tryptamine, tyramine, spermine and spermidine within 40 min.     

Concentration effects in the nucleophilic reactions of tertiary amines in aqueous solutions: Alkylation of amines with chloroacetic acid

In alkylations of tertiary amines with chloroacetic acid in aqueous solutions, an increase in the initial concentrations of reagents to a certain level led to an abrupt increase in the initial rates and conversions attained during the control time. Viscosimetric and refractometric data showed that association with reagents occurred in these systems. The structures of associates that determine the character of the concentration effects of the Menschutkin reaction in water were suggested.     

Coordination of secondary and tertiary amines to zinc tetraphenylporphyrin

Stability constants of 46 complexes of zinc(II) tetraphenylporphyrin with primary, secondary, and tertiary amines and thermodynamic parameters of their formation (ΔG ⁰, ΔH ⁰, ΔS ⁰) in chloroform at 283–308 K have been analyzed. Probable factors responsible for enhanced stability of the complexes with ligands containing n-octyl groups are discussed. The X-ray diffraction data for the 1: 1 complex of zinc(II) tetraphenylporphyrin with di-n-octylamine are given.