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Acyl transfer reaction from N-benzyl-8-S-(p-nitrobenzoyl)dihydrolipoamide to benzylamine was enhanced with oxidizing agents such as cobalt(II) ion or a soluble flavin under an oxygen atmosphere or with di-4-pyridyl disulfide, accompanied by the formation

A new green approach for the synthesis of amide through TBAI-catalyzed oxidative coupling of benzyl bromides with amine was developed in the presence of tert-butyl hydroperoxide (TBHP) as an oxidant. Various electron-donating and withdrawing groups containing benzyl bromides and various amines, were subjected to the reaction and transformed to the corresponding amide in good to excellent yields.

We report how the rearrangement of highly reactive nitrile imines derived from N-2-nitrophenyl hydrazonyl bromides can be harnessed for the facile construction of amide bonds. This amidation reaction was found to be widely applicable to the synthesis of primary, secondary, and tertiary amides and was used as the key step in the synthesis of the lipid-lowering agent bezafibrate. The orthogonality and functional group tolerance of this approach was exemplified by the N-acylation of unprotected amino acids.

A straightforward method for the direct synthesis of amides from amines and carboxylic acids without exclusion of air or moisture using diphenylsilane with N-methylpyrrolidine has been developed. Various amides are made efficiently, and broad functional group compatibility is shown through a Glorius robustness study. A gram-scale synthesis demonstrates the scalability of this method. This journal is

Ammonia-borane serves as an efficient substoichiometric (10%) precatalyst for the direct amidation of both aromatic and aliphatic carboxylic acids. In situ generation of amine-boranes precedes the amidation and, unlike the amidation with stoichiometric amine-boranes, this process is facile with 1 equiv of the acid. This methodology has high functional group tolerance and chromatography-free purification but is not amenable for esterification. The latter feature has been exploited to prepare hydroxyl- and thiol-containing amides.

The reduction of nitroarenes to anilines as well as azobenzenes to hydrazobenzenes using a single base-metal catalyst is reported. The hydrogenation reactions are performed with an air-and moisture-stable manganese catalyst and proceed under relatively mild reaction conditions. The transformation tolerates a broad range of functional groups, affording aniline derivatives and hydrazobenzenes in high yields. Mechanistic studies suggest that the reaction proceeds via a bifunctional activation involving metal-ligand cooperative catalysis.

A cheap, facile and metal-free photochemical protocol for the activation of aromatic aldehydes has been developed. Utilizing thioxanthen-9-one as the photocatalyst and cheap household lamps as the light source, a variety of aromatic aldehydes have been activated and subsequently converted in a one-pot reaction into amides, hydroxamic acids and esters in good to high yields. The applicability of this method was highlighted in the synthesis of Moclobemide, a drug against depression and social anxiety. Extended and detailed mechanistic studies have been conducted, in order to determine a plausible mechanism for the reaction.

Herein, we investigated the supramolecular assembly of a modified Yamaguchi reagent TCB-OBt. Interestingly, each molecule is interconnected through novel chalcogen-chalcogen (O?O) interaction, π-π stacking, and aromatic C-H?O interaction. Hirshfeld surface analysis confirmed the existence of uncommon O?O interactions. A well-organized supramolecular layer structure and helical arrangement were observed in the crystal structure. TCB-OBt crystallized in the O-substituted desmotropic form. DFT calculations suggest that the O-substituted form is more stable than theN-substituted form (TCB-(N)-OBt). Morphology analysis indicates the formation of a fantastically well organized, continuous block-shaped system. Furthermore, the designed reagent works as an efficient activating reagent for amide bond formation with good yields under mild reaction conditions. Use of this reagent avoided intractable acid chlorides, and this new mixed-anhydride-based reagent may further be applicable for many other organic transformations.

We have developed a Br?nsted acid mediated synthetic method to directly cleave stable amide C?N bonds by a variety of alcohol and amine nucleophiles. Reverse reactivity was observed and alcoholysis of amides by activated primary and secondary benzylic, and propargylic alcohols have been achieved instead of the expected nucleophilic substitution of alcohols. As an application, 2-substituted benzothiazole derivatives have been synthesized in one pot employing 2-aminothiophenol as nucleophile.

