Dialkyl Amides Research Articles

The silver catalyzed direct C-H functionalization of quinones with dialkyl amides.

DMA and other dialkylamides were successfully used as synthons for the C-H functionalization of quinones. This novel amidoalkylation reaction works with a variety of substituted quinones and dialkyl/alkyl amides, such as DMF, NMP and NMA, and the corresponding products were obtained in moderate to good yields. The amidoalkylation of quinones is demonstrated for the first time. A suitable mechanism and the synthetic utility of these compounds are demonstrated. The molecular docking of compound 5 with an Alzheimer's disease (AD) associated AChE target site was studied.

Comparative dispersion-free solvent extraction of Uranium(VI) and Thorium(IV) by TBP and dialkyl amides using a hollow fiber contactor

Abstract Dispersion-free solvent extraction of U(VI) and Th(IV) from nitric acid medium was studied employing microporous hollow fiber membrane with several monoamide extractants, viz. N,N-di-2-ethylhexyl isobutyramide (D2EHiBA), N,N-dihexyl hexanamide (DHHA), N,N-dihexyl decanamide (DHDA) and N,N-dihexyl octanamide (DHOA), and the results were compared with those obtained with conventional TBP extractant. Effects of flow rate and feed metal ion concentration on the extraction rate were examined. The extraction was principally controlled by the distribution coefficient of the metal ions with the extractants. The studies were performed under different hydrodynamic conditions and the overall mass transfer coefficients of the extracting species were calculated and found to be independent of the flow rates. The overall extraction rates were governed by the viscosity and density of the organic phase. The separation factor between U(VI) and Th(IV) was excellent with branched chain monoamides, viz. D2EHiBA, followed by DHOA. The results indicated the selective recovery of Uranium in the presence of large concentrations of Thorium by monoamides in dispersion-free solvent extraction method. A mathematical model was employed for predicting the extraction behavior of metal ions, which gave an excellent match between the calculated and the experimental results.

Effect of successive alkylation of N,N-dialkyl amides on the complexation behavior of uranium and thorium: solvent extraction, small angle neutron scattering, and computational studies.

The effect of successive alkylation of the Cα atom adjacent to the carbonyl group in N,N-dialkyl amides (i.e., di(2-ethylhexyl)acetamide (D2EHAA), di(2-ethylhexyl)propionamide (D2EHPRA), di(2-ethylhexyl)isobutyramide (D2EHIBA), and di(2-ethylhexyl)pivalamide (D2EHPVA)) on the extraction behavior of hexavalent uranium (U(VI)) and tetravalent thorium (Th(IV)) ions has been investigated. These studies show that the extraction of Th(IV) is significantly suppressed compared to that of U(VI) with increased branching at the Cα atom adjacent to the carbonyl group. Small angle neutron scattering (SANS) studies showed an increased aggregation tendency in the presence of nitric acid and metal ions. D2EHAA showed more aggregation compared to its branched homologues, which explains its capacity for higher extraction of metal ions. These experimental observations were further supported by density function theory calculations, which provided structural evidence of differential binding affinities of these extractants for uranyl cations. The complexation process is primarily controlled by steric and electronic effects. Quantum chemical calculations showed that local hardness and polarizability can be extremely useful inputs for designing novel extractants relevant to a nuclear fuel cycle.

