Zeitschriftenartikel: „Amides“

1

Soong, Chee-Leong, Jun Ogawa und Sakayu Shimizu. „A Novel Amidase (Half-Amidase) for Half-Amide Hydrolysis Involved in the Bacterial Metabolism of Cyclic Imides“. Applied and Environmental Microbiology 66, Nr. 5 (01.05.2000): 1947–52. http://dx.doi.org/10.1128/aem.66.5.1947-1952.2000.

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ABSTRACT A novel amidase involved in bacterial cyclic imide metabolism was purified from Blastobacter sp. strain A17p-4. The enzyme physiologically functions in the second step of cyclic imide degradation, i.e., the hydrolysis of monoamidated dicarboxylates (half-amides) to dicarboxylates and ammonia. Enzyme production was enhanced by cyclic imides such as succinimide and glutarimide but not by amide compounds which are conventional substrates and inducers of known amidases. The purified amidase showed high catalytic efficiency toward half-amides such as succinamic acid (Km = 6.2 mM; k cat = 5.76 s−1) and glutaramic acid (Km = 2.8 mM;k cat = 2.23 s−1). However, the substrates of known amidases such as short-chain (C2 to C4) aliphatic amides, long-chain (above C16) aliphatic amides, amino acid amides, aliphatic diamides, α-keto acid amides, N-carbamoyl amino acids, and aliphatic ureides were not substrates for the enzyme. Based on its high specificity toward half-amides, the enzyme was named half-amidase. This half-amidase exists as a monomer with an M r of 48,000 and was strongly inhibited by heavy metal ions and sulfhydryl reagents.

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2

Barham, Joshua P., und Jaspreet Kaur. „Site-Selective C(sp3)–H Functionalizations Mediated by Hydrogen Atom Transfer Reactions via α-Amino/α-Amido Radicals“. Synthesis 54, Nr. 06 (25.10.2021): 1461–77. http://dx.doi.org/10.1055/a-1677-6619.

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AbstractAmines and amides, as N-containing compounds, are ubiquitous in pharmaceutically-active scaffolds, natural products, agrochemicals, and peptides. Amides in nature bear a key responsibility for imparting three-dimensional structure, such as in proteins. Structural modifications to amines and amides, especially at their positions α to N, bring about profound changes in biological activity oftentimes leading to more desirable pharmacological profiles of small drug molecules. A number of recent developments in synthetic methodology for the functionalizations of amines and amides omit the need of their directing groups or pre-functionalizations, achieving direct activation of the otherwise relatively benign C(sp3)–H bonds α to N. Among these, hydrogen atom transfer (HAT) has proven a very powerful platform for the selective activation of amines and amides to their α-amino and α-amido radicals, which can then be employed to furnish C–C and C–X (X = heteroatom) bonds. The abilities to both form these radicals and control their reactivity in a site-selective manner is of utmost importance for such chemistries to witness applications in late-stage functionalization. Therefore, this review captures contemporary HAT strategies to realize chemo- and regioselective amine and amide α-C(sp3)–H functionalization, based on bond strengths, bond polarities, reversible HAT equilibria, traceless electrostatic-directing auxiliaries, and steric effects of in situ-generated HAT agents.1 Introduction2 Functionalizations of Amines3 Functionalizations of Carbamates4 Functionalizations of Amides5 Conclusion

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3

Zhou, Yongyun, Ruhima Khan, Baomin Fan und Lijin Xu. „Ruthenium-Catalyzed Selective Reduction of Carboxylic Esters and Carboxamides“. Synthesis 51, Nr. 12 (30.04.2019): 2491–505. http://dx.doi.org/10.1055/s-0037-1611524.

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Amines and alcohols are important classes of building blocks in organic synthesis. The synthesis of these compounds has been a topic of interest. A straightforward method for their synthesis is the reduction of esters and amides to alcohols and amines, respectively. Various transition-metal catalysts have been developed for the homogeneous hydrogenation of esters and amides to alcohols and amines. In this review, an overview of the ruthenium-catalyzed selective hydrogenation of esters and amides is provided.1 General Introduction2 Ru-Catalyzed Reduction of Esters3 Ru-Catalyzed Selective Reduction of Amides4 Conclusions

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4

Zarecki, Adam P., Jacek L. Kolanowski und Wojciech T. Markiewicz. „Microwave-Assisted Catalytic Method for a Green Synthesis of Amides Directly from Amines and Carboxylic Acids“. Molecules 25, Nr. 8 (11.04.2020): 1761. http://dx.doi.org/10.3390/molecules25081761.

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Amide bonds are among the most interesting and abundant molecules of life and products of the chemical pharmaceutical industry. In this work, we describe a method of the direct synthesis of amides from carboxylic acids and amines under solvent-free conditions using minute quantities of ceric ammonium nitrate (CAN) as a catalyst. The reactions are carried out in an open microwave reactor and allow the corresponding amides to be obtained in a fast and effective manner when compared to other procedures of the direct synthesis of amides from acids and amines reported so far in the literature. The amide product isolation procedure is simple, environmentally friendly, and is performed with no need for chromatographic purification of secondary amides due to high yields. In this report, primary amines were used in most examples. However, the developed procedure seems to be applicable for secondary amines as well. The methodology produces a limited amount of wastes, and a catalyst can be easily separated. This highly efficient, robust, rapid, solvent-free, and additional reagent-free method provides a major advancement in the development of an ideal green protocol for amide bond formation.

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Orsy, György, Sayeh Shahmohammadi und Enikő Forró. „A Sustainable Green Enzymatic Method for Amide Bond Formation“. Molecules 28, Nr. 15 (28.07.2023): 5706. http://dx.doi.org/10.3390/molecules28155706.

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A sustainable enzymatic strategy for the preparation of amides by using Candida antarctica lipase B as the biocatalyst and cyclopentyl methyl ether as a green and safe solvent was devised. The method is simple and efficient and it produces amides with excellent conversions and yields without the need for intensive purification steps. The scope of the reaction was extended to the preparation of 28 diverse amides using four different free carboxylic acids and seven primary and secondary amines, including cyclic amines. This enzymatic methodology has the potential to become a green and industrially reliable process for direct amide synthesis.

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Martinez-Rodríguez, Sergio, Rafael Contreras-Montoya, Jesús M. Torres, Luis Álvarez de Cienfuegos und Jose Antonio Gavira. „A New L-Proline Amide Hydrolase with Potential Application within the Amidase Process“. Crystals 12, Nr. 1 (23.12.2021): 18. http://dx.doi.org/10.3390/cryst12010018.

