- Nitrogen Atom Transfer Catalysis by Metallonitrene C?H Insertion: Photocatalytic Amidation of Aldehydes
-
C?H amination and amidation by catalytic nitrene transfer are well-established and typically proceed via electrophilic attack of nitrenoid intermediates. In contrast, the insertion of (formal) terminal nitride ligands into C?H bonds is much less developed and catalytic nitrogen atom transfer remains unknown. We here report the synthesis of a formal terminal nitride complex of palladium. Photocrystallographic, magnetic, and computational characterization support the assignment as an authentic metallonitrene (Pd?N) with a diradical nitrogen ligand that is singly bonded to PdII. Despite the subvalent nitrene character, selective C?H insertion with aldehydes follows nucleophilic selectivity. Transamidation of the benzamide product is enabled by reaction with N3SiMe3. Based on these results, a photocatalytic protocol for aldehyde C?H trimethylsilylamidation was developed that exhibits inverted, nucleophilic selectivity as compared to typical nitrene transfer catalysis. This first example of catalytic C?H nitrogen atom transfer offers facile access to primary amides after deprotection.
- Schmidt-R?ntsch, Till,Verplancke, Hendrik,Lienert, Jonas N.,Demeshko, Serhiy,Otte, Matthias,Van Trieste, Gerard P.,Reid, Kaleb A.,Reibenspies, Joseph H.,Powers, David C.,Holthausen, Max C.,Schneider, Sven
-
-
- Mechanochemical Synthesis of Primary Amides
-
Ball milling of aromatic, heteroaromatic, vinylic, and aliphatic esters with ethanol and calcium nitride afforded the corresponding primary amides in a transformation that was compatible with a variety of functional groups and maintained the integrity of a stereocenter α to carbonyl. This methodology was applied to α-amino esters and N-BOC dipeptide esters and also to the synthesis of rufinamide, an antiepileptic drug.
- Gómez-Carpintero, Jorge,Sánchez, J. Domingo,González, J. Francisco,Menéndez, J. Carlos
-
p. 14232 - 14237
(2021/10/20)
-
- Activated Mont K10-Carbon supported Fe2O3: A versatile catalyst for hydration of nitriles to amides and reduction of nitro compounds to amines in aqueous media
-
The iron oxide was successfully supported on activated clay/carbon through an experimentally viable protocol for both hydrations of nitrile to amide and reduction of nitro compounds to amines. The as-prepared catalyst has been extensively characterised by XPS, SEM-EDX, TEM, TGA, BET surface area measurements and powdered X-ray diffraction (PXRD). A wide variety of substrates could be converted to the desired products with good to excellent yields by using water as a green solvent for both the reactions. The catalyst was recyclable and reusable up to six consecutive cycles without compromising its catalytic proficiency. Graphical abstract: Activated Mont K10 carbon-supported Fe2O3 is a very efficient and versatile heterogeneous catalytic system for hydration of nitriles to amides and reduction of nitro compounds to amines and can be reused up to six consecutive cycles without significant loss in catalytic activity.[Figure not available: see fulltext.].
- Rahman, Taskia,Borah, Geetika,Gogoi, Pradip K
-
-
- Amide bond formation in aqueous solution: Direct coupling of metal carboxylate salts with ammonium salts at room temperature
-
Herein, we report a green, expeditious, and practically simple protocol for direct coupling of carboxylate salts and ammonium salts under ACN/H2O conditions at room temperature without the addition of tertiary amine bases. The water-soluble coupling reagent EDC·HCl is a key component in the reaction. The reaction runs smoothly with unsubstituted/substituted ammonium salts and provides a clean product without column chromatography. Our reaction tolerates both carboxylate (which are unstable in other forms) and amine salts (which are unstable/volatile when present in free form). We believe that the reported method could be used as an alternative and suitable method at the laboratory and industrial scales. This journal is
- Nielsen, John,Tung, Truong Thanh
-
supporting information
p. 10073 - 10080
(2021/12/10)
-
- Dihydronicotinamide riboside: synthesis from nicotinamide riboside chloride, purification and stability studies
-
In the present work, we describe an efficient method for scalable synthesis and purification of 1,4-dihydronicotinamide riboside (NRH) from commercially available nicotinamide riboside chloride (NRCl) and in the presence of sodium dithionate as a reducing agent. NRH is industrially relevant as the most effective, synthetic NAD+precursor. We demonstrated that solid phase synthesis cannot be used for the reduction of NRCl to NRH in high yield, whereas a reduction reaction in water at room temperature under anaerobic conditions is shown to be very effective, reaching a 55% isolation yield. For the first time, by using common column chromatography, we were able to highly purify this sensitive bio-compound with good yield. A series of identifications and analyses including HPLC, NMR, LC-MS, FTIR, and UV-vis spectroscopy were performed on the purified sample, confirming the structure of NRH as well as its purity to be 96%. Thermal analysis of NRH showed higher thermal stability compared to NRCl, and with two major weight losses, one at 218 °C and another at 805 °C. We also investigated the long term stability effects of temperature, pH, light, and oxygen (as air) on the NRH in aqueous solutions. Our results show that NRH can be oxidized in the presence of oxygen, and it hydrolyzed quickly in acidic conditions. It was also found that the degradation rate is lower under a N2atmosphere, at lower temperatures, and under basic pH conditions.
- Abbaspourrad, Alireza,Enayati, Mojtaba,Khazdooz, Leila,Madarshahian, Sara,Ufheil, Gerhard,Wooster, Timothy J.,Zarei, Amin
-
p. 21036 - 21047
(2021/07/01)
-
- Ring Opening/Site Selective Cleavage in N-Acyl Glutarimide to Synthesize Primary Amides
-
A LiOH-promoted hydrolysis selective C-N cleavage of twisted N-acyl glutarimide for the synthesis of primary amides under mild conditions has been developed. The reaction is triggered by a ring opening of glutarimide followed by C-N cleavage to afford primary amides using 2 equiv of LiOH as the base at room temperature. The efficacy of the reactions was considered and administrated for various aryl and alkyl substituents in good yield with high selectivity. Moreover, gram-scale synthesis of primary amides using a continuous flow method was achieved. It is noted that our new methodology can apply under both batch and flow conditions for synthetic and industrial applications.
