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Homogeneous Catalytic Photochemical Functionalization of Alkanes by Polyoxometalatas
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Renneke, Roman F.,Hill, Craig L.
p. 3528 - 3529
(1986)
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FTIR spectroscopic study of hydrogen bonding and solvent induced frequency shifts of N-tert-butylacetamide
This paper reports the results of FTIR study of N-tert-butylacetamide in carbon tetrachloride solution and in presence of seven different molecules as H acceptors. The spectroscopic characteristics for NH?O hydrogen bonded complexes are given. Also, the equilibrium constants for 1:1 complex formation, at 25 °C were determined by using IR measurements. Frequency shifts of carbonyl stretching vibration ν(CO) of N-tert-butylacetamide in the same organic H acceptors was also investigated. The wavenumbers of carbonyl stretching vibration ν(CO) were correlated with the solvent acceptor number (AN) and the linear solvation energy relationships (LSERs).
Jovi?, Branislav,Nikoli?, Aleksandar,Petrovi?
p. 140 - 143
(2013)
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Surface ligands enhance the catalytic activity of supported Au nanoparticles for the aerobic α-oxidation of amines to amides
The catalytic aerobic α-oxidation of amines in water is an atom economic and green alternative to current methods of amide synthesis. The reaction uses O2 as terminal oxidant, avoids hazardous reactants and gives water as the only byproduct. Here we report that the catalytic activity of silica-supported Au nanoparticles for the aerobic α-oxidation of amines can be improved by tethering pyridyl ligands to the support. In contrast, immobilization of thiol groups on the material gives activities comparable to Au supported on bare silica. Our studies indicate that the ligands affect the electronic properties of the Au nanoparticles and thereby determine their ability to activate O2 and mediate C-H cleavage in the amine substrate. The reaction likely proceeds via an Au catalyzed β-hydride elimination enabled by backdonation from electron-rich metal to the orbital. O2, which is also activated on electron-rich Au, acts as a scavenger to remove H from the metal surface and regenerate the active sites. The mechanistic understanding of the catalytic conversion led to a new approach for forming C-C bonds α to the N atoms of amines.
Chatterjee, Puranjan,Kanbur, Uddhav,Manzano, J. Sebastián,Sadow, Aaron D.,Slowing, Igor I.,Wang, Hsin
p. 1922 - 1933
(2022/04/07)

Preparation method of acetamide compound
The invention discloses a preparation method of an acetamide compound, the preparation method comprises the following steps: reacting tetracarbonyl dichloride rhodium, 1, 3-bis (diphenylphosphine) propane, tungsten carbonyl, sodium phosphate, sodium iodide, water, a nitro compound and dimethyl carbonate at 120 DEG C for 24 hours, and after the reaction is completed, performing post-treatment to obtain the acetamide compound. According to the preparation method, dimethyl carbonate serves as a C1 source and also serves as a green solvent, operation is easy, reaction starting raw materials are low in price and easy to obtain, the tolerance range of substrate functional groups is wide, and reaction efficiency is high. Various acetamide compounds can be synthesized according to actual needs, so that the practicability of the method is widened while the operation is convenient.
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Paragraph 0035-0047

(2021/05/19)

A novel construction of acetamides from rhodium-catalyzed aminocarbonylation of DMC with nitro compounds
Dimethyl carbonate (DMC), an environment-friendly compound prepared from CO2, shows diverse reactivities. In this communication, an efficient procedure using DMC as both a C1 building block and solvent in the aminocarbonylation reaction with nitro compounds has been developed. W(CO)6acts both a CO source and a reductant here.
Bao, Zhi-Peng,Miao, Ren-Guan,Qi, Xinxin,Wu, Xiao-Feng
supporting information
p. 1955 - 1958
(2021/03/02)

Chemoselective formation of C–N bond in wet acetonitrile using amberlyst-15(H) as a recyclable catalyst
An economically efficient and environmentally benign protocol for the chemoselective one-pot synthesis of diversely N-substituted amides has been developed in good yield through the reaction of benzylic secondary alcohols as well as aliphatic tertiary alcohols and alkyl/aryl nitriles. Commercially available Amberlyst-15(H) has been utilized at 80 °C as an air-stable and reusable heterogeneous inexpensive solid acid catalyst without any anhydrous and inert environment. The attractive features of the present synthetic protocol are mild reaction conditions, short reaction time, excellent chemoselectivity, high atom economy and tolerance of various sensitive moieties.
Nandy, Sneha,Das, Asit Kumar,Bhar, Sanjay
supporting information
p. 3326 - 3336
(2020/08/13)

