Amination Of Aldehydes Research Articles

Hydrogen-Transfer Amination of Aldehydes

Nickel nanoparticles (NiNPs) were generated from anhydrous nickel(II) chloride by treatment with lithium powder and a catalytic amount of 4,4¢-di-tert-butylbiphenyl (DTBB, 5 mol%) in THF at room temperature. The hydrogen-transfer reductive amination of aldehydes 1 with amines 2 was carried out in the presence of NiNPs in i-PrOH to give the corresponding products 3 in 30-99% yield (20 examples).

Synthesis and In Vivo Evaluation of Novel PET Radioligands for Imaging the Endothelin-A Receptor

The endothelin subtype-A (ETA) receptor is a member of a family of G-protein-coupled receptors that plays a central role in vasoconstriction, cell proliferation, and hormone production. The aim of this study was to synthesize and evaluate in vivo (11)C- and (18)F-labeled analogs of the potent and selective ETA antagonist N-[[2'-[[(4,5-dimethyl-3-isoxazolyl)amino]sulfonyl]-4-(2-oxazolyl)[1,1'-biphenyl]-2-yl]methyl]-N,3,3-trimethylbutanamide (BMS-207940). Protected precursors and authentic nonradioactive standards were synthesized by reductive amination and subsequent alkylation of protected aldehyde 1. Desmethyl precursor 2 was reacted with (11)C-methyl iodide followed by deprotection and high-performance liquid chromatography purification to produce (11)C-(N-[[2'-[[(4,5-dimethyl-3-isoxazolyl)amino]sulfonyl]-4-(2-oxazolyl)[1,1'-biphenyl]-2-yl]methyl]-N,1-methylindolecarboxamide) ((11)C-BMS-5p) 3. Nitro precursor 4 was reacted with (18)F-fluoride and purified by high-performance liquid chromatography to produce (18)F-(N-[[2'-[[(4,5-dimethyl-3-isoxazolyl)amino]sulfonyl]-4-(2-oxazolyl)[1,1'-biphenyl]-2-yl]methyl]-N,4-fluorobenzamide) ((18)F-FBzBMS) 5. Biodistribution was determined by injecting male CD-1 mice via the tail vein with either (11)C-BMS-5p 3 or (18)F-FBzBMS 5. Specific binding was determined by pretreatment with 1 mg of BMS-207940 per kilogram. PET scanning of a baboon using either (11)C-BMS-5p 3 or (18)F-FBzBMS 5 was performed at baseline and 40 min after intravenous administration of 1 mg of BMS-207940 per kilogram. (11)C-BMS-5p 3 was synthesized with 1.5% radiochemical yield in 36 min, with an average specific activity of 1,051 GBq/micromol (28,400 mCi/micromol; n=5) at the end of synthesis. (18)F-FBzBMS 5 was synthesized with 0.54% radiochemical yield in 130 min, with an average specific activity of 12.9 GBq/micromol (349 mCi/micromol, n=7) at the end of synthesis. In mice, the highest uptake of both radioligands was in the liver, lungs, and heart. Radioactivity in the liver washed out over time, and uptake in the lungs and heart remained relatively stable. Mice pretreated with 1 mg of BMS-207940 per kilogram showed greater than 64% specific binding in the lungs and kidneys at 60 min. Specific binding in the heart was determined to be 63% for (11)C-BMS-5p 3 and 81% for (18)F-FBzBMS 5. PET studies in a baboon showed high uptake of both radioligands in the myocardium. Between 35 and 85 min, the heart-to-blood ratio was 4.7 to 1. Pretreatment with a 1 mg/kg dose of BMS-207940 showed 85% specific binding in the myocardium at 85 min after injection. Both (11)C-BMS-5p 3 and (18)F-FBzBMS 5 bind selectively to the ETA receptor in vivo. Further development of these radioligands for imaging the ETA receptor in humans is warranted.

ChemInform Abstract: One‐Pot Reductive Amination of Aldehydes Catalyzed by a Hydrio‐Iridium(III) Complex in Aqueous Medium.

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ChemInform Abstract: Reductive Amination of Aldehydes and Ketones with Xylylene Ionene Bound Borohydride as a Novel Polymer Supported Reducing Agent.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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.

