N,N-Dimethylformamide: much more than a solvent

Interconvertible vanadium-seamed hexameric pyrogallol[4]arene nanocapsules

Research into stimuli-responsive controlled self-assembly and reversible transformation of molecular architectures has received much attention recently, because it is important to understand and reproduce this natural self-assembly behavior. Here, we report two coordination nanocapsules with variable cavities: a contracted octahedral V₂₄ capsule and an expanded ball-shaped V₂₄ capsule, both of which are constructed from the same number of subcomponents. The assemblies of these two V₂₄ capsules are solvent-controlled, and capable of reversible conversion between contracted and expanded forms via control of the geometries of the metal centers by association and dissociation with axial water molecules. Following such structural interconversions, the magnetic properties are significantly changed. This work not only provides a strategy for the design and preparation of coordination nanocapsules with adaptable cavities, but also a unique example with which to understand the transformation process and their structure-property relationships.

Adapting the cavity of a coordination capsule generally involves the addition or removal of subcomponents. Here, the authors report two vanadium-organic coordination nanocapsules with the same number of components but variable cavity sizes—an expanded ball and contracted octahedron—whose solvent-controlled interconversion is attributed to the versatile coordination geometry of the vanadium centers.

Direct defluorinative amidation-hydrolysis reaction of gem-difluoroalkenes with N,N-dimethylformamide, and primary and secondary amines

A novel and efficient method for the synthesis of arylacetamides by the reactions of gem-difluoroalkenes with N,N-dialkylformamides, and primary and secondary amines with the assistance of KOtBu and water was developed.

Myths and reality of HPbI3 in halide perovskite solar cells

All-inorganic perovskites have a special place in halide perovskite family because of their potential for better stability. However, the representative cesium lead iodide (CsPbI3) is metastable and spontaneously converts to the non-perovskite structure at room temperature. Here, we demonstrate that what appears to be all-inorganic CsPbI3 stabilized in its perovskite form using the purported intermediate known as hydrogen lead iodide (HPbI3) is, in fact, the hybrid perovskite cesium dimethylammonium lead iodide (Cs1-xDMAxPbI3, x = 0.2 to 0.5). Thus, many of the reported all-inorganic perovskites are actually still hybrid organic-inorganic perovskites, as strongly evidenced by a wide battery of experimental techniques presented here. Solar cells based on the representative composition Cs0.7DMA0.3PbI3 can achieve an average power conversion efficiency of 9.27 ± 1.28% (max 12.62%). These results provide an alternative angle to look at previous results pertaining all-inorganic CsPbI3 while the DMA cation is now revealed as an alternative A site cation.

Ag(I)-Catalyzed [3 + 2]-Annulation of Cyclopropenones and Formamides via C-C Bond Cleavage

An unprecedented Ag-catalyzed [3 + 2]-annulation of cyclopropenones and DMF via C-C bond cleavage is disclosed. This protocol exhibited excellent chemo- and regio-selectivity, and tolerated various functional groups. More importantly, DMF served as the C═O bond in the cycloaddition reaction, providing an efficient way to construct γ-aminobutenolides. In addition, transesterification reaction occurred when DMF was replaced by esters.

Metal-Organic Frameworks with Organogold(III) Complexes for Photocatalytic Amine Oxidation with Enhanced Efficiency and Selectivity

Luminescent organogold(III) complex Au^III with highly emissive triplet excited state was encapsulated in two metal-organic frameworks (MOFs) with different pore sizes and structures (MOF1 and ZJU-28). Compared with the Au^III complex in solution, the resultant composites Au^III @MOF1 and Au^III @ZJU-28 exhibit enhanced emission intensity, lifetime, and quantum yield. Under irradiation, Au^III @MOFs are efficient, selective, and recyclable catalysts for light-induced aerobic C-N bond formation. When used as a heterogeneous catalyst for oxidizing secondary amines to the corresponding imines, Au^III @ZJU-28 achieved high TONs of 876-1548, which are about 2.8-3.5 times higher than that of the homogenous Au^III complex. In addition, different selectivities in oxidizing mixed substrates is realized by means of different host MOFs, and thus encapsulating the Au^III complex in an appropriate MOF allowed the desired product to be obtained. Inherent shortcomings of homogeneous catalysts in cyclic use are also overcome by using composite catalysts, and high conversion of the Au^III @ZJU-28 catalyst was still observed after ten cycles.

