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In the present work, inexpensive and commercially available diethyltriamine pentaacetic acid (DTPA) was used as an initiator to catalyze the N-formylation reaction of CO2 with amines via the construction of C-N bonds in the presence of xanthone as the photosensitizer and PhSiH3 as the reducing agent. After a systematic study of various factors, the optimal conditions for the photocatalytic reaction were obtained: 2.5 mmol of amine, 2.5 mmol of PhSiH3, 10 mol% of DTPA, 20 mol% of xanthone, 1 mL of dimethylsulfoxide (DMSO), atmospheric pressure, and 35 W UV lamp irradiation for 48 h. Under the optimal conditions, the catalyst system afforded high performance for the N-formylation of amines (primary and secondary amines) and CO2, and the yields of the N-formylated products of dialkylamines were above 70%. Further studies exhibit that the catalytic system has a wide scope of substrate applications. For various alicyclic secondary amines, heterocyclic secondary amines, aliphatic primary amines, and aromatic primary amines, the corresponding N-formylation products can be obtained efficiently. In addition, the catalyst can be recycled by simple precipitation and filtration. After five cycles of recycling, there was no significant change in the catalytic and structural properties of DTPA. Finally, a possible reaction mechanism is proposed. [ABSTRACT FROM AUTHOR]

The reactivity of dimethylamine borane (DMAB) towards amines and nitroarenes was investigated in the presence of the CO2 and Pd/PVP (PVP=polyvinylpyrrolidone) nanocatalyst. The formation of borane formate, Me2NH.BH2(OCHO), by the insertion of CO2 into the B−H bond was evidenced by NMR. The reaction of DMAB with CO2 also produced a second product, DMF, formed via self‐formylation. In the presence of aromatic or aliphatic amines corresponding N‐formamides were formed efficiently. Under the same conditions nitroarenes were hydrogenated to anilines or to azoxyarenes in the absence of CO2. In both reactions very high TOF values, up to 30 min−1, were obtained. Applying a higher excess of DMAB enabled the transformation of nitroarenes to N‐formamides. The Pd/PVP catalyst was used in 7 consecutive cycles of N‐methylaniline formylation with excellent selectivity and a total TON equal to 4700. [ABSTRACT FROM AUTHOR]

The N‐formylation of amines using CO2 hydrogenation, conducted under additive‐free conditions, represents a crucial methodology in organic synthesis. Herein, we demonstrated a highly efficient ruthenium pincer complex for the selective conversion of a wide array of amines into their corresponding formamides under additive‐free condition with a turnover number (TON) of 980,000 within a single‐batch. Controlled studies suggested the initial reduction of CO2 to ammonium formate, followed by dehydration to generate formamide. NMR experiments revealed the potential intermediates and indicated the involvement of metal‐ligand cooperativity of catalyst during substrate activation. In addition, this methodology was examined to establish a carbon neutral hydrogen storage cycle by capitalizing on the reversible transformation of formamides. [ABSTRACT FROM AUTHOR]

The reduction of CO2 is an important method to produce chemicals such as methanol, formic acid, formaldehyde, etc. In general, the reduction of CO2 is carried out at high temperatures and pressures with precious metals as catalysts, which is not favorable for industrial procedures. Thus, it will be very useful if researchers can find cost-effective catalysts for industrial application in CO2 reduction. In this work, commercially available ethylenediaminetetraacetic acid (EDTA) was tested as a cheap, non-toxic, and recyclable catalyst to initiate the N-carbonylation reaction of CO2 with amines. After screening various reaction parameters, including temperature, pressure, time, solvent, and reducing agent, the optimal reaction conditions were obtained: 80 °C, 2 MPa, 6 h, 50 mmol% catalyst dosage, 1 mL DMSO, and 1:1 molar ratio of amine to reducing agent. Notably, further studies confirmed that EDTA could also be effective for N-formylation even under ambient conditions (0.1 MPa and room temperature). The suitability of the catalyst for 26 kinds of substrates (including aliphatic amines, aromatic amines, and alicyclic amines) and its reusability were also investigated, with satisfactory results. Scale-up research has been performed effectively with a high conversion of amine (83%) to obtain the mono-formylated product selectively. Finally, the mechanism of the reaction between amine and CO2 has been proposed via control experiments and compared with results in the literature. [ABSTRACT FROM AUTHOR]

Developing efficient catalysts to convert CO2 into value‐added chemicals is valuable for reducing carbon emissions. Herein, a kind of novel thiolate‐based ionic liquid with sulfur as the active site was designed and synthesized, which served as highly efficient catalyst for the reductive N‐functionalization of CO2 by amines and hydrosilane. By adjusting the CO2 pressure, various N‐formamides and N‐methylamines were selectively obtained in high yields. Remarkably, at the catalyst loading of 0.1 mol %, the N‐formylation reaction of N‐methylaniline exhibited an impressive turnover frequency (TOF) up to 600 h−1, which could be attributed to the roles of the ionic liquids in activating hydrosilane and amine. In addition, control experiments and NMR monitoring experiments provided evidence that the reduction of CO2 by hydrosilane yielded formoxysilane intermediates that subsequently reacted with amines to form N‐formylated products. Alternatively, the formoxysilane intermediates could further react with hydrosilane and amine to produce 4‐electron‐reduced aminal products. These aminal products served as crucial intermediates in the N‐methylation reactions. [ABSTRACT FROM AUTHOR]

Abstract In the current report, we introduce a simple, mild efficient and green protocol for N-formylation and N-acetylation of anilines using formamide, formic acid, and acetic acid as inexpensive, nontoxic, and easily available starting materials just with heating along stirring in [ChCl][ZnCl2]2 as a durable, reusable deep eutectic solvent (DES), which acts as a dual catalyst and solvent system to produce a wide range of formanilides and acetanilides. Also, a variety of unsymmetrical urea derivatives were synthesized by the reaction of phenyl isocyanate with a range of amine compounds using this benign DES in high to excellent yields. [ChCl][ZnCl2]2 showed good recycling and reusability up to four runs without considerable loss of its catalytic activity.