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L-proline amide hydrolase (PAH, EC 3.5.1.101) is a barely described enzyme belonging to the peptidase S33 family, and is highly similar to prolyl aminopeptidases (PAP, EC. 3.4.11.5). Besides being an S-stereoselective character towards piperidine-based carboxamides, this enzyme also hydrolyses different L-amino acid amides, turning it into a potential biocatalyst within the Amidase Process. In this work, we report the characterization of L-proline amide hydrolase from Pseudomonas syringae (PsyPAH) together with the first X-ray structure for this class of L-amino acid amidases. Recombinant PsyPAH showed optimal conditions at pH 7.0 and 35 °C, with an apparent thermal melting temperature of 46 °C. The enzyme behaved as a monomer at the optimal pH. The L-enantioselective hydrolytic activity towards different canonical and non-canonical amino-acid amides was confirmed. Structural analysis suggests key residues in the enzymatic activity.

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Khalimon, Andrey, Kristina Gudun und Davit Hayrapetyan. „Base Metal Catalysts for Deoxygenative Reduction of Amides to Amines“. Catalysts 9, Nr. 6 (28.05.2019): 490. http://dx.doi.org/10.3390/catal9060490.

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The development of efficient methodologies for production of amines attracts significant attention from synthetic chemists, because amines serve as essential building blocks in the synthesis of many pharmaceuticals, natural products, and agrochemicals. In this regard, deoxygenative reduction of amides to amines by means of transition-metal-catalyzed hydrogenation, hydrosilylation, and hydroboration reactions represents an attractive alternative to conventional wasteful techniques based on stoichiometric reductions of the corresponding amides and imines, and reductive amination of aldehydes with metal hydride reagents. The relatively low electrophilicity of the amide carbonyl group makes this transformation more challenging compared to reduction of other carbonyl compounds, and the majority of the reported catalytic systems employ precious metals such as platinum, rhodium, iridium, and ruthenium. Despite the application of more abundant and environmentally benign base metal (Mn, Fe, Co, and Ni) complexes for deoxygenative reduction of amides have been developed to a lesser extent, such catalytic systems are of great importance. This review is focused on the current achievements in the base-metal-catalyzed deoxygenative hydrogenation, hydrosilylation, and hydroboration of amides to amines. Special attention is paid to the design of base metal catalysts and the mechanisms of such catalytic transformations.

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8

Fournand, David, Frederic Bigey und Alain Arnaud. „Acyl Transfer Activity of an Amidase from Rhodococcussp. Strain R312: Formation of a Wide Range of Hydroxamic Acids“. Applied and Environmental Microbiology 64, Nr. 8 (01.08.1998): 2844–52. http://dx.doi.org/10.1128/aem.64.8.2844-2852.1998.

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ABSTRACT The enantioselective amidase from Rhodococcus sp. strain R312 was produced in Escherichia coli and was purified in one chromatographic step. This enzyme was shown to catalyze the acyl transfer reaction to hydroxylamine from a wide range of amides. The optimum working pH values were 7 with neutral amides and 8 with α-aminoamides. The reaction occurred according to a Ping Pong Bi Bi mechanism. The kinetic constants demonstrated that the presence of a hydrophobic moiety in the carbon side chain considerably decreased the K m amide values (e.g.,K m amide = 0.1 mM for butyramide, isobutyramide, valeramide, pivalamide, hexanoamide, and benzamide). Moreover, very high turnover numbers (k cat) were obtained with linear aliphatic amides (e.g.,k cat = 333 s−1 with hexanoamide), whereas branched-side-chain-, aromatic cycle- or heterocycle-containing amides were sterically hindered. Carboxylic acids, α-amino acids, and methyl esters were not acyl donors or were very bad acyl donors. Only amides and hydroxamic acids, both of which contained amide bonds, were determined to be efficient acyl donors. On the other hand, the highest affinities of the acyl-enzyme complexes for hydroxylamine were obtained with short, polar or unsaturated amides as acyl donors (e.g.,K m NH2OH = 20, 25, and 5 mM for acetyl-, alanyl-, and acryloyl-enzyme complexes, respectively). No acyl acceptors except water and hydroxylamine were found. Finally, the purified amidase was shown to bel-enantioselective towards α-hydroxy- and α-aminoamides.

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Ding, Wen, Shaoyu Mai und Qiuling Song. „Molecular-oxygen-promoted Cu-catalyzed oxidative direct amidation of nonactivated carboxylic acids with azoles“. Beilstein Journal of Organic Chemistry 11 (11.11.2015): 2158–65. http://dx.doi.org/10.3762/bjoc.11.233.

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A copper-catalyzed oxidative direct formation of amides from nonactivated carboxylic acids and azoles with dioxygen as an activating reagent is reported. The azole amides were produced in good to excellent yields with a broad substrate scope. The mechanistic studies reveal that oxygen plays an essential role in the success of the amidation reactions with copper peroxycarboxylate as the key intermediate. Transamidation occurs smoothly between azole amide and a variety of amines.

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Krieck, Sven, Philipp Schüler, Jan Peschel und Matthias Westerhausen. „Straightforward One-Pot Syntheses of Silylamides of Magnesium and Calcium via an In Situ Grignard Metalation Method“. Synthesis 51, Nr. 05 (13.12.2018): 1115–22. http://dx.doi.org/10.1055/s-0037-1610407.

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Calcium bis[bis(trimethylsilyl)amide] (Ca(HMDS)2) is a widely used reagent in diverse stoichiometric and catalytic applications. These processes necessitate a straightforward and large-scale access of this complex. Calcium does not react with primary and secondary amines, but the addition of excess bromoethane to a mixture of calcium turnings and amines in THF at room temperature yields the corresponding calcium bis(amides), calcium bromide and ethane. This in situ Grignard metalation method (iGMM) allows the preparation of calcium bis(amides) from secondary and primary trialkylsilyl-substituted amines and anilines on a multigram scale.1 Background2 The In Situ Grignard Metalation Method (iGMM)3 Properties of [(thf)2M(HMDS)2]4 Applications and Perspective

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11

Meerakrishna, Ramakrishnan Suseela, und Ponnusamy Shanmugam. „Synthesis of blue-red emissive amido-substituted di(het)aryl and tri(het)aryl amine derivatives via chemoselective N-mono and N,N-diarylation of (het) aryl amino amides using benzyne/arynes“. New Journal of Chemistry 43, Nr. 6 (2019): 2550–58. http://dx.doi.org/10.1039/c8nj05823g.

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Chemoselective synthesis of amide-substituted triaryl and diaryl amines by N-mono and N,N-diarylation of (het)aryl amino amides using arynes has been reported. Selected triarylamines showed blue-red emission.