- Govindan, Karthick,Lin, Wei-Yu
-
supporting information
p. 1600 - 1605
(2021/03/03)
-
- Direct Oxidative Amination of the Methyl C-H Bond in N-Heterocycles over Metal-Free Mesoporous Carbon
-
Direct oxidative amination of the sp3C-H bond is an attractive synthesis route to obtain amides. Conventional catalytic systems for this transformation are based on transition metals and complicated synthesis processes. Herein, direct and efficient oxidative amination of the methyl C-H bond in a wide range of N-heterocycles to access the corresponding amides over metal-free porous carbon is successfully developed. To understand the fundamental structure-activity relationships of carbon catalysts, the surface functional groups and the graphitization degree of porous carbon have been purposefully tailored through doping with nitrogen or phosphorus. The results of characterization, kinetic studies, liquid-phase adsorption experiments, and theoretical calculations indicate that the high activity of the carbon catalyst is attributed to the synergistic effect of surface acidic functional groups (hydroxyl/carboxylic acid/phosphate) and more graphene edge structures exposed on the surface of carbon materials with a high graphitization degree, in which the role of acidic functional groups is to adsorb the substrate molecule and the role of the graphene edge structure is to activate O2
- Long, Xiangdong,Wang, Jia,Gao, Guang,Nie, Chao,Sun, Peng,Xi, Yongjie,Li, Fuwei
-
p. 10902 - 10912
(2021/09/08)
-
- Aerobic oxidation of primary amines to amides catalyzed by an annulated mesoionic carbene (MIC) stabilized Ru complex
-
Catalytic aerobic oxidation of primary amines to the amides, using the precatalyst [Ru(COD)(L1)Br2] (1) bearing an annulated π-conjugated imidazo[1,2-a][1,8]naphthyridine-based mesoionic carbene ligand L1, is disclosed. This catalytic protocol is distinguished by its high activity and selectivity, wide substrate scope and modest reaction conditions. A variety of primary amines, RCH2NH2 (R = aliphatic, aromatic and heteroaromatic), are converted to the corresponding amides using ambient air as an oxidant in the presence of a sub-stoichiometric amount of KOtBu in tBuOH. A set of control experiments, Hammett relationships, kinetic studies and DFT calculations are undertaken to divulge mechanistic details of the amine oxidation using 1. The catalytic reaction involves abstraction of two amine protons and two benzylic hydrogen atoms of the metal-bound primary amine by the oxo and hydroxo ligands, respectively. A β-hydride transfer step for the benzylic C-H bond cleavage is not supported by Hammett studies. The nitrile generated by the catalytic oxidation undergoes hydration to afford the amide as the final product. This journal is
- Yadav, Suman,Reshi, Noor U Din,Pal, Saikat,Bera, Jitendra K.
-
p. 7018 - 7028
(2021/11/17)
-
- Product selectivity controlled by manganese oxide crystals in catalytic ammoxidation
-
The performances of heterogeneous catalysts can be effectively tuned by changing the catalyst structures. Here we report a controllable nitrile synthesis from alcohol ammoxidation, where the nitrile hydration side reaction could be efficiently prevented by changing the manganese oxide catalysts. α-Mn2O3 based catalysts are highly selective for nitrile synthesis, but MnO2-based catalysts including α, β, γ, and δ phases favour the amide production from tandem ammoxidation and hydration steps. Multiple structural, kinetic, and spectroscopic investigations reveal that water decomposition is hindered on α-Mn2O3, thus to switch off the nitrile hydration. In addition, the selectivity-control feature of manganese oxide catalysts is mainly related to their crystalline nature rather than oxide morphology, although the morphological issue is usually regarded as a crucial factor in many reactions.
- Hui, Yu,Luo, Qingsong,Qin, Yucai,Song, Lijuan,Wang, Hai,Wang, Liang,Xiao, Feng-Shou
-
p. 2164 - 2172
(2021/09/20)
-
- Catalyst, preparation method thereof and preparation method of amide compound
-
The invention relates to a catalyst, a preparation method thereof, and a preparation method for hydrating nitrile groups into amides. The catalyst is used for catalyzing nitrile groups to be hydratedinto amides, and the structural general formula of the catalyst is shown in the specification. In the formula, a plurality of R are respectively and independently ones selected from aromatic groups, heteroaromatic groups and non-aromatic ring groups; a plurality of R are ones respectively and independently selected from linear alkyl groups and alkane aromatic groups; X is one selected from Cl and Br; and L is one selected from OTf, BF4, PF6 and SbF6. The catalyst can catalyze nitrile groups to be hydrated into amides, and the nitrile groups can be catalyzed to be hydrated into amides even at a low temperature (20-80 DEG C); besides, compared with existing common catalysts for catalyzing nitrile groups to be hydrated into amides, the catalyst has the advantages that the equivalent weight of the catalyst can be obviously reduced, and nitrile groups can reach a relatively high conversion rate when the equivalent weight of the catalyst is only 0.01 mol%-0.5 mol%; and meanwhile, the catalyst is wider in application range and can catalyze various nitrile compounds to be hydrated into amide compounds.
- -
-
Paragraph 0142-0146; 0147
(2020/01/12)
-
- METHODS AND COMPOSITIONS FOR RAPIDLY DECREASING EPIGENETIC AGE AND RESTORATION OF MORE YOUTHFUL FUNCTION
-
Disclosed are methods and compositions of reducing the epigenetic age of mammalian organism, especially an adult human of geriatric age. The methods provide for the proliferation of endogenous stem cells using mitochondrial fusion and a UCP2 blocker or other stimulants; supplying stem cells with nutrition to prevent cell cycle arrest; and removal of senescent somatic cells using senolytic treatments. The proliferation of endogenous neural stem cells after plaque removal for the treatment of Alzheimer's is also disclosed.
- -
-
-
- Catalyst-Free N-Deoxygenation by Photoexcitation of Hantzsch Ester
-
A mild and operationally simple protocol for the deoxygenation of a variety of heteroaryl N-oxides and nitroarenes has been developed. A mixture of substrate and Hantzsch ester is proposed to result in an electron donor-acceptor complex, which upon blue-light irradiation undergoes photoinduced electron transfer between the two reactants to afford the products. N-oxide deoxygenation is demonstrated with 22 examples of functionally diverse substrates, and the chemoselective reduction of nitroarenes to the corresponding hydroxylamines is also shown.
- Cardinale, Luana,Jacobi Von Wangelin, Axel,Konev, Mikhail O.