A novel Pd-catalysed sequential carbonylation/cyclization approach toward bis-N-heterocycles: rationalization by electronic structure calculations

An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy, using carbon monoxide and structurally different aliphatic diamines as N-nucleophiles, gives access, in one pot, to a new family of indole-based N-heterocyclic derivatives (hydropyrazinones, benzodiazepinones and hydroquinoxalines). Optimization of the reaction conditions towards double carbonylation (P _CO = 30 bar, T = 80°C, iodoindole/diamine ratio = 1 : 1.5, toluene as solvent) allowed the target cyclic products, which are formed in situ via intramolecular cyclization of the ketocarboxamide intermediates, to be obtained through a nucleophilic addition/elimination reaction with the pendant terminal amine groups. The structure of the diamine nucleophile was revealed to affect the reaction's selectivity, with the best yields for the cyclic products being obtained in the presence of (1S,2S)-(+)-cyclohexane-1,2-diamine (a) as the nucleophile, using either 5- or 7-iodoindole as the substrate. The reaction's selectivity was rationalized based on electronic structure calculations, which explain the effect of the diamine structure on the predominant formation of the cyclic products.

Recent Uses of N,N-Dimethylformamide and N,N-Dimethylacetamide as Reagents

N,N-Dimethylformamide and N,N-dimethylacetamide are multipurpose reagents which deliver their own H, C, N and O atoms for the synthesis of a variety of compounds under a number of different experimental conditions. The review mainly highlights the corresponding literature published over the last years.

Beyond a solvent: triple roles of dimethylformamide in organic chemistry

N,N-Dimethylformamide (DMF) is frequently used as an aprotic solvent in chemical transformations in laboratories of academia as well as in those of chemical industry. In the present review, we will reveal that DMF is actually something much more than a solvent. It is a unique chemical since, as well as being an effective polar aprotic solvent, it can play three other important roles in organic chemistry. It can be used as a reagent, a catalyst, and a stabilizer.

Selective α-Monomethylation by an Amine-Borane/N,N-Dimethylformamide System as the Methyl Source

A new and practical α-monomethylation strategy using an amine-borane/N,N-dimethylformamide (R₃ N-BH₃ /DMF) system as the methyl source was developed. This protocol has been found to be effective in the α-monomethylation of arylacetonitriles and arylacetamides. Mechanistic studies revealed that the formyl group of DMF delivered the carbon and one hydrogen atoms of the methyl group, and R₃ N-BH₃ donated the remaining two hydrogen atoms. Such a unique reaction pathway enabled controllable assemblies of CDH₂ -, CD₂ H-, and CD₃ - units using Me₂ NH-BH₃ /d₇ -DMF, Me₃ N-BD₃ /DMF and Me₃ N-BD₃ /d₇ -DMF systems, respectively. Further application of this method to the facile synthesis of anti-inflammatory flurbiprofen and its varied deuterium-labeled derivatives was demonstrated.

Green synthesis of amphiphilic carbon dots from organic solvents: application in fluorescent polymer composites and bio-imaging

Carbon dots (CDs) have sparked tremendous attention due to their unique properties and vast potential in diverse fields. Herein, we report a green and cost-effective hydrothermal route for the synthesis of a series of CDs from readily available organics solvents. Since the organics were completely recyclable after the separation of CDs, this method holds immense potential for the large-scale synthesis of CDs. We found the DMF-CDs and DMAc-CDs possessed amphiphilicity and the diameter of amphiphilic DMF-CDs was ca. 3.5 nm with a narrow distribution. Moreover, these amphiphilic CDs emitted blue light under UV irradiation (365 nm) and the quantum yield could reach more than 30%. Due to their good solubility in organic solvent, DMF-CDs were successfully imbedded into polymers (i.e., PS and PMMA), which revealed their potential in painting, coating, and optical devices. In addition, benefiting from high quantum yield and low cytotoxicity, the DMF-CDs in aqueous media were used as fluorescent probes in living cells, which demonstrated their great potential in bio-imaging.

Cesium carbonate promoted cascade reaction involving DMF as a reactant for the synthesis of dihydropyrrolizino[3,2-b]indol-10-ones

A cesium carbonate promoted cascade reaction for the synthesis of dihydropyrrolizino[3,2-b]indol-10-ones has been developed.

Transamidación y transamidación-reducción de N-benciltiramina con DMF

La tiramina y la N-benciltiramina reaccionan con formaldehído para formar azaciclofanos por medio de condensaciones tipo Mannich aromáticas y reaccionan con aldehídos no enolizables para formar las respectivas bases de Schiff. En este artículo se presenta la síntesis inesperada de N-bencil-N-formiltiramina y N-bencil-N-metiltiramina por medio de reacciones de transamidación y de transamidación-reducción de N-benciltiramina con N,N-dimetilformamida. Para explicar el curso de la reacción se propuso un mecanismo que involucra la formilación de N-benciltiramina y posterior reducción de Leuckart-Wallach inducida por ácido fórmico generado in situ.

