Synthesis Of Formamides Research Articles

Photocatalytic Formamide Synthesis via Coupling of Electrophilic and Nucleophilic Radicals over Atomically Dispersed Bi Sites.

Formamide (HCONH2) plays a pivotal role in the manufacture of a diverse array of chemicals, fertilizers, and pharmaceuticals. Photocatalysis holds great promise for green fabrication of carbon-nitrogen (C-N) compounds owing to its environmental friendliness and mild redox capability. However, the selective formation of the C-N bond presents a significant challenge in the photocatalytic synthesis of C-N compounds. This work developed a photocatalytic radical coupling method for the formamide synthesis from co-oxidation of ammonia (NH3) and methanol (CH3OH). An exceptional formamide yield rate of 5.47±0.03 mmol ⋅ gcat -1 ⋅ h-1 (911.87±5 mmol ⋅ gBi -1 ⋅ h-1) was achieved over atomically dispersed Bi sites (BiSAs) on TiO2. An accumulation of 45.68 mmol ⋅ gcat -1 (2.0 g ⋅ gcat -1) of formamide was achieved after long-term illumination, representing the highest level of photocatalytic C-N compounds synthesis. The critical C-N coupling for formamide formation originated from the "σ-σ" interaction between electrophilic ⋅CH2OH with nucleophilic ⋅NH2 radical. The BiSAs sites facilitated the electron transfer between reactants and photocatalysts and enhanced the nucleophilic attack of ⋅NH2 radical on the ⋅CH2OH radical, thereby advancing the selective C-N bond formation. This work deepens the understanding of the C-N coupling mechanism and offers an intriguing photocatalytic approach for the efficient and sustainable production of C-N compounds.

Photocatalytic Formamide Synthesis via Coupling of Electrophilic and Nucleophilic Radicals over Atomically Dispersed Bi Sites

AbstractFormamide (HCONH2) plays a pivotal role in the manufacture of a diverse array of chemicals, fertilizers, and pharmaceuticals. Photocatalysis holds great promise for green fabrication of carbon‐nitrogen (C−N) compounds owing to its environmental friendliness and mild redox capability. However, the selective formation of the C−N bond presents a significant challenge in the photocatalytic synthesis of C−N compounds. This work developed a photocatalytic radical coupling method for the formamide synthesis from co‐oxidation of ammonia (NH3) and methanol (CH3OH). An exceptional formamide yield rate of 5.47±0.03 mmol ⋅ gcat−1 ⋅ h−1 (911.87±5 mmol ⋅ gBi−1 ⋅ h−1) was achieved over atomically dispersed Bi sites (BiSAs) on TiO2. An accumulation of 45.68 mmol ⋅ gcat−1 (2.0 g ⋅ gcat−1) of formamide was achieved after long‐term illumination, representing the highest level of photocatalytic C−N compounds synthesis. The critical C−N coupling for formamide formation originated from the “σ–σ” interaction between electrophilic ⋅CH2OH with nucleophilic ⋅NH2 radical. The BiSAs sites facilitated the electron transfer between reactants and photocatalysts and enhanced the nucleophilic attack of ⋅NH2 radical on the ⋅CH2OH radical, thereby advancing the selective C−N bond formation. This work deepens the understanding of the C−N coupling mechanism and offers an intriguing photocatalytic approach for the efficient and sustainable production of C−N compounds.

Innentitelbild: Aerobic Oxidative Synthesis of Formamides from Amines and Bioderived Formyl Surrogates (Angew. Chem. 26/2024)

Innentitelbild: Aerobic Oxidative Synthesis of Formamides from Amines and Bioderived Formyl Surrogates (Angew. Chem. 26/2024)

Inside Cover: Aerobic Oxidative Synthesis of Formamides from Amines and Bioderived Formyl Surrogates

Inside Cover: Aerobic Oxidative Synthesis of Formamides from Amines and Bioderived Formyl Surrogates

Aerobic Oxidative Synthesis of Formamides from Amines and Bioderived Formyl Surrogates