This document provides information on various compounds, specifically N-formyl derivatives, and their spectroscopic data. The compounds mentioned include a wide range of derivatives with different functional groups. The compounds were purified and their spectroscopic data were compared to existing literature, confirming their identities. The document also acknowledges the scholarship awarded to one of the researchers. [Extracted from the article]

Borohydride imidazolium ionic liquids, [IL]BH4, used for the first time as reductants in the N‐formylation of various amines with CO2, provided an excellent yield of formamides. Under the same conditions, 5 bar CO2 and 80 °C, NaBH4 produced a mixture of N‐formylated and N‐methylated products in a ratio of 1 : 2. An alternative approach, based on the addition of halide imidazolium salts ([IL]Cl or [IL]Br) to the reactions of amine with NaBH4 and CO2, resulted in a significant increase of selectivity to formamide. However, no effect was noted for [IL]BF4 and [IL]PF6. Monitoring the reaction course in time using 1H NMR brought about new insight into the role of BH3 in the reduction of CO2 and the functionalization of amines. The formation of N‐methylaniline – borane intermediate was evidenced. [ABSTRACT FROM AUTHOR]

In the current report, we introduce a simple, mild efficient and green protocol for N-formylation and N-acetylation of anilines using formamide, formic acid, and acetic acid as inexpensive, nontoxic, and easily available starting materials just with heating along stirring in [ChCl][ZnCl2]2 as a durable, reusable deep eutectic solvent (DES), which acts as a dual catalyst and solvent system to produce a wide range of formanilides and acetanilides. Also, a variety of unsymmetrical urea derivatives were synthesized by the reaction of phenyl isocyanate with a range of amine compounds using this benign DES in high to excellent yields. [ChCl][ZnCl2]2 showed good recycling and reusability up to four runs without considerable loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

In the current report, we introduce a simple, mild efficient and green protocol for N-formylation and N-acetylation of anilines using formamide, formic acid, and acetic acid as inexpensive, nontoxic, and easily available starting materials just with heating along stirring in [ChCl][ZnCl2]2 as a durable, reusable deep eutectic solvent (DES), which acts as a dual catalyst and solvent system to produce a wide range of formanilides and acetanilides. Also, a variety of unsymmetrical urea derivatives were synthesized by the reaction of phenyl isocyanate with a range of amine compounds using this benign DES in high to excellent yields. [ChCl][ZnCl2]2 showed good recycling and reusability up to four runs without considerable loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

C-scorpionate metal complexes, specifically, [NiCl2(tpm)]·3H2O, [CoCl2(tpm)]·3H2O and [PdCl2(tpm)] [tpm = hydrotris(1H-pyrazol-1-yl)methane], were effective in the N-formylation and N-methylation of amines using carbon dioxide, as carbon source, in the presence of sodium borohydride. Various parameters were studied, including reaction time, temperature, solvent volume, presence of additives, and catalyst amount. These parameters were found to have a significant impact on the selectivity of the product. [NiCl2(tpm)]·3H2O exhibited good conversion at 80 °C, but its selectivity towards formamide decreased with prolonged reaction time. Increasing the amount of [NiCl2(tpm)]·3H2O, the selectivity changed. [PdCl2(tpm)] showed different selectivity compared to [NiCl2(tpm)]·3H2O, while [CoCl2(tpm)]·3H2O presented poor results. Monitoring the reaction course by 1H NMR revealed the presence of an intermediate species that influenced product formation. These results highlight the versatility and catalytic potential of C-scorpionate metal complexes in the N-formylation/N-methylation of amines in the catalytic system (NaBH4/MeCN/CO2). [ABSTRACT FROM AUTHOR]

Formamides are important feedstocks for the manufacture of many fine chemicals. State‐of‐the‐art synthesis of formamides relies on the use of an excess amount of reagents, giving copious waste and thus poor atom‐economy. Here, we report the first example of direct synthesis of N‐formamides by coupling two challenging reactions, namely reductive amination of carbonyl compounds, particularly biomass‐derived aldehydes and ketones, and fixation of CO2 in the presence of H2 over a metal‐organic framework supported ruthenium catalyst, Ru/MFM‐300(Cr). Highly selective production of N‐formamides has been observed for a wide range of carbonyl compounds. Synchrotron X‐ray powder diffraction reveals the presence of strong host‐guest binding interactions via hydrogen bonding and parallel‐displaced π⋅⋅⋅π interactions between the catalyst and adsorbed substrates facilitating the activation of substrates and promoting selectivity to formamides. The use of multifunctional porous catalysts to integrate CO2 utilisation in the synthesis of formamide products will have a significant impact in the sustainable synthesis of feedstock chemicals. [ABSTRACT FROM AUTHOR]