Silver-catalyzed ring-opening [3+2] annulation of cyclopropenones with amides

A silver(i)-catalyzed ring-opening [3+2] annulation between cyclopropenones and amides has been achieved to afford 5-amino-2-furanones.

Synthesis and coordination studies of 5-(4′-carboxyphenyl)-10,15,20-tris(pentafluorophenyl)porphyrin and its pyrrolidine-fused chlorin derivative

An efficient strategy was developed to obtain carboxyphenyl porphyrin, chlorins and metal complexes, with potential applications in photonics and biology.

The vinylogous Catellani reaction: a combined computational and experimental study

In the presence of 5 mol% Pd(OAc)₂, 1 equiv. of norbornene, and K₂CO₃, the reaction of 4-iodo-2-quinolones with tertiary o-bromobenzylic alcohols produced the desired benzopyran-fused 2-quinolones in moderate to high yields.

In the presence of 5 mol% Pd(OAc)₂, 1 equiv. of norbornene, and K₂CO₃, the reaction of 4-iodo-2-quinolones with tertiary o-bromobenzylic alcohols produced the desired benzopyran-fused 2-quinolones in moderate to high yields. A Catellani-type mechanism involving vinylic C–H cleavage is proposed based on the results of control experiments and density functional theory calculations.

Amide synthesis via nickel-catalysed reductive aminocarbonylation of aryl halides with nitroarenes

A nickel-catalysed reductive aminocarbonylation of (hetero)aryl halides employing readily available nitro(hetero)arenes as the nitrogen source has been developed.

Aminocarbonylation of aryl halides is one of the most useful methods in amide synthesis, but nitroarenes have not been used as a nitrogen source in this method even though they are more economical and accessible than anilines. Reported here is the development of nickel catalysis for the first three-component reactions of aryl halides, Co₂(CO)₈, and nitroarenes under reductive conditions to produce aryl amides. A wide range of (hetero)aryl iodides and bromides as well as nitro(hetero)arenes are suitable reaction partners, and high functional group compatibility has been achieved. The method might be used for the streamlined synthesis of aryl amides.

Origins of high catalyst loading in copper(i)-catalysed Ullmann-Goldberg C-N coupling reactions

A mechanistic investigation of Ullmann-Goldberg reactions using soluble and partially soluble bases led to the identification of various pathways for catalyst deactivation through (i) product inhibition with amine products, (ii) by-product inhibition with inorganic halide salts, and (iii) ligand exchange by soluble carboxylate bases. The reactions using partially soluble inorganic bases showed variable induction periods, which are responsible for the reproducibility issues in these reactions. Surprisingly, more finely milled Cs2CO3 resulted in a longer induction period due to the higher concentration of the deprotonated amine/amide, leading to suppressed catalytic activity. These results have significant implications on future ligand development for the Ullmann-Goldberg reaction and on the solid form of the inorganic base as an important variable with mechanistic ramifications in many catalytic reactions.

N,N-Dimethylformamide (DMF) as a Source of Oxygen To Access α-Hydroxy Arones via the α-Hydroxylation of Arones

An unprecedented α-hydroxylation strategy was developed for the synthesis of α-hydroxy arones using N,N-dimethylformamide (DMF) as an oxygen source. Control experiments demonstrated that the oxygen atom of the hydroxy group in the α-hydroxy arones produced in this reaction was derived from DMF. This new reaction therefore not only provides an alternative strategy for the α-hydroxylation of arones but also highlights the possibility of using the inexpensive common solvent DMF as a source of oxygen in organic synthesis.

Oxidative amidation of benzaldehydes and benzylamines withN-substituted formamides over a Co/Al hydrotalcite-derived catalyst

A highly efficient synthetic strategy for amidesviaoxidative amidation of benzaldehydes or benzylamines withN-substituted formamides has been developed using cobalt based heterogeneous catalyst.

Introducing tetramethylurea as a new methylene precursor: a microwave-assisted RuCl3-catalyzed cross dehydrogenative coupling approach to bis(indolyl)methanes

The microwave-assisted synthesis of symmetrical/unsymmetrical bis(indolyl)methanes using tetramethylurea as a methylene source.

Nickel-catalyzed carbonylation of arylboronic acids with DMF as a CO source

By using N,N-dimethylformamide (DMF) as a CO source, nickel-catalyzed carbonylation of arylboronic acids was demonstrated as an efficient and facile protocol for the synthesis of diaryl ketones.