Supercritical fluid extraction of uranium and thorium employing dialkyl amides

N,N-dialkyl aliphatic amides with varying alkyl groups viz. N,N-dibutyl-2-ethyl hexanamide (DBEHA), N,N-dibutyl-3,3-dimethyl butanamide (DBDMBA), N,N-dihexyl octanamide (DHOA), N,N-di-sec-butyl pentanamide (DBPA), N,N-dibutyl octanamide (DBOA), have been evaluated for supercritical fluid extraction (SFE) of uranium and thorium from nitric acid medium as well as from tissue paper matrix. The trend in extraction efficiency could be correlated to the structure of the amides and the amide complex of uranium/thorium. Straight chain amide DBOA was found suitable for SFE of both uranium and thorium. Under optimised conditions (200atm. pressure, 323K temperature, 30min static time followed by 30min dynamic time, 0.5M amide in methanol), (94±3)% uranium and (85±4)% thorium could be extracted from 4M nitric acid medium. For tissue paper matrix, under optimised conditions (200atm pressure, 323K temperature, 45min static time followed by 30min dynamic time, 0.2M amide in methanol) (87±7)% uranium and (88±7)% thorium were extractable. For the amide having branching at Cα, DBEHA, extraction efficiency of thorium was as low as 7% for 2M HNO3 medium while extraction efficiency of uranium was still 95%. For tissue paper matrix, extraction efficiency for uranium with 0.2M DBEHA (in methanol) was 86% while only 11% thorium was extractable under same conditions. This fact could be exploited for separation of thorium and uranium.

Non-Dispersive Solvent Extraction of Uranium from Nitric Acid Medium by Several Amides and their Mixture with TODGA using a Hollow Fiber Contactor

Non-dispersive solvent extraction (NDSX) of uranium from nitric acid feed solutions was studied using three dialkyl amides, viz. N,N-di-n-hexylhexanamide (DHHA), N,N-di-n-hexyloctanamide (DHOA), N,N-di-n-hexyldecanamide (DHDA), and their binary mixtures with TODGA (N,N,N’,N’-tetra-n-octyldiglycolamide) in normal paraffinic hydrocarbon (NPH) as the carrier solvents. The feed solution usually contained 10.6 g/L of uranium in 3 M HNO3 and the extraction studies were carried out using a commercial hollow fiber contactor operating in recirculation mode at a flow rate of 3 L/h. In a separate set of experiments, the stripping studies were carried out in the NDSX mode using the U loaded organic extract and 0.01 M HNO3 or 1 M Na2CO3 as the strippant. Use of TODGA along with the amides resulted in faster mass transfer rates though the extraction and stripping efficiencies of the dialkylamides were reversed in the mixture as compared to that observed in the absence of TODGA.

Dynamic light scattering studies on the aggregation behavior of tributyl phosphate and straight chain dialkyl amides during thorium extraction

Dynamic light scattering (DLS) studies were carried out to investigate the aggregation behavior of 1.1M solutions of tributyl phosphate (TBP), N,N-dihexyl octanamide (DHOA) and of N,N-dihexyl decanamide (DHDA) in n-dodecane equilibrated with varying concentrations of nitric acid (0.1–6M) and of Th (10–200g/L). There was a gradual increase in thorium extraction with increased aqueous phase acidities. A significant enhancement in the aggregate sizes was observed with increasing concentration of thorium in the organic phase. The effect of 1-octanol as phase modifier was also investigated on the aggregation behavior of extracted species for TBP system.

Optimization Studies for the Recovery of Thorium from Advanced Heavy Water Reactor High Level Waste (AHWR-HLW) Solutions Using Green Solvents

An Advanced Heavy Water Reactor (AHWR) has been specifically designed to exploit Th/233U as fuels. The reprocessing is focused mainly on the recovery of 233U and Pu from the spent fuels leaving bulk of Th (∼100 g/L) in the High Level Waste (HLW) solutions. No systematic attempts have been made so far to identify suitable solvents for the recovery of thorium from high level waste (HLW) solutions generated after AHWR spent fuel reprocessing. Tri-n-butyl phosphate (TBP), though the work horse for nuclear fuel reprocessing as an extractant, suffers from the serious limitation of third-phase formation during the extraction of macro concentrations of thorium. Two straight chain dialkyl amides such as N,N-dihexyl octanamide (DHOA), and N,N-dihexyl decanamide (DHDA) as well as TBP were evaluated for the recovery of the thorium from AHWR-HLW solutions. Attempts were made to identify suitable solvent (extractant + diluent) system and optimize the conditions for the recovery of thorium from HLW solutions. Selectivity of the solvents was examined for thorium extraction over fission products/structural materials under AHWR raffinate solutions. Counter-current centrifugal contactor runs were also carried out on simulated waste solutions to validate the optimized conditions for the recovery of thorium from the simulated AHWR waste solutions.