In the present work, inexpensive and commercially available diethyltriamine pentaacetic acid (DTPA) was used as an initiator to catalyze the N-formylation reaction of CO2 with amines via the construction of C-N bonds in the presence of xanthone as the photosensitizer and PhSiH3 as the reducing agent. After a systematic study of various factors, the optimal conditions for the photocatalytic reaction were obtained: 2.5 mmol of amine, 2.5 mmol of PhSiH3, 10 mol% of DTPA, 20 mol% of xanthone, 1 mL of dimethylsulfoxide (DMSO), atmospheric pressure, and 35 W UV lamp irradiation for 48 h. Under the optimal conditions, the catalyst system afforded high performance for the N-formylation of amines (primary and secondary amines) and CO2, and the yields of the N-formylated products of dialkylamines were above 70%. Further studies exhibit that the catalytic system has a wide scope of substrate applications. For various alicyclic secondary amines, heterocyclic secondary amines, aliphatic primary amines, and aromatic primary amines, the corresponding N-formylation products can be obtained efficiently. In addition, the catalyst can be recycled by simple precipitation and filtration. After five cycles of recycling, there was no significant change in the catalytic and structural properties of DTPA. Finally, a possible reaction mechanism is proposed.

The reduction of CO2 is an important method to produce chemicals such as methanol, formic acid, formaldehyde, etc. In general, the reduction of CO2 is carried out at high temperatures and pressures with precious metals as catalysts, which is not favorable for industrial procedures. Thus, it will be very useful if researchers can find cost-effective catalysts for industrial application in CO2 reduction. In this work, commercially available ethylenediaminetetraacetic acid (EDTA) was tested as a cheap, non-toxic, and recyclable catalyst to initiate the N-carbonylation reaction of CO2 with amines. After screening various reaction parameters, including temperature, pressure, time, solvent, and reducing agent, the optimal reaction conditions were obtained: 80 °C, 2 MPa, 6 h, 50 mmol% catalyst dosage, 1 mL DMSO, and 1:1 molar ratio of amine to reducing agent. Notably, further studies confirmed that EDTA could also be effective for N-formylation even under ambient conditions (0.1 MPa and room temperature). The suitability of the catalyst for 26 kinds of substrates (including aliphatic amines, aromatic amines, and alicyclic amines) and its reusability were also investigated, with satisfactory results. Scale-up research has been performed effectively with a high conversion of amine (83%) to obtain the mono-formylated product selectively. Finally, the mechanism of the reaction between amine and CO2 has been proposed via control experiments and compared with results in the literature.

CO2 emissions are constantly increasing, so it is necessary to continue working to mitigate the excess of CO2 in the atmosphere and reduce the effects it has on the environment. In this regard, we have developed novel catalysts by synthesizing ionic liquids based on imidazolium chloride, supported on hyper-crosslinked polymers (HCP-BzmimCl and HCP-Bis(BzmimCl)). These catalysts enable the highly selective N-formylation of secondary amines, utilizing CO2 as a carbon source, phenylsilane as a hydrogen donor, and DMF as a crucial polar additive. The reactions were carried out under mild conditions, with CO2 pressure at 5 bar and a temperature of 35ºC, yielding formamides in excellent yields. HCP-Bis(BzmimCl) has emerged as a particularly promising catalyst, boasting shorter reaction times, exceptional recyclability, and scalability for potential industrial applications.

Aldehydes serve as the key functional group in organic synthesis and are valuable intermediates. The various advanced methods of direct formylation reactions have been reviewed in this article. Overcoming the drawbacks of the traditional methods of formylation, newer methods involving homo and heterogenous catalysts, one pot reactions, solvent free techniques are elaborated, which can be performed under mild conditions and using inexpensive resources. [ABSTRACT FROM AUTHOR]

In recent years, transamidation has been an essential topic in the formation of amide bonds over the conventional route due to chemoselectivity and greenside products. So many groups have disclosed new amide transformation techniques. Transamidation is typically classified into two categories based on amide activation: activated amide and unactivated amide. We conducted a review of the pertinent literature that discusses the cross amidation reactions of unactivated amides employing a variety of reagents, enabling contemporary research professionals to overcome synthetic barriers. [ABSTRACT FROM AUTHOR]

In this paper, the synthesis of formamides via N-formylation of amines using magnetic lignosulfonate@4H-1,2,4-triazol-3-amine-copper complex (MLS-TA@Cu) catalyst is reported. The catalyst was prepared via immobilization of the Cu(II) complex on magnetic lignosulfonate (MLS). The catalyst structure was identified using various analyses such as XRD, FESEM, EDS, TEM, VSM, and FT-IR. The obtained catalyst showed excellent catalytic activity in the preparation of formamides in high yields in the absence of solvent. Moreover, MLS-TA@Cu can be reused consecutively without considerable loss of efficacy and simply separated using an external magnet, demonstrating high recyclability and great chemical stability. The remarkable advantages of this process are the operational simplicity, solvent-free nature, simple work-up procedure, and formation of pure products in high yields. The antibacterial activity of MLS-TA@Cu was tested on Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria. [ABSTRACT FROM AUTHOR]

A facile and convenient one-pot protocol for the N-formylation of aryl amines has been furnished using Tf2O. This approach involves N-formylation of anilines and its derivatives employing formic acid as a formyl source and triflic anhydride (Tf2O) as an activator as the key step. This work highlights the ability of Tf2O as an activating agent, includes operational simplicity, easy applicability to gram-scale preparation and to afford the N-formyl aryl amines in moderate to good yields. [ABSTRACT FROM AUTHOR]

Chemical utilization of CO2 is one of the fundamental strategies to synthesize value-added chemicals and reduce the CO2 emission. N-formyl-1,2,3,4-tetrahydroisoquinoline derivatives (FTHIQs) are important chemicals for the synthesis of medical intermediates and alkaloids. N-formylation of isoquinoline derivatives (IQs) with CO2 is an ideal protocol to synthesize the FTHIQs and utilize the CO2 source. In the present work, we prepared a heterogeneous Ru/ZIF-8 catalyst with a Ru loading of 2 wt% by a simple impregnation method and assessed its performances in the N-formylation of IQs and CO2 with H2. The Ru/ZIF-8 catalyst offered high IQ conversion of 98% and FTHIQ selectivity of 93% in the reaction under relatively mild conditions (150 °C, 2 MPa CO2, and 6 MPa H2). The catalyst possessed good universality and reusability, showing a potential in wide application of N-formylation of highly unsaturated nitrogen-containing isoquinolines.