AbstractHerein we present a new strategy for the oxidative synthesis of formamides from various types of amines and bioderived formyl sources (DHA, GLA and GLCA) and molecular oxygen (O2) as oxidant on g‐C3N4 supported Cu catalysts. Combined characterization data from EPR, XAFS, XRD and XPS revealed the formation of single CuN4 sites on supported Cuphen/C3N4 catalysts. EPR spin trapping experiments disclosed ⋅OOH radicals as reactive oxygen species and ⋅NR1R2 radicals being responsible for the initial C−C bond cleavage. Control experiments and DFT calculations showed that the successive C−C bond cleavage in DHA proceeds via a reaction mechanism co‐mediated by ⋅NR1R2 and ⋅OOH radicals based on the well‐equilibrated CuII and CuI cycle. Our catalyst has much higher activity (TOF) than those based on noble metals.

Electrochemical synthesis of formamide by C–N coupling with amine and CO2 with a high faradaic efficiency of 37.5%

Electrochemical synthesis of formamide by C–N coupling with amine and CO2 with a high faradaic efficiency of 37.5%

One-pot two-step reduction of CO2 with amines and NaBH4 to N-substituted compounds at atmospheric pressure

In this paper, the reductive N-formylation, methylation and cyclization of amines with carbon dioxide (CO2) using sodium borohydride (NaBH4) at atmospheric pressure, via a one-pot two-step procedure, is presented. Formato borohydride (NaBHn(OCHO)4-n), in situ formed in the reaction of NaBH4 with CO2, as an efficient agent to promote the corresponding reaction, and the mechanism is proposed on the basis of experiments. This wide substrate scope and simple operational methodology also facilitates the effective synthesis of formamides, methylamines, benzimidazoles and other heterocyclic compounds avoiding high temperature and pressure.

Formamide synthesis in the interstellar medium catalyzed by damaged water ice

Context. Formamide is one of the possible precursors of life because it has a bond analogous to the peptide bond. Aims. In this work, we examine the reaction pathways that lead from HCN or HNC and OH to formamide. Both HCN and HNC are present in the interstellar medium, while OH could be present in interstellar water ice, which under the effect of cosmic rays, partially decomposes into H and OH. Methods. We carried out first principles calculations. We represented the solid state either by a model of clusters or by a model of slabs that takes into account periodicity. The confrontation of these two models and with the reaction in the gas phase enabled us to find reactivity trends. Results. For HCN, the formation of the C-N bond presents an energy barrier that cannot be overcome in the interstellar medium. The presence of water ice grains does not catalyze this step. The formation of the same bond from HNC is spontaneous, even without the presence of the solid. The second step of the pathway is a transposition of H. This step requires the presence of water ice for the barrier to allow the reaction to take place in the interstellar medium. The last step is a hydrogenation of a barrier-free radical. Our work therefore concludes that the synthesis of formamide can take place in the interstellar medium through water ice, which not only catalyzes the reaction but also constitutes a reservoir of OH.

Efficient DMF-assisted synthesis of formamides from amines using CO2 catalyzed by heterogeneous metal-free imidazolium-hypercrosslinked polymers

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.

Direct Synthesis of N-formamides by Integrating Reductive Amination of Ketones and Aldehydes with CO2 Fixation in a Metal-Organic Framework.

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.

Decarboxylative N-Formylation of Amines with Glyoxylic Acid Promoted by H2O2.

A novel method for the synthesis of formamides through the decarboxylative N-formylation of amines with glyoxylic acid has been developed. This transformation provides an efficient protocol for the synthesis of various formamides with moderate to excellent yields, and it can accommodate a wide range of functional groups under metal free and base free conditions. In addition, the large-scale experiments and high chemoselectivity have shown great potential application of this strategy.

Direct Synthesis of Formamide from CO2 and H2O with Nickel-Iron Nitride Heterostructures under Mild Hydrothermal Conditions.

