Structure Of Amino Alcohols Research Articles

The properties of novel hydroxyl contained polyurethaneurea prepared from CO2 derived chain extenders

A series of novel amino-alcohol compounds were synthesized from ethylenediamine and cyclic carbonates derived from different glycidyl ethers and CO2. The amino-alcohols were applied as chain extender for the preparation of polyurethaneurea (PUU) containing hydroxyl groups. The influence of the amino-alcohols on the structure and property of PUU were studied by mechanical testing, Fourier transform infrared spectroscopy (FT-IR), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetry (TG) et. al. The tensile strength of hydroxyl contained polyurethaneurea CDMEDA-PUU could reach 28.27 MPa, about 260% higher than the hydroxyl shielded one. The results proved that the introduced hydroxyl groups greatly enhanced the hydrogen bonding within PUU and the structure of amino-alcohol had certain impact on PUU performance. The cyclic tensile test results further disclosed the existence of strong hydrogen bonding among the hard segments and the long-range connectivity of the permeable hard domains.

One-Pot Synthesis of α-Haloketones Employing a Membrane-Based Semibatch Diazomethane Generator

The crucial structural motive in viral protease inhibitors such as atazanavir and darunavir is a chiral aminoalcohol structure. The structure is generally introduced during the synthesis of the protease inhibitor via an α-chloroketone intermediate. The α-chloroketone can be synthesized in a multistep sequence from naturally occurring l-phenylalanine. Herein, we report a onepot synthesis of an α-chloroketone starting from N-Boc-l-phenylalanine in a novel type of “tube-in-flask” semi-batch diazomethane generator. Activation of the amino acid to the mixed anhydride was carried out in the flask, while diazomethane was generated from in situ formed N-nitroso-N-methylurea within a gas-permeable tubing contained inside the flask. The diazomethane diffused through the gas-selective membrane into the flask, and reacted with the anhydride to the diazoketone (Arndt—Eistert reaction). The addition of aqueous hydrogen chloride provided the α-chloroketone and destroyed any excess of diazomethane. The desired product wa...

Enantioseparations of 11 Amino Alcohols Using Di-n-amyl l-Tartrate–Boric Acid Complex as Chiral Mobile Phase Additive by RP-HPLC

An effective method for the enantioseparations of 11 amino alcohols was developed by reversed-phase high-performance liquid chromatography (RP-HPLC) using a self-prepared di-n-amyl l-tartrate–boric acid complex as the chiral mobile phase additive. Mass spectrometry (MS) directly confirmed that the negatively charged di-n-amyl l-tartrate–boric acid complex counter ion with a complex ratio of 2:1 was the real chiral selector in the RP-HPLC chiral separation system. In order to achieve good enantioseparations, the effects of di-n-amyl l-tartrate and boric acid concentrations, the type, concentration and pH of buffers, methanol content as well as analyte molecular structures were extensively investigated. Under the optimized conditions, baseline enantioseparations were achieved for 9 amino alcohols including cycloclenbuterol, clenbuterol, bambuterol, tulobuterol, terbutaline, metoprolol, esmolol, bisoprolol, and propranolol; partial enantioseparations were obtained for sotalol and atenolol. The effect of the molecular structure of amino alcohols on enantioseparation was discussed in terms of molecular interactions. The ion-pair interactions between the negatively charged chiral selector and the basic enantiomers were thought to be the key factor giving the complex chiral selector a superior chiral recognition capability.

ChemInform Abstract: A Synthesis of 5‐Hydroxysedamine Using Hydroformylation.

Abstract A synthesis of 5-hydroxysedamine, a Sedum alkaloid, has been completed using N,O-heterocycle chemistry to establish the aminoalcohol structure, hydroformylation to form the piperidine ring and diastereoselective dihydroxylation to introduce the 5-hydroxy group.

Nickel(II) and copper(II) complexes based on N-(2-carboxyethyl)alkanolamines: Influence of the amino alcohol structure on the coordination sphere of the metal center

New nickel(II) complexes based on N-(3-hydroxypropyl)-β-alanine, N-(bis(hydroxymethyl)methyl)-β-alanine, and N-(tris(hydroxymethyl)methyl)-β-alanine are synthesized, and their structures are studied by X-ray diffraction analysis. The coordination spheres of the nickel and copper metal centers in the condensed phase are compared for a series of N-substituted β-alaninate ligands with the regularly changed dentate mode. In the case of the copper(II) complexes, an increase in the size of the alkanolamine chelate ring or the number of hydroxymethyl groups provides the formation of achiral coordination structures, whereas the structures of the nickel(II) complexes are independent of the size of the alkanolamine chelate ring or the number of hydroxymethyl groups, thus providing the formation of the complexes as racemic modifications.