New half-sandwich (η6-p-cymene)ruthenium(II) complexes with benzothiazole hydrazone Schiff base ligand: Synthesis, structural characterization and catalysis in transamidation of carboxamide with primary amines
Few half-sandwich (η6-p-cymene) ruthenium(II) complexes supported by benzothiazole hydrazone Schiff bases were synthesized. The new complexes possess the general formulae [Ru(η6-p-cymene)(L)Cl] (1-3) (L = salicyl((2-(benzothiazol-2-yl)hydrazono)methylphenol) (SAL-HBT), 2-((2-(benzothiazol-2-yl)hydrazono)methyl)-6 methoxyphenol) (VAN-HBT) or naphtyl-2-((2-(benzothiazol-2-yl)hydrazono)methyl phenol) (NAP-HBT). All compounds were fully studied by analytical, spectroscopic techniques (IR, NMR) and also by mass spectrometry. The solid state structure of the complex 3 reveals the coordination of p-cymene moieties with ruthenium(II) in a three-legged piano-stool geometry along with benzothiazole hydrazone Schiff base ligand in a monobasic bidentate fashion. The catalytic properties of the complexes were screened in transamidation of primary amide with amines after optimization with respect to solvent, substituents, time and catalyst loading. The results show that the complex 3 is the most efficient catalyst for the transamidation of carboxamides with amines.
Vijayapritha, Subbarayan,Viswanathamurthi, Periasamy
supporting information

(2020/10/18)

CoFe2O4?SiO2-NH-βCD-BF3 as a supramolecular nanocomposite: Synthesis, characterization and catalytic activity
This manuscript describes synthesis of BF3-functionlized β-cylcodextrine grafted magnetic CoFe2O4 nanaoparticles as a hybrid magnetic nano-composite (CoFe2O4?SiO2-NH-βCD-BF3). The CoFe2O4?SiO2-NH-βCD-BF3 was fabricated by grafting of 6-O-toluenesulfonyl cyclodextrin (6-Ts-βCD) to 3-aminopropyl triethoxysilane coated magnetic CoFe2O4?SiO2 nanoparticles followed by combination with BF3. The CoFe2O4?SiO2-NH-βCD-BF3was characterized by FT-IR, TGA, VSM and SEM techniques. The feasibility of using CoFe2O4?SiO2-NH-βCD-BF3 as a magnetically recoverable catalyst was confirmed in the modified-Ritter reaction. The result showed that this novel nano-composite could serve as an efficient nanoreactor bearing super-acidic sites formed by immobilized BF3 and reuse at least for 6 times without loss in activity.
Hamadi, Hosein,Zanjani, Zohreh,Yadollahi, Mahtab
(2019/11/14)

Silicon-Mediated Coupling of Carbon Monoxide, Ammonia, and Primary Amines to Form Acetamides
For the first time, a direct transformation of CO, NH3, and primary amines into acetamides, mediated by a main-group element (silicon), is reported. Starting point is the selective deoxygenative reductive homocoupling of two CO molecules by the Fc-bis(silylene) 1 a (Fc=ferrocendiyl) as a reducing agent, which forms the ferrocendiyl-bridged disila(μ-O)(μ-CCO)ketene intermediate 2 a. Exposing 2 a to NH3 (1 bar, 298 K) and benzylamine yields the Fc-disiloxanediamines [Fc(RHNSi-O-SiNHR)] 5 a (R=H) and 5 b (R=benzyl) under release of the respective acetamides H3CC(O)NHR, as confirmed by 13C-isotope-labelling experiments. IR and NMR studies of the reaction reveal a four-step mechanism involving an N-silylated carboxamide that can be isolated and fully characterized. The striking reaction mechanism for this unprecedented transformation involves a facile Si?C bond cleavage and ammonolysis of a Si?O bond, and has been demonstrated experimentally and by quantum-chemical calculations.
Luecke, Marcel-Philip,Kostenko, Arseni,Wang, Yuwen,Yao, Shenglai,Driess, Matthias
supporting information
p. 12940 - 12944
(2019/07/18)

Air-stable Bis(pentamethylcyclopentadienyl) Zirconium Perfluorooctanesulfonate as an Efficient and Recyclable Catalyst for the Synthesis of N-substituted Amides
Bis(pentamethylcyclopentadienyl) zirconium perfluorooctanesulfonate is an air-stable and water-tolerant Lewis acid. This complex exhibited good thermal stability and high solubility in polar organic solvents. The compound showed relatively strong acidity, with an acid strength of 0.8Ho≤3.3, and high catalytic efficiency for the synthesis of N-substituted amides via the reaction of carboxylic acids with amines, the Ritter reaction of nitriles with alcohols, and the amination of alcohols with amides. Moreover, the complex had good reusability. This catalytic system affords a simple and efficient way to synthesize N-substituted amides.
Li, Ningbo,Wang, Lingxiao,Zhang, Liting,Zhao, Wenjie,Qiao, Jie,Xu, Xinhua,Liang, Zhiwu
p. 3532 - 3538
(2018/08/01)

Sulfated choline ionic liquid-catalyzed acetamide synthesis by grindstone method
Sulfated choline ionic liquid (SCIL) has been found to be an efficient solid acid IL catalyst for the protection of amine groups with acetic anhydride under solvent-free grindstone conditions. The attractive features of this new catalytic methodology include its sustainability, facile work-up procedure, economic viability, and biodegradability. The SCIL catalyst was characterized using infrared spectroscopy, wide-angle X-ray scattering analysis, and scanning electron microscopy with energy dispersive X-ray spectroscopy. The catalyst could be reused six times without significant loss in activity. Furthermore, no chromatographic separations were needed to obtain the desired products.
Kalla, Reddi Mohan Naidu,Lim, Jaehwa,Bae, Jaeyeong,Kim, Il
supporting information
p. 1595 - 1599
(2017/04/03)

