Primary Amines In Water Research Articles

Fe-Catalyzed Synthesis of Sulfide-Based Aromatic Primary Amines in Water Promoted by Sodium-Ascorbate

Fe-Catalyzed Synthesis of Sulfide-Based Aromatic Primary Amines in Water Promoted by Sodium-Ascorbate

Use of Vitamin B12 as a Nontoxic and Natural Catalyst for the Synthesis of Benzoxazoles via Catechols and Primary Amines in Water under Aerobic Oxidation

Use of Vitamin B₁₂ as a Nontoxic and Natural Catalyst for the Synthesis of Benzoxazoles via Catechols and Primary Amines in Water under Aerobic Oxidation

Selective EPR Detection of Primary Amines in Water with a Calix[6]azacryptand-Based Copper(II) Funnel Complex.

A water-soluble calix[6]arene-based azacryptand was synthesized. The corresponding tren [tris(2-aminoethyl)amine] cap grafted at the small rim coordinates strongly a copper(II) ion over a wide range of pH. The host-guest properties of the complex were explored by EPR spectroscopy. Due to second coordination sphere effects and the hydrophobic effect ascribed to the calixarene cavity, this funnel complex selectively binds neutral molecules (alcohols, nitriles, amines) versus anions in water near physiological pH. Among the coordinating guests, hydrophobic primary amines are preferentially recognized thanks to the combined effect of the better metal-ligand interaction and hydrogen bonding to the oxygen atoms present at the small rim. Hence, this Cu(II) calix[6]arene-based funnel complex behaves as a sensitive and selective EPR probe for primary amines, including biologically important molecules such as tyramine and tryptamine, in water, over a large pH window.

Na2S2O8-mediated efficient synthesis of isothiocyanates from primary amines in water

Two procedures to synthesize isothiocyanates from primary amines are developed, with water as a solvent and sodium persulfate as an oxidant.

D-Glucose: An Efficient Reducing Agent for a Copper(II)-Mediated Arylation of Primary Amines in Water.

A copper-catalyzed Ullmann-type amination with primary amines in water with a combination of copper(II) triflate [Cu(OTf)2 ], dipivaloylmethane, and d-glucose is reported. The mild conditions and the use of an inexpensive catalyst as well as a renewable feedstock (d-glucose and the surfactant TPGS-750-M, which is derived from vitamin E) make this protocol a safe and convenient strategy for efficient C-N bond formation. This easy-to-handle procedure is extremely competitive compared to palladium-based reactions and may be used to synthesize N-containing molecules, such as drugs or organic light-emitting diodes (OLEDs).

Reaction of sugar oxazolines with primary amines

Sugar oxazolines, obtained by a dehydration reaction of 2-acetylamino pyranosides, reacted with primary amines in water to produce sugar imidazolines, which, when heated in water, were converted to sugar imidazoles by a dehydration reaction. The structures of these rather unexpected reaction products were determined by spectroscopic data. This offers a simple process to introduce a glycan onto peptides, proteins, and other biologically important compounds.

α,β-Unsaturated aldehyde of hyaluronan—Synthesis, analysis and applications

Hyaluronic acid (HA) modified with an aldehyde group (HA-CHO or HA-aldehyde) has been extensively used for various biomedical applications. The main advantage of the aldehyde moieties is the ability to react with a wide range of amino compounds under physiological conditions. Reactions of aldehydes with primary amines in water are reversible and equilibrium is thoroughly shifted towards starting aldehyde and amine. This work presents an unique modification of HA: α,β-unsaturated aldehyde of HA (4,5-anhydro-6(GlcNAc)-oxo HA or ΔHA-CHO), which allows the primary amines to be attached to HA more effectively in comparison to the saturated HA-CHO. Higher hydrolytic stability is caused by the conjugation of imine with an adjacent CC double bond. Two strategies for the preparation of unsaturated HA-aldehyde were developed and chemical structures were studied in details. Cross-linked materials prepared from this precursor are biocompatible and suitable for applications in drug delivery and regenerative medicine.

Efficient synthesis of functionalized hydroindoles via catalyst-free multicomponent reactions of ninhydrin in water

Abstract An efficient synthesis of hydroindeno[1,2-b]indoles is described via three-component reaction of ninhydrin and cycloalkan-1,3-dione in the presence of primary amines in water as the green solvent in excellent yield.

Synthesis and anti-bacterial activity of novel dihydrochromeno[8,7-e][1,3]oxazine-2(8H)-thiones

A novel series of sulfur-containing dihydrochromeno[8,7-e][1,3]oxazine-2(8H)-thiones has been synthesized through an eco-friendly Mannich-type condensation cyclization reaction of 7-hydroxy-4-methyl-2-thiocoumarin or 6-chloro-7-hydroxy-4-methyl-2-thiocoumarin with formaldehyde and primary amines in water at 80–90°C for 2 h. All the synthesized compounds were screened for their in vitro anti-bacterial efficacy against two Gram-positive and three Gram-negative bacterial strains by using the disc diffusion method. The compound (8c) was found to be most potent with the zone of inhibition of 16 and 15 mm against Staphylococcus aureus ATCC 2937 and Klebsiella pneumoniae ATCC 31488, respectively.

Recognition of primary amines in water by a zinc funnel complex based on calix[6]arene

A water-soluble calix[6]arene-based tris(imidazole) ligand behaves as a highly selective receptor for primary amines in the presence of Zn(II) in water near physiological pH. It represents the first compound of this family of ligands that binds a Zn dication and an organic guest in water, thus giving rise to a stable host–guest adduct in spite of the highly competitive medium. The herein described self-assembly process displays a remarkable set of biomimetic properties. The ternary system (calix/Zn/amine) is formed in a very synergistic and allosteric manner and stabilizes the neutral form of the amino guest with a spectacular pseudo-pKa shift of ca. 7 units. This system constitutes an interesting structural model of metalloenzymes in aqueous solution.

