Aliphatic Amine Derivatives Research Articles

A dual emitting CsPbBr3/Eu-BDC composite as a ratiometric photoluminescent turn-on probe for aliphatic amine sensing.

The impressive photoluminescence properties of all inorganic cesium lead halide perovskite quantum dots (PeQDs) make them highly intriguing for fluorescence chemosensor applications. Herein, a ratiometric dual emitting perovskite-based sensor was designed by synthesizing fluorescent CsPbBr3 PeQDs in situ within a matrix of Eu-BDC (Eu(III) benzene-1,4-dicarboxylate). The results presented here establish the suggested sensor's quick and selective turn-on PL response to volatile primary aliphatic amine derivatives. In the presence of amines, the designed CsPbBr3/Eu-BDC sensor exhibits an enhancement of the PL signal of CsPbBr3 at 518 nm and the Eu-BDC signal at 615 nm served as a standard for constructing the ratiometric sensing system. Thereby, a visual color change from red to green was observed with the incremental addition of methylamine to the probe. A low detection limit of 0.083 ppm was determined for methylamine. In both the solution and vapor phases, this ratiometric sensor responds to a variety of primary aliphatic amines with very quick and strong fluorescence. Moreover, the sensor was effectively used for monitoring meat spoilage owing to the emission of biogenic amine vapor from meat products.

Photoredox/nickel dual-catalyzed deaminative cross-electrophile for allenylic alkylation with non-activated alkyl katritzky salts

The first allenylic alkylation with non-activated aliphatic amine derivatives, Katritzky salts, has been developed via photoredox/nickel dual-catalyzed reductive deaminative cross-electrophile coupling.

N-tosylhydrazones as acceptors for nucleophilic alkyl radicals in photoredox catalysis: A short case study on possible side reactions

We report the attempted development of a photoredox-catalyzed α-C–H alkylation reaction of aliphatic amine derivatives, using N-tosylhydrazones as radical alkylating partners. The original intention was to intercept α-aminoalkyl radical intermediates with N-tosylhydrazones, followed by the expulsion of a sulfonyl radical by β-scission to generate N-H diazene species. Facile denitrogenation of these intermediates would remove all traces of the hydrazone moiety and provide a net C–H alkylation process. However, our plans were derailed by issues with the low reactivity of N-tosylhydrazones toward intermolecular capture by nucleophilic radicals, and several unexpected side reactions. Our findings, though unsuccessful, do serve to identify challenges for future researchers attempting to develop similar transformations.

Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications.

Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.

Imine-Based Catechols and o-Benzoquinones: Synthesis, Structure, and Features of Redox Behavior.

Novel sterically hindered catechols of the type 3-(RN=CH)-4,6-DBCatH2 with iminoalkyl or iminoaryl groups in the third position of the aromatic ring have been synthesized and characterized in detail. The o-benzoquinones 3-(RN=CH)-4,6-DBBQ have been synthesized by the oxidation of the corresponding catechols. The oxidation of methylimino-substituted catechol with K3[Fe(CN)6] in alkaline medium leads to the formation of two products: o-quinone and diene–dione, the product of the water addition to the corresponding o-quinone. Some o-benzoquinones react with water or methanol to yield products of water or methanol addition. A prototropic tautomerism is characteristic of catecholaldimines: a quinomethide form is observed in the case of aliphatic amine derivatives, while aryl-substituted catecholaldimines can exist both in the catechol and quinomethide forms in the crystalline state. The formation of dimeric structures motifs is observed in crystals. The electrochemical oxidation of imino-based catechols proceeds via two one-electron processes; the second wave is quasi-reversible, which is unusual for catechols.

Flexible, N-sulfonyl-substituted aliphatic amine ligands in palladium-catalyzed Suzuki–Miyaura C[sbnd]C coupling: Influence of substituents bulkiness and co-ligand size