Electrophilic Fluorination of Secondary Phosphine Oxides and Its Application to P-O Bond Construction
A novel and efficient electrophilic fluorination of secondary phosphine oxides with Selectfluor has been achieved. This transformation provides direct access to phosphoric fluorides in up to 92% yield under mild conditions. In addition, P-O bond construction via a one-pot coupling process of secondary phosphine oxides with water or alcohols in the presence of Selectfluor leads to the formation of phosphinic acids or phosphinates in up to 96% yield.
Chen, Qian,Zeng, Jiekun,Yan, Xinxing,Huang, Yulin,Wen, Chunxiao,Liu, Xingguo,Zhang, Kun
p. 10043 - 10048
(2016/11/02)

Homoleptic zirconium amidates: Single source precursors for the aerosol-assisted chemical vapour deposition of ZrO2
We report the development of a true single source precursor (i.e. without any need for an exogenous source of oxygen) for the growth of zirconia thin films by aerosol-assisted chemical vapour deposition (AACVD) using an original family of zirconium(iv) amidate derivatives, which are easily prepared by protonolysis of [Zr(NMe2)4] with the free amide pro-ligands. In all but one case the reactions resulted in the isolation of the corresponding homoleptic eight-coordinate zirconium(iv)tetrakis(amidato) derivatives. Three of these species along with a tris(amidato)dimethylamido zirconium(iv) derivative have been characterised by single crystal X-ray diffraction analysis. The materials potential of the homoleptic compounds was identified through the application of design criteria derived from consideration of the existing knowledge base relating to the pyrolysis of wholly organic amides. In this manner the thermal decomposition of the homoleptic derivatives benefits from facile, molecularly imposed pyrolysis pathways, which provide for the privileged generation of volatile small molecule by-products and the production of contaminant-free solid oxide material. Thermogravimetric analysis, in conjunction with NMR spectroscopic analysis of the volatile products resulting from their thermal decomposition, indicated the potential of the homoleptic species as exquisite single source precursors to ZrO2 at moderate temperatures. The compound bearing both N- and C-iso-propyl substituents was, thus, applied as a true single source precursor under ambient pressure AACVD conditions. The resultant films, deposited on either SiO2-coated glass or quartz substrates, are smooth and comprise small and densely packed crystalline particulates that are shown by XRD to be primarily cubic ZrO2. Compositional analysis by X-ray photoelectron spectroscopy (XPS) revealed that the oxygen delivered, and the decomposition pathway provided, by the amidate ligand structure yields ZrO2 films which, though slightly sub-stoichiometric (ZrO1.8-1.9), contain undetectable levels of carbon incorporation.
Catherall, Amanda L.,Hill, Michael S.,Johnson, Andrew L.,Kociok-K?hn, Gabriele,Mahon, Mary F.
supporting information
p. 10731 - 10739
(2016/11/29)

TfOH catalyzed One-Pot Schmidt–Ritter reaction for the synthesis of amides through N-acylimides
A One-Pot tandem Schmidt–Ritter process for the synthesis of amides has been developed using the super acid as catalyst. The in situ generated aryl/aliphatic nitriles from the reaction of aldehydes and sodium azide in the presence of TfOH and AcOH (Schmidt reaction) react with suitable alcohol (Ritter reaction) to give the amides. For the first time we observed that during the Schmidt process N-acylimides were generated along with nitriles, interestingly these N-acylimides also participated in the Ritter reaction.
Singh, Garima,Dada, Ravikrishna,Yaragorla, Srinivasarao
supporting information
p. 4424 - 4427
(2016/09/13)

Tert-Butyl Iodide Mediated Reductive Fischer Indolization of Conjugated Hydrazones
A novel reductive Fischer indolization of readily available N-aryl conjugated hydrazones with tert-butyl iodide has been developed. In this reaction, tert-butyl iodide is used as anhydrous HI source, and the generated HI acts as a Br?nsted acid and a reducing agent. This operationally simple method allows access to various indole derivatives. Furthermore, the procedure can be applied to the synthesis of biologically active compounds.
Ito, Yuta,Ueda, Masafumi,Takeda, Norihiko,Miyata, Okiko
supporting information
p. 2616 - 2619
(2016/02/26)

Efficient and Green Ritter Reaction for the Synthesis of N-(t-Butyl)- and N-Benzylamides from t-Butyl and Benzyl Acetates
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Nasr-Esfahani, Masoud,Montazerozohori, Morteza,Karami, Zeinab
p. 321 - 327
(2016/08/02)

Mechanochemical ritter reaction: A rapid approach to functionalized amides at room temperature
A fast and efficient mechanochemical Ritter reaction between alcohols and nitriles under mild conditions is demonstrated. The reaction proceeds rapidly at room temperature in a solvent-free or low-solvent environment by using a Br?nsted acid catalyst. Its general application has been verified through a substrate screening comprising a wide range of functionalized nitriles as well as secondary and tertiary alcohols. Gentle Ritter: A fast and efficient mechanochemical Ritter reaction under mild conditions is described. The reaction proceeds rapidly at room temperature in a solvent-free or low-solvent environment by using sulfuric acid as catalyst.
Dokli, Irena,Gredi?ak, Matija
supporting information
p. 2727 - 2732
(2015/04/27)