Two easily accessible routes for preparing an array of formylated and acetylated amines under mechanochemical conditions are presented. The two methodologies exhibit complementary features as they enable the derivatization of aliphatic and aromatic amines.

Heterogeneously catalyzed N‐formylation of amines to formamide with CO2/H2 is highly attractive for the valorization of CO2. However, the relationship of the catalytic performance with the catalyst structure is still elusive. Herein, mixed valence catalysts containing Cu2O/Cu interface sites were constructed for this transformation. Both aliphatic primary and secondary amines with diverse structures were efficiently converted into the desired formamides with good to excellent yields. Combined ex and in situ catalyst characterization revealed that the presence of Cu2O/Cu interface sites was vital for the excellent catalytic activity. Density functional theory (DFT) calculations demonstrated that better catalytic activity of Cu2O/Cu(111) than Cu(111) is attributed to the assistance of oxygen at the Cu2O/Cu interface (Ointer) in formation of Ointer‐H moieties, which not only reduce the apparent barrier of HCOOH formation but also benefit the desorption of the desired N‐formylated amine, leading to high activity and selectivity. [ABSTRACT FROM AUTHOR]

Heterogeneously catalyzed N‐formylation of amines to formamide with CO2/H2 is highly attractive for the valorization of CO2. However, the relationship of the catalytic performance with the catalyst structure is still elusive. Herein, mixed valence catalysts containing Cu2O/Cu interface sites were constructed for this transformation. Both aliphatic primary and secondary amines with diverse structures were efficiently converted into the desired formamides with good to excellent yields. Combined ex and in situ catalyst characterization revealed that the presence of Cu2O/Cu interface sites was vital for the excellent catalytic activity. Density functional theory (DFT) calculations demonstrated that better catalytic activity of Cu2O/Cu(111) than Cu(111) is attributed to the assistance of oxygen at the Cu2O/Cu interface (Ointer) in formation of Ointer‐H moieties, which not only reduce the apparent barrier of HCOOH formation but also benefit the desorption of the desired N‐formylated amine, leading to high activity and selectivity. [ABSTRACT FROM AUTHOR]

Heterogeneously catalyzed N‐formylation of amines to formamide with CO2/H2 is highly attractive for the valorization of CO2. However, the relationship of the catalytic performance with the catalyst structure is still elusive. Herein, mixed valence catalysts containing Cu2O/Cu interface sites were constructed for this transformation. Both aliphatic primary and secondary amines with diverse structures were efficiently converted into the desired formamides with good to excellent yields. Combined ex and in situ catalyst characterization revealed that the presence of Cu2O/Cu interface sites was vital for the excellent catalytic activity. Density functional theory (DFT) calculations demonstrated that better catalytic activity of Cu2O/Cu(111) than Cu(111) is attributed to the assistance of oxygen at the Cu2O/Cu interface (Ointer) in formation of Ointer‐H moieties, which not only reduce the apparent barrier of HCOOH formation but also benefit the desorption of the desired N‐formylated amine, leading to high activity and selectivity. [ABSTRACT FROM AUTHOR]

Heterogeneously catalyzed N‐formylation of amines to formamide with CO2/H2 is highly attractive for the valorization of CO2. However, the relationship of the catalytic performance with the catalyst structure is still elusive. Herein, mixed valence catalysts containing Cu2O/Cu interface sites were constructed for this transformation. Both aliphatic primary and secondary amines with diverse structures were efficiently converted into the desired formamides with good to excellent yields. Combined ex and in situ catalyst characterization revealed that the presence of Cu2O/Cu interface sites was vital for the excellent catalytic activity. Density functional theory (DFT) calculations demonstrated that better catalytic activity of Cu2O/Cu(111) than Cu(111) is attributed to the assistance of oxygen at the Cu2O/Cu interface (Ointer) in formation of Ointer‐H moieties, which not only reduce the apparent barrier of HCOOH formation but also benefit the desorption of the desired N‐formylated amine, leading to high activity and selectivity. [ABSTRACT FROM AUTHOR]

C-scorpionate metal complexes, specifically, [NiCl2(tpm)]·3H2O, [CoCl2(tpm)]·3H2O and [PdCl2(tpm)] [tpm = hydrotris(1H-pyrazol-1-yl)methane], were effective in the N-formylation and N-methylation of amines using carbon dioxide, as carbon source, in the presence of sodium borohydride. Various parameters were studied, including reaction time, temperature, solvent volume, presence of additives, and catalyst amount. These parameters were found to have a significant impact on the selectivity of the product. [NiCl2(tpm)]·3H2O exhibited good conversion at 80 °C, but its selectivity towards formamide decreased with prolonged reaction time. Increasing the amount of [NiCl2(tpm)]·3H2O, the selectivity changed. [PdCl2(tpm)] showed different selectivity compared to [NiCl2(tpm)]·3H2O, while [CoCl2(tpm)]·3H2O presented poor results. Monitoring the reaction course by 1H NMR revealed the presence of an intermediate species that influenced product formation. These results highlight the versatility and catalytic potential of C-scorpionate metal complexes in the N-formylation/N-methylation of amines in the catalytic system (NaBH4/MeCN/CO2).