-
supporting information
(2020/02/15)
-
- Preparation method of aromatic amide compound
-
The present invention provides a preparation method of an aromatic amide compound. In an organic solvent, under the effect of a catalyst, an aromatic acid compound and an amine source are subjected toa dehydration reaction to obtain the aromatic amide compound, wherein the aromatic acid compound is an aromatic acid, a substituted aromatic acid, a heterocyclic aromatic acid or a substituted heterocyclic aromatic acid; and the substituent group of amide is any substituent group of H, a C1-C8 straight-chain alkyl or branched-chain alkyl group, a benzene ring or an aromatic ring. The aromatic amide compound is an important chemical intermediate, and the synthesis method is mild in reaction condition and high in yield.
- -
-
Paragraph 0048-0049
(2020/07/15)
-
- Arene-ruthenium(II)-phosphine complexes: Green catalysts for hydration of nitriles under mild conditions
-
Three new arene-ruthenium(II) complexes were prepared by treating [{RuCl(μ-Cl)(η6-arene)}2] (η6-arene = p-cymene) dimer with tri(2-furyl)phosphine (PFu3) and 1,3,5-triaza-7-phosphaadamantane (PTA), respectively to obtain [RuCl2(η6-arene)PFu3] [Ru]-1, [RuCl(η6-arene)(PFu3)(PTA)]BF4 [Ru]-2 and [RuCl(η6-arene)(PFu3)2]BF4 [Ru]-3. All the complexes were structurally identified using analytical and spectroscopic methods including single-crystal X-ray studies. The effectiveness of resulting complexes as potential homogeneous catalysts for selective hydration of different nitriles into corresponding amides in aqueous medium and air atmosphere was explored. There was a remarkable difference in catalytic activity of the catalysts depending on the nature and number of phosphorus-donor ligands and sites available for catalysis. Experimental studies performed using structural analogues of efficient catalyst concluded a structural-activity relationship for the higher catalytic activity of [Ru]-1, being able to convert huge variety of aromatic, heteroaromatic and aliphatic nitriles. The use of eco-friendly water as a solvent, open atmosphere and avoidance of any organic solvent during the catalytic reactions prove the reported process to be truly green and sustainable.
- Vyas, Komal M.,Mandal, Poulami,Singh, Rinky,Mobin, Shaikh M.,Mukhopadhyay, Suman
-
-
- Substrate Profiling of the Cobalt Nitrile Hydratase from Rhodococcus rhodochrous ATCC BAA 870
-
The aromatic substrate profile of the cobalt nitrile hydratase from Rhodococcus rhodochrous ATCC BAA 870 was evaluated against a wide range of nitrile containing compounds (>60). To determine the substrate limits of this enzyme, compounds ranging in size from small (90 Da) to large (325 Da) were evaluated. Larger compounds included those with a biaryl axis, prepared by the Suzuki coupling reaction, Morita–Baylis–Hillman adducts, heteroatomlinked diarylpyridines prepared by Buchwald–Hartwig crosscoupling reactions and imidazo[1,2a]pyridines prepared by the Groebke–Blackburn–Bienaymé multicomponent reaction. The enzyme active site was moderately accommodating, accepting almost all of the small aromatic nitriles, the diarylpyridines and most of the biaryl compounds and Morita–Baylis–Hillman products but not the Groebke–Blackburn–Bienaymé products. Nitrile conversion was influenced by steric hindrance around the cyano group, the presence of electron donating groups (e.g., methoxy) on the aromatic ring, and the overall size of the compound.
- Mashweu, Adelaide R.,Chhiba‐Govindjee, Varsha P.,Bode, Moira L.,Brady, Dean
-
-
- Method for preparing aryl primary amide by adopting metal-catalyzed one-pot method
-
The invention discloses a method for synthesizing aryl primary amide by adopting a metal-catalyzed one-pot method. The method comprises the steps of: taking aryl bromidess as raw materials, allowing the aryl bromidess to react with a cyanide source under the action of a palladium catalyst, substituting bromine on an aromatic ring with cyano to obtain cyano aromatic hydrocarbon, directly adding anaqueous solution of alkali into the reaction solution without aftertreatment, and carrying out hydrolysis reaction to obtain aryl primary amide. Compared with the prior art, the method for preparing aryl primary amide from the aryl bromides has the advantages of the short synthesis route, fewer reaction steps, simple operation, mild conditions, the high conversion rate, low toxicity and industrialproduction potential.
- -
-
Paragraph 0029; 0030
(2020/04/06)
-
- Photorelease of Pyridines Using a Metal-Free Photoremovable Protecting Group
-
The photorelease of bioactive molecules has emerged as a valuable tool in biochemistry. Nevertheless, many important bioactive molecules, such as pyridine derivatives, cannot benefit from currently available organic photoremovable protecting groups (PPGs). We found that the inefficient photorelease of pyridines is attributed to intramolecular photoinduced electron transfer (PET) from PPGs to pyridinium ions. To alleviate PET, we rationally designed a strategy to drive the excited state of PPG from S1 to T1 with a heavy atom, and synthesized a new PPG by substitution of the H atom at the 3-position of 7-dietheylamino-coumarin-4-methyl (DEACM) with Br or I. This resulted in an improved photolytic efficiency of the pyridinium ion by hundreds-fold in aqueous solution. The PPG can be applied to various pyridine derivatives. The successful photorelease of a microtubule inhibitor, indibulin, in living cells was demonstrated for the potential application of this strategy in biochemical research.
- Dong, Zaizai,Fang, Xiaohong,Kou, Xiaolong,Tan, Weihong,Tang, Xiao-Jun,Wu, Yayun,Zhang, Zhen,Zhao, Rong,Zhou, Wei
-
supporting information
p. 18386 - 18389
(2020/08/24)
-
- Nicotinamide riboside-amino acid conjugates that are stable to purine nucleoside phosphorylase
-
The nutraceutical Nicotinamide Riboside (NR), an efficacious biosynthetic precursor to NAD, is readily metabolized by the purine nucleoside phosphorylase (PNP). Access to the PNP-stable versions of NR is difficult because the glycosidic bond of NR is easily cleaved. Unlike NR, NRH, the reduced form of NR, offers sufficient chemical stability to allow the successful functionalisation of the ribosyl-moiety. Here, we report on a series of NRH and NR derived amino acid conjugates, generated in good to excellent yields and show that O5′-esterification prevents the PNP-catalyzed phosphorolysis of these NR prodrugs.
- Hayat, Faisal,Migaud, Marie E.