A synthesis of 5-hydroxysedamine using hydroformylation

A synthesis of 5-hydroxysedamine, a Sedum alkaloid, has been completed using N,O-heterocycle chemistry to establish the aminoalcohol structure, hydroformylation to form the piperidine ring and diastereoselective dihydroxylation to introduce the 5-hydroxy group.

Molecular structure of amino alcohols on aluminum surface

Quantum chemical calculations were applied on monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) as corrosion inhibitors for aluminum exterior using ab initio Møller–Plesset (MP2) and Density Function Theory (DFT-B3LYP) at 6-311++G(d,p) ground set. Quantum chemical parameters such as the maximum employed molecular orbital energy (EHOMO), the minimum unemployed molecular orbital energy (ELUMO), energy disparity (ΔE), dipole moment (μ), sum of the total negative charge (TNC), molecular volume (MV), electronegativity (χ), chemical potential (Pi), global hardness (η), softness (σ) and the fraction of electrons transferred (ΔN), were calculated. Further calculations were done to explore the effects of inhibitors and solvent. Furthermore, the inhibitors’ interactions with the metal exterior were studied by applying COMPASS method. R2 values showed good correlations between the corrosion inhibitors’ effectiveness and several quantum parameters.

The control of Novozym® 435 chemoselectivity and specificity by the solvents in acylation reactions of amino-alcohols

Acylation of amino-alcohols by Novozym ® 435 (immobilized Candida antarctica lipase B). • Rates of N -acylation were higher for the short chain amino-alcohol. • Rates of O -acylation were higher for the long chains amino-alcohols. • The formation of the product was strongly affected by the nature of the solvent. The current work describes the differential behaviour of Novozym ® 435 (immobilized Candida antarctica lipase B) in O -acylation and N -acylation catalysis of bifunctional amino-alcohols acyl acceptors. We performed acylation experiments on three amino-alcohols (alaninol, 4-amino-1-pentanol and 6-amino-1-hexanol) using myristic acid as an acyl donor. Two organic solvents ( tert -amyl alcohol and n -hexane) and one ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate: Bmim [PF 6 ]) were used to determine the effect of the solvent. The influence of the amino-alcohol carbon chain length between the alcohol and amino groups on chemoselectivity C ( k cat,app O -acylation / k cat,app N -acylation ) was highlighted. N -acylation is improved using alaninol, a short chain amino-alcohol (no mono- O -acylation in tert -amyl alcohol and C = 0.12 in n -hexane) whereas O -acylation is improved using 4-amino-1-pentanol and 6-amino-1-hexanol which are amino-alcohols with longer chain ( C = 10.5 in tert -amyl alcohol and C = 539 in n -hexane). On the other hand, the production of the acylated amino-alcohols after 96 h of reaction was shown to be strongly affected by the solvent nature and the amino-alcohol structure: starting from alaninol as an acyl acceptor, the yield of amide synthesis reaches up to 98% in tert -amyl alcohol using 0.7 equivalents of myristic acid while the yield of amido-ester synthesis reaches up to 88% in Bmim [PF 6 ] using 1.75 equivalents of myristic acid.

Synthesis of an Inherently Chiral Calix[4]arene Amino Acid and Its Derivatives: Their Application to Asymmetric Reactions as Organocatalysts

AbstractThe synthesis of an inherently chiral calix[4]arene amino acid as a chiral building block has been achieved in order for subsequent transformation to various types of inherently chiral calix[4]arenes. The optically pure, inherently chiral calix[4]arene amino acids were prepared by the separation of a diastereomeric mixture of calix[4]arene amino acid derivatives bearing a (R)‐BINOL moiety. The separated optically pure calix[4]arene amino acid derivatives with a (R)‐BINOL moiety were easily transformed to novel inherently chiral calix[4]arenes containing an amino alcohol structure or a quaternary ammonium moiety. These optically pure chiral calix[4]arenes were applied to asymmetric reactions as organocatalysts.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Synthesis, solubilities, and cyclic capacities of amino alcohols for CO2 capture from flue gas streams