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12

Selvakumar, Kumaravel, Kesamreddy Rangareddy und John F. Harrod. „The titanocene-catalyzed reduction of acetamides to tertiary amines by PhMeSiH2“. Canadian Journal of Chemistry 82, Nr. 8 (01.08.2004): 1244–48. http://dx.doi.org/10.1139/v04-063.

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A variety of acetamide derivatives are reduced in excellent yields to tertiary amines by PhMeSiH2 in the presence of Cp2TiX2 (X = F or Me) catalysts. The reactions are very clean at 80 °C. At room temperature a secondary reaction, hydrogenolysis of the C(O)N bond, intervenes and reduces the chemoselectivity. Nevertheless, this chemistry provides a simple methodology for the amide/alkylamine transformation using inexpensive, commercially available reagents.Key words: amides, reduction, secondary amides, methylphenylsilane, titanocene, catalysis.

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13

Yao, Lei, Ming-Yi Wang, Xin-Ke Wang, Yi-Jun Liu, Hang-Fei Chen, Jun Zheng, Wei Nie et al. „Detection of atmospheric gaseous amines and amides by a high-resolution time-of-flight chemical ionization mass spectrometer with protonated ethanol reagent ions“. Atmospheric Chemistry and Physics 16, Nr. 22 (23.11.2016): 14527–43. http://dx.doi.org/10.5194/acp-16-14527-2016.

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Abstract. Amines and amides are important atmospheric organic-nitrogen compounds but high time resolution, highly sensitive, and simultaneous ambient measurements of these species are rather sparse. Here, we present the development of a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) method, utilizing protonated ethanol as reagent ions to simultaneously detect atmospheric gaseous amines (C1 to C6) and amides (C1 to C6). This method possesses sensitivities of 5.6–19.4 Hz pptv−1 for amines and 3.8–38.0 Hz pptv−1 for amides under total reagent ion signals of ∼ 0.32 MHz. Meanwhile, the detection limits were 0.10–0.50 pptv for amines and 0.29–1.95 pptv for amides at 3σ of the background signal for a 1 min integration time. Controlled characterization in the laboratory indicates that relative humidity has significant influences on the detection of amines and amides, whereas the presence of organics has no obvious effects. Ambient measurements of amines and amides utilizing this method were conducted from 25 July to 25 August 2015 in urban Shanghai, China. While the concentrations of amines ranged from a few parts per trillion by volume to hundreds of parts per trillion by volume, concentrations of amides varied from tens of parts per trillion by volume to a few parts per billion by volume. Among the C1- to C6-amines, the C2-amines were the dominant species with concentrations up to 130 pptv. For amides, the C3-amides (up to 8.7 ppb) were the most abundant species. The diurnal and backward trajectory analysis profiles of amides suggest that in addition to the secondary formation of amides in the atmosphere, industrial emissions could be important sources of amides in urban Shanghai. During the campaign, photo-oxidation of amines and amides might be a main loss pathway for them in daytime, and wet deposition was also an important sink.

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14

Khaldoun, Khadidja, Abdelmounaim Safer, Salima Saidi-Besbes, Bertrand Carboni, Rémy Le Guével und François Carreaux. „An Efficient Solvent-Free Microwave-Assisted Synthesis of Cinnamamides by Amidation Reaction Using Phenylboronic Acid/Lewis Base Co-catalytic System“. Synthesis 51, Nr. 20 (29.07.2019): 3891–900. http://dx.doi.org/10.1055/s-0039-1690132.

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A microwave-assisted dehydrative amide condensation reaction is reported as an efficient access to cinnamamide derivatives under solvent-free conditions. This protocol between conjugated carboxylic acids and amines is based on the use of a co-catalytic system, including the presence of the commercially available phenylboronic acid and 4-(N,N-dimethylamino)pyridine N-oxide (DMAPO), with a complete chemoselectivity in favor of the corresponding α,β-unsaturated amides. The implementation of the reaction needs no special precaution, and less reactive amines, such as substituted anilines, are also efficient under these conditions. A series of novel conjugated amides have been evaluated for their cytotoxic activities against several human cancer cell lines.

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Trott, Sandra, Sibylle Bürger, Carsten Calaminus und Andreas Stolz. „Cloning and Heterologous Expression of an Enantioselective Amidase from Rhodococcus erythropolis Strain MP50“. Applied and Environmental Microbiology 68, Nr. 7 (Juli 2002): 3279–86. http://dx.doi.org/10.1128/aem.68.7.3279-3286.2002.

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ABSTRACT The gene for an enantioselective amidase was cloned from Rhodococcus erythropolis MP50, which utilizes various aromatic nitriles via a nitrile hydratase/amidase system as nitrogen sources. The gene encoded a protein of 525 amino acids which corresponded to a protein with a molecular mass of 55.5 kDa. The deduced complete amino acid sequence showed homology to other enantioselective amidases from different bacterial genera. The nucleotide sequence approximately 2.5 kb upstream and downstream of the amidase gene was determined, but no indications for a structural coupling of the amidase gene with the genes for a nitrile hydratase were found. The amidase gene was carried by an approximately 40-kb circular plasmid in R. erythropolis MP50. The amidase was heterologously expressed in Escherichia coli and shown to hydrolyze 2-phenylpropionamide, α-chlorophenylacetamide, and α-methoxyphenylacetamide with high enantioselectivity; mandeloamide and 2-methyl-3-phenylpropionamide were also converted, but only with reduced enantioselectivity. The recombinant E. coli strain which synthesized the amidase gene was shown to grow with organic amides as nitrogen sources. A comparison of the amidase activities observed with whole cells or cell extracts of the recombinant E. coli strain suggested that the transport of the amides into the cells becomes the rate-limiting step for amide hydrolysis in recombinant E. coli strains.

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Šilhánková, Alexandra, Karel Šindelář, Karel Dobrovský, Ivan Krejčí, Jarmila Hodková und Zdeněk Polívka. „Synthesis of New L-Proline Amides with Anticonvulsive Effect“. Collection of Czechoslovak Chemical Communications 61, Nr. 7 (1996): 1085–92. http://dx.doi.org/10.1135/cccc19961085.

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Series of heterocyclic L-proline amides were prepared from BOC-L-proline and heterocyclic amines (mostly substituted piperazines and morpholines) via active ester with hydroxysuccinimide. 4-(4-Fluorobenzoyl)piperidine afforded L-proline 4-(4-(4-(4-fluorobenzoyl)piperidin-1-yl)benzoyl)piperidine (7b) simultaneously with expected L-proline 4-(4-fluorobenzoyl)piperidide (7a). D-Proline N-(3-(4-(3-chlorophenyl)piperazin-1-yl)propyl)amide (2) was prepared starting from D-proline. The amides were tested by methods of biochemical and behavioural pharmacology.