-
supporting information
p. 2877 - 2885
(2020/04/28)
-
- Method for synthesizing amide compound by catalyzing heterocyclic compound through non-metal porous carbon
-
The invention discloses a method for synthesizing an amide compound by catalyzing a heterocyclic compound through non-metal porous carbon. The preparation method comprises the following steps of: taking a methyl-containing heterocyclic compound as a raw material, adopting a small molecular nitrogen-containing compound as a nitrogen source, and taking non-metal porous carbon as a catalyst, carryingout reaction for 0.5-48h in an oxidizing atmosphere under a pressure of 0.1-10MPa and a temperature of 50-200DEG C to obtain the amide compound. The method starts from an sp3 C-H bond, adopts oxygenor air serves as an oxidizing agent, takes the nitrogen-containing organic small molecule as a nitrogen source, and employs porous carbon as the catalyst to synthesize the amide compound by one step,and the whole catalytic reaction process has the advantages of high efficiency, short route, low cost, easily available raw materials, etc. In addition, the porous carbon catalyst can be recycled, andmeets the technical requirements of China for establishing a green ecological society.
- -
-
Paragraph 0024-0025
(2020/06/20)
-
- (η6-Benzene)Ru(II) half-sandwich complexes of pyrazolated chalcogenoethers for catalytic activation of aldehydes to amides transformation
-
The reaction of [(η6-C6H6)RuCl(μ-Cl)]2 with chalcogenoether substituted 1H-pyrazole ligands (L1-L3) in methanol have yielded three novel Ru(II) half-sandwich complexes [(η6-C6H6)RuCl(L)]PF6 (1–3) in high yield under the ambient reaction conditions. The NMR, MS and FT-IR analytical techniques were used to identify their structures. The molecular structures of the complexes 2 and 3 were established with X-ray crystallographic analysis and revealed a pseudo-octahedral half sandwich piano-stool geometry around ruthenium in each complex. Complexes 1–3 are thermally robust and were found to be insensitive towards the air and moisture. All the complexes were found to be catalytically active and produced the excellent yields of amides (up to 95%) from corresponding aldehydes. In contrast to the previous reported catalytic systems for aldehyde to amide transformation, the present complexes 1–3 are very efficient and have several advantages in terms of low catalyst loading, reaction time, temperature and wide applicability for various substituted aldehydes. Owing to the stronger σ-donor coordination properties of selenium containing ligands, the complex 2 was found to be more efficient as compare to the sulphur and tellurium analogues.
- Sharma, Kamal Nayan,Ali, Munsaf,Srivastava, Avinash Kumar,Joshi, Raj Kumar
-
-
- Chemoselective Synthesis of Aryl Ketones from Amides and Grignard Reagents via C(O)-N Bond Cleavage under Catalyst-Free Conditions
-
Conversion of a wide range of N-Boc amides to aryl ketones was achieved with Grignard reagents via chemoselective C(O)-N bond cleavage. The reactions proceeded under catalyst-free conditions with different aryl, alkyl, and alkynyl Grignard reagents. α-Ketoamide was successfully converted to aryl diketones, while α,β-unsaturated amide underwent 1,4-addition followed by C(O)-N bond cleavage to provide diaryl propiophenones. N-Boc amides displayed higher reactivity than Weinreb amides with Grignard reagents. A broad substrate scope, excellent yields, and quick conversion are important features of this methodology.
- Sureshbabu, Popuri,Azeez, Sadaf,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
-
p. 11823 - 11838
(2019/10/02)
-
- Metal-free nitrogen -doped carbon nanosheets: A catalyst for the direct synthesis of imines under mild conditions
-
Herein, a highly stable, porous, multifunctional and metal-free catalyst was developed, which exhibited significant catalytic performance in the oxidation of amines and transfer hydrogenation of nitriles under mild conditions; this could be attributed to the presence of numerous active sites and their outstanding BET surface area. The obtained results showed that most of the yields of imines exceeded 90%, and the cycling performance of the catalyst could be at least seven runs without any decay in the reaction activity, which could be comparable to those of metal catalysts. Subsequently, a kinetic study has demonstrated that the apparent activation energy for the direct synthesis of imines from amines is 67.39 kJ mol-1, which has been performed to testify that the catalytic performances are rational. Via catalyst characterizations and experimental data, graphitic-N has been proven to be the active site of the catalyst. Hence, this study is beneficial to comprehend the mechanism of action of a metal-free N-doped carbon catalyst in the formation of imines.
- Wang, Kaizhi,Jiang, Pengbo,Yang, Ming,Ma, Ping,Qin, Jiaheng,Huang, Xiaokang,Ma, Lei,Li, Rong
-
p. 2448 - 2461
(2019/05/17)
-
- Hydration of nitriles using a metal-ligand cooperative ruthenium pincer catalyst
-
Nitrile hydration provides access to amides that are important structural elements in organic chemistry. Here we report catalytic nitrile hydration using ruthenium catalysts based on a pincer scaffold with a dearomatized pyridine backbone. These complexes catalyze the nucleophilic addition of H2O to a wide variety of aliphatic and (hetero)aromatic nitriles in tBuOH as solvent. Reactions occur under mild conditions (room temperature) in the absence of additives. A mechanism for nitrile hydration is proposed that is initiated by metal-ligand cooperative binding of the nitrile.
- Guo, Beibei,Otten, Edwin,De Vries, Johannes G.
-
p. 10647 - 10652
(2019/12/02)
-
- Trash to treasure: Eco-friendly and practical synthesis of amides by nitriles hydrolysis in WepPA
-
The hydration of nitriles to amides in a water extract of pomelo peel ash (WEPPA) was realized with moderate to excellent yields without using external transition metals, bases or organic solvents. This reaction features a broad substrate scope, wide functional group tolerance, prominent chemoselectivity, and good reusability. Notably, a magnification experiment in this bio-based solvent at 100 mmol further demonstrated its practicability.
- Sun, Yajun,Jin, Weiwei,Liu, Chenjiang
-
supporting information
(2019/11/11)
-
- Ru (III) Schiff-base complex anchored on nanosilica as an efficient and retrievable catalyst for hydration of nitriles
-
Transition metal catalyzed hydration of nitriles is an attractive methodology for amide synthesis, and hence recently attracted wide attention. It is one of the significant organic transformations as amides play a vital role in biological, pharmaceutical and industrial applications. In this work, we report the synthesis of a new solid supported Ru (III) Schiff base complex, Ru@imine-nanoSiO2 immobilized on nanosilica obtained from rice husk. The complex was characterized by FTIR, powder X-ray diffraction, BET surface area measurement, UV–vis, SEM–EDX, TEM, ESR, X-ray photoelectron spectroscopy and ICP-AES analysis. Using Ru@imine-nanoSiO2 as the catalyst, the hydration of nitriles in i-PrOH at 40?°C was studied which resulted in good isolated yields (60–99%). The catalyst can be recycled and reused up to 5th cycle without any loss in activity. The products were characterized by FTIR, GC–MS and 1H-NMR spectroscopy and compared with authentic samples.