The N-formylation of amines with CO2 and hydrosilanes is an emerging yet important reaction in fine chemical industry. Herein, we have reported a methyltrioctylammonium cation (TOMA) stabilized Nb oxocluster catalyst that can effectively realize two electron reduction of CO2 and form C-N bond simultaneously, leading to the corresponding formamides. The oxocluster catalyst exhibits excellent catalytic activity to transform secondary and primary amines into the corresponding formamides, with the conversion ranging from 81.5% to 99.2% under room temperature conditions. Furthermore, the Nb oxocluster catalyst shows the unique characteristics of ionic liquids, and it is highly robust and easy to be recycled for five times with negligible loss of catalytic activity. On the basis of the activity tests and structure characterization of Nb catalysts, it was found that TOMA cation played an important role in modulating the Nb oxocluster with high stability and uniform dispersion. The mechanism studies demonstrate that the formylation reaction proceeds through the formation of silyl formate intermediate rather than carbamate, and the Lewis base site of negative oxygen atoms from polyoxoniobate anions can exert a favorable impact on activation both CO2 and Si-H bond of PhSiH3, allowing that N-formylation reaction proceed smoothly under very mild reaction conditions.

The anaerobic fermentation gas (AFG) with CO2 removed is a sustainable energy resource, and converting CO2 in AFG to value‐added chemicals can kill two birds with one stone. Herein, an ionic porous organic polymer (IPOP‐3) catalyst, with triply synergistic effect of its hydroxide anions, nitrogen activation sites and porous structure, is synthesized. IPOP‐3 exhibits an excellent ability to enrich and convert 50 vol.% CO2 by the reactions with various amines into corresponding formamides. The catalyst is also successfully applied to the N‐formylation of CO2 in AFG, and can be easily recovered and reused. The plausible mechanism for the catalytic N‐formylation is proposed. The hydroxide anion in IPOP‐3 activates the Si−H bond of phenyl silane which reacts with the captured CO2 to form formate anion to facilitate the subsequent conversion into formamide. Our work provides a new idea for the purification of AFG and the resource utilization of CO2. [ABSTRACT FROM AUTHOR]

Alkaline salt of platinum‐incorporated heteropolyoxoniobate [Pt(Nb6O19)2]12− (Pt(Nb6)2) was fabricated and applied for N‐formylation of various amines including piperidine under CO2 and H2 atmosphere. Pt(Nb6)2 achieved the selective formation of 1‐formylpiperidine, whereas the absence of Pt species, H2, and CO2 resulted in a trace amount of the product. The structural characterization revealed that the sandwich‐type structure of Pt(Nb6)2 was transformed into Pt nanoparticles incorporated with polyoxoniobates ([Nb6O19]8−) on the NbOx bulk matrix (NbPOM‐PtNPs/NbOx) under reaction conditions. The N‐formylation of amines in the presence of CO2 and H2 proceeded by the bifunctional NbPOM‐PtNPs/NbOx where the basic sites of [Nb6O19]8− and the redox property of Pt promoted the generation of formamides. [ABSTRACT FROM AUTHOR]

Chemical utilization of CO2 is one of the fundamental strategies to synthesize value-added chemicals and reduce the CO2 emission. N-formyl-1,2,3,4-tetrahydroisoquinoline derivatives (FTHIQs) are important chemicals for the synthesis of medical intermediates and alkaloids. N-formylation of isoquinoline derivatives (IQs) with CO2 is an ideal protocol to synthesize the FTHIQs and utilize the CO2 source. In the present work, we prepared a heterogeneous Ru/ZIF-8 catalyst with a Ru loading of 2 wt% by a simple impregnation method and assessed its performances in the N-formylation of IQs and CO2 with H2. The Ru/ZIF-8 catalyst offered high IQ conversion of 98% and FTHIQ selectivity of 93% in the reaction under relatively mild conditions (150 °C, 2 MPa CO2, and 6 MPa H2). The catalyst possessed good universality and reusability, showing a potential in wide application of N-formylation of highly unsaturated nitrogen-containing isoquinolines. [ABSTRACT FROM AUTHOR]

One of the synthetic intermediates is used in many organic transformations. We have developed highly efficient N-formylation of anilines (3a–l) under solvent- and catalyst free using 150 W tungsten lamp under visible light. High yields of products, simple work-up and environmental benign conditions are the attractive features of the present methodology. All synthesized (3a–l) compounds were characterized by IR, 1H NMR and mass spectral analysis. [ABSTRACT FROM AUTHOR]

Carbon dioxide was one of the main green‐house gas, using CO2 as a C1 source to produce functional chemicals can relieve environmental issues. With the development of the N‐formylation reaction of amines under a CO2 atmosphere, a promising route for the synthesis of diacylhydrazines is the N‐formylation of hydrazide with CO2 in the presence of a reducing agent. Triethylamine (TEA) is an organic base commonly used in organic synthesis, which has a low boiling point to easily separated from the system by decompression distillation. We herein describe TEA‐ catalyzed selective N‐formylation of amines/ hydrazide using CO2 and NaBH4 to construct various formamide and N′‐formyl‐hydrazide. Utilizing N‐formylation of amines reaction to tune the reaction solvent, base, and temperature given a lower boiling catalyst and solvent system and the product can be separated easily. The selective synthesis method of formamides is achieved in good yields, which is also equally adapted to hydrazides. Finally, 1,3,4‐oxadiazole skeleton having synthetic drugs and material application was obtained by cyclization of N′‐formyl‐hydrazide. [ABSTRACT FROM AUTHOR]