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Haake, Paul, und Donald A. Tyssee. „Estimation of Charge Density on Nitrogen in Amides by Measurement of One-Bond Carbon-Hydrogen Nuclear Coupling Constants in N-CH3 Group“. Zeitschrift für Naturforschung A 48, Nr. 1-2 (01.02.1993): 58–62. http://dx.doi.org/10.1515/zna-1993-1-216.

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Abstract One-bond, 13C-1H coupling constants, J1(C-H), 'in amines, ammonium ions, and carboxylic amides correlate with structure and support the concept that the value of J1(C-H) is related to the charge density on the nitrogen atom; for example, amine oxides have nearly the same charge density at nitrogen as does the tetramethylammonium ion. The J1(C-H) values for methyls bonded to nitrogen in various amides then give an experimental estimate of the charge density at the nitrogen atom that enables an estimate of the bond order in the C-N amide-bond; the data suggest that carboxylic amides have a C-N bond order of about 1.35, that sulfonamides have an S-N bond order of about 1.45, and that phosphinamides, R2 P(O)N(CH3)2 , have a P-N bond order of about 1.3. In contrast, aminephosphines have a P-N single bond. The value for carboxylic amides is in reasonable agreement with bond distances in amides.

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18

Qu, Jing, Shishan Yu, Wenzhao Tang, Yunbao Liu, Yue Liu und Jing Liu. „Progress on Cassaine-Type Diterpenoid Ester Amines and Amides (Erythrophleum Alkaloids)“. Natural Product Communications 1, Nr. 10 (Oktober 2006): 1934578X0600101. http://dx.doi.org/10.1177/1934578x0600101005.

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The structures, spectral characteristics, and bioactivities of 39 natural cassaine-type diterpenoid ester amines and amides (Erythrophleum alkaloids) and 31 synthetic analogues are reviewed. Cassaine-type diterpenoid ester amines and amides, the so called Erythrophleum alkaloids, have the skeleton of cassane-type diterpenoids with a N-containing side chain, and are classified into two groups, ester amines and amides. Cassaine-type diterpenoid ester amines and amides show remarkable inotropic action on the heart, inhibition of Na+/K+-ATPase, cytotoxities, and other major bioactivities. Structural modification of cassaine-type diterpenoid ester amines and amides has been carried out to furnish many derivatives to study the structure-activity relationships.

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Zahardis, J., S. Geddes und G. A. Petrucci. „The ozonolysis of primary aliphatic amines in single and multicomponent fine particles“. Atmospheric Chemistry and Physics Discussions 7, Nr. 5 (15.10.2007): 14603–38. http://dx.doi.org/10.5194/acpd-7-14603-2007.

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Abstract. The oxidative processing by ozone of the particulate amines octadecylamine (ODA) and hexadecylamine (HDA) is reported. Ozonolysis of these amines resulted in strong NO2− and NO3− ion signals that increased with ozone exposure as monitored by photoelectron resonance capture ionization aerosol mass spectrometry. These products suggest a mechanism of progressive oxidation of the particulate amines to nitro alkanes. Additionally, a strong ion signal at 125 m/z is assigned to the ion NO3−(HNO3). For ozonized mixed particles containing ODA or HDA + oleic acid (OL), with pO3≥3×10−7 atm, imine, secondary amide, and tertiary amide products were measured. These products most likely arise from reactions of amines with aldehydes (for imines) and stabilized Criegee intermediates (SCI) or secondary ozonides (for amides) from the fatty acid. The routes to amides via SCI and/or secondary ozonides was shown to be more important than comparable amide forming reactions between amines and organic acids, using azelaic acid as a test compound. Finally, direct evidence is provided for the formation of a surface barrier in the ODA + OL reaction system that resulted in the retention of OL at high ozone exposures (up to 10−3 atm for 17 s). This effect was not observed in HDA + OL or single component OL particles, suggesting that it may be a species-specific surfactant effect from an in situ generated amide or imine. Implications to tropospheric chemistry, including particle bound amines as sources of oxidized gas phase nitrogen species (e.g. NO2, NO3), formation of nitrogen enriched HULIS via ozonolysis of amines and source apportionment are discussed.

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Zahardis, J., S. Geddes und G. A. Petrucci. „The ozonolysis of primary aliphatic amines in fine particles“. Atmospheric Chemistry and Physics 8, Nr. 5 (29.02.2008): 1181–94. http://dx.doi.org/10.5194/acp-8-1181-2008.

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Abstract. The oxidative processing by ozone of the particulate amines octadecylamine (ODA) and hexadecylamine (HDA) is reported. Ozonolysis of these amines resulted in strong NO2– and NO3– ion signals that increased with ozone exposure as monitored by photoelectron resonance capture ionization aerosol mass spectrometry. These products suggest a mechanism of progressive oxidation of the particulate amines to nitroalkanes. Additionally, a strong ion signal at 125 m/z is assigned to the ion NO3– (HNO3). For ozonized mixed particles containing ODA or HDA + oleic acid (OL), with pO3≥3×10–7 atm, imine, secondary amide, and tertiary amide products were measured. These products most likely arise from reactions of amines with aldehydes (for imines) and stabilized Criegee intermediates (SCI) or secondary ozonides (for amides) from the fatty acid. The routes to amides via SCI and/or secondary ozonides were shown to be more important than comparable amide forming reactions between amines and organic acids, using azelaic acid as a test compound. Finally, direct evidence is provided for the formation of a surface barrier in the ODA + OL reaction system that resulted in the retention of OL at high ozone exposures (up to 10−3 atm for 17 s). This effect was not observed in HDA + OL or single component OL particles, suggesting that it may be a species-specific surfactant effect from an in situ generated amide or imine. Implications to tropospheric chemistry, including particle bound amines as sources of oxidized gas phase nitrogen species (e.g.~NO2, NO3), formation of nitrogen enriched HULIS via ozonolysis of amines and source apportionment are discussed.

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Waseem Abbasi, Sana, Naveed Zafar Ali, Martin Etter, Muhammad Shabbir, Zareen Akhter, Stacey J. Smith, Hammad Ismail und Bushra Mirza. „Synthesis, Characterization and Biological Studies of Ether–Based Ferrocenyl Amides and their Organic Analogues“. Crystals 10, Nr. 6 (04.06.2020): 480. http://dx.doi.org/10.3390/cryst10060480.