Direct Reductive Amination of Aldehydes and Ketones with 2,4-Ionene-Based Borohydride Exchange Resin as a Novel Polymer-Supported Reducing Agent

Direct reductive amination of aldehydes and ketones were accomplished efficiently using high-capacity, ionene-based, polymer-supported borohydride reagent in isopropyl alcohol at reflux under neutral conditions. The reagent is easily prepared by mixing aqueous solution of 2,4-ionene bromide with an alkaline solution of sodium borohydride at room temperature. The generality of reaction was established using both aliphatic and aromatic aldehydes, ketones, and amines.

Hydrogen-Transfer Reductive Amination of Aldehydes Catalysed by Nickel Nanoparticles

Nickel nanoparticles have been found to catalyse the reductive amination of aldehydes by transfer hydrogenation with isopropanol at 76 °C.

First stereoselective synthesis and assignment of the absolute configuration of the nebracetam eutomer and derivatives

(−)-Nebracetam 1 was stereoselectively prepared for the first time, allowing the determination of its absolute configuration as ( R). The pivotal intermediate in the synthesis, 1-benzyl-4-[( S)-2,2-dimethyl-1,3-dioxolan-4-yl]-pyrrolidin-2-one 6, was previously obtained in 60% yield and 90% ee from an enoate derived from d-mannitol. Two approaches were investigated to synthesize ( R)-(−)-nebracetam 1 and analogues 4 and 5 from 6. Compound 6 was transformed into WEB-1868 2. Mesylation of the hydroxyl group in 2, followed by nucleophilic substitution with azide and reduction led to target 1. Compounds 4 and 5 were synthesized by using morpholine and N-methyl piperazine as nucleophiles. Compounds 4 and 5 were also prepared, in higher yields and similar ee, through the reductive amination of aldehyde 10, obtained in two steps from 6.

ChemInform Abstract: ZrCl4/Hantzsch 1,4‐Dihydropyridine as a New and Efficient Reagent Combination for the Direct Reductive Amination of Aldehydes and Ketones with Weakly Basic Amines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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.

ChemInform Abstract: Reductive Amination of Aldehydes and Ketones in a Heterogeneous System in THF and under Solvent‐Free Conditions Using Sodium Borohydride‐Silica Phosphoric Acid.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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.

Reductive Amination of Aldehydes and Ketones with Xylylene Ionene Bound Borohydride as a Novel Polymer Supported Reducing Agent

An efficient reductive amination of aldehydes and ketones in the preparation of aliphatic and aromatic secondary and tertiary amines with xylylene ionene borohydride as a high capacity polymer supported reducing agent in isopropanol at reflux under neutral conditions is described. Xylylene ionene borohydride is easily prepared by mixing an aqueous solution of xylylene ionene chloride with an alkaline solution of sodium borohydride at room temperature. The chemoselective reductive amination in the presence of functional groups such as chloride, C=C bond, nitro and cyano groups was also achieved. The generality of reaction was established using variety of aldehydes, ketones and amines. Keywords: Ionene borohydride, reductive amination, aldehyde, ketone

Photochemical Functionalization of Polymer Surfaces for Microfabricated Devices

Herein we report the topochemical modification of polymer surfaces with perfluorinated aromatic azides. The aryl azides, which have quaternary amine or aldehyde functional groups, were linked to the surface of the polymer by UV irradiation. The polymer substrates used in this study were cyclic olefin copolymer and poly(methyl methacrylate). These substrates were characterized before and after modification using reflection-absorption infrared spectroscopy, sessile water contact angle measurements, and X-ray photoelectron spectroscopy. Analysis of the surface confirmed the presence of aromatic groups with aldehyde or quaternary amine functionality. Enzyme immobilization and patterning onto polymer surfaces were studied using confocal microscopy. Enzymatic digests of protein were carried out on modified probes manufactured from thermoplastic substrates, and the resulting peptide analysis was completed using matrix-assisted laser desorption/ionization mass spectrometry. The use of functionalized perfluorinated aromatic azides allows the surface chemistry of thermoplastics to be tailored for specific lab-on-a-chip applications.

Metal‐Free One‐Pot Oxidative Amination of Aldehydes to Amides.