This paper described a mild and efficient direct amidation of non-activated carboxylic acid and amine derivatives catalyzed by TiCp2Cl2. Arylacetic acid derivatives reacted with different amines to afford the corresponding amides in good to excellent yield except of aniline. Aryl formic acids failed to react with aniline but smoothly reacted with aliphatic amines and benzylamine in moderate to good yield, fatty acids reacting with benzyl and aliphatic amines give amides in good to excellent yield. Chiral amino acids derivatives were transformed into amides without racemization in moderate yield. The possible mechanism of direct amidation catalyzed by TiCp2Cl2 was discussed. This catalytic method is very suitable for the amidation of low sterically hindered arylacetic acid, fatty acids with different low sterically hindered amines except aniline, as well as the amidation of aryl formic acid with benzyl and aliphatic amines.

We report reductive alkylation reactions of amines using carboxylic acids as nominal electrophiles. The two-step reaction exploits the dual reactivity of phenylsilane and involves a silane-mediated amidation followed by a Zn(OAc)2-catalyzed amide reduction. The reaction is applicable to a wide range of amines and carboxylic acids and has been demonstrated on a large scale (305 mmol of amine). The rate differential between the reduction of tertiary and secondary amide intermediates is exemplified in a convergent synthesis of the antiretroviral medicine maraviroc. Mechanistic studies demonstrate that a residual 0.5 equivalents of carboxylic acid from the amidation step is responsible for the generation of silane reductants with augmented reactivity, which allow secondary amides, previously unreactive in zinc/phenylsilane systems, to be reduced.

The atom-efficient formation of amide bonds has emerged as a top-priority research field in organic synthesis, as amide bonds constitute the backbones of proteins and represent an important structural motif in drug molecules. Currently, the increasing demand for novel discoveries in this field has focused substantial attention on this challenging subject. Herein, the degradable 1,3,5-triazo-2,4,6-triphosphorine (TAP) motif is presented as a new condensation system for the dehydrative formation of amide bonds between diverse combinations of aromatic carboxylic acids and amines. The underlying reaction mechanism was investigated, and potential catalyst intermediates were characterized using 31 P NMR spectroscopy and ESI mass spectrometry.

Here we report a facile method for the synthesis of nickel oxide-nickel (NiO@Ni) Mott-Schottky catalyst employing metal-organic framework (MOF) as the precursor. A direct amidation protocol of aldehydes with amines has been optimized under mild conditions using NiO@Ni Mott-Schottky catalyst and it shows far better catalytic activity than the NiO?Ni nanoparticles prepared from simple Ni2+ salt under similar reaction conditions. The heterogeneous catalyst is robust, recyclable and efficient to provide comparable yield to costly ligand-based homogeneous Ni catalysts. The scope of the reaction protocol has been explored with variably substituted substrates. The reaction initiates by homolytic cleavage of peroxide and proceeds through radical mechanism.

Herein, we report a graphene oxide (GO) catalyzed condensation of non-activated esters and amines, that can enable diverse amides to be synthesized from abundant ethyl esters forming only volatile alcohol as a by-product. GO accelerates ester to amide conversion in the absence of any additives, unlike other catalysts. A wide range of ester and amine substrates are screened to yield the respective amides in good to excellent yields. The improved catalytic activity can be ascribed to the oxygenated functionalities present on the graphene oxide surface which forms H-bonding with the reactants accelerating the reaction. Improved yields and a wide range of functional group tolerance are some of the important features of the developed protocol.

Amide functional groups are prominent in a broad range of organic compounds with diverse beneficial applications. In this work, we report the synthesis of these functional groups via an iron(iii) chloride-catalyzed direct amidation of esters. The reactions are conducted under solvent-free conditions and found to be compatible with a range of amine and ester substrates generating the desired amides in short reaction times and good to excellent yields at a catalyst loading of 15 mol%.

First total syntheses of (?)-emestrin H and (?)-asteroxepin are described. To find the appropriate protecting group on the amide nitrogen of the diketopiperazine core, we conducted model studies using a simple diketopiperazine derivative. As a result, allyloxymethyl (Allom) group was the most suitable protecting group, which tolerated Nicolaou's sulfenylation conditions, and was easily cleavable under the mild conditions using Pd(PPh3)4 and N,N-dimethylbarbituric acid leaving methylthioethers intact. The general utility of Allom group for protection of amides was studied using simple substrates. Finally, the effectiveness of Allom group was proved by the accomplishment of the first total synthesis of (?)-emestrin H. Allom group was robust enough during installation of two methylthioethers to the diketopiperazine core and easily removed at the final step. The first total synthesis of (?)-asteroxepin was also completed by acylation of (?)-emestrin H.