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Ferrocenyl amides (FB1-FB13) and their organic analogues (BZ1-BZ13) were prepared by a low-temperature condensation method. Ferrocenyl amides were synthesised using 4-ferrocenylbenzoyl chloride and ether-based amines and diamines. Benzoyl chloride was used to synthesise organic analogues by reacting with various amines. The synthesised compounds were characterised by elemental, spectroscopic (FT-IR and NMR) and single crystal X-ray diffraction methods. Crystal structures of the representative organic analogues (BZ2 and BZ6) were solved by single crystal X-ray diffraction. BZ2 crystallises in the triclinic space group P 1 ¯ with a unit cell volume of V = 1056.6(3) Å3 and with two formula units per unit cell. Whereas BZ6 assembles in the orthorhombic space group Pbca with four formula units per unit cell and a unit cell volume of V = 1354.7(2) Å3. Spectral studies confirmed the presence of amide linkages in the synthesised compound with a strong N—H·····O=C hydrogen bonding network established between amide groups of neighbouring molecular scaffolds further stabilising the molecular stacking in accordance with the archetypal crystal structures. The bioactive nature of each compound was assessed by DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity, hydrogen peroxide scavenging activity and total antioxidant activity. Antidiabetic, anticholinesterase enzyme inhibition tests, as well as antibacterial activities, were performed showing significant biological activity for ferrocenyl amides as compared to their organic analogues.

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Sonke, Theo, Sandra Ernste, Renate F. Tandler, Bernard Kaptein, Wilco P. H. Peeters, Friso B. J. van Assema, Marcel G. Wubbolts und Hans E. Schoemaker. „l-Selective Amidase with Extremely Broad Substrate Specificity from Ochrobactrum anthropi NCIMB 40321“. Applied and Environmental Microbiology 71, Nr. 12 (Dezember 2005): 7961–73. http://dx.doi.org/10.1128/aem.71.12.7961-7973.2005.

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ABSTRACT An industrially attractive l-specific amidase was purified to homogeneity from Ochrobactrum anthropi NCIMB 40321 wild-type cells. The purified amidase displayed maximum initial activity between pH 6 and 8.5 and was fully stable for at least 1 h up to 60°C. The purified enzyme was strongly inhibited by the metal-chelating compounds EDTA and 1,10-phenanthroline. The activity of the EDTA-treated enzyme could be restored by the addition of Zn2+ (to 80%), Mn2+ (to 400%), and Mg2+ (to 560%). Serine and cysteine protease inhibitors did not influence the purified amidase. This enzyme displayed activity toward a broad range of substrates consisting of α-hydrogen- and (bulky) α,α-disubstituted α-amino acid amides, α-hydroxy acid amides, and α-N-hydroxyamino acid amides. In all cases, only the l-enantiomer was hydrolyzed, resulting in E values of more than 150. Simple aliphatic amides, β-amino and β-hydroxy acid amides, and dipeptides were not converted. The gene encoding this l-amidase was cloned via reverse genetics. It encodes a polypeptide of 314 amino acids with a calculated molecular weight of 33,870. Since the native enzyme has a molecular mass of about 66 kDa, it most likely has a homodimeric structure. The deduced amino acid sequence showed homology to a few other stereoselective amidases and the acetamidase/formamidase family of proteins (Pfam FmdA_AmdA). Subcloning of the gene in expression vector pTrc99A enabled efficient heterologous expression in Escherichia coli. Altogether, this amidase has a unique set of properties for application in the fine-chemicals industry.

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Dunn, P., E. A. Parkes und J. B. Polya. „Amides IX: Acylation of amides and amines“. Recueil des Travaux Chimiques des Pays-Bas 71, Nr. 7 (02.09.2010): 676–83. http://dx.doi.org/10.1002/recl.19520710708.

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Xu, Qing, Huamei Xie, Er-Lei Zhang, Xiantao Ma, Jianhui Chen, Xiao-Chun Yu und Huan Li. „Selective catalytic Hofmann N-alkylation of poor nucleophilic amines and amides with catalytic amounts of alkyl halides“. Green Chemistry 18, Nr. 14 (2016): 3940–44. http://dx.doi.org/10.1039/c6gc00938g.

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A selective Hofmann N-alkylation reaction of amines/amides catalytic in alkyl halides is achieved by using alcohols as the alkylating reagents, affording mono- or di-alkylated amines/amides in high selectivities.

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North, Michael. „Amines and amides“. Journal of the Chemical Society, Perkin Transactions 1, Nr. 16 (1999): 2209–29. http://dx.doi.org/10.1039/a903369f.

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North, Michael. „Amines and amides“. Contemporary Organic Synthesis 1, Nr. 6 (1994): 475. http://dx.doi.org/10.1039/co9940100475.

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North, Michael. „Amines and amides“. Contemporary Organic Synthesis 2, Nr. 4 (1995): 269. http://dx.doi.org/10.1039/co9950200269.

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North, Michael. „Amines and amides“. Contemporary Organic Synthesis 3, Nr. 4 (1996): 323. http://dx.doi.org/10.1039/co9960300323.

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North, Michael. „Amines and amides“. Contemporary Organic Synthesis 4, Nr. 4 (1997): 326. http://dx.doi.org/10.1039/co9970400326.

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North, Michael. „Amines and amides“. Journal of the Chemical Society, Perkin Transactions 1, Nr. 17 (1998): 2959–72. http://dx.doi.org/10.1039/a802125b.

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Kumagai, Naoya, und Masakatsu Shibasaki. „7-Azaindoline Auxiliary: A Versatile Attachment Facilitating Enantioselective C–C Bond-Forming Catalysis“. Synthesis 51, Nr. 01 (30.11.2018): 185–93. http://dx.doi.org/10.1055/s-0037-1610412.

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This short review provides an overview of 7-azaindoline auxiliaries in asymmetric catalysis. 7-Azaindoline serves as a useful attachment to carboxylic acids, and the thus-formed 7-azaindoline amides are amenable to atom-economical C–C bond-forming reactions with high stereoselectivity. The attachment is used for the sake of gaining traction in promoting the reaction of interest and can be easily removed after enantioselective reactions. Both nucleophilic and electrophilic catalyses are realized with broad tolerance for functional groups, showcasing the usefulness of 7-azaindoline auxiliaries for practical and streamlined synthesis of a wide range of acyclic chiral building blocks.1 Introduction2 7-Azaindoline as a Key Auxiliary3 7-Azaindoline Amide as a Pronucleophile3.1 α-Carbon-Substituted 7-Azaindoline Amide3.2 α-Nitrogen-Substituted 7-Azaindoline Amide3.3 α-Oxygen-Substituted 7-Azaindoline Amide3.4 α-Fluorocarbon-Substituted 7-Azaindoline Amide3.5 α-Halogen-Substituted 7-Azaindoline Amide3.6 α-Sulfur-Substituted 7-Azaindoline Amide4 7-Azaindoline Amide as an Electrophile4.1 Conjugate Addition of Butenolides4.2 1,3-Dipolar Cycloaddition of Nitrones5 Transformation of 7-Azaindoline Amide6 Conclusion

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Cheng, Hua, Cheng Chen, Rui Zhang, Jun-Chao Zhang, Wei-Yi Zhang, Yu-Qing He und Yu-Cheng Gu. „A Practical Approach for the Transamidation of N,N-Dimethyl Amides with Primary Amines Promoted by Sodium tert-Butoxide under Solvent-Free Conditions“. Synthesis 52, Nr. 21 (08.09.2020): 3286–94. http://dx.doi.org/10.1055/s-0040-1705892.