An efficient heterogeneous catalytic system for the N‐formylation of amines using CO2 as a sustainable C1 source was developed using unsupported nanoporous palladium (PdNPore). The PdNPore‐catalyzed N‐formylation of amines and CO2 with hydrosilane proceeded smoothly under mild reaction conditions to yield formamides in satisfactory to excellent yields. Various synthetically useful functional groups, such as halogen, hydroxyl, allyl, and cyano groups, remained intact during the N‐formylation of amines. No palladium leached from PdNPore during the hydrogenation reaction. Moreover, the catalyst was easily recovered and reused without any loss of catalytic activity. This study is the first to demonstrate that PdNPore catalyzed CO2 conversion to form C−N bond, which enriches the reaction types of CO2 conversion catalyzed by PdNPore catalyst. [ABSTRACT FROM AUTHOR]

A new class of sulfonic acid functionalized HY zeolite (HY-N-SA) catalyst has been prepared and characterized by some method such as XRD, FT-IR, FESEM, TEM, TGA, NH3-TPD and N2 physisorption. The result shows the micro-meso structure for catalyst without ordering in the mesophase. Then, the HY-N-SA micro-meso structure was used as an acidic catalyst to synthesize of coumarins via Pechmann reaction and facile transformation of amines to formamides under solvent-free condition. To consider the effect of acidity and kind and size of porous on the catalyst activity, this catalyst was compared with NaY-N-SA and MCM-N-SA and pure porous material (NaY and MCM-41). The significant advantages of HY-N-SA with respect to other catalysts are short reaction times, high yields, pure products, mild conditions and easy work-up. In addition, we report an original and environmentally friendly solvent-free procedure which reusability of catalyst makes this method nearly green and environmentally friendly. [ABSTRACT FROM AUTHOR]

Catalytic upgrading of CO2 into value‐added chemicals to build the excess carbon cycle is of great significance. In this work, carboxylate‐functionalized zeolitic imidazolate framework (F‐ZIF‐90) with good crystallinity and porosity is constructed from ZIF‐90 and employed as a robust heterogeneous catalyst to boost the reductive N‐functionalization of various amines with CO2 to furnish N‐formyl compounds (up to 99% yield) in the presence of PhSiH3 under an ambient environment. The imidazole carboxylate species (COO‐) can not only activate hydrosilane and CO2 to form the key intermediate formoxysliane but also activate amines to participate in the N‐formylation reaction to obtain the target product. Moreover, it can enhance the catalyst capture and exchange ability toward ambient CO2. The powerful adsorption capacity of the F‐ZIF‐90 catalyst toward CO2 is conducive to elevating CO2 concentration around the active species. Theoretical calculations show that the carboxylate‐mediated conversion path undergoes the transition state of hydrosilane activation with a relatively lower energy barrier (ΔG = 26.9 kcal mol–1). F‐ZIF‐90 exhibits good thermochemical stability with no obvious activity attenuation after repeated use 5 times. This strategy opens a new avenue based on ZIFs to develop heterogeneous catalysts for reductive upgrading of CO2. [ABSTRACT FROM AUTHOR]

The photocatalytic reductive N-formylation of nitroarenes is carried out over a Pd nanoparticle (Pd NP)-embedded nanostructured Ti-metal–organic framework (MOF) using sunlight or a household white light-emitting diode (LED). Herein, the Ti-MOF is used as a visible-light-absorbing material, and the Pd NPs boost the photogenerated charge-carrier separation and transfer to the active sites for catalyzing the photocatalytic N-formylation of nitroarenes. The surface characteristics, oxidation states, and elemental compositions of the nanostructured materials were characterized by several physicochemical characterization techniques. Optical property and photoelectrochemical measurements were conducted to determine the bandgap, electron–hole recombination rate, band edge potentials, photocurrent density, charge-carrier separation, and so on. N-formylation of nitroarenes was achieved using HCOOH as a sustainable hydrogen and formylating source with simple household white LED bulbs. The yield of N-formylated arene was excellent in an aqueous medium. The structure–activity relationship was revealed using photocatalytic activity data, physicochemical and optoelectronic characteristics, control experiments, and scavenging studies. The high photocatalytic performance of the Pd/Ti-MOF can be ascribed to the direct contact between the Pd NPs and MOF, the generation of abundant catalytically active sites, and the superior electrical conductivity that leads to rapid electron transfer processes. The Pd/Ti-MOF exhibited excellent photostability and recyclability. The efficient catalyst design, an economical and sustainable light source for the direct formylation of nitroarenes, would attract researchers to develop similar catalytic protocols to other industrially important chemicals. [ABSTRACT FROM AUTHOR]

Developing efficient catalysts to convert CO 2 into value-added chemicals is valuable for reducing carbon emissions. Herein, a kind of novel thiolate-based ionic liquid with sulfur as the active site was designed and synthesized, which served as highly efficient catalyst for the reductive N-functionalization of CO 2 by amines and hydrosilane. By adjusting the CO 2 pressure, various N-formamides and N-methylamines were selectively obtained in high yields. Remarkably, at the catalyst loading of 0.1 mol %, the N-formylation reaction of N-methylaniline exhibited an impressive turnover frequency (TOF) up to 600 h -1 , which could be attributed to the roles of the ionic liquids in activating hydrosilane and amine. In addition, control experiments and NMR monitoring experiments provided evidence that the reduction of CO 2 by hydrosilane yielded formoxysilane intermediates that subsequently reacted with amines to form N-formylated products. Alternatively, the formoxysilane intermediates could further react with hydrosilane and amine to produce 4-electron-reduced aminal products. These aminal products served as crucial intermediates in the N-methylation reactions., (© 2024 Wiley-VCH GmbH.)