The reaction of activated phenolic compounds, 2,4,6-triaryloxy-1,3,5-triazine (aryl-triazine ethers), with various isocyanates or carbodiimides in the presence of a nickel pre-catalyst resulted in the synthesis of aryl amides in good to excellent yields.

A simple, safe, and inexpensive amide bond formation directly from nonactivated carboxylic acids and free amines is presented in this work. Readily available Zr(IV)- and Hf(IV)-substituted polyoxometalates (POM) are shown to be catalysts for the amide bond formation reaction under mild conditions, low catalyst loading, and without the use of water scavengers, dry solvents, additives for facilitating the amine attack, or specialized experimental setups commonly employed to remove water. Detailed mechanistic investigations revealed the key role of POM scaffolds which act as inorganic ligands to protect Zr(IV) and Hf(IV) Lewis acidic metals against hydrolysis and preserve their catalytic activity in amide bond formation reactions. The catalysts are compatible with a range of functional groups and heterocycles useful for medicinal, agrochemical, and material chemists. The robustness of the Lewis acid-POM complexes is further supported by the catalyst reuse without loss of activity. This prolific combination of Zr(IV)/Hf(IV) and POMs inaugurates a powerful class of catalysts for the amide bond formation, which overcomes key limitations of previously established Zr(IV)/Hf(IV) salts and boron-based catalysts.

A scalable homogeneous metal-catalyzed protocol for direct amidation of carboxylic acids is presented. The use of 2–10?mol% of the commercially available Zr(Cp)2(OTf)2·THF results in high yields of amides at moderate temperature, using an operationally convenient reaction protocol that circumvents the use of water scavenging techniques.

An efficient heterogeneous amidation catalyst has been prepared by co-polymerisation of styrene, DVB with 4-styreneboronic acid, which shows wide substrate applicability and higher reactivity than the equivalent homogeneous phenylboronic acid, suggesting potential cooperative catalytic effects. The catalyst can be easily recovered and reused; suitable for use in packed bed flow reactors.

To improve the in vivo antidepressant activity of previously reported serotonin (5-HT) and norepinephrine (NE) dual reuptake inhibitors, three series of arylamidine derivatives were designed and synthesized. The in vitro 5-HT and NE reuptake inhibitory activities of these compounds were evaluated, and compound II-5 was identified as the most potent 5-HT (IC50 = 620 nM) and NE (IC50 = 10 nM) dual reuptake inhibitor. Compound II-5 exhibited potent antidepressant activity in the rat tail suspension test and showed an acceptable safety profile in a preliminary acute toxicity test in mice. Our results show that these arylamidine derivatives exhibit potent 5-HT/NE dual reuptake inhibition and should be explored further as antidepressant drug candidates.

An efficient method for the oxidative amidation of aldehydes with primary aromatic and aliphatic amines has been developed for the synthesis of a wide variety of amides using inexpensive Cu2(BDC)2DABCO (Cu-metal-organic framework [MOF]) as a recyclable heterogeneous catalyst, and N-chlorosuccinimide and aqueous tert-butyl hydroperoxide as oxidants in acetonitrile. This amidation reaction is operationally straightforward and provides secondary amides in good yields in most cases, utilizing inexpensive and readily available reagents under mild conditions.

An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage of a C–C bond followed by formation of a new C–N/C–O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High functional group tolerance, broad substrate scope and operational simplicity are the prominent advantages of the current protocol.

An efficient and inexpensive synthesis of N-substituted amides from the reaction of nitriles with methyl ethers catalyzed by Fe(ClO4)3·H2O is described. Fe(ClO4)3·H2O is an economically efficient catalyst for the Ritter Reaction under solvent-free conditions. A range of methyl ethers (benzyl, sec-alkyl and tert-butyl ethers) were reacted with nitriles to provide the corresponding amides in high–excellent yields.

A mild and efficient method is demonstrated for the transamidation of secondary amides with various amines including primary, secondary, cyclic and acyclic amines in the presence of tert-butyl nitrite. The reaction proceeds through the N-nitrosamide intermediate and provides the transamidation products in good to excellent yields at room temperature. Moreover, the developed methodology does not require any catalyst or additives.

An efficient and inexpensive synthesis of N-substituted amides from the Ritter reaction of nitriles with various halohydrocarbons catalyzed by FeCl2·4H2O is described. FeCl2·4H2O economically efficiently catalyzed the Ritter reaction under solvent-free conditions. A range of halohydrocarbons (benzyl, tert-butyl and sec-alkyl halohydrocarbons) were coupled with nitriles to provide the corresponding amides in high to excellent yields.