Ionic liquids as silica deactivating agents in gas chromatography for direct analysis of primary amines in water

Analysis of primary amines in aqueous samples remains a challenging analytical issue. The preferred approach by gas chromatography is hampered by interactions of free silanol groups with the highly reactive amine groups, resulting in inconsistent measurements. Here, we report a method for direct analysis of aliphatic amines and diamines in aqueous samples by gas chromatography (GC) with silanol deactivation using ionic liquids (ILs). ILs including trihexyl(tetradecyl)phosphonium bis 2,4,4-(trimethylpentyl)phosphinate (Cyphos IL-104), 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide [pmim][Tf(2)N] and N″-ethyl-N,N,N',N'-tetramethylguanidinium tris(pentafluoroethyl)trifluorophosphate [etmg][FAP] were tested as deactivating media for the GC liner. Solutions of these ILs in methanol were injected in the system prior to the analysis of primary amines. Butane-1,4-diamine (putrescine, BDA) was used as a reference amine. The best results were obtained using the imidazolium IL [pmim][Tf(2)N]. With this deactivator, excellent reproducibility of the analysis was achieved, and the detection limit of BDA was as low as 1mM. The applicability of the method was proven for the analysis of two different primary amines (C4-C5) and pentane-1,5-diamine.

An eco-friendly synthesis and antimicrobial activities of dihydro-2 H-benzo- and naphtho-1,3-oxazine derivatives

A series of 3,4-dihydro-2 H-benzo[e]-, 2,3-dihydro-1 H-naphtho[1,2-e]-, 3,4-dihydro-2 H-naphtho[2,1-e][1,3]oxazine and 1,2-bis(3,4-dihydrobenzo[e][1,3]oxazin-3(4 H)-yl)ethane derivatives was obtained through an eco-friendly Mannich type condensation–cyclization reaction of phenols or naphthols with formaldehyde and primary amines in water at ambient temperature. Preliminary in vitro antimicrobial activity of the synthesized compounds was assessed against six pathogenic fungi, two Gram-negative and two Gram-positive bacteria. Some of the screened compounds have shown significant in vitro antimicrobial effect. Cytotoxic activities of the lead compounds ( 2m, 2n, 3c and 3d) against mouse fibroblast cell line (L929) were determined by MTT method. The assay results revealed that these molecules offered remarkable viability (>90%) of L929 cells at concentration of 25 μg/mL.

Synthesis of Functionalized Pyrroles by Reaction of 3,4‐Diacetylhexane‐2,5‐dione with Primary Amines in Water.

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Synthesis of Functionalized Pyrroles by Reaction of 3,4‐Diacetylhexane‐2,5‐dione with Primary Amines in Water

3,4‐Diacetylhexane‐2,5‐dione (tetra‐acetylethane) undergoes a complex reaction with primary amines in boiling water to produce N‐alkyl‐3‐acetyl‐2,5‐dimethylpyrroles, together with small quantities of N‐alkyl‐3,4‐diacetyl‐2,5‐dimethylpyrroles and 2,5‐dimethyl‐1H‐pyrrol‐3‐yl‐vinyl‐acetamides. When the reaction was carried out in methanol at room temperature, the yields of the latter products increased.

Synthesis of trifluoroacetylketene O,N-acetals in water

The enamination of the trifluoroacetylketene O,O-acetal 1 with primary amines in water under mild conditions is described. Products 2 (trifluoroacetylketene O,N-acetals) were isolated after short reaction times (0.5-8 hours) in good yields (60-89%).

Rapid fluorimetric assay for primary amine groups in water samples.

Bond Elut C(18) solid-phase extraction cartridges were used for pre-concentration followed by derivatization with o-phthaldialdehyde-N-acetylcysteine (OPA-NAC) of primary amines in water. Optimal conditions were: conditioning the cartridges with borate buffer pH 10.4, retention of the primary amines, addition of the OPA-NAC(3.7 mmol L(-1)) 1:1 molar ratio and borate buffer pH 8, elution of the isoindol with MeOH-borate buffer (9:1) pH 10.2 and fluorescence measurement. The equations of the calibration graphs for methylamine, ethylamine, propylamine, butylamine, pentylamine, and beta-phenylethylamine at lambda(excitation)=330 nm and lambda(emission)=440 nm, in the optimal conditions are presented. The solid-phase extraction procedure improved ten times the detection limits of the solution derivatization. Those values are in the 0.01-0.06 mg L(-1) interval in function of the amine. Also, it is possible to estimate the total primary aliphatic amine concentration in water, expressed as molar concentration of -NH(2) group or -NH(2)-N mg L(-1). On the basis of these studies, the method was applied for the determination of primary amino groups in tap, ground, factory and source water samples.

Photosubstitution-photoreduction mechanistic duality in the SET photoreactions of nitrophenyl ethers with amines. The role of the steps that follow the ET

Nitrophenyl ethers are photoreduced by primary amines in water through a mechanism initiated by single electron transfer that is in direct competition with the single electron transfer photosubstitution mechanism (S NAr∗-SET). Our results indicate that the preferred pathway does not depend on the electron donor or proton donor ability of the amine. The key factor that determines the progress of the photoreaction is the structure of the carbon skeleton of the amine, particularly the type of hydrogens on the carbon α to the amino group. A mechanistic rationale that includes hydrogen atom transfer as a key step is discussed.

Micellphänomene bei desaminierungsreaktionen

Desamination reactions of primary amines in water in the presence of chloride and bromide ions yield ROH, RCl and RBr besides alkenes; the competition constants κ for the nucleophilic substitution reactions are strongly influenced by micelles.