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AbstractA practical sodium tert-butoxide (NaOtBu)-mediated protocol is disclosed for the transamidation of various N,N-dimethyl amides with primary amines to afford the corresponding amides in moderate to good yields at room temperature under solvent-free conditions. This protocol features a facile work-up procedure and good functional group compatibility, especially for N,N-dimethyl amides with long-chain alkyl groups and heteroatom-containing amines. Notably, a few representative gram-scale reactions proceed smoothly to furnish the desired amides in high yields, which demonstrates the potential of this process for further practical applications. Several control experiments are carried out and a plausible mechanism is provided.

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Ocampo Gutiérrez de Velasco, Diego, Aoze Su, Luhan Zhai, Satowa Kinoshita, Yuko Otani und Tomohiko Ohwada. „Unexpected Resistance to Base-Catalyzed Hydrolysis of Nitrogen Pyramidal Amides Based on the 7-Azabicyclic[2.2.1]heptane Scaffold“. Molecules 23, Nr. 9 (15.09.2018): 2363. http://dx.doi.org/10.3390/molecules23092363.

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Non-planar amides are usually transitional structures, that are involved in amide bond rotation and inversion of the nitrogen atom, but some ground-minimum non-planar amides have been reported. Non-planar amides are generally sensitive to water or other nucleophiles, so that the amide bond is readily cleaved. In this article, we examine the reactivity profile of the base-catalyzed hydrolysis of 7-azabicyclo[2.2.1]heptane amides, which show pyramidalization of the amide nitrogen atom, and we compare the kinetics of the base-catalyzed hydrolysis of the benzamides of 7-azabicyclo[2.2.1]heptane and related monocyclic compounds. Unexpectedly, non-planar amides based on the 7-azabicyclo[2.2.1]heptane scaffold were found to be resistant to base-catalyzed hydrolysis. The calculated Gibbs free energies were consistent with this experimental finding. The contribution of thermal corrections (entropy term, –TΔS‡) was large; the entropy term (ΔS‡) took a large negative value, indicating significant order in the transition structure, which includes solvating water molecules.

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Yang, Guo-Ping, Ke Li, Wei Liu, Kai Zeng und Yu-Feng Liu. „Copper-catalyzed aerobic oxidative C–C bond cleavage of simple ketones for the synthesis of amides“. Organic & Biomolecular Chemistry 18, Nr. 35 (2020): 6958–64. http://dx.doi.org/10.1039/d0ob01601b.

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Bittner, Nataly, Andy Boon, Evert H. Delbanco, Christof Walter und Angela Mally. „Assessment of aromatic amides in printed food contact materials: analysis of potential cleavage to primary aromatic amines during simulated passage through the gastrointestinal tract“. Archives of Toxicology 96, Nr. 5 (05.03.2022): 1423–35. http://dx.doi.org/10.1007/s00204-022-03254-w.

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AbstractRecent analyses conducted by German official food control reported detection of the aromatic amides N-(2,4-dimethylphenyl)acetamide (NDPA), N-acetoacetyl-m-xylidine (NAAX) and 3-hydroxy-2-naphthanilide (Naphthol AS) in cold water extracts from certain food contact materials made from paper or cardboard, including paper straws, paper napkins, and cupcake liners. Because aromatic amides may be cleaved to potentially genotoxic primary amines upon oral intake, these findings raise concern that transfer of NDPA, NAAX and Naphthol AS from food contact materials into food may present a risk to human health. The aim of the present work was to assess the stability of NDPA, NAAX and Naphthol AS and potential cleavage to 2,4-dimethylaniline (2,4-DMA) and aniline during simulated passage through the gastrointestinal tract using static in vitro digestion models. Using the digestion model established by the National Institute for Public Health and the Environment (RIVM, Bilthoven, NL) and a protocol recommended by the European Food Safety Authority, potential hydrolysis of the aromatic amides to the respective aromatic amines was assessed by LC–MS/MS following incubation of the aromatic amides with digestive fluid simulants. Time-dependent hydrolysis of NDPA and NAAX resulting in formation of the primary aromatic amine 2,4-DMA was consistently observed in both models. The highest rate of cleavage of NDPA and NAAX was recorded following 4 h incubation with 0.07 M HCl as gastric-juice simulant, and amounted to 0.21% and 0.053%, respectively. Incubation of Naphthol AS with digestive fluid simulants did not give rise to an increase in the concentration of aniline above the background that resulted from the presence of aniline as an impurity of the test compound. Considering the lack of evidence for aniline formation from Naphthol AS and the extremely low rate of hydrolysis of the amide bonds of NDPA and NAAX during simulated passage through the gastrointestinal tract that gives rise to only very minor amounts of the potentially mutagenic and/or carcinogenic aromatic amine 2,4-DMA, risk assessment based on assumption of 100% cleavage to the primary aromatic amines would appear to overestimate health risks related to the presence of aromatic amides in food contact materials.

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Box, Vernon G. S. „Biocidal Amidic Natural Products“. Natural Product Communications 3, Nr. 11 (November 2008): 1934578X0800301. http://dx.doi.org/10.1177/1934578x0800301111.

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Some of the more potent, and interesting, natural products that have marked biocidal properties have one, or more, amide functional groups. On the other hand, there are countless amides that are non-toxic. Thus, there is a need to try to identify the structural features of biocidal amides that could indicate their potential toxicity. A review of the structures of some of these toxic amides, using the molecular modeling program STR3DI32, has established that these amide groups are non-delocalized.

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Xia, Ji-Bao, Yan-Lin Li und Zheng-Yang Gu. „Transition-Metal-Catalyzed Intermolecular C–H Carbonylation toward Amides“. Synlett 32, Nr. 01 (17.08.2020): 07–13. http://dx.doi.org/10.1055/s-0040-1706416.