- Sultana, Samim,Borah, Geetika,Gogoi, Pradip K.
-
-
- The reductive deaminative conversion of nitriles to alcohols using: Para -formaldehyde in aqueous solution
-
We report herein, for the first time, the application of para-formaldehyde (pFA) to the reductive deamination of both aliphatic and aromatic nitriles in aqueous solution under transfer hydrogenation conditions. A broad range of primary alcohols have been synthesized selectively with very good to excellent yields under the optimized conditions. The study disclosed that the air-stable, inexpensive and commercially available catalyst [Ru(p-cymene)Cl2]2 acts as the catalyst precursor in this reaction, converting to other more active catalytic species in the presence of pFA, resulting in its degradation to CO2 and H2. Nitriles are also showed to play a dual role in this transformation, both as a substrate and as a ligand, where the dimeric catalyst structures convert to monomeric ones upon the coordination of nitrile molecules.
- Tavakoli, Ghazal,Prechtl, Martin H. G.
-
p. 6092 - 6101
(2019/11/11)
-
- [VO(PS-BBMA)](SO4) catalyzed Α-oxygenation of benzylamines to amides in solvent free condition
-
Polymer anchored [VO(PS-BBMA)]SO4 and unsupported [VO(BBMA)]SO4 catalysts were synthesized and characterized by elemental analyses, FT-IR, ESR, UV–vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM). A protocol for the synthesis of benzamides from benzylamine has been developed using [VO(PS-BBMA]SO4 as an effective catalyst under solvent free conditions in presence of H2O2. The reactions provide good yields of the corresponding amide products with substrate scope and excellent functional group compatibility. The developed catalyst can be facilely recovered, heterogeneous, compared with unsupported analogue and reused six times without significant decrease in its activity.
- Renuka,Gayathri
-
-
- Ionic liquid catalysed aerobic oxidative amidation and thioamidation of benzylic amines under neat conditions
-
Tetrabutylammonium hydroxide (TBAOH) was discovered as a highly efficient and green catalyst for aerobic oxidation of the α-methylene carbon of primary amines as well as benzylic groups into the corresponding amides and ketones under neat conditions. We described herein, ionic liquid TBAOH catalysed aerobic oxidation of benzyl amines to benzamides and with elemental sulfur; the corresponding benzylbenzothioamides were obtained under metal-free, oxidant-free and base-free conditions. Applicability at the gram scale for the synthesis of the desired amides/ketones is also demonstrated with the present protocol.
- Joshi, Abhisek,Kumar, Rahul,Semwal, Rashmi,Rawat, Deepa,Adimurthy, Subbarayappa
-
supporting information
p. 962 - 967
(2019/03/11)
-
- Aerobic Activation of C-H Bond in Amines Over a Nanorod Manganese Oxide Catalyst
-
The development of heterogeneous catalysts for the synthesis of pharmaceutically relevant compounds is always important for chemistry research. Here, we report a selective aerobic oxidation of aromatic and aliphatic amines to corresponding amides over a nanorod manganese oxide (NR-MnOx) catalyst. The kinetic studies reveal that the NR-MnOx catalyzed amine-to-amide reaction proceeds the oxidative dehydrogenation of the amines into nitriles, followed by hydrolysis of nitrile into amides. The NR?MnOx exhibits fast kinetics and high selectivities in these steps, as well as hinders the by-product formation. More importantly, the NR-MnOx catalyst is stable and reusable in the continuous recycle tests with water as a sole by-product, exhibiting superior sustainability and significant advancement to outperform the traditional amide production route in acidic or basic media with toxic by-products.
- Wang, Hai,Wang, Liang,Wang, Sai,Dong, Xue,Zhang, Jian,Xiao, Feng-Shou
-
p. 401 - 406
(2018/08/11)
-
- Synthetic method for nicotinamide
-
The invention belongs to the field of organic chemistry, and discloses a synthetic method for nicotinamide. The method comprises the following steps: using ethanol as a solvent, using 3-methylpyridineas a raw material, introducing a dried nitrosyl chloride gas, performing a photonitrosation-isomerization reaction under irradiation of visible light at temperature of 0-30 DEG C, after the reactionis completed, introducing a nitrogen gas, adding an alkali to adjust pH of the reaction solution to be 6-9, and performing filtration to obtain a filtrate; and adding a copper salt and a nitrile intothe filtrate as a catalyst, performing heating, performing reflux, performing an aldoxime Beckmann rearrangement reaction, after the reaction is completed, adding ethyl acetate crystals into the reaction solution, performing filtration to obtain a crude product of the nicotinamide, and performing recrystallization on the crude product of the nicotinamide to obtain a pure product of the nicotinamide. The synthetic method provided by the invention has mild reaction conditions, a simple process and a high yield, can obtain the high-purity nicotinamide product, has less three waste (waste water, waster gas and solid waste) and high economy, and is suitable for industrialized large-scale production.
- -
-
Paragraph 0028; 0030; 0031; 0033; 0034; 0036
(2018/09/11)
-
- Corresponding amine nitrile and method of manufacturing thereof
-
The invention relates to a manufacturing method of nitrile. Compared with the prior art, the manufacturing method has the characteristics of significantly reduced using amount of an ammonia source, low environmental pressure, low energy consumption, low production cost, high purity and yield of a nitrile product and the like, and nitrile with a more complex structure can be obtained. The invention also relates to a method for manufacturing corresponding amine from nitrile.
- -
-
Paragraph 0135; 0136; 0137; 0145
(2018/05/07)
-
- Water-soluble superbulky (η6- p -cymene) ruthenium(ii) amine: An active catalyst in the oxidative homocoupling of arylboronic acids and the hydration of organonitriles
-
A phosphine free water-soluble superbulky amine-ruthenium-arene complex (2) encompassing 2,6-bis(diphenylmethyl)-4-methylaniline was synthesised in good yield. 2 was characterized by FT-IR, 1H NMR, and 13C NMR spectroscopies, TGA and elemental analyses. The structure of 2 was confirmed by a single-crystal X-ray diffraction study. The ruthenium centre in 2 adopts the pseudo-octahedral geometry due to the η6-p-cymene ring and bulky aniline ligand along with two chloro groups. Besides, complex 2 was efficaciously employed as a catalyst in the hydration of organonitriles to amides. This reaction proceeds efficiently for a wide range of substrates in an environmentally benign medium and is an economically reasonable synthetic route to amides in good yields. In addition, 2 acts as an excellent catalyst in the oxidative homocoupling of arylboronic acids in water. A range of arylboronic acids undergo a homocoupling reaction in the presence of catalyst 2 to yield symmetrical biaryls in reasonable to good yields.