ChemInform Abstract: Rhodium‐Catalyzed Synthesis of Branched Amines by Direct Addition of Benzamides to Imines.

AbstractIn contrast to the pyrrolidine amide moiety (Pya), other directing groups such as dialkyl amides decrease the yields.

Dialkylaminoacetonitrile Derivatives as Amide Synthons. A One‐Pot Preparation of Heteroaryl Amides via a Strategy of Sequential SNAr Substitution and Oxidation.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Dialkylaminoacetonitrile derivatives as amide synthons. A one-pot preparation of heteroaryl amides via a strategy of sequential SNAr substitution and oxidation.

Dialkylamino acetonitrile derivatives were utilized as alternative to cyanohydrin synthons for preparation of the corresponding heteroaryl dialkyl amides via a strategy of sequential base-mediated coupling and oxidation. The most advantageous oxidant, NiO(2)-H(2)O, can readily oxidize 2-substituted aminoacetonitriles to the corresponding amides under both basic and neutral conditions by forming cyanohydrins in situ.

Effect of structure of N,N dialkyl amides on the extraction of U(VI) and Th(IV): a thermodynamic study

The temperature effect on the extraction behaviour of U(VI) and Th(IV) from 3 M HNO3 employing 1 M solutions of N,N diallkyl amides with varying alkyl substituents on the Cα atom viz. di(2-ethylhexyl)acetamide (D2EHAA), di(2-ethylhexyl)propionamide (D2EHPRA), di(2-ethylhexyl)isobutyramide (D2EHIBA) and di(2-ethylhexyl)pivalamide (D2EHPVA) in n-dodecane has been investigated. These studies indicate that the extraction reactions of U(VI) and Th(IV) are enthalpy stabilised while the entropy factor counteracts the extraction. An attempt has been made to correlate the thermodynamic parameters with the structure of the extractant molecules.

New auxiliaries for copper-catalyzed asymmetric Michael reactions: generation of quaternary stereocenters at room temperature.

Dialkyl amides of L-valine, L-isoleucine, and L-tert-leucine (2) are excellent chiral auxiliaries for the construction of quaternary stereocenters at ambient temperature. Enaminoesters 3, prepared from these auxiliaries 2 and Michael donors 1, undergo a copper-catalyzed asymmetric Michael reaction with methyl vinyl ketone (MVK, 4) to afford products 5 in 70-90% yield and 90-99% ee (enantiomeric excess). The exclusion of moisture or oxygen is not necessary. The auxiliaries 2 are readily available by standard procedures. After workup they can be recovered almost quantitatively.

A Caveat in the Application of the Exciton Chirality Method to N,N-Dialkyl Amides. Synthesis and Structural Revision of AT2433-B1

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Caveat in the Application of the Exciton Chirality Method to N,N-Dialkyl Amides. Synthesis and Structural Revision of AT2433-B1John D. Chisholm, Jerzy Golik, Bala Krishnan, James A. Matson, and David L. Van VrankenView Author Information Department of Chemistry, University of California Irvine, California 92697 Bristol-Myers Squibb Pharmaceutical Research Institute 5 Research Parkway, Wallingford, Connecticut 06492-7660 Cite this: J. Am. Chem. Soc. 1999, 121, 15, 3801–3802Publication Date (Web):April 7, 1999Publication History Received14 December 1998Published online7 April 1999Published inissue 1 April 1999https://doi.org/10.1021/ja9842924Copyright © 1999 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views424Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (152 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Alcohols,Amides,Carbohydrates,Chirality,Stereochemistry Get e-Alerts

Formation of high axial ratio microstructures from peptides modified with glutamic acid dialkyl amides