Formamide can serve as a key building block for the synthesis of organic molecules relevant to premetabolic processes. Natural pathways for its synthesis from CO2 under early earth conditions are lacking. Here, we report the thermocatalytic conversion of CO2 and H2O to formate and formamide over Ni-Fe nitride heterostructures in the absence of synthetic H2 and N2 under mild hydrothermal conditions. While water molecules act as both a solvent and hydrogen source, metal nitrides serve as nitrogen sources to produce formamide in the temperature range of 25-100 °C under 5-50 bar. Longer reaction times promote the C-C bond coupling and formation of acetate and acetamide as additional products. Besides liquid products, methane and ethane are also produced as gas-phase products. Postreaction characterization of Ni-Fe nitride particles reveals structural alteration and provides insights into the potential reaction mechanism. The findings indicate that gaseous CO2 can serve as a carbon source for the formation of C-N bonds in formamide and acetamide over the Ni-Fe nitride heterostructure under simulated hydrothermal vent conditions.

Cu-Catalysed sustainable synthesis of formamide with glycerol derivatives as a carbonyl source via a radical-relay mechanism

N-Formylation of amines to formamides was achieved at a low temperature by total utilization of the carbon atoms of glycerol derivatives as the C1 feedstock over CuZr/5A via a ˙OH–˙OOH radical mechanism.

CO2 conversion to formamide using a fluoride catalyst and metallic silicon as a reducing agent

Metallic silicon could be an inexpensive, alternative reducing agent for CO2 functionalization compared to conventionally used hydrogen or hydrosilanes. Here, metallic silicon recovered from solar panel production is used as a reducing agent for formamide synthesis. Various amines are converted to their corresponding amides with CO2 and H2O via an Si-H intermediate species in the presence of a catalytic amount of tetrabutylammonium fluoride. The reaction system exhibits a wide substrate scope for formamide synthesis. Spectroscopic analysis, including in situ Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N2 adsorption/desorption analyses, and isotopic experiments reveal that the fluoride catalyst effectively oxidizes Si atoms on both surface and interior of the powdered silicon particles. The solid recovered after catalysis contained mesopores with a high surface area. This unique behavior of the fluoride catalyst in the presence of metallic silicon may be extendable to other reductive reactions, including those with complex substrates. Therefore, this study presents a potential strategy for the efficient utilization of abundant resources.

MnO2 nanostructures as sustainable catalysts for selectivity tuning and syntheses of amine coupling products with bio-derived glycerol

This work reports crystalline MnO2 nanomaterials as a sustainable catalyst, for economical synthesis of N-substituted formamides and N-methyl amine products in the presence of air:O2 mixture (9:1) using bio-derived glycerol. This process provides flexible selectivity tuning between N-formamides and N-methyl amines, based on MnO2 crystal structure and glycerol concentration. The as-prepared (α, β, γ & δ) MnO2 nanostructures have been characterized in detail. This process was tested further with γ-MnO2 nanorods, which delivers yields in the range of 43-90% for a diverse substrate library of 16 amine substrates for N-formamide products and β-MnO2 for synthesis of N-methyl amines from secondary amines. The varied crystalline MnO2 nanostructures and their surface Mn (III)/Mn (IV) species ratios have been shown to steer the selectivity of the reaction differently, where α- and γ-MnO2 forming N-formamide with higher selectivity, while β- and δ-MnO2 leans more towards formation of N-methyl amine and N-formamide equally. The reusability of MnO2 catalysts up to 7 runs has been shown. The gram scale synthesis of formamides also shows yields of up to 75% using γ-MnO2 at pre-determined parameters.

Ionic liquid-based periodic mesoporous organosilicas: Metal/solvent-free synthesis of formamides and formamidines