- Nirmala, Muthukumaran,Adinarayana, Mannem,Ramesh, Karupnaswamy,Maruthupandi, Mannarsamy,Vaddamanu, Moulali,Raju, Gembali,Prabusankar, Ganesan
-
supporting information
p. 15221 - 15230
(2018/09/29)
-
- Monomeric nickel hydroxide stabilized by a sterically demanding phosphorus-nitrogen PN3P-pincer ligand: synthesis, reactivity and catalysis
-
A terminal nickel hydroxide complex (PN3P)Ni(OH) (3) bearing the 2nd generation phosphorus-nitrogen PN3P-pincer ligand has been synthesized and structurally characterized. As a nucleophile, 3 reacts with CO to afford the hydroxycarbonyl complex 4, (PN3P)Ni(COOH). 3 can also activate CO2 and CS2 to produce nickel bicarbonate (PN3P)Ni(OCOOH) (5) and bimetallic dithiocarbonate [(PN3P)NiS]2CO (6) respectively, as well as to promote aryl isocyanate and isothiocyanate insertion into the Ni-OH bond to give the corresponding (PN3P)NiEC(O)NHAr complexes (E = O, 7; E = S, 8). In addition, 3 catalyzes the nitrile hydration to various amides with well-defined intermediates (PN3P)Ni-NHC(O)R (R = Me, 9; R = Ph, 10).
- Yao, Changguang,Chakraborty, Priyanka,Aresu, Emanuele,Li, Huaifeng,Guan, Chao,Zhou, Chunhui,Liang, Lan-Chang,Huang, Kuo-Wei
-
p. 16057 - 16065
(2018/11/30)
-
- Bifunctional organometallic catalysts for selective hydration of nitriles to amides
-
In this report, we highlight our recent contributions towards the development of bifunctional catalysts for selective hydration of nitriles to amides.
- Singh, Kuldeep,Sarbajna, Abir,Bera, Jitendra K.
-
p. 853 - 861
(2020/06/26)
-
- Nitrile Hydration Reaction Using Copper Iodide/Cesium Carbonate/DBU in Nitromethane-Water
-
The catalytic nitrile hydration (amide formation) in a copper iodide/cesium carbonate/1,8-diazabicyclo[5.4.0]undec-7-ene/nitromethane-water system is described. The protocol is robust and reliable; it can be applied to a broad range of substrates with high chemoselectivity.
- Kuwabara, Jun,Sawada, Yoshiharu,Yoshimatsu, Mitsuhiro
-
supporting information
p. 2061 - 2065
(2018/09/14)
-
- Mn(i) organometallics containing the iPr2P(CH2)2PiPr2 ligand for the catalytic hydration of aromatic nitriles
-
The first example of a homogeneous hydration of aromatic nitriles catalyzed by manganese molecular compounds is reported. The Mn(i) organometallics fac-[(CO)3Mn(dippe)(Z)]1-nX1-n (n = 0, 1; Z = Br, OTf, PhCN; X = OTf) were synthesized and characterized, and their reactivity was studied. The species fac-[(CO)3Mn(dippe)(OTf)] (2) was used as a catalyst precursor for the selective hydration of benchmark benzonitrile (2 mol% 2, THF/H2O 1:2 v/v, 18 h, 100 °C) to produce benzamide in 90% isolated yield. A series of (hetero)aromatic nitriles were hydrated to synthesize the corresponding amides in very good to excellent yields (88-94%). Isotopic labeling studies accounted for a proton transfer as the rate-determining step.
- Gardu?o, Jorge A.,Arévalo, Alma,Flores-Alamo, Marcos,García, Juventino J.
-
p. 2606 - 2616
(2018/05/30)
-
- Highly Active Platinum Catalysts for Nitrile and Cyanohydrin Hydration: Catalyst Design and Ligand Screening via High-Throughput Techniques
-
Nitrile hydration provides access to amides that are indispensable to researchers in chemical and pharmaceutical industries. Prohibiting the use of this venerable reaction, however, are (1) the dearth of biphasic catalysts that can effectively hydrate nitriles at ambient temperatures with high turnover numbers and (2) the unsolved challenge of hydrating cyanohydrins. Herein, we report the design of new "donor-acceptor"-type platinum catalysts by precisely arranging electron-rich and electron-deficient ligands trans to one other, thereby enhancing both the nucleophilicity of the hydroxyl group and the electrophilicity of the nitrile group. Leveraging a high-throughput, automated workflow and evaluating a library of bidentate ligands, we have discovered that commercially available, inexpensive DPPF [1,1′-ferrocenendiyl-bis(diphenylphosphine)] provides superior reactivity. The corresponding "donor-acceptor"-type catalyst 2a is readily prepared from (DPPF)PtCl2, PMe2OH, and AgOTf. The enhanced activity of 2a permits the hydration of a wide range of nitriles and cyanohydrins to proceed at 40 °C with excellent turnover numbers. Rational reevaluation of the ligand structure has led to the discovery of modified catalyst 2c, harboring the more electron-rich 1,1′-bis[bis(5-methyl-2-furanyl)phosphino] ferrocene ligand, which demonstrates the highest activity toward hydration of nitriles and cyanohydrins at room temperature. Finally, the correlation between the electron-donating ability of the phosphine ligands with catalyst efficiencies of 2a, 2c, 2d, and 2e in the hydration of nitrile 7 are examined, and the results support the "donor-acceptor" hypothesis.
- Xing, Xiangyou,Xu, Chen,Chen, Bo,Li, Chengcheng,Virgil, Scott C.,Grubbs, Robert H.
-
supporting information
p. 17782 - 17789
(2019/01/04)
-
- Chemoselective hydrogenation of nitriles to primary amines catalyzed by water-soluble transition metal catalysts
-
The water-soluble rhodium complex generated in situ from [Rh (COD)Cl]2 in aqueous ammonia has been revealed as a highly efficient catalyst for the hydrogenation of aromatic nitriles, to primary amines with excellent yields. The catalyst is also highly selective towards primary amines in the case of sterically hindered aliphatic nitriles. The catalytic system can also be recycled and re-used with no significant loss of activity.