A growing number of amphiphiles are known to form high axial ratio microstructures (HARMs) such as the hollow cylindrical microstructures called lipid tubules. As a prelude to exploring the potential of HARMs formed from lipopeptides in controlled release drug delivery, several microstructure formation conditions were investigated. We report the preparation of several glutamic acid dialkyl amides with varying alkyl chain lengths bearing a variety of peptides (1–4 amino acids) [peptide-Glu-(NHC n H 2 n+1 ) 2, n=12, 14, 16]. These surfactants have been rapidly and efficiently converted into HARMs in aqueous buffer at physiological pH and ionic strength, or in buffer containing MeOH or EtOH. Helical ribbons and tubular HARMs were produced that were stable for as long as 6 months below the phase transition temperatures of the compounds. To estimate the stability of HARMs in vivo, HARMs formed from (Pro) 3–Glu(NHC 16H 33) 2 were incubated with DOPC liposomes or fetal calf serum at 40°C. HARM size and shape did not change significantly, suggesting that such lipopeptide particles can retain their morphology long enough in vivo to be useful as drug delivery vehicles.

ChemInform Abstract: Asymmetric Reduction of Chiral Titanates of α‐Keto Aromatic Acids with Lithium Dialkyl Amides.

AbstractChemInform 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.

Asymmetric Reduction of Chiral Titanates of α-Keto Aromatic Acids with Lithium Dialkyl Amides

Asymmetric reduction of titanates of α-keto aromatic acids with chiral alcohol ligands by lithium dialkyl amides yielded the acids' corresponding mandelic acids in 20.1 to 43.3%ee.

Stereochemical differences in the michael addition of phenylacetic acid esters and dialkyl amides to methyl cinnamate or methyl crotonate

The stereochemistry of the conjugate addition of phenylacetic acid esters and dialkylamides to methyl crotonate is studied. The stereochemical results are compared with these previously obtained for the addition to methyl cinnamate. The differences observed are explained in terms of cyclic transition states with decreasing of the sterical interactions as a result of replacement of a phenyl group by methyl in position 2 of the 1,2-diphenylpropanic skeleton.

Mild hydrolysis or alcoholysis of amides. Ti(IV) catalyzed conversion of primary carboxamides to carboxylic acids or esters

Reaction of primary amides (e.g., 1a or 6–13) or O-methylhydroxamates (1b and 1c) with a catalytic amount of TiCl4 and one equivalent of aqueous HCl converts these compounds in good yields to carboxylic esters (when an alcohol is used as solvent) or to carboxylic acids (when 9:1 dioxane:H2O is used as solvent). These conversions are chemoselective for primary amides: mono- and dialkyl amides are not affected by the reaction conditions. The hydrolysis conditions described do not compromise the stereochemical integrity of an adjacent chiral center. This is exemplified by the hydrolysis of naproxen amide (34) to naproxen (33) without detectable racemization as determined by chiral HPLC.

REVIEW ARTICLE LONG CHAIN DISUBSTITUTED ALIPHATIC AMIDES AS EXTRACTING AGENTS IN INDUSTRIAL APPLICATIONS OF SOLVENT EXTRACTION

ABSTRACT In comparison with tri-n-butyl phosphate (TBP), N,N'dialkyl aliphatic amides present some potential advantages as extracting agents of actinides in the reprocessing of Irradiated nuclear fuels. One of the more evident of these advantages is the benign nature of amide degradation products; solvent treatment is thus simplified, and higher irradiation doses can be tolerated- A second advantage over TBP is the greater selectivity of dialkyl amides for several important fission products thus providing higher decontamination of uranium and plutonium products. On the other hand, the tendency of amides to form slightly soluble adducts with uranium in nitric acid media restricts the number of amides suitable for practical applications. N,N'dialkyl amides may also present some interest in hydrometallurgical applications in non-nuclear fields. A review of our own research with these compounds Integrated with results obtained by other authors in previous papers is presented here.

Michael reaction. V. Stereochemistry of the NaNH2 catalyzed two-step reaction between phenylacetic acid dialkyl amides and methyl cinnamate or cinnamic acid dialkyl amides

The reaction is investigated between sodium-metallated (NaNH2) phenylacetic acid dialkyl amides and methyl cinnamate or cinnamic acid dialkyl amides. The thermodynamic equilibrium between the diastereomeric 2,3-diphenylglutaric acid amidoesters or diamides is 5/95 in favour of thethreo-isomer. Under kinetic conditions the stereochemistry of the reaction depends on the nature of the donor and the solvent.