We prepared a novel ionic liquid-based Periodic Mesoporous Organosilicas (PMOs) using a post-synthetic method. First, PMO containing amine unit (PMO-NH) was prepared as a result of the co-condensation of amine bis-silane precursor [bis[3-(triethoxysilyl)propyl]amine] and tetraethylorthosilicate (TEOS) in the presence of pluronic-123 under acidic conditions. In a second step, the amine units (NH) were reacted with perchloric acid and yielded ionic-PMO material (PMO-NH2+ClO4−). The materials possessed a hexagonal lattice with the highly ordered mesostructured being retained after the functionalization as evidenced by X-ray diffraction (XRD) analysis. The N2 adsorption-desorption measurement revealed that the final material (PMO-NH2+ClO4−) had a high BET surface area (350 m2/g) and pore size (4.8 nm). The obtained material was subsequently evaluated as a heterogeneous catalyst in the coupling reaction of amine/formic acid towards formamides and also in the preparation of formamidine derivatives. The reactions between various aryl amines and formic acid or triethyl orthoformate could proceed smoothly in the presence of PMO-NH2+ClO4−, giving a high yield of 85–99% with great selectivity (> 99%). This outstanding catalytic performance can be attributed to the presence of acidic ionic sites together with a high surface area of the obtained material.

A green, efficient reductive N-formylation of nitro compounds catalyzed by metal-free graphitic carbon nitride supported on activated carbon

Metal-free graphitic carbon nitride supported on activated carbon was fabricated via a simple pyrolysis for one-pot reductive N-formylation of nitro compounds with formic acid and sodium formate was employed as promoter. Under the conditions, this transformation was successfully achieved without any solvent. The support activated carbon and pyrolysis atmosphere had important influence on catalytic behavior of catalyst. SEM, TEM, XRD, XPS, EPR, FT-IR, Raman spectrum and N2 adsorption/desorption characterizations revealed that air pyrolysis enabled g-C3N4 to generate more carbon defects and the support AC effectively dispersed g-C3N4 to expose more active sites. Using our procedure, a broad set of nitro compounds was converted to their corresponding formamides with various functional group tolerances. The catalyst could be recycled several times without marked loss of activity. In short, we provided an efficient and sustainable protocol for the expedient synthesis of formamides from nitro compounds.

Catalytic Synthesis of Formamides by Integrating CO2 Capture and Morpholine Formylation on Supported Iridium Catalyst

AbstractHerein we report an efficient and recyclable catalytic system for tandem CO2 capture and N‐formylation to value‐added chemicals. CO2 is apt to be captured by morpholine solution, while a highly efficient heterogeneous catalyst, isolated iridium atoms supported over nanadiamond/graphene, is discovered to be highly reactive for the formylation of morpholine, leading to the formation of N‐formylmorpholine with excellent productivity (with a turnover number of 5 120 000 in a single batch reaction) and selectivity (>99 %). In addition, the CO2 captured by morpholine under atmospheric conditions can be converted to N‐formylmorpholine with decent conversion (51 %), which realizes the integration of CO2 capture and conversion to value‐added chemicals.

Catalytic Synthesis of Formamides by Integrating CO2 Capture and Morpholine Formylation on Supported Iridium Catalyst.

Herein we report an efficient and recyclable catalytic system for tandem CO2 capture and N-formylation to value-added chemicals. CO2 is apt to be captured by morpholine solution, while a highly efficient heterogeneous catalyst, isolated iridium atoms supported over nanadiamond/graphene, is discovered to be highly reactive for the formylation of morpholine, leading to the formation of N-formylmorpholine with excellent productivity (with a turnover number of 5 120 000 in a single batch reaction) and selectivity (>99 %). In addition, the CO2 captured by morpholine under atmospheric conditions can be converted to N-formylmorpholine with decent conversion (51 %), which realizes the integration of CO2 capture and conversion to value-added chemicals.

Catalysis of Positively Charged Ru Species Stabilized by Hydroxyapatite in Amine Formylation

AbstractFormamide is an important solvent and synthetic intermediate. Herein, we designed a hydroxyapatite (HAP)‐stabilized, positively charged Ru‐based catalysts which can efficiently catalyze the formylation reaction of amines with CO for the synthesis of formamide. The Ru‐HAP showed excellent catalytic performance in N,N‐Dimethylformamide (DMF) synthesis, with about 75 % dimethylamine conversion and >99 % DMF selectivity at 300 h of continuous reaction. The combination of characterization results and control experiments showed that positively charged Ru species, including hydrated RuOx and Ru3+ species, were catalytically active. In particular, the surface RuOx species were more active than the Ru3+ species located within the HAP framework.