- Nait Ajjou, Abdelaziz,Robichaud, André
-
-
- PHP-Tethered N-Acyl Carbamate: A Photocage for Nicotinamide
-
The synthesis of a new photocaged nicotinamide having an N-acyl carbamate linker and a p-hydroxyphenacyl (pHP) chromophore is described. The photophysical and photochemical studies showed an absorption maximum at λ = 330 nm and a quantum yield for release of 11% that are dependent upon both pH and solvent. While the acyl carbamate releases nicotinamide efficiently, a simpler amide linker was inert to photocleavage. This photocaged nicotinamide has significant advantages with respect to quantum yield, absorbance wavelength, rate of release, and solubility that make it the first practical example of a photocaged amide.
- Salahi, Farbod,Purohit, Vatsal,Ferraudi, Guillermo,Stauffacher, Cynthia,Wiest, Olaf,Helquist, Paul
-
p. 2547 - 2550
(2018/05/22)
-
- Method for using 3-methylpyriine to synthesize nicotinamide through one-step method
-
The invention provides a method for using 3-methylpyriine to synthesize nicotinamide through a one-step method, and relates to the field of organic synthesis. The method comprises the following stepsof 1, adding 3-methylpyriine and magnesium dioxide into a high-pressure reactor, introducing carbon dioxide and ammonia gas, conducting a reaction under the high-temperature and high-pressure condition, and after the reaction is finished, lowering the temperature and filtering to remove magnesium dioxide; 2, using ethyl alcohol to wash magnesium dioxide, firstly conducting reduced pressure distillation to remove ethyl alcohol, and then conducting reduced pressure distillation to remove unreacted 3-methylpyriine; 3, using diethyl ether to wash the obtained solid to obtain nicotinamide. By meansof the method for using 3-methylpyriine to synthesize nicotinamide through the one-step method, one-step reaction is conducted, the reaction time is short, the yield coefficient is high, the aftertreatment is simple, and obtained nicotinamide is high in purity.
- -
-
Paragraph 0022-0056
(2018/04/21)
-
- Highly Selective Ruthenium-Catalyzed Direct Oxygenation of Amines to Amides
-
Reports on aerobic oxidation of amines to amides are rare, and those reported suffer from several limitations like poor yield or selectivity and make use of pure oxygen under elevated pressure. Herein, we report a practical and an efficient ruthenium-catalyzed synthetic protocol that enables selective oxidation of a broad range of primary aliphatic, heterocyclic and benzylic amines to their corresponding amides, using readily available reagents and ambient air as the sole oxidant. Secondary amines instead, yield benzamides selectively as the sole product. Mechanistic investigations reveal intermediacy of nitriles, which undergo hydration to afford amide as the final product.
- Ray, Ritwika,Hazari, Arijit Singha,Chandra, Shubhadeep,Maiti, Debabrata,Lahiri, Goutam Kumar
-
supporting information
p. 1067 - 1071
(2018/01/03)
-
- The use of a manganese oxide of the amine of preparation of amides oxidation method (by machine translation)
-
The invention relates to the synthesis of amide compound catalyst, and aims at providing a oxidation using manganese oxide of the amine of preparation of amides method. Including: the pressure in the container adding organic solvent, organic amine substrate and catalyst and uniformly mixed, and then filled with oxygen, the reaction process through the catalyst in the catalytic oxidation, organic amine substrate of alpha nanotube growing C=O double bond is formed, thereby obtaining the amide group and finally generates the amide compound. The invention relates to catalyst of the cheap and easy to obtain, in the catalyst of gas relates to oxide, unused to any noble metal, so that the preparation cost of the catalyst is relatively low, conducive to the realization of large-scale production of the catalyst. The method the reaction temperature is low, and in the course of synthesizing reaction assistant without additional added, after reaction without harmful toxic by-product to produce, in the whole synthesis process is environment-friendly. (by machine translation)
- -
-
Paragraph 0087; 0088
(2018/10/19)
-
- Mechanistic Studies of Palladium-Catalyzed Aminocarbonylation of Aryl Chlorides with Carbon Monoxide and Ammonia
-
Mechanistic information on a reliable, palladium-catalyzed aminocarbonylation of aryl chlorides with ammonia is reported. The reaction occurs with ethylene complex 1 as catalyst, and mechanistic information was gained by isolation of catalytic intermediates and kinetic measurements, including the first mechanistic data on the oxidative addition of aryl chloride to a palladium(0) complex in the presence of CO. Arylpalladium and phenacylpalladium halide intermediates were synthesized, and kinetic measurements of the formation and reactions of these intermediates were undertaken to determine the mechanism of the oxidative addition of aryl bromides and chlorides to a Pd(0) dicarbonyl compound in the presence of CO and the mechanism of the reaction of ammonia with a Pd(II) phenacyl complex to form benzamide. The oxidative addition of aryl chlorides and aryl bromides was determined to occur with rate-limiting reaction of the haloarene with a three-coordinate Pd(0) species bearing a bidentate phosphine and one CO ligand. A primary 13C kinetic isotope effect suggested that this step involves cleavage of the carbon-halogen bond. Our data show that the formation of benzamide from the reaction of phenacylpalladium halide complexes with ammonia occurs by a pathway involving reversible displacement of chloride from a phenacylpalladium chloride complex by ammonia, deprotonation of the bound ammonia to form a phenacylpalladium amido complex, and reductive elimination to form the C-N bond. Consistent with this mechanism, the reaction of an aryl palladium amido complex with CO formed the corresponding primary benzamide. A catalyst deactivation pathway involving the formation of a Pd(I) dimer also was elucidated.
- Wang, Justin Y.,Strom, Alexandra E.,Hartwig, John F.
-
supporting information
p. 7979 - 7993
(2018/06/11)
-
- Hexagonal Mesoporous Silica-Supported Copper Oxide (CuO/HMS) Catalyst: Synthesis of Primary Amides from Aldehydes in Aqueous Medium
-
Hexagonal mesoporous silica (HMS)-supported copper oxides (CuO/HMS) have been prepared by a sol–gel method and characterized by X-ray diffraction, FTIR spectroscopy, transmission electron microscopy, N2 sorption, inductively coupled plasma (ICP), X-ray photoelectron spectroscopy (XPS), H2 temperature-programed reduction (TPR), NH3 temperature-programed desorption (TPD), and high-resolution (HR)-TEM techniques. An analysis of these results revealed a mesoporous material system with a high surface area (974 m2 g?1) and uniform pore-size distribution. The catalytic efficacy of CuO on the HMS support with varying Cu loadings (1, 3, 5, 10, and 15 wt %) was investigated for the transformation of aldehydes to primary amides; 3 wt % CuO/HMS exhibited good catalytic performance with good to excellent yields of amides (60–92 %) in benign aqueous medium. The intrinsically heterogeneous catalyst could be recovered after the reaction and reused without any noticeable loss in activity.