Widespread use of commercially available palladium precatalysts is limited by high costs and their synthetic challenges. In this report, series of synthetically affordable, phosphine-free ligands were examined as supports for palladium active centers. 2-(2-Aminoethylamino)ethanol, diethylenetriamine and tris(2-aminoethyl)amine were condensed with sulfonyl chloride reagents in order to obtain flexible, aliphatic amine derivatives with varied steric bulk at the chain ends (ligands 1-Me and 1-tol = RSO2NHCH2CH2N(SO2R)CH2CH2Cl; ligands 2-ipr and 2-iprNH = RSO2NHCH2CH2NYCH2CH2OSO2R where Y is H or R; ligands 3-Me, 3-tol and 3-ipr = RSO2N(CH2CH2NHSO2R)2; 3-iprNH = HN(CH2CH2NHSO2R)2; ligands 4-tol and 4-ipr = N(CH2CH2NHSO2R)3; R = methyl, tolyl or triiso-propyl). Despite the flexibility of the alkyl fragments in these ligands, placement of sterically demanding groups at amine donors enables formation of active species, which supports high turnover frequencies and yields up to 91% within 5 min and at 0.2 mol % palladium loading. Such activity from synthetically simple alkyl ligand frameworks, which are generally not regarded in Pd catalysis, is unprecedented. In situ catalyst generation is favorable for ligands with less than tridentate chelation capacity and presence of poorly chelating secondary NH-amine donor in the central position of the polyamines hinders catalyst performance. However, the preformed tridentate complexes yielded more attractive and living coupling catalyst efficiencies than their corresponding in situ reactions especially when bulkier co-ligand such as pyridine occupies the fourth coordination position (TOF of 5460 h−1 for Pd(4-tol)py and 4800 h−1 for Pd(4-ipr)py). Therefore, mutual steric demands between the tridentate-chelated steric ligands such as 4-tol and 4-ipr, and bulky co-ligand fragments cooperatively aids the generation of active species from assembled precatalyst.

Heterogeneously catalyzed self-condensation of primary amines to secondary amines by supported copper catalysts

Self-condensation of primary amines to symmetrically substituted secondary amines could efficiently be promoted by an inexpensive supported copper catalyst, Cu/Al2O3, easily prepared by the reduction of the hydroxide precursor, Cu(OH)x/Al2O3. Various kinds of structurally diverse primary amines including benzylamine, picolylamine, and aliphatic amine derivatives could selectively be converted into the corresponding secondary amines in moderate to excellent yields without any cocatalysts such as bases and stabilizing ligands in 1 atm of Ar or H2. The reactions in H2 showed higher selectivities to desired secondary amines than those in Ar. The roles of H2 are the promotion of hydrogenation of N-alkylimines and the stabilization of active Cu(0) species. In addition, in the presence of Cu/Al2O3, unsymmetrically substituted secondary amines could efficiently be synthesized by N-alkylation of primary amines with alcohols and reductive amination of aldehydes. The observed catalysis was truly heterogeneous, and the retrieved Cu/Al2O3 catalyst could be reused for self-condensation without a significant loss of its catalytic performance. The reaction mechanism involving dehydrogenation of primary amines and condensation to N-alkylimines followed by hydrogenation, the so-called “borrowing hydrogen pathway”, has been proposed.

Integration of Pillar Array Columns into a Gradient Elution System for Pressure-Driven Liquid Chromatography

A gradient elution system for pressure-driven liquid chromatography (LC) on a chip was developed for carrying out faster and more efficient chemical analyses. Through computational fluid dynamics simulations and an experimental study, we found that the use of a cross-Tesla structure with a 3 mm mixing length was effective for mixing two liquids. A gradient elution system using a cross-Tesla mixer was fabricated on a 20 mm × 20 mm silicon chip with a separation channel of pillar array columns and a sample injection channel. A mixed solution of water and fluorescein in methanol was delivered to the separation channel 7 s after the gradient program had been started. Then, the fluorescence intensity increased gradually with the increasing ratio of fluorescein, which showed that the gradient elution worked well. Under the gradient elution condition, the retention times of two coumarin dyes decreased with the gradient time. When the gradient time was 30 s, the analysis could be completed in 30 s, which was only half the time required compared to that required for an isocratic elution. Fluorescent derivatives of aliphatic amines were successfully separated within 110 s. The results show that the proposed system is promising for the analyses of complex biological samples.

ChemInform Abstract: N-Lithiated Derivatives of Aliphatic Amines in the Synthesis of 1- Alkyl-2-phenyldiazene 2-Oxides.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Mass Spectrometric Identification of Aliphatic Amines Using 2-[2-(7H-dibenzo[a,g]-carbazol-7-yl)-ethoxy] Ethyl Chloroformate as Novel Fluorescence Labeling Reagent

On a reversed-phase Eclipse XDB C8 ( 150 mm x 4.6 mm, 5 mu m) column, 12 aliphatic amine derivatives were derivatized using 2-[2-(7H-dibenzo[a, g] carbazol-7-yl)-ethoxy] ethyl chloroformate (DBCEC-Cl) as a new pre-column derivatization reagent. The complete baseline resolution was obtained in conjunction with a gradient elution with acetonitrile/H(2)O as mobile phase. Detection was carried out by the fluorescence and online post-column atmospheric pressure chemical ionization(APCI) in positive-ion mode. The maximum excitation and emission wavelengths were at 300 nm and 400 nm, respectively. Identification of aliphatic amine derivatives was carried out by the online post-column Ion trap/mass spectrometry with positive-ion detection mode of APCI-MS. A rapid, accurate method for the determination of free aliphatic amine extracted from soil was proposed. The established method exhibited excellent reproducibility and recovery. Excellent linear responses were observed with the correlation coefficients > 0.9991. The detection limits( at signal-to-noise of 3:1) were 10.1-0.3 fmol.