Porous materials with heterogeneous nature occupy a pivotal position in the chemical industry. This work described a facile pre- and post-synthetic approach to modify porous hypercrosslinked polymer with quaternary ammonium bromide, rendering it as efficient catalyst for CO2 conversion. The as-prepared porous ionic polymer (PiP@QA) displayed an improved specific surface area of 301 m2·g−1 with hierarchically porous structure, good selective adsorption of CO2, as well as high ion density. Accordingly, PiP@QA catalyst exhibited excellent catalytic performances for the solvent-free synthesis of various formamides from CO2, amines and phenylsilane under 35 °C and 0.5 MPa. We speculated that the superior catalytic efficiency and broad substrate scope of this catalyst could be resulted from the synergistic effect of flexible ionic sites with unique nanoporous channel that might increase the collision probability of reactants and active sites as well as enhance the diffusion of reactants and products during the reaction process. With the good reusability, PiP@QA was also available for the efficient conversion of simulated flue gas (15% CO2 in N2, v/v) into target formamides with quantitative selectivity at room temperature, which further highlighted its industrial application potential in chemical recycling the real-word CO2 to valuable products. [ABSTRACT FROM AUTHOR]

A facile, eco‐friendly, efficient, and recyclable heterogeneous catalyst is synthesized by immobilizing copper impregnated on mesoporous magnetic nanoparticles. The surface chemistry analysis of Fe3O4−CuO nanocomposites (NCs) by XRD and XPS demonstrates the synergistic effect between Fe3O4 and CuO nanoparticles, providing mass‐transfer channels for the catalytic reaction. TEM images clearly indicate the impregnation of CuO onto mesoporous Fe3O4. This hydrothermally synthesized eco‐friendly and highly efficient Fe3O4−CuO NCs are applied as a magnetically retrievable heterogeneous catalyst for the N‐formylation of wide range of aliphatic, aromatic, polyaromatic and heteroaromatic amines using formic acid as a formylating agent at room temperature. The catalytic activity of the NCs for N‐formylation is attributable to the synergistic effect between Fe3O4 and CuO nanoparticles. The N‐formylated product is further employed for the synthesis of biologically active quinolone moieties. [ABSTRACT FROM AUTHOR]

Porous Zr-based metal–organic frameworks (MOF-808 and MOF-808/H2SO4, UiO-66 and UiO-66-SO3H) were used as solid acid catalysts for N-formylation of aniline with formic acid (aniline/formic acid 1/2 mol/mol, 35 °C). The yield of N-formylaniline was demonstrated to depend on structure of active sites and decrease in the order: MOF-808/H2SO4 > MOF-808 > UiO-66-SO3H > UiO-66. The activity of Zr-MOFs was dependent on the key properties of solvent, i.e. polarity and basicity. The MOF-808/H2SO4 was found to be the best catalyst, resulting in the formation of N-formylaniline in 96% yield under solvent free conditions. Efficiencies of MOF-808 and MOF-808/H2SO4 were higher in comparison with H-ZSM-5, zeolite natrolite and zeolite heulandite. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ir single-atom substituted-polyoxometalate salt K 4 [PW 11 O 39 Ir] was constructed. • [BMIM] 2 [Mal] can act as a shuttle to transport CO 2 via tricarboxylate intermediate. • K-PWIr/[BMIM] 2 [Mal] system showed outstanding activity for N-formylation of amines. • The catalytic system was highly stable and can be recycled in consecutive catalytic cycles. In this work, we have constructed a Ir single-atom substituted polyoxometalate (POM) salt K 4 [PW 11 O 39 Ir] (K-PWIr). The characterization by XRD, FT-IR, HAADF-STEM and XAFS confirmed that the single-atom Ir was anchored into the framework of the POM. The binary catalytic system K-PWIr and ionic liquid bis(1-butyl-3-methylimidazolium) malonate ([BMIM] 2 [Mal]) demonstrated outstanding catalytic activity for N-formylation of amines with CO 2 /H 2 , and TON values can reach as high as 448000. The [BMIM] 2 [Mal] played a crucial role in adsorption of CO 2 and the isotopically labeled experiments confirmed that the ionic liquid aced as a shuttle to transport carbon dioxide from gas phase to catalytic Ir sites. Besides, the [BMIM] 2 [Mal] showed electron interaction with Ir sites, which can stabilize the catalytically active Ir+ sites. Detailed investigations confirmed the H 2 underwent heterolytic dissociation on Ir-O sites and the reaction was proceeded via a formate intermediates. [ABSTRACT FROM AUTHOR]

• Photocatalytic CO 2 N -formylation of amines is realized over Pt-Bi/CeO 2− x catalyst. • 100 % conversion and 90.8 % selectivity are achieved after 3 h radiation. • The photocatalyst shows good stability and universality. • A possible reaction mechanism is proposed. N -formylation of amines with CO 2 is a promising approach to high-efficient utilization of CO 2 as C1 feedstock, while conventional thermocatalytic processes suffer from harsh reaction condition and intense energy consumption. In this work, photocatalytic N -formylation of amines with CO 2 is achieved at room temperature over Pt-Bi/CeO 2− x composite catalyst. The Pt-Bi bimetallic sites increase the concentration of surface oxygen vacancies. Furthermore, the synergistic effects of Pt and Bi improve the light absorption capacity, reduce the band gap energy of the photocatalyst and promote the separation of photoinduced charge carriers. Using PhSiH 3 as the reducing agent, the conversion of N -methylaniline reaches 100 % after 3 h irradiation in N, N -dimethylformamide solvent with a N- methylformanilide selectivity of 90.8 %. The composite photocatalyst shows promising cycling stability and universality. [Display omitted] [ABSTRACT FROM AUTHOR]