- Kadam, Ravishankar G.,Rathi, Anuj K.,Cepe, Klara,Zboril, Radek,Varma, Rajender S.,Gawande, Manoj B.,Jayaram, Radha V.
-
p. 467 - 473
(2017/04/13)
-
- Deoxygenation of tertiary amine N-oxides under metal free condition using phenylboronic acid
-
A simple and efficient method for the deoxygenation of amine N-oxides to corresponding amines is reported using the green and economical reagent phenylboronic acid. Deoxygenation of N,N-dialkylaniline N-oxides, trialkylamine N-oxides and pyridine N-oxides were achieved in good to excellent yields. The reduction susceptible functional groups such as ketone, amide, ester and nitro groups are well tolerated with phenylboronic acid during the deoxygenation process even at high temperature. In addition, an indirect method for identification and quantification of tert-amine N-oxide is demonstrated using UV–Vis spectrometry which may be useful for drug metabolism studies.
- Gupta, Surabhi,Sureshbabu, Popuri,Singh, Adesh Kumar,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
-
supporting information
p. 909 - 913
(2017/02/15)
-
- Amidation of carboxylic acids via the mixed carbonic carboxylic anhydrides and its application to synthesis of antidepressant (1S,2R)-tranylcypromine
-
Primary amidations of carboxylic acids 1 or 3 with NH4Cl in the presence of ClCO2Et and Et3N were developed to afford the corresponding primary amides in 22% to quantitative yields. Additionally, we have applied the amidation to the preparation of various amides containing hydroxamic acids and achieved the synthesis of (1S,2R)-tranylcypromine as an antidepressant medicine via Lossen rearrangement.
- Ezawa, Tetsuya,Kawashima, Yuya,Noguchi, Takuya,Jung, Seunghee,Imai, Nobuyuki
-
p. 1690 - 1699
(2017/11/14)
-
- Hemilability-Driven Water Activation: A NiII Catalyst for Base-Free Hydration of Nitriles to Amides
-
The NiII complex 1 containing pyridyl- and hydroxy-functionalized N-heterocyclic carbenes (NHCs) is synthesized and its catalytic utility for the selective nitrile hydration to the corresponding amide under base-free conditions is evaluated. The title compound exploits a hemilabile pyridyl unit to interact with a catalytically relevant water molecule through hydrogen-bonding and promotes a nucleophilic water attack to the nitrile. A wide variety of nitriles is hydrated to the corresponding amides including the pharmaceutical drugs rufinamide, Rifater, and piracetam. Synthetically challenging α-hydroxyamides are accessed from cyanohydrins under neutral conditions. Related catalysts that lack the pyridyl unit (i.e., compounds 2 and 4) are not active whereas those containing both the pyridyl and the hydroxy or only the pyridyl pendant (i.e., compounds 1 and 3) show substantial activity. The linkage isomer 1′ where the hydroxy group is bound to the metal instead of the pyridyl group was isolated under different crystallization conditions insinuating a ligand hemilabile behavior. Additional pKa measurements reveal an accessible pyridyl unit under the catalytic conditions. Kinetic studies support a ligand-promoted nucleophilic water addition to a metal-bound nitrile group. This work reports a Ni-based catalyst that exhibits functional hemilability for hydration chemistry.
- Singh, Kuldeep,Sarbajna, Abir,Dutta, Indranil,Pandey, Pragati,Bera, Jitendra K.
-
supporting information
p. 7761 - 7771
(2017/06/06)
-
- Method for preparing nicotinamide from 3-methylpyridine
-
The invention provides a method for preparing nicotinamide from 3-methylpyridine. The 3-methylpyridine is taken as a raw material; 3-cyanopyridine is obtained through catalytic oxidation under the action of a VPO/SiO2 catalyst; and a phase transfer cataly
- -
-
Paragraph 0022; 0026; 0030; 0034; 0037; 0040; 0043; 0046
(2017/07/19)
-
- I2-Catalyzed Oxidative Amidation of Benzylamines and Benzyl Cyanides under Mild Conditions
-
We report a novel and efficient method for the oxidation of benzylic carbons (amines and cyanides) into corresponding benzamides using a catalytic amount of I2 and TBHP as the green oxidant via the C-H bond cleavage of the benzylic carbon under mild reaction conditions. According to the literature survey, this is the first report for the oxidative amidation of benzylamines and decyanation of benzyl cyanides in one pot under metal-free conditions.
- Nageswara Rao, Sadu,Reddy, N. Naresh Kumar,Samanta, Supravat,Adimurthy, Subbarayappa
-
p. 13632 - 13642
(2017/12/26)
-
- Emissive Synthetic Cofactors: An Isomorphic, Isofunctional, and Responsive NAD+ Analogue
-
The synthesis, photophysics, and biochemical utility of a fluorescent NAD+ analogue based on an isothiazolo[4,3-d]pyrimidine core (NtzAD+) are described. Enzymatic reactions, photophysically monitored in real time, show NtzAD+ and NtzADH to be substrates for yeast alcohol dehydrogenase and lactate dehydrogenase, respectively, with reaction rates comparable to that of the native cofactors. A drop in fluorescence is seen as NtzAD+ is converted to NtzADH, reflecting a complementary photophysical behavior to that of the native NAD+/NADH. NtzAD+ and NtzADH serve as substrates for NADase, which selectively cleaves the nicotinamide's glycosidic bond yielding tzADP-ribose. NtzAD+ also serves as a substrate for ribosyl transferases, including human adenosine ribosyl transferase 5 (ART5) and Cholera toxin subunit A (CTA), which hydrolyze the nicotinamide and transfer tzADP-ribose to an arginine analogue, respectively. These reactions can be monitored by fluorescence spectroscopy, in stark contrast to the corresponding processes with the nonemissive NAD+.
- Rovira, Alexander R.,Fin, Andrea,Tor, Yitzhak
-
supporting information
p. 15556 - 15559
(2017/11/14)
-