Magnetically separable γ-Fe2O3 nanoparticles: An efficient catalyst for acylation of alcohols, phenols, and amines using sonication energy under solvent free condition
This paper reports a facile synthesis of magnetically separable iron oxide (γ-Fe2O3) nanoparticles using thermolysis method. The structural and morphological study of the synthesized γ-Fe2O3 nanoparticles was carried out using X-ray diffraction (XRD), field emission gun-scanning electron microscopy (FEG-SEM), energy dispersive X-ray spectrum (EDS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) techniques. The electron microscopy reveals that the γ-Fe2O3 nanoparticles have spherical morphology with a particle size in the range of 40-100 nm. The XPS study confirmed the Fe is in +3 oxidation state. The synthesized γ-Fe2O3 nanoparticles have been used as an efficient heterogeneous catalyst for the organic transformation between phenols, alcohols, and amines with acetic anhydride under sonication using mild reaction conditions. Various electrons withdrawing and electrons donating substrates show an excellent yield of desired products with the advantage of magnetic separation and reusability of γ-Fe2O3 nanocatalyst.
Bhosale, Manohar A.,Ummineni, Divya,Sasaki, Takehiko,Nishio-Hamane, Daisuke,Bhanage, Bhalchandra M.
p. 8 - 17
(2015/04/27)

Direct Preparation of Amides from Amine Hydrochloride Salts and Orthoesters: A Synthetic and Mechanistic Perspective
The conversion of a wide range of primary and secondary aliphatic and a few arylamine hydrochloride salts to their corresponding acetamides with trimethyl orthoacetate is described. Mechanistic studies using NMR and gas chromatography-mass spectrometry techniques indicate these reactions proceed via an O-methylimidate intermediate that undergoes in situ demethylation by chloride, affording the corresponding acetamides. Synthetically, this reaction represents a practical, high-yielding protocol with a simple workup for the rapid conversion of amine hydrochloride salts to acetamides.
Di Grandi, Martin J.,Bennett, Caitlin,Cagino, Kristen,Muccini, Arnold,Suraci, Corey,Saba, Shahrokh
supporting information
p. 2601 - 2607
(2015/11/28)

Synthesis of N-tert-butyl amides by reaction of tert-butyl bromide with amides in the presence of manganese compounds
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Khusnutdinov,Shchadneva,Khisamova
p. 1502 - 1504
(2015/11/25)

Generation and trapping of ketenes in flow
Ketenes were generated by the thermolysis of alkoxyalkynes under flow conditions, and then trapped with amines and alcohols to cleanly give amides and esters. For a 10 min reaction time, temperatures of 180, 160, and 140 °C were required for >95% conversion of EtO, iPrO, and tBuO alkoxyalkynes, respectively. Variation of the temperature and flow rate with inline monitoring of the output by IR spectroscopy allowed the kinetic parameters for the conversion of 1-ethoxy-1-octyne to be easily estimated (Ea = 105.4 kJ/mol). Trapping of the in-situ-generated ketenes by alcohols to give esters required the addition of a tertiary amine catalyst to prevent competitive [2+2] addition of the ketene to the alkoxyalkyne precursor.
Henry, Cyril,Bolien, David,Ibanescu, Bogdan,Bloodworth, Sally,Harrowven, David C.,Zhang, Xunli,Craven, Andy,Sneddon, Helen F.,Whitby, Richard J.
p. 1491 - 1499
(2015/03/04)

Synthesis of secondary amides from N-Substituted amidines by tandem oxidative rearrangement and isocyanate elimination
In this work an efficient tandem process transforming N-substituted amidines into secondary amides has been described. The process involves N-acylurea formation by reaction of the substrate with bis(acyloxy)(phenyl)-λ3-iodane followed by isocyanate elimination. The periodinane reagents are obtained from the commercially available phenyl-iodine(III) diacetate [PhI(OAc)2, (PIDA)] by ligand exchange with carboxylic acids. The N-substituted amidine substrates are easily synthesized from readily available nitriles. The method is applicable for secondary amide synthesis, based on both aliphatic and (hetero)aromatic amines, including challenging amides consisting of sterically hindered acids and amines. Moreover, the protocol allows one to combine steric bulk with electron deficiency in the target amides (aniline based). Such compounds are difficult to synthesize efficiently based on classical condensation reactions involving carboxylic acids and amines. Overall, the synthetic protocol transforms a nitrile into a secondary amide in both aliphatic and (hetero)aromatic systems.
Debnath, Pradip,Baeten, Mattijs,Lefvre, Nicolas,Van Daele, Stijn,Maes, Bert U. W.
supporting information
p. 197 - 209
(2015/03/03)

Microwave assisted, Ca(II)-catalyzed Ritter reaction for the green synthesis of amides
An efficient solvent-free synthesis of amides by Ca(II) catalyzed Ritter reaction has been reported under microwave irradiation. This green protocol tolerates the substrate diversity and delivers the high yielding amides with minimal loading of inexpensive and more abundant Ca(II) catalyst.
Yaragorla, Srinivasarao,Singh, Garima,Lal Saini, Pyare,Reddy, M. Kesava
p. 4657 - 4660
(2014/12/10)