We present a base free method for amide bond construction via oxidative coupling of alcohols with amines catalyzed by Silver(I) N-heterocyclic carbenes (Ag(I)-NHCs) and mediated by tert-butyl hydroperoxide (TBHP) in ethanol. The results of controlled experiments suggest that the oxidative coupling proceeds through the formation of aldehyde, then subsequent attack by amine to give hemiaminal, which can then be oxidized to amide.

Tetrakis(dimethylamido)diboron and tetrahydroxydiboron are herein reported as new catalysts for the synthesis of aryl amides by catalytic condensation of aromatic carboxylic acids with amines. The developed protocol is both simple and highly efficient over a broad range of substrates. This method thus represents an attractive approach for the use of diboron catalysts in the synthesis of amides without having to resort to stoichiometric or additional dehydrating agents.

A visible light promoted process for desulfonylation of N-sulfonylamides and -amines has been developed, in which 1,3-dimethyl-2-hydroxynaphthylbenzimidazoline (HONap-BIH) serves as a light absorbing, electron and hydrogen atom donor, and a household white light-emitting diode serves as a light source. The process transforms various N-sulfonylamide and -amine substrates to desulfonylated products in moderate to excellent yields. The observation that the fluorescence of 1-methyl-2-naphthoxy anion is efficiently quenched by the substrates suggests that the mechanism for the photoinduced desulfonylation reaction begins with photoexcitation of the naphthoxide chromophore in HONap-BIH, which generates an excited species via intramolecular proton transfer between the HONap and BIH moieties. This process triggers single electron transfer to the substrate, which promotes loss of the sulfonyl group to form the free amide or amine. The results of studies employing radical probe substrates as well as DFT calculations suggest that selective nitrogen-sulfur bond cleavage of the substrate radical anion generates either a pair of an amide or amine anion and a sulfonyl radical or that of an amidyl or aminyl radical and sulfinate anion, depending on the nature of the N-substituent on the substrate. An intermolecular version of this protocol, in which 1-methyl-2-naphthol and 1,3-dimethyl-2-phenylbenzimidazoline are used concomitantly, was also examined.

A ligand free method has been developed for the amidation of benzylic hydrocarbons. A range of benzylic amides has been prepared with the use of dicumyl peroxide and a copper catalyst in good to excellent yields.

A new polymer supported Cu(II) complex has been synthesized and characterized by CHN analyses, IR and UV–Vis spectral studies, ESR and thermogravimetric analyses, ICP-OES, surface area measurements. This complex was screened for their catalytic study towards the direct amidation reaction. The effects of solvents, reaction time, temperature and catalyst amount for the direct formation of amides from aldehydes and benzylamine with the aid of heterogeneous copper complex were reported. The polymer supported Cu(II) catalyst could be reused more than five times without appreciable loss of its initial activity. The plausible reaction mechanism has been proposed. The catalytic activity of the unsupported complex was also compared with the polymer supported Cu(II) complex.

A convenient and high yielding procedure for the synthesis of amides by the Ritter reaction of nitriles and halohydrocarbons in the presence of Zn(ClO4)2·6H2O as a highly stable, effective and available catalyst is described.

An efficient and inexpensive synthesis of N-substituted amides from the Ritter reaction of nitriles with esters catalyzed by Fe(ClO 4) 3 ·H 2 O is described. Fe(ClO 4) 3 ·H 2 O is an economically efficient catalyst for the Ritter reaction under solvent-free conditions. Reactions of a range of esters (benzyl, sec-alkyl, and tert-butyl esters) with nitriles (primary, secondary, tertiary, and aryl nitriles) were performed to provide the corresponding amides in high to excellent yields.

Development of catalytic amide bond formation reactions has been the subject of the intensive investigations in the past decade. Herein we report an efficient organophosphorus-catalysed amidation reaction between unactivated carboxylic acids and amines. Poly(methylhydrosiloxane), a waste product of the silicon industry, is used as an inexpensive and green reducing agent for in situ reduction of phosphine oxide to phosphine. The reported method enables the synthesis of a wide range of secondary and tertiary amides in very good to excellent yields.