Preactivated Carboxyl Linker for the Rapid Conjugation of Alkylamines to Oligonucleotides on Solid Support

A C10 linker phosphoramidite reagent terminated with a succinimidyl-activated carboxyl group was prepared and used to couple to the 5'-end of an oligonucleotide synthesized on a solid support. The succinimidyl-activated carboxyl functionality can be used for rapid conjugation of amines to oligonucleotides on solid support or it can be hydrolyzed to form a carboxylic acid functionality. The activated linker was successfully used for conjugation of several primary and secondary aliphatic amine derivatives (including biotin and fluorescein cadaverine) onto a solid support-bound 12-mer DNA oligonucleotide at scales ranging from 0.15 to 1.0 micromol. The overall yields of the conjugation products after AMA deprotection and cleavage from the solid support ranged from 43 to 75% of the total oligonucleotide product. This value is significant, as it includes oligonucleotide synthesis, coupling of the linker, and conjugation of the amine. In addition, the entire process of oligonucleotide synthesis, linker coupling, amine conjugation, deprotection, and cleavage of the oligonucleotide from solid support can be accomplished in 1 day.

Pre-column Derivatization-High Performance Liquid Chromatography for the Determination of Aliphatic Amines with Fluorescence Detection and Mass Spectrometry Identification

A simple and highly sensitive method based on the derivatization of aliphatic amines with 2-(2-phenyl-1 H-phenanthro-[9,10- d]imidazole-1-yl)-acetic acid (PPIA) followed by high-performance liquid chromatography (HPLC) with fluorescence detection and on-line post-column mass spectrometric identification has been developed. Optimum derivatization, giving the corresponding stable fluorescent derivatives, was obtained by the reaction of aliphatic amines with PPIA at 60 ° for 15 min in the presence of N-ethyl- N′-(3-dimethylamino propyl)carbodiimide hydrochloride (EDC) catalyst in acetonitrile solvent. The fluorescence detection wavelength of PPIA derivatives was 380 nm (260 nm of excitation wavelength). Separation of the derivatized amines with a good baseline resolution in conjunction with a gradient elution was carried out on a reversed phase Eclipse XDB-C 8 column (4.6 mm × 150 mm, 5 μm), in this way, the contents of aliphatic amines in waste water of paper mill, telencephalon tissue of rat and acidophilus milk were determined. The identification of aliphatic amine derivatives was carried out by post-column online mass spectrometry with atmospheric pressure chemical ionization (APCI) source in positive ion mode. In virtue of the MS and MS/MS information of intermediates of derivatization reaction, the derivatization reaction mechanism was confirmed. The established method exhibits excellent reproducibility and recovery. Excellent linear responses were observed with coefficients >0.9996, and detection limits (at signal-to-noise of 3:1) were 3.1–18.2 fmol.

Bifunctional chelates with mixed aromatic and aliphatic amine donors for labeling of biomolecules with the {Tc(CO) 3} + and {Re(CO) 3} + cores

A series of tridentate ligands consisting of mixed aromatic and aliphatic amine derivatives of single amino acid chelates and phenylpiperazine have been developed, and their reactions with [NEt 4] 2[ReBr 3(CO) 3] have been investigated. The compounds [Re(CO) 3{(NC 5H 4CH 2)NCH 3(C 2H 4)NHCH 3}]Br ( 4), [Re(CO) 3{(NC 5H 4CH 2)NCH 3(C 2H 4)NCH 3(CH 2) x COOC 2H 5}]Br ( x = 1, 5; x = 4, 6) [Re(CO) 3{(NC 5H 4CH 2)NH(C 2H 4)N(CH 3) 2}]Br ( 7), [Re(CO) 3{(NC 5H 4CH 2)N(CH 2COOC 2H 5)(C 2H 4)N(CH 3) 2}]Br ( 8) and [Re(CO) 3(NC 5H 4CH 2)(C 2H 4NH 2)N(CH 2) 3–CH 3Ophenpip]Br ( 9) (phenpip: phenylpiperazine, –C 6H 4–(CH 2CH 2) 2N–) were prepared and characterized by elemental analysis, NMR, IR, HSMS and X-ray crystallography. All complexes exhibit fac-{Re(CO) 3N 3} coordination geometry in the cationic molecular unit. Crystal data for C 13H 17BrN 3O 3Re ( 4): orthorhombic, Pbca, a = 13.4510(8) Å, b = 10.5728(6) Å, c = 22.5378(13) Å, V = 3205.2(3) Å 3, Z = 8; C 17H 23BrN 3O 5Re ( 5): orthorhombic, Pcca, a = 16.5907(7) Å, b = 14.8387(6) Å, c = 16.7075(7) Å, V = 4113.1(3) Å 3, Z = 8; C 13H 25BrN 3O 7Re ( 7 · 4H 2O): monoclinic, P2 1/ n, a = 14.0698(17) Å, b = 9.6760(12) Å, c = 15.6099 (19) Å, β = 114.930(2)°, V = 1927.1(4) Å 3, Z = 4; C 17H 23BrN 3O 5Re ( 8): monoclinic, P2 1/ n, a = 7.5312(5) Å, b = 16.0366(10) Å, c = 16.8741(10) Å, β = 98.9990(10)°, V = 2012.9(2) Å 3, Z = 4.