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The amide linkage is one of the most important structural moieties in both chemistry and biology. Here, we briefly discuss recent advances in catalytic intermolecular C–H carbonylation reactions for the synthesis of amides, with particular attention to our intermolecular C–H amidation of arenes with carbon monoxide and organic azides to produce amides.1 Introduction2 Representative Methods for Amide Synthesis3 C–H Aminocarbonylation with Carbon Monoxide and Amines4 C–H Amidation to Amides with Carbon Monoxide and Azides5 Summary and Outlook

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Laclef, Sylvain, Maria Kolympadi Marković und Dean Marković. „Amide Synthesis by Transamidation of Primary Carboxamides“. Synthesis 52, Nr. 21 (04.06.2020): 3231–42. http://dx.doi.org/10.1055/s-0040-1707133.

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The amide functionality is one of the most important and widely used groups in nature and in medicinal and industrial chemistry. Because of its importance and as the actual synthetic methods suffer from major drawbacks, such as the use of a stoichiometric amount of an activating agent, epimerization and low atom economy, the development of new and efficient amide bond forming reactions is needed. A number of greener and more effective strategies have been studied and developed. The transamidation of primary amides is particularly attractive in terms of atom economy and as ammonia is the single byproduct. This review summarizes the advancements in metal-catalyzed and organocatalyzed transamidation methods. Lewis and Brønsted acid transamidation catalysts are reviewed as a separate group. The activation of primary amides by promoter, as well as catalyst- and promoter-free protocols, are also described. The proposed mechanisms and key intermediates of the depicted transamidation reactions are shown.1 Introduction2 Metal-Catalyzed Transamidations3 Organocatalyzed Transamidations4 Lewis and Brønsted Acid Catalysis5 Promoted Transamidation of Primary Amides6 Catalyst- and Promoter-Free Protocols7 Conclusion

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Das, Hari S., Shyamal Das, Kartick Dey, Bhagat Singh, Rahul K. Haridasan, Arpan Das, Jasimuddin Ahmed und Swadhin K. Mandal. „Primary amides to amines or nitriles: a dual role by a single catalyst“. Chemical Communications 55, Nr. 79 (2019): 11868–71. http://dx.doi.org/10.1039/c9cc05856g.

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Blondiaux, Enguerrand, und Thibault Cantat. „Efficient metal-free hydrosilylation of tertiary, secondary and primary amides to amines“. Chem. Commun. 50, Nr. 66 (2014): 9349–52. http://dx.doi.org/10.1039/c4cc02894e.

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Hydrosilylation of secondary and tertiary amides to amines is described using catalytic amounts of B(C₆F₅)₃. The organic catalyst enables the reduction of amides with cost-efficient, non-toxic and air stable PMHS and TMDS hydrosilanes. The methodology was successfully extended to the more challenging reduction of primary amides.

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Hao, Hong-Yan, Shao-Jie Lou, Shuang Wang, Kun Zhou, Qiu-Zi Wu, Yang-Jie Mao, Zhen-Yuan Xu und Dan-Qian Xu. „Pd-catalysed β-selective C(sp3)–H arylation of simple amides“. Chemical Communications 57, Nr. 65 (2021): 8055–58. http://dx.doi.org/10.1039/d1cc02261j.

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Bhalla, Tek Chand, und Harish Kumar. „Nocardia globerula NHB-2: a versatile nitrile-degrading organism“. Canadian Journal of Microbiology 51, Nr. 8 (01.08.2005): 705–8. http://dx.doi.org/10.1139/w05-046.

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A versatile nitrile-degrading bacterium was isolated by enrichment culture from the soil of a forest near Manali, Himachal Pradesh, India, and was identified as Nocardia globerula. This organism contains 3 enzymes with nitrile-degrading activity: nitrilase, nitrile hydratase, and amidase. Nocardia globerula NHB-2 cells grown on nutrient broth supplemented with 1% glucose and 0.1% yeast extract exhibited nitrile hydratase–amidase activity specific for saturated aliphatic nitriles or amide, while addition of acetonitrile in nutrient broth yielded cells with nitrile hydratase–amidase that in addition to saturated aliphatic nitriles–amide also hydrolyzed aromatic amide. Nocardia globerula NHB-2 cultivated on nutrient broth containing propionitrile exhibited nitrilase activity that hydrolyzed aromatic nitrile and unsaturated aliphatic nitrile. The versatility of this organism in the hydrolysis of various nitriles and amides makes it a potential bioresource for use in organic synthesis.Key words: Nocardia globerula NHB-2, nitrilase, nitrile hydratase, amidase, nitrile–amide degradation.

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Radenović, Čedomir, Danica Bajuk-Bogdanović, Milica Radosavljević, Nenad Delić, Aleksandar Popović, Mile Sečanski und Miloš Crevar. „Assaying of structural parts of hybrid ZP677 grain by IC method disordered Total reflection“. Selekcija i semenarstvo 28, Nr. 1 (2022): 9–22. http://dx.doi.org/10.5937/selsem2201009r.

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In this paper, the grain and structural parts of the grain of maize hybrid ZP 677 were studied, using Infrared Spectroscopy - Attenuated Total Reflectance (ATR). The ATR spectra of grain, endosperm, pericarp and germ of maize hybrid are characterized by a number of bands, band intensity, band kinetics and band location distribution in the wavelength range 400 cm-1 to 4000 cm-1. These parameters were specifically tested for both, the grain and the endosperm, pericarp and germ. Spectral bands that are very high and high intensity usually range from 3 to 5, characterized by different intensity, kinetic forms, as well as by the distribution of origin in the wavelength range. These spectral bands enable the identification of the following organic compounds: proteins, carotenoids, ethers, cellulose, lipids, carboxylic acids, amino acids, protein amides, alkanes, sugars, carbohydrates, ketones, alcohols, phenols, aldehydes and amines. Spectral bands of grains, endosperm, pericarp and germs that are low and very low intensity are also characterized by the number of bands, low bandwidth, distribution of the place of origin, and especially by the oscillation frequency of valence bonds of functional groups of organic molecules. Spectral bands that are low and very low intensity enable the identification of organic molecules, compounds and their fragments, as well as the identification of various forms of excited states of molecular structures and excited states of valence bonds of organic molecules. The excited state of molecular structures and the excited state of valence bonds of functional groups of organic molecules are manifested in various forms of oscillatory motion. Examples of functional groups of organic molecules in which all the mentioned excited states of molecular structures and excited states of valence bonds occur are alcohols, amines, alkynes, ketones, alkenes, ester, lipids, carbonyl group (ester), amides, nitrogen-hydrogen group, (NH), primary amines, carboxylic acids, amides, acid chlorides, nitrites, amides, carbonyl group (amide), aliphatic carbon-hydrogen bond and aldehydes.