A effective amidation reaction of carboxylic acids with various amines promoted by triphenylphosphine oxide and oxalyl chloride under mild and neutral conditions has been developed. The feature of this procedure was the using and recycling of triphenylphosphine oxide at room temperature in 0.5?h. Furthermore a plausible mechanism also be deduced with the help of 31P NMR spectroscopy.

We report a cheap and simple method for the acetylation of a variety of amines using catalytic acetic acid and either ethyl acetate or butyl acetate as the acyl source. Catalyst loadings as low as 10 mol% afforded acetamide products in excellent yields at temperatures ranging from 80-120 °C. The methodology can also be successfully applied for the synthesis of a broad range of other amides, including the formation of formamides at 20 °C.

Two coordination polymers of ytterbium were synthesized by employing 4,4′,4″-s-triazine-2,4,6-triyl-tribenzoic acid (H3TATB), 4,4′,4-benzene-1,3,5-triyl-tribenzoic acid (H3BTB), and 3,5-pyridinedicarboxylic acid (3,5-PDC) ligands and were characterized by single-crystal X-ray diffraction analysis. Reaction of ytterbium(III) chloride in the presence of H3BTB and 3,5-PDC ligands gives preferred complexation with the 3,5-PDC ligand, producing [Yb2(3,5-PDC)(ClO4)3][NH(Me)3] (1). However, under exactly the same reaction conditions, reaction of ytterbium(III) chloride in the presence of 3,5-PDC and H3TATB resulted in complexation with H3TATB to form [(CH3)2NH2][Yb4(TATB)4(HCO2)(H2O)2]·3H2O (2). The crystal structure results showed a layered structure for 1 and a metal-organic framework structure for 2. This indicates that the complexation preference of the ytterbium ion is H3TATB?≥?3,5-PDC?≥?H3BTB. Conversely, the uncomplexed ligand in the metal-organic framework (2) is an auxiliary agent during the synthesis, which shows polytopic linker controls crystal properties, to form suitable crystals for single-crystal structure determination. The prepared coordination compounds were used as heterogeneous catalysts in an oxidation amidation reaction with different aldehydes and benzylamine hydrochloride.

The invention provides a method for preparing amide. The method includes weighing triphenyl phosphine oxide, oxalyl chloride, organic acid and organic amine according to a molar ratio of 1-5:1-5:1:0.3-4; adding the triphenyl phosphine oxide, the oxalyl chloride, the organic acid and the organic amine into a reaction vessel, stirring the triphenyl phosphine oxide, the oxalyl chloride, the organic acid and the organic amine in N2 environments and carrying out reaction on the organic acid and the organic amine in the presence of organic solvents at the reaction temperature of 10-40 DEG C for the reaction time of 0.5-5 hours to generate the corresponding amide. The method has the advantages that the triphenyl phosphine oxide is used as a novel carboxylic acid activating agent to promote synthesis of the amide, the method is low in reaction temperature and short in reaction time, and the triphenyl phosphine oxide which is the carboxylic acid activating agent is inexpensive, is easily available and can be recycled; only reaction byproducts CO and CO2 can be generated, and accordingly the method is high in atom utilization rate.

To date, many known G protein-coupled receptor 55 (GPR55) ligands are those identified among the cannabinoids. In order to further study the function of GPR55, new potent and selective ligands are needed. In this study, we utilized the screening results from PubChem bioassay AID 1961 which reports the results of Image-based HTS for Selective Agonists of GPR55. Three compounds, CID1792579, CID1252842 and CID1011163, were further evaluated and used as a starting point to create a series of nanomolar potency GPR55 agonists with N-(4-sulfamoylphenyl)thiourea scaffold. The GPR55 activity of the compounds were screened by using a commercial β-arrestin PathHunter assay and the potential compounds were further evaluated by using a recombinant HEK cell line exhibiting GPR55-mediated effects on calcium signalling. The designed compounds were not active when tested against various endocannabinoid targets (CB1R, CB2R, FAAH, MGL, ABHD6 and ABHD12), indicating compounds' selectivity for the GPR55. Finally, structure-activity relationships of these compounds were explored.

This article describes a selective reduction of functionalized amides, including N-acyl amino esters and dipeptides, to the corresponding amines using simple [Rh(acac)(cod)]. The catalyst shows excellent chemoselectivity in the presence of different sensitive functional moieties. A selective reduction of functionalized amides, including N-acyl amino esters and dipeptides, to the corresponding amines using simple [Rh(acac)(cod)] is described (see scheme). The catalyst shows excellent chemoselectivity in the presence of different sensitive functional moieties. Even the selective reduction of a secondary amide bond in the presence of a ketone is possible.