Natural organic acids promoted Beckmann rearrangement: Green and expeditious synthesis of amides under solvent-free conditions
Naturally occurring organic acids are reported to be highly efficient promoters of the Beckmann rearrangement. Citric, oxalic, tartaric, malic, succinic, malonic, and fumaric acids efficiently promote the Beckmann rearrangement under solvent-free conditions and thermal and microwave irradiation. Tartaric acid was found to be the best promoter of the Beckmann rearrangement under conventional conditions as well as under microwave irradiation. Compared with conventional heating, microwave irradiation provides higher reaction rate and slightly higher yields.
Rohokale, Sandeep Vasantrao,Kote, Santosh Rajaram,Deshmukh, Santosh Rangnath,Thopate, Shankar Ramchandra
p. 575 - 578
(2014/01/17)

Dimethyl sulfoxide participant iron-mediated cascade oxidation/α-formylation reaction of substituted 2,3-dihydropyrroles under air and protonic acid free condition
An efficient and Bronsted acid free one-pot protocol to directly generate structurally sophisticated α-formylpyrrole derivatives in moderate to good yields has been demonstrated, involving an iron-mediated domino oxidation/formylation reaction of readily available 2,3-dihydro-1H-pyrroles in dimethyl sulfoxide and air atmosphere, in which dimethyl sulfoxide acts as the formyl donor. A possible mechanism is presented.
Zhang, Zhiguo,Tian, Qing,Qian, Jingjing,Liu, Qingfeng,Liu, Tongxin,Shi, Lei,Zhang, Guisheng
p. 8182 - 8188
(2015/03/18)

Catalytic properties and acidity of 1,2-benzenedisulfonimide and some of its derivatives. An experimental and computational study
1,2-Benzenedisulfonimide (1) has previously been found to be an excellent and, importantly, safe Br?nsted acid catalyst. In this work we present the results of a search for derivatives of 1 that are more acidic and effective. Instead of blindly synthesizing a series of analogues, we have carried out a screening process in which the pKa of 1 and a set of its derivatives were calculated. The calculated pKa values were confirmed experimentally by carrying out determination through potentiometric titrations of some of the compounds: 1, 4-methyl and 4-nitro derivatives of 1. The calculations indicated that the dinitro and 4-nitro derivatives are among the best candidates for the synthesis. The latter was obtained in good yields and tested as a catalyst. Results were excellent as the reactions took place more quickly and at lower temperatures in all cases, and in a number of cases it was even possible to reduce the amount of catalyst.
Barbero, Margherita,Berto, Silvia,Cadamuro, Silvano,Daniele, Pier Giuseppe,Dughera, Stefano,Ghigo, Giovanni
p. 3212 - 3217
(2013/04/24)

Application of SiO2-Pr-SO3H as an efficient catalyst in the Ritter reaction
Sulfonic-acid-functionalized silica was applied as an efficient heterogeneous acid catalyst in the Ritter reaction to prepare amides by reaction of various benzylic, allylic, and tertiary alcohols with various nitriles in good to excellent yields under solvent-free conditions. The simplicity of the reaction, recovery of catalyst without loss of reactivity, high yield of products, and short reaction time represent improvements over many existing methods.
Mohammadi Ziarani, Ghodsi,Badiei, Alireza,Dashtianeh, Zeinab,Gholamzadeh, Parisa,Mohtasham, Nina Hosseini
p. 3157 - 3163
(2013/09/23)

Ritter reactions between alcohols and acetonitrile mediated by the conducting polymer poly-(3,4-ethylenedioxy thiophene) (Pedot)
Herein, we report new reactivity of the conducting polymer, poly-(3,4-ethylenedioxy thiophene) (PEDOT), where PEDOT mediates a Ritter reaction between alcohols and acetonitrile. The yields were variable and in most cases competitive with results obtained using sulfuric acid. Attempts at a stoichiometric reaction between benzonitrile and diphenylmethanol are also reported herein. Finally, described here are preliminary mechanistic studies that suggest PEDOT is behaving as an alcohol-selective or specific Lewis acid. Taylor & Francis Group, LLC.
D-Angelo, John G.,Cody, Jeremy A.,Larrabee, Christian,Ostrander, Danica J.,Rugg, Kyle W.,Mamangun, Donna
supporting information
p. 3224 - 3232
(2014/01/06)