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One-pot reductive amination of aldehydes catalyzed by a hydrio-iridium(III) complex in aqueous medium

A combination of sodium tetrakis[3,5-di(trifluoromethyl)phenyl]borate [NaBAr F 4] and hydrio-iridium(III) complex efficiently catalyzed the one-pot reductive amination of aldehydes with various amines and ammonia in water under mild conditions in good to excellent yields.

Reductive Amination of Aldehydes and Ketones in a Heterogeneous System in THF and under Solvent-Free Conditions Using Sodium Borohydride-Silica Phosphoric Acid

A chemoselective, fast, efficient, and high yielding method for the preparation of amines by reductive amination of aldehydes and ketones using sodium borohydride in the presence of silica phosphoric acid in THF and under solvent-free conditions at room temperature is described.

Reductive Amination of Carbonyl Compounds with NaBH4-H3PW12O40 in THF and Under Solvent-Free Conditions

A simple, completely chemoselective, and convenient procedure for reductive amination of aldehydes and ketones using NaBH4 in the presence of H3PW12O40 in THF and under solvent-free conditions at ambient temperature is described.

Reductive Amination of Aldehydes and Ketones with 2-(Tributylamino)-ethoxyborohydride

A new ionic liquid is presented as a medium and reducing agent for the reductive amination of aldehydes and ketones.

Synthesis of 7-arylmethyl-substituted derivatives of 2-amino-2-pyrrolydin-1-yl-5,6,7,8-tetrahydropyrido-[3,4-d]pyrimidine

7-Benzyl-2-pyrrolidin-1-yl-5,6,7,8-tetrahydro-3H-pyrido[3,4-d]pyrimidin-4-one was prepared by condensation of 1-benzyl-4-ethoxycarbonyl-3-oxopiperidine with pyrrolidine-1-carboxamidine. Subsequent treatment of the product with trifluoromethansulfonyl anhydride, aqueous ammonia, and hydrogen in the presence of palladium on carbon gave 4-amino-2-pyrrolidin-1-yl-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidine in 80% yield. The given compound was used in the reductive amination of aldehydes in the synthesis of various 7-arylmethyl-substituted derivatives of 4-amino-2-pyrrolidin-1-yl-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidine.

Thiourea-Catalyzed Transfer Hydrogenation of Aldimines

The authors report a practical method for the reductive amination of aldehydes and reduction of aldimines using thiourea catalyst 1 and also question some of the published results on the reductive amination of aldehydes and ketones. They found that thiourea catalyst 2 is inefficient for the reductive amination of benz­aldehyde but thiourea catalyst 1 smoothly gave the product in 86% yield. In addition, with 1 mol% of catalyst 1, good to excellent yields (80-93%) were obtained for the reduction of different preformed aromatic and aliphatic aldimines.

Metal-Free One-Pot Oxidative Amination of Aldehydes to Amides

Metal-free oxidative amination of aromatic aldehydes in the presence of TBHP provides convenient access to amides in 85-99% under mild reaction conditions within 5 h. This method avoids free carboxylic acid intermediates and integrates aldehyde oxidation and amide bond formation, which are usually accomplished separately, into a single operation. Proline-derived amides can be prepared in excellent yields without noticeable racemization.

Interactions of polysaccharide-based tissue adhesives with clinically relevant fibroblast and macrophage cell lines

The effects of polysaccharide-based tissue adhesives on cell survival and inflammatory cell activation were determined using in vitro mouse cell cultures. Cytotoxicity of tissue adhesives was evaluated by placing adhesives in direct contact with 3T3 fibroblast cells. Polysaccharide-based tissue adhesives composed of dextran aldehyde and star PEG amine were non-cytotoxic to fibroblasts; in contrast, a commercial adhesive composed of 2-octyl cyanoacrylate was highly cytotoxic to fibroblasts. The inflammatory potential of tissue adhesives was evaluated by exposing J774 macrophage cells to adhesives, and measuring TNF-alpha release from macrophages. Polysaccharide-based tissue adhesives did not elicit inflammatory TNF-alpha release from macrophages. These results suggest that polysaccharide-based tissue adhesives are non-cytotoxic and non-inflammatory; the results are therefore significant in the design of in vitro cell culture systems to study biomaterials.