Photocatalytic N -formylation of amines with CO 2 is a promising strategy to convert CO 2 into value-added chemicals sustainably. In this work, Pd-Bi bimetallic modified ZnO enriched in oxygen vacancies is constructed for photocatalytic CO 2 formylation of benzylamine at room temperature without any reductants. The Pd and Bi sites reduce the band gap energy of ZnO, promote the separation of the photogenerated charge carriers and enhance the adsorption capacity of CO 2. The yield of N -benzylformamide reaches 31.7 mmol g−1 with a selectivity of 85.3 % after 3-hour radiation in N , N -dimethylformamide (DMF) solvent. The aldehyde group involved in the formylation of benzylamine is derived from the decomposition of DMF, which is regenerated with the aldehyde group coming from the reduction of CO 2. The decomposition-regeneration cycle of DMF solvent enlarges the reaction region, which is beneficial to the activity and selectivity of the formylation process. The synergistic photocatalytic system shows a good universality. This study provides a new approach to high-efficiency CO 2 utilization and formamide production. [Display omitted] • Pd/Bi-ZnO x catalyst is developed for photocatalytic CO 2 formylation of benzylamine. • No extra reductant is used for the reduction of CO 2. • A high activity and a high selectivity of N -benzylformamide are obtained. • A decomposition-regeneration cycle of DMF solvent is involved in the reaction. [ABSTRACT FROM AUTHOR]

In the search for convenient, green, and practical catalytic methods for the current interest in organic synthesis, a simple, green, and highly efficient protocol for N-formylation of various amines was carried out in the presence of immobilized sulfuric acid on silica gel (H2SO4–SiO2). All reactions were performed in refluxing triethyl orthoformate (65 °C). The product formamides were obtained with high-to-excellent yields within 4 min to 2 h. The current approach is advantageous, due to its short reaction time and high yields. The catalyst is recyclable with no significant loss in catalytic efficiency.

A series of pyridine functionalized porous organic polymers (POPs‐Py&PPh3) have been synthesized by polymerizing tris(4‐vinylphenyl)phosphane and 4‐vinylpyridine. The pyridine moieties in the copolymer materials contribute to CO2 adsorption and promote the subsequent conversion of CO2. The POP supported Ru catalyst (Ru/POP3‐Py&PPh3) shows a high catalytic activity (TON up to 710) in the N‐formylation of various primary and secondary amines with CO2/H2, affording the corresponding formamides in good yields (55–95%) under mild reaction conditions. The heterogeneous catalyst can be easily separated from the reaction system and reused for at least eight cycles in the N‐formylation of morpholine. [ABSTRACT FROM AUTHOR]

A series of pyridine functionalized porous organic polymers (POPs‐Py&PPh3) have been synthesized by polymerizing tris(4‐vinylphenyl)phosphane and 4‐vinylpyridine. The pyridine moieties in the copolymer materials contribute to CO2 adsorption and promote the subsequent conversion of CO2. The POP supported Ru catalyst (Ru/POP3‐Py&PPh3) shows a high catalytic activity (TON up to 710) in the N‐formylation of various primary and secondary amines with CO2/H2, affording the corresponding formamides in good yields (55–95%) under mild reaction conditions. The heterogeneous catalyst can be easily separated from the reaction system and reused for at least eight cycles in the N‐formylation of morpholine. [ABSTRACT FROM AUTHOR]

Several research studies have been conducted on N-formylation of amines using phenylsilane and CO2. However, most of these studies involved tedious processes of catalyst preparation or complex procedures. In the present study, we describe the use of a simple and commercially available ZnO catalyst for selective N-formylation of amines under mild condition. High-yielding N-formylation products with good recyclability and wide substrate scope were obtained, which can promote fine chemical synthesis and CO2 capture.

The valorization of carbon dioxide (CO2) to fine chemicals is one of the most promising approaches for CO2 capture and utilization. Herein we demonstrated a series of porous organometallic polymers could be employed as highly efficient and recyclable catalysts for this purpose. Synergetic effects of specific surface area, iridium content, and CO2 adsorption capability are crucial to achieve excellent selectivity and yields towards N‐formylation of diverse amines with CO2 and H2 under mild reaction conditions even at 20 ppm catalyst loading. Density functional theory calculations revealed not only a redox‐neutral catalytic pathway but also a new plausible mechanism with the incorporation of the key intermediate formic acid via a proton‐relay process. Remarkably, a record turnover number (TON=1.58×106) was achieved in the synthesis of N,N‐dimethylformamide (DMF), and the solid catalysts can be reused up to 12 runs, highlighting their practical potential in industry. [ABSTRACT FROM AUTHOR]

Inspired by the serendipitous isolation of N-formylpiperazines when we attempted the synthesis of a series of piperazines, we have developed a straightforward methodology for the N- and O- formylation of secondary cyclic amines, anilines and steroids, respectively. Such approach is based on the hitherto non-reported use of DMF·HCl complex, as a versatile and easily-available formylating system that can be stored without apparent loss of activity. [ABSTRACT FROM AUTHOR]