N-Lithium derivatives of aliphatic amines in the synthesis of 1-alkyl-2-phenyldiazene 2-oxides

Magnesium derivatives of aliphatic amines containing α-hydrogen atoms, in contrast to t-BuNHMgBr, do not form phenylaliphatic diazene oxides upon reaction with nitrobenzene, but rather reduce it to azobenzene and azoxybenzene. Asymmetric diazene oxides are formed when the magnesium derivatives are replaced by lithium derivatives. The reaction of t-BuNHLi with dimethylnitramine gives 1,3,5-trimethyl-1,3,5-triazacyclohexane.

Neoglycolipid analogs of ganglioside GM1 as functional receptors of cholera toxin

We synthesized several lipid analogues of ganglioside GM1 by attaching its oligosaccharide moiety (GM1OS) to aminophospholipids, aliphatic amines, and cholesteryl hemisuccinate. We incubated GM1-deficient rat glioma C6 cells with each of the derivatives as well as native GM1 and assayed the cells for their ability to bind and respond to cholera toxin. On the basis of the observed increase in binding of 125I-labeled cholera toxin, it was apparent that the cells took up and initially incorporated most of the derivatives into the plasma membrane. In the case of the aliphatic amine derivatives, the ability to generate new toxin binding sites was dependent on chain length; whereas the C10 derivative was ineffective, C12 and higher analogues were effective. Increased binding was dependent on both the concentration of the neoglycolipid in the medium and the time of exposure. Cells pretreated with the various derivatives accumulated cyclic AMP in response to cholera toxin, but there were differences in their effectiveness. The cholesterol and long-chain aliphatic amine derivatives were more effective than native GM1, whereas the phospholipid derivatives were less effective. The distance between GM1OS and the phospholipid also appeared to influence its functional activity. The neoglycolipid formed by cross-linking the amine of GM1OS to phosphatidylethanolamine (PE) with disuccinimidyl suberate was less effective than the neoglycolipid formed by directly attaching GM1OS to PE by reductive amination. Furthermore, insertion of a C8 spacer in the former neoglycolipid rendered it even less effective.(ABSTRACT TRUNCATED AT 250 WORDS)

Separation and identification of aliphatic amine derivatives with a new fluorescent reagent using high-performance liquid chromatography and thin-layer chromatography

The use of 1,2-naphthoylenebenzimidazole-6-sulphochloride has been proposed as the reagent for derivatization of aliphatic amines prior to their separation, identification and quantitation both in HPLC and in TLC. The reaction of amines with this compound is quantitative and highly fluorescent derivatives are formed that provide favourable detection limits and sensitivity as compared to Dansyl derivatives of aliphatic amines. Actual detection limits achieved correspond to ca. 10−10 mol of the amine in a spot after elution from the thin-layer plate and to ca. 5·10−14 mol of the amine in a sample volume of 10 μl injected into the liquid chromatograph. The use of this derivatization reagent offers good potential for the analysis of trace amounts of amines in environmental samples and in biological material.

Comparison of the relationships between the retention of dansyl derivatives of aliphatic amines and eluent composition for normal-and reversed-phase liquid-solid TLC systems

Dansyl derivatives of four long-chain primary aliphatic amines and five secondary aliphatic amines were chromatographed in two adsorption systems: heptane+diisopropyl ether — silica and water+methanol — octadecyl cilica. In the normal-phase system RM (log k′) values were approximately linearly dependent on the log concentration of diisopropyl ether in the eluent; the separation selectivity of dansyl C8−C12 primary amines was poor. For the reversed-phase system the derivatives of both primary and secondary amines were well separated, the log k′ values being linearly dependent on per cent concentration of methanol in the eluent.

Dipole moments of some aminobenzoates

1. The dipole moments of eight molecular compounds, formed by various aliphatic amine derivatives with benzcic acid and its nitro derivatives, were measured. 2. All of the studied compounds are dimeric in nonpolar solvents. 3. A theory was expressed regarding the structure of the studied complexes. 4. With the exception of tho-nitrobenzoates, a definite similarity of slope was found to exist between the values of the dipole moments and the basicity constants of the components.