Immobilization of Candida cylindracea lipase on poly lactic acid, polyvinyl alcohol and chitosan based ternary blend film: Characterization, activity, stability and its application for N-a
The ecofriendly ternary blend polymer film was prepared from the chitosan (CH), polylactic acid (PLA) and polyvinyl alcohol (PVA). Immobilization of Candida cylindracea lipase (CCL) was carried out on ternary blend polymer via entrapment methodology. The ternary blend polymer and immobilized biocatalyst were characterized by using N2 adsorption-desorption isotherm, SEM, FTIR, DSC, and (%) water content analysis through Karl Fischer technique. Biocatalyst was then subjected for the determination of practical immobilization yield, protein loading and specific activity. Immobilized biocatalyst was further applied for the determination of biocatalytic activity for N-acylation reactions. Various reaction parameters were studied such as effect of immobilization support (ratio of PLA:PVA:CH), molar ratio (dibutylamine:vinyl acetate), solvent, biocatalyst loading, time, temperature, and orbital speed rotation. The developed protocol was then applied for the N-acylation reactions to synthesize several industrially important acetamides with excellent yields. Interestingly, immobilized lipase showed fivefold higher catalytic activity and better thermal stability than the crude extract lipase CCL. Furthermore various kinetic and thermodynamic parameters were studied and the biocatalyst was efficiently recycled for four successive reuses. It is noteworthy to mention that immobilized biocatalyst was stable for period of 300 days.
Badgujar, Kirtikumar C.,Dhake, Kishor P.,Bhanage, Bhalchandra M.
p. 1335 - 1347
(2013/09/12)

C-S bond cleavage in aromatic sulfide radical cations
The results of our recent studies of the structural effects on the C-S bond fragmentation process of aromatic sulfur radical cations are reported.
Lanzalunga, Osvaldo
p. 322 - 330
(2013/07/25)

Structural effects on the C-S bond cleavage in aryl tert -butyl sulfoxide radical cations
The oxidation of a series of aryl tert-butyl sulfoxides (4-X-C 6H4SOC(CH3)3: 1, X = OCH 3; 2, X = CH3; 3, X = H; 4, X = Br) photosensitized by 3-cyano-N-methylquinolinium perchlorate (3-CN-NMQ+) has been investigated by steady-state irradiation and nanosecond laser flash photolysis (LFP) under nitrogen in MeCN. Products deriving from the C-S bond cleavage in the radical cations 1+?-4+? have been observed in the steady-state photolysis experiments. By laser irradiation, the formation of 3-CN-NMQ? (λmax = 390 nm) and 1 +?-4+? (λmax = 500-620 nm) was observed. A first-order decay of the sulfoxide radical cations, attributable to C-S bond cleavage, was observed with fragmentation rate constants (k f) that decrease by increasing the electron donating power of the arylsulfinyl substituent from 1.8 × 106 s-1 (4 +?) to 2.3 × 105 s-1 (1 +?). DFT calculations showed that a significant fraction of the charge is delocalized in the tert-butyl group of the radical cations, thus explaining the small substituent effect on the C-S bond cleavage rate constants. Via application of the Marcus equation to the kinetic data, a very large value for the reorganization energy (λ = 62 kcal mol-1) has been calculated for the C-S bond scission reaction in 1+?-4 +?.
Cavattoni, Tullio,Del Giacco, Tiziana,Lanzalunga, Osvaldo,Mazzonna, Marco,Mencarelli, Paolo
p. 4886 - 4894
(2013/07/11)

KAl(SO4)2.12H2O as an eco-friendly and reusable catalyst for the synthesis of amides by the Ritter reaction
KAl(SO4)2.12H2O (Alum) is an eco-friendly, inexpensive, readily available and reusable and was applied as catalyst to the synthesis of N-alkyl amides from nitriles and alcohols by the Ritter reaction. This solvent-free procedure is very simple with excellent yields and easy work-up.
Sadeghi, Bahareh,Farahzadi, Ebrahim,Hassanabadi, Alireza
p. 539 - 540
(2012/10/30)

Amberlyst-15 as a recyclable heterogeneous catalyst for synthesis of N-tert-butylamides via Ritter-type reaction
Highly efficient method for the preparation of N-tert-butylamides by reaction of nitriles with tert-butylacetate is described using Amberlyst-15 as a recyclable heterogeneous catalyst. Selective amidation of benzonitrile in the presence of acetonitrile was also achieved.
Mokhtary, Masoud,Goodarzi, Gholamreza
experimental part
p. 293 - 296
(2012/05/07)

Ritter reaction in subcritical water: An efficient and green method for amides synthesis
Ritter reaction was carried out efficiently in subcritical water with catalytic amount of trifluoromethanesulfonic acid. The amides were formed in good to excellent yields from secondary alcohols and tert-butanol with various nitriles.
Jiang, Shengqian,Wang, Zhouyu,Jiang, Zhenju,Li, Jianhui,Zhou, Shulin,Pu, Long
experimental part
p. 24 - 28
(2012/08/08)

Isopropenyl acetate, a remarkable, cheap and acylating agent of amines under solvent- and catalyst-free conditions: A systematic investigation
Isopropenyl acetate was proved to be an efficient reagent for acetylation of amine in the absence of solvent and catalyst. The corresponding acetamides were obtained in very high yields without any purification.
Pelagalli, Romina,Chiarotto, Isabella,Feroci, Marta,Vecchio, Stefano
supporting information; experimental part
p. 2251 - 2255
(2012/09/08)

Ritter reactions in flow
Flow me a Ritter: Ritter reactions are performed in a simple microreactor setup using tert-butylacetate as versatile carbocation source. The protocol avoids the handling of large amounts of hot concentrated sulfuric acid as low concentrations are optimal for rapid access tert-butyl- or diphenylmethyl- protected amides. Copyright
Audiger, Logan,Watts, Kevin,Elmore, Simon C.,Robinson, Richard I.,Wirth, Thomas
scheme or table
p. 257 - 260
(2012/05/04)