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Weaver-Guevara, Holly M., Ryan W. Fitzgerald und Arthur Greenberg. „Rotational barriers in five related amides“. Canadian Journal of Chemistry 95, Nr. 3 (März 2017): 271–77. http://dx.doi.org/10.1139/cjc-2016-0344.

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Interest in the low carbonyl IR frequency of 2-hydroxy-N,N-bis(2-hydroxyethyl)acetamide (2) initially prompted our interest in the amide rotational barrier of this molecule and four related amides that present a variety of hydrogen-bonding possibilities. In the course of this study, a previously incorrect structural assignment was established as N,N-bis[2-(acetyloxy)ethyl]-acetamide (6). In acetonitrile-d3, the carbonyl IR frequencies of the five amides were all essentially normal amide frequencies. Despite very different hydrogen-bonding possibilities in the five amides, no clear trends emerged in the comparison of the rotational barriers (ΔG‡), and the rotational barriers were essentially normal for amides. The rotational barrier of 2 did not vary over one order of magnitude difference in concentration.

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Garg, Jai Anand, Subrata Chakraborty, Yehoshoa Ben-David und David Milstein. „Unprecedented iron-catalyzed selective hydrogenation of activated amides to amines and alcohols“. Chemical Communications 52, Nr. 30 (2016): 5285–88. http://dx.doi.org/10.1039/c6cc01505k.

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The first example of hydrogenation of activated amides to amines and alcohols catalyzed by an earth-abundant iron metal complex is discovered. A wide range of trifluoromethyl-substituted secondary and tertiary aromatic and aliphatic amides were hydrogenated.

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Bock, Hans, und Erik Heigel. „Wechselwirkungen in Molekülkristallen, 162 [1, 2]. Di(arylsulfonyl)amine – geeignete Liganden für lipophil umhüllte Polyionen-Aggregate mit Cs⊕ -Schichten variabler Dicke / Interaction in Molecular Crystals, 162 [1, 2]. Di(arylsulfonyl)amines – Ligands for Lipophilically Wrapped Polyion Aggregates with Cs⊕ -Layers of Variable Thickness“. Zeitschrift für Naturforschung B 55, Nr. 11 (01.11.2000): 1053–66. http://dx.doi.org/10.1515/znb-2000-1111.

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Di(arylsulfonyl)amides are presented as novel anionic ligands for polycation aggregates. Starting from the structures of Ag⊕ and Na⊕ salts registered in the Cambridge Structural Database, the largest alkali cation Cs⊕ with high coordination number has been selected and in extreme low gradient crystallisation single crystals of both cesium-di(benzenesulfonyl)amide and cesium-di(4-toluenesulfonyl)amide were grown. Their structure determinations revealed that both polymeric salts contain cation layers (Cs⊕)∝: The one lipophilically wrapped by di(benzenesulfonyl)amide ligands exhibits hexagonal (Cs⊕)6 subunits, whereas the methylsubstituted di(4-toluenesulfonyl)amide ligands of the other one are interspersed within (Cs⊕)^ layers. The resulting lipophilically wrapped sheets with Cs⊕ cations of ten- and twelve-fold coordination to disulfonyl O and C centers vary in their overall thickness of 1.77 nm and 1.39 nm because the toluene substituents in the thinner one are tilted. The remarkable effects caused by the 4-methyl substitution of the phenyl rings determine the structures of the parent di(arylsulfonyl)amines as well: Contrary to the polymeric phenyl substituted derivative, the toluene homologue crystallizes in dimers. The single crystals grown of the closely related di(arylsulfonyl)amides with or without para methyl substituents and their poly(Cs⊕) aggregates without any solvent inclusion show hitherto unknown structural motifs and, therefore, further improve our knowledge of alkali salt self-organisation phenomena in crystals.

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Saha, Sayantani, und Moris S. Eisen. „Mild catalytic deoxygenation of amides promoted by thorium metallocene“. Dalton Transactions 49, Nr. 36 (2020): 12835–41. http://dx.doi.org/10.1039/d0dt02770g.

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The organoactinide-catalyzed (Cp*₂ThMe₂) hydroborated reduction of a wide range of tertiary, secondary, and primary amides to the corresponding amines/amine–borane adducts via deoxygenation of the amides is reported herein.

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Glover, Stephen A., Arvi Rauk, Jeanne M. Buccigross, John J. Campbell, Gerard P. Hammond, Guoning Mo, Luke E. Andrews und Ashley-Mae E. Gillson. „The HERON reaction Origin, theoretical background, and prevalence“. Canadian Journal of Chemistry 83, Nr. 9 (01.09.2005): 1492–509. http://dx.doi.org/10.1139/v05-150.

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The origin of the HERON reaction is reviewed from a historical perspective and shown to have its foundation in the unusual properties of bisheteroatom-substituted amides, so-called anomeric amides. The reaction involves migration of anomerically destabilized oxo-substituents on an amide nitrogen to the amide carbon and dissociation of the amide bond. Computational work providing a theoretical basis for the reaction is presented, together with physical organic measurements that support results therefrom. The rearrangement has been observed in a number of chemical transformations of N-alkoxy-N-aminoamides, reactions of 1-acyloxy-1-alkoxydiazenes, N-alkoxy-N-aminocarbamates, N-alkoxyhydroxamic acids, as well as in the gas-phase reactions of N-acyloxy-N-alkoxyamides.Key words: HERON reaction, anomeric amides, rearrangements, hindered esters, concerted reactions.

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Schuhmacher, Anne, Tomoya Shiro, Sarah J. Ryan und Jeffrey W. Bode. „Synthesis of secondary and tertiary amides without coupling agents from amines and potassium acyltrifluoroborates (KATs)“. Chemical Science 11, Nr. 29 (2020): 7609–14. http://dx.doi.org/10.1039/d0sc01330g.

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Oxidative amidation of potassium acyltrifluoroborates (KATs) and amines via trifluoroborate iminiums (TIMs) delivers amides without coupling agents. This unusual approach to amides can be applied for the late-stage modification of bioactive molecules and for solid-phase peptide synthesis.

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Yanev, Pavel, und Plamen Angelov. „Synthesis of functionalised β-keto amides by aminoacylation/domino fragmentation of β-enamino amides“. Beilstein Journal of Organic Chemistry 14 (10.10.2018): 2602–6. http://dx.doi.org/10.3762/bjoc.14.238.

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Ethylenediamine-derived β-enamino amides are used as equivalents of amide enolate synthons in C-acylation reactions with N-protected amino acids. Domino fragmentation of the obtained intermediates leads to functionalised β-keto amides, bearing a protected amino group in their side chain.

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