Abstract Amines that have been widely used in post combustion CO 2 capture processes are monoethanolamine (MEA), diethanolamine (DEA) and N-methyldiethanolamine (MDEA). If used individually, these solvents have their limitations, and efforts to resolve these have produced formulated solvents consisting of blends of amines and some chemical additives. The advantages derivable from amine blends are also limited to commercially available individual amines. It is therefore desirable to synthesize new amines or amino alcohols that could incorporate the advantages of amine blends in the same molecule or provide new materials for blending in a formulated solvent. Recently, such amino alcohols have been synthesized based on an approach of rational molecular design and synthesis. This involved a systematic modification of the structure of amino alcohols by an appropriate placement of substituent functional groups, especially the hydroxyl function, relative to the position of the amino group. Some of the resulting amino alcohols were 4-(diethylamino)-2-butanol (Reg 1); 4-(piperidino)-2-butanol (Reg 2); 4- propylamino-2-butanol (Reg 3) and 4-(ethyl-methyl-amino)-2-butanol (Reg 4). The performance of these amino alcohols in aqueous solutions in terms of solubility of CO 2 and cyclic capacity were compared with those of aqueous MEA using tests conducted at temperatures of 40, 60 and 80 ∘ C at CO 2 partial pressures of 15 and 100 kPa. All the listed amino alcohols provided a much higher CO 2 absorption capacity than MEA with Reg 3 showing the highest absorption capacities at all the temperature considered. The cyclic capacity (derived as the difference between the solubilities at 40 and 80 ∘ C) of the listed solvents were also much higher than that for MEA with Reg 4 showing the highest cyclic capacity. These characteristics result in a much higher CO 2 absorption and a much less energy consumption for absorbent regeneration, such as in CO 2 stripping, compared to conventional amines.

Chiral separation of sympathomimetics and β‐blockers by ligand‐exchange CE using Cu(II) complexes of L‐tartaric acid and L‐threonine as chiral selectors

This paper deals with the use of Cu(II) complexes of L-tartaric acid or L-threonine as selectors for the chiral separation of drugs containing amino alcohol structure by ligand-exchange CE. Using Cu(II) ions as a complexing agent, a series of sympathomimetics and beta-blockers were resolved. It was found that the resolution strongly depends on selector concentration and pH. The optimum pH for complexation was 12.

Chiral separation based on ligand-exchange capillary electrophoresis using a copper(II)-L-ornithine ternary complex as selector.

A ligand-exchange capillary electrophoresis was explored, with L-ornithine as the ligand and copper(II) as the central ion. Its applicability was demonstrated with underivatized and dansyl amino acids, a dipeptide, and drugs with amino alcohol structure. The enantioselectivity was found to be strongly dependent on pH and copper(II)-L-Orn complex concentration. Due to the adsorption of the positively charged species onto the capillary inner walls, the chiral separation selectivity is very high while the efficiency is relatively low. Permanent 1,3-propanediamine-coated capillaries show an improved separation efficiency and theoretical plate numbers increasing from 10(4) to 10(5). Similar phenomena were observed when sodium dodecyl sulfate (SDS) micelles were added to the copper(II) complex solution. The poor separation efficiency of chiral compounds in uncoated capillaries may result from the low rate of the ligand-exchange reactions, and the high enantioselectivity may derive from the complexing process in the adsorbed phase.

Enantioseparation of amino acids and drugs by CEC, pressure supported CEC, and micro-hPLC using a teicoplanin aglycone stationary phase

Chiral separation of amino acids, drugs with amino alcohol structure, and other drugs has been investigated by capillary electrochromatography (CEC), pressure supported CEC, and micro-HPLC on a teicoplanin aglycone stationary phase. The teicoplanin aglycone lacks the D-glucosamine and the D-mannose moieties and shows different separation behavior compared to a teicoplanin stationary phase. The selector is bonded to 3.5-μm silica gel and separations are carried out either in the reversed phase or the polar organic mode. This chiral stationary phase (CSP) shows high enantioselectivity especially for amino acids, e. g. for DOPA a Rs value of 10.5 was achieved. Although the chiral recognition ability for drugs is lower than that of intact teicoplanin, out of 22 β-blockers investigated, 16 are baseline separated by CEC.

Highly Enantioselective Diethylzinc Addition to Imines Employing Readily Available N‐Monosubstituted Amino Alcohols.

An easily accessible chiral ligand 3c, which promoted diethylzinc addition to imines with 96−98% ee, has been found by finely screening N,N-disubstituted and N-monosubstituted amino alcohols. N-Monosubstituted amino alcohols, on average, gave slightly higher enantioselectivities than their N,N-disubstituted analogues. These results imply that the restricted and rigid structure of amino alcohol is not the absolute requirement for the highly enantioselective dialkylzinc addition to diphenylphosphinoylimines.

