Chemoselective reductive alkylation of ammonia with carbonyl compounds: synthesis of primary and symmetrical secondary amines

An efficient, general procedure for highly chemoselective reductive mono-alkylation of ammonia with ketones is reported. Treatment of ketones with ammonia in ethanol and titanium(IV) isopropoxide, followed by in situ sodium borohydride reduction, and a straightforward workup afforded primary amines in good to excellent yields. Reductive alkylation of ammonia with aldehydes, on the other hand, afforded the corresponding symmetrical secondary amines selectively.     

Amines made easily: a highly selective hydroaminomethylation of olefins

A highly chemo- and regioselective hydroaminomethylation of simple as well as functionalized alpha-olefins using a cationic rhodium precatalyst together with Xantphos as ligand is reported. Studies of the influence of ligands and reaction conditions led to an unprecedented selective hydroaminomethylation procedure. The novel procedure constitutes an economically attractive and environmentally favorable synthesis of secondary and tertiary aliphatic amines.     

Phosphine‐ and Hydrogen‐Free: Highly Regioselective Ruthenium‐Catalyzed Hydroaminomethylation of Olefins

A highly regioselective ruthenium‐catalyzed hydroaminomethylation of olefins is reported. Using easily available trirutheniumdodecacarbonyl an efficient sequence consisting of a water‐gas shift reaction, hydroformylation of olefins, with subsequent imine or enamine formation and final reduction is realized. This novel procedure is highly practical (ligand‐free, one pot) and economic (low catalyst loading and inexpensive metal). Bulk industrial as well as functionalized olefins react with various amines to give the corresponding tertiary amines generally in high yields (up to 92 %), excellent regioselectivities (n/iso>99:1), and full chemoselectivity in favor of terminal olefins.     

An efficient synthesis of thiazol-2-imine derivatives via a one-pot,three-component reaction

A simple and highly efficient one-pot, three-component procedure for the synthesis of thiazol-2-imines, via the reaction of aromatic α-bromoketones, primary amines, and phenyl isothiocyanate in the presence of a catalytic amount of triethylamine, is described.     

Water-promoted highly regio- and stereoselective synthesis of α-dehydro-β-amino esters and nitriles from Baylis-Hillman acetates

The nucleophilic addition of amines to Baylis-Hillman acetates has been efficiently carried out in water at room temperature in the absence of any base, acid, or metal catalyst to produce α-dehydro-β-amino esters and nitriles. This procedure addresses a variety of aliphatic open-chain and cyclic amines and anilines. All the reactions are highly regio- and stereoselective, fast and high yielding.     

HPLC post column derivatization of aromatic amines usingN-methyl-9-chloroacridinium triflate

An HPLC post column chemical derivatization procedure based on the interaction between an acridinium triflate and amines to form highly colored derivatives on-line is described for the determination of aromatic amines. Benzocaine and butesin, local anesthetic agents that contain the aromatic amine group, were used as model compounds. Reversed-phase HPLC conditions were developed for both the separation of analytes and the reaction between analytes and the acridinium triflate in the system. Three-dimensional knitted teflon shape coils and the internal diameter and length of the coils were important parameters in reducing band broadening and background noise.N-Methyl-9-chloroacridinium triflate was shown to be applicable to the determination of primary aromatic amines, selected secondary aromatic amines, hydrazides, and hydrazines. Application of the on-line chemical derivatization procedure to the analysis of pharmaceutical dosage forms containing procainamide (primary aromatic amine), isoniazid (hydrazide), and hydralazine (hydrazine) is also described.     

Efficient three-component one-pot benzylation and allylation of aldehydes and amines for synthesis of homobenzylamines and homoallylamines

A highly efficient, three-component one-pot benzylation and allylation of aromatic and aliphatic aldehydes and amines affords the corresponding homobenzylamines and homoallylamines in good to excellent yield. The procedure is lauded by its simplicity and manipulability.     

Highly regioselective synthesis of amino-functionalized dendritic polyglycerols by a one-pot hydroformylation/reductive amination sequence

[reaction: see text] Dendritic architectures with neutral core structures and amines groups in the shell are a synthetic challenge, and there is a need for an efficient access. In this paper, highly selective Rh-catalysts are used for sequential hydroformylation/reductive amination of dendritic perallylated polyglycerols 1 with various amines in a one-pot procedure to give dendritic polyamines 3a-e in high yields (73-99%). In all cases, complete conversion of the allyl ether and aldehyde intermediate has been observed. Furthermore, the use of protected amines provides reactive core-shell-type architectures after deprotection. These soluble but membrane filterable multifunctional dendritic polyamines are of high interest as reagents in synthesis or as supports in homogeneous catalysis as well as nonviral vectors for DNA-transfection.     

Multialkylation of aqueous ammonia with alcohols catalyzed by water-soluble Cp*Ir-ammine complexes

Novel water-soluble Cp*Ir-ammine complexes have been synthesized, and a new and highly atom-economical system for the synthesis of organic amines using aqueous ammonia as a nitrogen source has been developed. With a water-soluble and air-stable Cp*Ir-ammine catalyst, [Cp*Ir(NH(3))(3)][I](2), a variety of tertiary and secondary amines were synthesized by the multialkylation of aqueous ammonia with theoretical equivalents of primary and secondary alcohols. The catalyst could be recycled by a facile procedure maintaining high activity. A one-flask synthesis of quinolizidine starting with 1,5,9-nonanetriol was also demonstrated. This new catalytic system would provide a practical and environmentally benign methodology for the synthesis of various organic amines.     