N -acyl DBN tetraphenylborate salts as N -acylating agents
Air-stable and crystalline N-acyl DBN tetraphenylborate salts have been synthesized from 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and the corresponding acyl chloride in the presence of sodium tetraphenylborate. The salts have been shown to be effective N-acylating agents, reacting with primary amines, secondary amines, and sulfonamides to form the corresponding N-acylated products in good yields. The DBN hydrotetraphenylborate byproduct can be conveniently removed by filtration, providing pure N-acylated products without the need for further purification. The N-acyl DBN tetraphenylborate salts are attractive alternatives to acyl halides as they can be stored in air without decomposition, avoid the production of free acid during acylation reactions, and can be used under more forcing thermal conditions.
Taylor, James E.,Jones, Matthew D.,Williams, Jonathan M. J.,Bull, Steven D.
experimental part
p. 2808 - 2818
(2012/04/23)

Amidate Precursors For Depositing Metal Containing Films
Volatile metal amidate metal complexes are exemplified by bis(N-(tert-butyl)ethylamidate)bis(ethylmethylamido) titanium; (N-(tert-butyl)(tert-butyl)amidate)tris(ethylmethylamido) titanium; bis(N-(tert-butyl)(tert-butyl)amidate)bis(dimethylamido) titanium and (N-(tert-butyl)(tert-butyl)amidate)tris(dimethylamido) titanium. The term “volatile” referes to any precursor of this invention having vapor pressure above 0.5 torr at temperature less than 200° C. Metal-containing film depositions using these metal amidate ligands are also described.
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(2012/03/10)

SO42-/CexZr1-xO2-catalyzed synthesis of N-tert-butylamides from various nitriles under solvent-free conditions
The synthesis of N-tert-butylamides using SO4 2-/CexZr1-x O2 catalysts under solvent-free conditions is reported. The methodology has several advantages such as reusability of the catalyst, solvent-free conditions, easy workup, and comparable yield of N-tert-butylamides. A variety of aliphatic, aromatic, and acid-sensitive substrates give high to moderate yields of the corresponding N-tert-butylamides. Surface acidities of the catalysts were correlated with the results obtained. To the best of our knowledge, this is the first report of a modified Ritter reaction on SO42-/CexZr1-x O2 using tert-butyl acetate as carbocationic source.
Kahandal, Sandeep S.,Kale, Sandip R.,Disale, Shamrao T.,Jayaram, Radha V.
experimental part
p. 738 - 740
(2012/09/22)

Highly efficient synthesis of amides via Ritter chemistry with ionic liquids
The utility of Br?nsted-acidic imidazolium ionic liquid [BMIM(SO3H)][OTf] as catalyst for the high yield synthesis of a wide variety of amides under mild conditions via the Ritter reaction of alcohols with nitriles has been demonstrated. As alternative methods for the carbocation generation step, NOPF6 immobilized in [BMIM][PF6] ionic liquid was used in the Ritter reaction of bromides with nitriles and for the synthesis of adamantyl amides from adamantane and nitriles.
Kalkhambkar, Rajesh G.,Waters, Sarah N.,Laali, Kenneth K.
supporting information; experimental part
p. 867 - 871
(2011/03/18)

Organocatalytic synthesis of amides from nitriles via the Ritter reaction
A simple, inexpensive, environmentally friendly, and efficient route for the synthesis of a wide variety of amides in high yields via the Ritter reaction of alcohols with nitriles has been demonstrated. Pentafluorophenyl ammonium triflate (PFPAT) is used as an organocatalyst and is air-stable, cost-effective, easy to handle, and easily removed from the reaction mixtures.
Khaksar, Samad,Fattahi, Eskandar,Fattahi, Esmail
experimental part
p. 5943 - 5946
(2011/11/28)

Sulfated tungstate: An efficient catalyst for the Ritter reaction
The use of sulfated tungstate as an efficient and reusable catalyst for the preparation of amides from alcohols and nitriles via the Ritter reaction pathway is discussed. The reaction proceeds under solvent free conditions. The Royal Society of Chemistry.
Katkar, Kamlesh V.,Chaudhari, Pramod S.,Akamanchi, Krishnacharya G.
supporting information; experimental part
p. 835 - 838
(2011/05/15)

Silver triflate catalyzed acetylation of alcohols, thiols, phenols, and amines
A variety of alcohols, thiols, phenols, and amines were subjected to acetylation reaction using acetic anhydride in the presence of catalytic quantity of silver triflate. The method described has a wide range of applications, proceeds under mild conditions, does not involve cumbersome workup, and the resulting products are obtained in high yields within a reasonable time. Georg Thieme Verlag Stuttgart · New York.
Das, Rima,Chakraborty, Debashis
experimental part
p. 1621 - 1625
(2011/06/25)

Citric acid catalysed Beckmann rearrangement, under solvent free conditions
Citric acid is reported to be a highly efficient and eco-friendly catalyst for the Beckmann rearrangement under solvent free conditions.
Thopate, Shankar Ramchandra,Kote, Santosh Rajaram,Rohokale, Sandeep Vasantrao,Thorat, Nitin Madhukar
experimental part
p. 124 - 125
(2011/07/07)