Poly(amide ester)s from 2,6‐pyridinedicarboxylic acid and ethanolamine derivatives: identification of macrocycles by matrix‐assisted laser desorption/ionization mass spectrometry

The influence of the polycondensation pathway and aminoalcohol structure was investigated in the synthesis of poly(amide ester)s by polytransesterification from ethyl pyridine-2,6-dicarboxylate and 2-amino-2-methylpropan-1-ol or the corresponding bis(amide alcohol), or by polycondensation from the diacid dichloride. Both linear and cyclic structures were identified by steric exclusion chromatography (SEC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). Transesterification led to cyclic oligomers (macrocycles) with 2-14 pyridine moities in the ring whereas polycondensation from the diacid dichloride gave low molecular weight polymers (Mn = 1800) and macrocycles.

Highly enantioselective diethylzinc addition to imines employing readily available N-monosubstituted amino alcohols.

An easily accessible chiral ligand 3c, which promoted diethylzinc addition to imines with 96-98% ee, has been found by finely screening N,N-disubstituted and N-monosubstituted amino alcohols. N-monosubstituted amino alcohols, on average, gave slightly higher enantioselectivities than their N,N-disubstituted analogues. These results imply that the restricted and rigid structure of amino alcohol is not the absolute requirement for the highly enantioselective dialkylzinc addition to diphenylphosphinoylimines. [structure: see text]

Application of ligand-exchange capillary electrophorersis to the chiral separation of α-hydroxy acids and β-blockers

The application of the principle of ligand-exchange capillary electrophoresis to two substance classes is described. As chiral selector N-(2-hydroxyoctyl)- l-4-hydroxyproline–copper(II) complex was used. This principle was applied to the chiral separation of α-hydroxy acids and drugs containing amino alcohol structure such as β-blockers. The enantioselectivity was found to be strongly dependent on pH corresponding to the optimal conditions for complex formation for each structure class.

Chiral separation of sympathomimetics by ligand exchange capillary electrophoresis.

A rapid and simple approach to the chiral separation of sympathomimetic drugs with amino alcohol structure by ligand exchange capillary electrophoresis is described. An N-(2-hydroxyoctyl)-L-4-hydroxyproline/copper(II) complex is used as chiral selector. Thirteen sympathomimetics were resolved, nine with baseline resolution. The influence of pH and composition of the electrolyte on resolution was investigated. The optimal pH for complexation of these amino alcohols was found to be 12.

Gas phase FT-IR spectra and structure of aminoalcohols with intramolecular hydrogen bonds: I. The shape of the ν(OH) vibrational bands in R 2NC 3H 6OH (R=H, CH 3)

Gas phase FT-IR spectra of 3-dimethylamino-1-propanol ( 1) and 3-amino-1-propanol ( 2) are recorded. It is found that the forms with intramolecular hydrogen bonds strongly predominate up to 100°C in both compounds. The origin of multicomponent structure of ν(OH) bands is discussed on the assumption of conformational equilibria as well as the coupling between the ν(OH) vibration mode with the low frequency chelate ring deformation modes affecting the N⋯O distance. DFT ab initio calculations are performed at 6-31G(d,p) and 6-311++G(2d,2p) levels. It is concluded that the ν(OH) band structure in 1 results from high/low frequency modes coupling.

Vanadium(V) Complexes of Polydentate Amino Alcohols: Fine-Tuning Complex Properties

In aqueous solution, the stability, the structure, and the lability of 12 vanadium(V) complexes were determined and related to the amino alcohol ligand properties. The amino alcohols were chosen to maintain a five-coordinate vanadium geometry in the vanadium complex and were based on diethanolamine as the parent ligand. Apparent and composite stability constants were determined for all 12 complexes. Selected complexes were further examined to determine solution structure, lability, and thermodynamic properties. We empirically show that the formation constants for the series of 12 complexes, when plotted as a function of the pKa value for the protonated amino alcohol, generate a curve that initially increases as the pKa value increases and then decreases as the pKa value continues to increase. The observed associations suggest that the electron-donating capacity of the amino alcohol plays a major role in complex stability; however, metal coordination number, sterics in the amino alcohol, and solvation also are found to affect the stability. Determination of the thermodynamic parameters of selected complexes showed that the enthalpic component was the major contributor to the stability of the complex, but that the entropic component opposed this term. A series of studies was conducted to examine whether the lability of these complexes varied from the parent complexes. Unfortunately, the variation in the lability of these complexes was much less than the variation in complex stability. In summary, these studies describe quantitatively the variation in complex stability and lability as the structure of amino alcohol is modified and explain why some complexes show less stability than predicted on the basis of the pKa value. In short, this study provides valuable information for the design of additional vanadium complexes with specific properties.