A simple and efficient procedure for the synthesis of amides directly from aldehydes and amines catalyzed by heteropolyanion-based ionic liquids under solvent-free conditions has been reported. The practical protocol was found to tolerate a wide range of substrates with different functional groups. Moderate to excellent yields, solvent-free media, and operational simplicity are the main highlights. The proposed dual-catalysis mechanistic pathway was briefly investigated. Furthermore, the heteropolyanion-based ionic liquids were easily reusable for this oxidative amidation.

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Using only catalytic amounts of alkyl halides in the reactions of poor nucleophilic amines/amides and alcohols led to a selective Hofmann N-alkylation reaction catalytic in alkyl halides, providing a practical and efficient method for the practical synthesis of mono- or di-alkylated amines/amides in high selectivities. This new method avoids the use of large amounts of bases, alkyl halides, and solvents, and generates water as the only byproduct. Preliminary mechanistic studies showed that alkyl halides are key intermediates/catalysts regeneratable in the reaction cycle.

A highly efficient approach to transamidation of carboxamides with amines over nanosized zeolite beta under solvent-free conditions has been successfully demonstrated. Transamidation of a variety of amides with amines produced the respective N-alkyl amides in moderate to excellent yields.

Triphenylphosphine (PPh3)/N-chlorobenzotriazole (NCBT), and amine (primary and secondary aliphatic amines and also substituted anilines) in CH2Cl2 efficiently converted carboxylic acids, α-amino acids, and sulfonic acids to the corresponding amides and sulfonamides at room temperature. Good to excellent yields, inexpensive, and fast reaction conditions are the important features of this procedure.

A novel imidazolium salt-supported Mukaiyama reagent (2-chloropyridinium salt) has been developed and explored as an efficient coupling agent for amide bond formation. The use of an ionic liquid-supported reagent enabled isolation of the amide products by simple extraction with organic solvents in high purity and avoiding column chromatography purification. This journal is

Abstract The catalytic role of PPh3 and its polymer bound analog was investigated in the 2,4,6-trichloro-1,3,5-triazine (TCT) mediated amidation of carboxylic acids. In the presence of inorganic bases which were inert toward TCT, carboxylic acids rapidly reacted with amines to afford amides in good to excellent yields. The described method also enabled the synthesis of optically active protected dipeptides without racemization. Formation of triazinylphosphonium chloride during the PPh3 catalyzed acid activation was confirmed based on 31P NMR studies.

A rapid, facile, and efficient mechanochemical synthesis of amides from carboxylic acids has been developed through an in situ acid activation with 2,4,6-trichloro-1,3,5-triazine and a catalytic amount of PPh3. Under room temperature solvent-drop grinding of the reactants in the presence of an inorganic base, a variety of carboxylic acids including aromatic acids, aliphatic acids, and N-protected α-amino acids undergo amidation to afford amides in moderate to excellent yields. The method is also compatible with Fmoc, Cbz, and Boc protecting groups which yields protected optically active dipeptides without detectable racemization.

Direct amide synthesis from equimolar amounts of carboxylic acid and amine using mesoporous silica as a versatile heterogeneous catalyst is reported.

An azobenzene-containing zirconium metal-organic framework was demonstrated to be an effective heterogeneous catalyst for the direct amidation of benzoic acids in tetrahydrofuran at 70°C. This finding was applied to the synthesis of several important, representative bioactive compounds.

The AgI-promoted coupling reaction of thioamides and carboxylic acids is shown to be a useful method for the generation of unsymmetrical imides. The reaction proceeds efficiently with unhindered and electron-rich or neutral coupling partners, but not with hindered thioamides (such as thiopivalamides) or electron deficient thioamides (such as trifluorothioacetamides). Intriguingly, thioformamides are also ineffective coupling partners, despite having minimal steric or electronic influence. Hindered carboxylic acid coupling partners (such as pivalic acid) are tolerated, but electron deficient acids, such as trifluoroacetic acid, are ineffective coupling partners. Furthermore, an interplay of both steric and electronic effects is observed in the subsequent hydrolysis of unsymmetrical imides. Imides with a dimethoxybenzoyl group give high regioselectivity upon hydrolysis, favouring cleavage of the distal acyl group. Imides with a p-nitrobenzoyl or pivaloyl group give reversed selectivity, favouring cleavage of the proximal acyl group.