Beckmann rearrangement of oximes using pivaloyl chloride/DMF complex
A new complex of pivaloyl chloride and DMF was found to be very effective for converting ketoximes into their corresponding amides or lactams with excellent conversion via the Beckmann rearrangement. This method offers significant advantages such as efficiency and mild reaction conditions with shorter reaction time.
Narahari, Srinivasa Reddy,Reguri, Buchi Reddy,Mukkanti
experimental part
p. 4888 - 4891
(2011/10/05)

Synthesis of 3,3-dimethylglutamic acid derivatives as DPP-IV inhibitors and evaluation of their chemical stability
A novel five-step synthesis of Boc-3,3-dimethylglutamic acid α-ethyl ester 11 is reported. All the steps are high yielding and simple to carry out. By use of the 3,3-dimethylglutamic acid building block, we successfully discovered a novel class of DPP-IV inhibitors, Glu-Pro-Nitrile dipeptide mimics 2, with high potency (IC50 40 nM). The consequence of 3,3-dimethyl substituent on the rate of intramolecular cyclization between N-terminal amine and 5-position amide bond in different buffer solutions was also evaluated.
Hsu, Tsu,Tsai, Ting-Yueh,Tseng, Ya-Ju,Chiou, Mei-Chun,Lu, Cheng-Tai,Chao, Yu-Sheng,Jiaang, Weir-Torn
experimental part
p. 108 - 117
(2011/11/12)

One-pot esterification and Ritter reaction: Chemo- and regioselectivity from tert-butyl methyl ether
tert-Butyl methyl ether (TBME) has been effectively used as a reagent for esterification of carboxylic acids. By varying amounts of sulfuric acid, a remarkable regioselectivity in esterification has been demonstrated. Additionally, under the present reaction conditions, one-pot esterification and Ritter reaction are achieved in almost quantitative yield.
Dawar, Pankaj,Bhagavan Raju,Ramakrishna, Ramesha A.
scheme or table
p. 4262 - 4265
(2011/08/21)

One-pot synthesis of N-tert-butyl amides from alcohols, ethers and esters using ZnCl2/SiO2 as a recyclable heterogeneous catalyst
ZnCl2/SiO2 has been found to be an efficient and reusable catalyst for conversion of alcohols, ethers and esters to corresponding amides via the Ritter reaction in high yield. It was found that benzonitrile reacted with tert-butyl acetate faster than the other sources of tert-butyl carbocation.
Tamaddon, Fatemeh,Tavakoli, Fatemeh
experimental part
p. 52 - 55
(2011/04/24)

The Ritter reaction under incredibly green protocol: Nano magnetically silica-supported Br?nsted acid catalyst
HClO4-functionalized silica-coated magnetic nanoparticles [γ-Fe2O3@SiO2-HClO4] (2.5 mol%) has been found to be a capable biocompatible and recyclable catalyst for highly efficient conversion of a variety of alcohols to corresponding amides via modified Ritter reaction in good to excellent yields. Since this heterogeneous catalyst can be simply removed by using an external magnetic device then recovered, it also enhances product purity and promises economic.
Ma'mani, Leila,Heydari, Akbar,Sheykhan, Mehdi
experimental part
p. 122 - 127
(2010/11/04)

Safe and efficient ritter reactions in flow
Efficient mixing, temperature control and small environmental exposures allow reactions carried out in microfluidic de-vices to perform superior to their batch-type counterparts in conventional flasks. The Ritter reaction has been optimised for flow conditions leading to short reaction times and higher yields and also is more feasible with regards to safety, productivity and tolerance towards substrate functionalities.
Brandt, Johan C.,Elmore, Simon C.,Robinson, Richard I.,Wirth, Thomas
experimental part
p. 3099 - 3103
(2011/02/25)

6-Phenyl-1H-imidazo[4,5-c]pyridine-4-carbonitrile as cathepsin S inhibitors
6-Phenyl-1H-imidazo[4,5-c]pyridine-4-carbonitrile analogues were identified as potent and selective cathepsin S inhibitor against both purified enzyme and in human JY cell based cellular assays. This core has a very stable thio-trapping nitrile war-head in comparison with the well reported pyrimidine-2-carbonitrile cysteine cathepsin inhibitors. Compound 47 is also very potent in in vivo mouse spleenic Lip10 accumulation assays.
Cai, Jiaqiang,Baugh, Mark,Black, Darcey,Long, Clive,Jonathan Bennett,Dempster, Maureen,Fradera, Xavier,Gillespie, Jonathan,Andrews, Fiona,Boucharens, Sylviane,Bruin, John,Cameron, Kenneth S.,Cumming, Iain,Hamilton, William,Jones, Philip S.,Kaptein, Allard,Kinghorn, Emma,Maidment, Maurice,Martin, Iain,Mitchell, Ann,Rankovic, Zoran,Robinson, John,Scullion, Paul,Uitdehaag, Joost C.M.,Vink, Paul,Westwood, Paul,Van Zeeland, Mario,Van Berkom, Leon,Bastiani, Martijn,Meulemans, Tommi
scheme or table
p. 4350 - 4354
(2010/09/11)