Synthesis of hemilabile P,N-ligands with a pentane-2,4-diyl backbone

A general and convenient two-step synthetic method has been developed for the preparation of a novel class of aminoalkyl-phosphine type compounds, which involves nucleophilic ring-opening of cyclic sulfate esters. The ring-opening step was performed using several different aliphatic and aromatic amines to produce aminoalkyl sulfates that were reacted with LiPPh₂ to give the corresponding P,N-ligands. The desymmetrization procedure affords an easy route to synthesize enantiomerically pure pentane-2,4-diyl based P,N-ligands with a highly tunable structure. The ligands derived from primary amines have a stereogenic N-atom that can be useful in asymmetric catalytic syntheses.     

Direct-type catalytic three-component mannich reactions leading to an efficient synthesis of alpha,beta-diamino acid derivatives

[reaction: see text] The first example of the Lewis acid-catalyzed three-component direct-type Mannich reaction of simple aromatic and enolizable aliphatic aldehydes, secondary amines, and glycine derivatives is described. The procedure is highly atom economical and can be performed in a simple one-pot operation under mild conditions to afford a wide variety of synthetically important anti-alpha,beta-diamino ester derivatives in high yields with high diastereoselectivities.     

Mild and eco‐friendly chemoselective acylation of amines in aqueous medium using a green,superparamagnetic, recoverable nanocatalyst

Copper‐grafted guanidine acetic acid‐modified magnetite nanoparticles (Fe₃O₄@GAA‐Cu(II)) as a green, superparamagnetic and recoverable nanocatalyst is found to promote quantitative N ‐acylation of various amines in a very short time with an equimolar amount of thioacetic acid in water at room temperature. This method is found to be highly selective for amines and not sensitive to other functional groups. Mild reaction condition, high selectivity, efficiency, simple workup and excellent yields are some of the major advantages of the procedure.     

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.     

Synthesis of tertiary alkyl amines from terminal alkenes: copper-catalyzed amination of alkyl boranes

A method for highly selective anti-Markovnikov hydroamination of terminal alkenes is reported. The one-pot procedure involves hydroboration of the alkene followed by a novel electrophilic amination of the alkyl borane catalyzed by an NHC-Cu complex. Terminal alkenes are successfully transformed into tertiary alkyl amines in the presence of a variety of functional groups in yields ranging from 80 to 97% with excellent regioselectivity. Results of a preliminary study of the reaction mechanism are also described.     

Preparative synthesis of heterocyclic and aromatic N-benzyl amines

A simple and highly efficient procedure has been proposed for the synthesis of heterocyclic and aromatic N-benzyl amines via reductive amination of substituted aromatic aldehydes in the presence of sodium tetrahydridoborate-acetic acid system generating reactive sodium triacetoxyhydridoborate.     

Silica‐supported Perchloric Acid Catalyzed One‐pot Synthesis of 1,4‐Dihydropyridines

An environmentally friendly and highly efficient procedure for the preparation of 1,4‐dihydropyridines by the reaction between α,β‐unsaturated aldehydes, aromatic amines and β‐keto esters in the presence of silica supported perchloric acid is described.     

Diastereoselective Synthesis of Cyclopenta[c]furans by a Catalytic Multicomponent Reaction

A diastereoselective three‐component reaction between alkynyl enones, aldehydes and secondary amines is reported. With the aid of a benign indium catalyst, a range of highly substituted cyclopenta[c]furan derivatives can be obtained in a single‐step procedure. The formation of the stereodefined heterocyclic motifs takes place via in situ generation of enamines followed by two sequential cyclization steps.     

One-pot reductive amination of aldehydes and ketones with α-picoline-borane in methanol, in water, and in neat conditions

A one-pot reductive amination of aldehydes and ketones with amines using α-picoline-borane as a reducing agent is described. The reaction has been carried out in MeOH, in H₂O, and in neat conditions in the presence of small amounts of AcOH. This is a highly efficient and mild procedure that is applicable for a wide variety of substrates. In particular, this is the first successful demonstration that this type of reaction can be carried out in water and in neat conditions.     

An efficient protocol for regioselective ring opening of epoxides using sulfated tungstate: application in synthesis of active pharmaceutical ingredients atenolol,propranolol and ranolazine

Sulfated tungstate was found to be a new and highly efficient catalyst for opening of epoxide rings by amines to give β-amino alcohols with high regioselectivity. Various advantages associated with this novel and environmental friendly protocol include solvent-free conditions, short reaction times, high product yields, simple workup procedure and easy recovery and reusability of the catalyst. This protocol has been applied for the synthesis of active pharmaceutical ingredients atenolol, propranolol and ranolazine.     

Reductive amination of aldehydes and ketones using sodium borohydride in the presence of silica chloride under solvent free conditions

<正>A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described.A variety of aliphatic and aromatic aldehydes,ketones and amines when mixed with NaBH_4/silica chloride at room temperature,afforded excellent yield of the corresponding amines.