Dimethylamine as the key intermediate generated in situ from dimethylformamide (DMF) for the synthesis of thioamides

Water as a green solvent for sustainable sample preparation: single drop microextraction of N-nitrosamines from losartan tablets

Water, renowned for its sustainability and minimal toxicity, is an ideal candidate for environmentally friendly solvent-based microextraction. However, its potential as an extractant solvent in miniaturized sample preparation remains largely unexplored. This paper pioneers using water as the extraction solvent in headspace single-drop microextraction (HS-SDME) for N-nitrosamines from losartan tablets. Autonomous HS-SDME is executed by an Arduino-controlled, lab-made Cartesian robot, using water for the online preconcentration of enriched extracts through direct injection into a column-switching system. Critical experimental parameters influencing HS-SDME performance are systematically explored through univariate and multivariate experiments. While most previously reported methods for determining N-nitrosamines in pharmaceutical formulations rely on highly selective mass spectrometry detection techniques to handle the strong matrix effects typical of pharmaceutical samples, the water-based HS-SDME method efficiently eliminates the interfering effects of a large amount of the pharmaceutical active ingredient and tablet excipients, allowing straightforward analysis using high-performance liquid chromatography with ultraviolet detection (HPLC-UV-Vis). Under optimized conditions, the developed method exhibits linear responses from 100 to 2400 ng g-1, demonstrating appropriate detectability, precision, and accuracy for the proposed application. Additionally, the environmental sustainability of the method is assessed using the AGREEprep methodology, positioning it as an outstanding green alternative for determining hazardous contaminants in pharmaceutical products.

Solvent-free cross aldol condensation of aldehydes and ketones over SrMo1-xNixO3-δ perovskite nanocrystals as heterogeneous catalysts

Aldol condensation is arguably one of the most fascinating reactions that leads to the formation of C-C bonds. Its use in the pharmaceutical industry to synthesis complex drugs from simple aldehydes and ketones has become of paramount importance. Although this is one reaction that has lured a lot of attention, not enough has been explored in heterogeneous catalysis. In this work we have successfully synthesized multicationic perovskites via the soft-template method and characterized them thoroughly. The synthesized perovskite nanocrystals were found to have small SBET however their catalytic application in the conversion of benzaldehyde (BAL) in the aldol condensation with diethyl ketone (DEK) was found to be astonishing. The synthesis was confirmed using many techniques, from determining the oxidation states of the materials using XPS. This gave access to determine the coordination of the metals in the perovskite lattice and also qualitatively assess the oxygen environments that exist. The oxygen vacancies and SBET were used to assess the activity of the perovskite catalysts in the cross-aldol condensation reaction. The optimal conditions for this aldol condensation were found to be 120 °C after 25 h with no solvent using SrMo0.5Ni0.5O3-δ inorganic perovskite which had the highest amount of oxygen vacant sites which gave a conversion of 88 % and an 82 % selectivity towards the desired cross-aldol condensation product. The use of dimethylformamide (DMF) for this reaction is discouraged as it reacts with BAL to produce a higher amide.

Towards More Practical Methods for the Chemical Synthesis of Thioamides Using Sulfuration Agents: A Decade Update

Compounds possessing a thioamide function play a crucial role in organic synthesis, serving as key building blocks. They are also important in the pharmaceutical chemistry and drug design, owing to their ability to mimic the amide function in biomolecules while retaining or developing biological activity. From the synthetic viewpoint, several methods have been developed for preparing thioamides using sulfuration agents. The purpose of this review is to give an update of the last decade of contributions focusing on the formation of thioamides employing different sulfur sources. When appropriate, the cleanness and practicality of the new methods are highlighted.

Water Mediated Direct Thioamidation of Aldehydes at Room Temperature

A mild, greener approach toward thioamide synthesis has been developed. Its unique features include water-mediated reaction with no input energy, additives, or catalysts as well. The presented protocol is attractive with readily available starting materials and the use of different array amines, along with a scaled-up method. Biologically active molecules such as thionicotinamide and thioisonicotinamide can be synthesized from this procedure.

A genome-wide portrait of pervasive drug contaminants

Using a validated yeast chemogenomic platform, we characterized the genome-wide effects of several pharmaceutical contaminants, including three N-nitrosamines (NDMA, NDEA and NMBA), two related compounds (DMF and 4NQO) and several of their metabolites. A collection of 4800 non-essential homozygous diploid yeast deletion strains were screened in parallel and the strain abundance was quantified by barcode sequencing. These data were used to rank deletion strains representing genes required for resistance to the compounds to delineate affected cellular pathways and to visualize the global cellular effects of these toxins in an easy-to-use searchable database. Our analysis of the N-nitrosamine screens uncovered genes (via their corresponding homozygous deletion mutants) involved in several evolutionarily conserved pathways, including: arginine biosynthesis, mitochondrial genome integrity, vacuolar protein sorting and DNA damage repair. To investigate why NDMA, NDEA and DMF caused fitness defects in strains lacking genes of the arginine pathway, we tested several N-nitrosamine metabolites (methylamine, ethylamine and formamide), and found they also affected arginine pathway mutants. Notably, each of these metabolites has the potential to produce ammonium ions during their biotransformation. We directly tested the role of ammonium ions in N-nitrosamine toxicity by treatment with ammonium sulfate and we found that ammonium sulfate also caused a growth defect in arginine pathway deletion strains. Formaldehyde, a metabolite produced from NDMA, methylamine and formamide, and which is known to cross-link free amines, perturbed deletion strains involved in chromatin remodeling and DNA repair pathways. Finally, co-administration of N-nitrosamines with ascorbic or ferulic acid did not relieve N-nitrosamine toxicity. In conclusion, we used parallel deletion mutant analysis to characterize the genes and pathways affected by exposure to N-nitrosamines and related compounds, and provide the data in an accessible, queryable database.

Copper-catalyzed synthesis of aminoquinolines from β-(2-aminophenyl)-α,β-ynones using DMF as dual synthon

A new and efficient method has been developed for the synthesis of 4-aminoquinoline through aerobic Cu(i)-catalyzed cyclization of β-(2-aminophenyl)-α,β-ynones. Under the optimized conditions, DMF could serve as a methine source to introduce C2 carbon and a nitrogen source to incorporate amino functionality in the 4th position. Mechanistic studies using 13C- and DMF-d7 revealed that the methine group was derived from a methyl substituent.

Direct synthesis of 2-oxo-acetamidines from methyl ketones, aromatic amines and DMF via copper-catalyzed C(sp3)-H amidination

A convenient method for the synthesis of 2-oxo-acetamidines from methyl ketones using aromatic amines and DMF as nitrogen sources is reported via copper-catalyzed C(sp3)-H amidination. Various methyl ketones react readily with aromatic amines and DMF, producing 2-oxo-acetamidines in yields of 47 to 92%. This protocol features the simultaneous formation of C-N and C[double bond, length as m-dash]N bonds using DMF and aromatic amines as two different nitrogen sources. It thus provides an efficient approach to construct acyclic amidines via three C(sp3)-H bond amidination. Based on the preliminary experiments, a plausible mechanism of this transformation is disclosed.

Selective synthesis of aryl thioamides and aryl-α-ketoamides from α-oxocarboxylic acids and tetraalkylthiuram disulfides: an unexpected chemoselectivity from aryl sulfonyl chlorides

Tosyl chloride-controlled generation of thioamides and α-ketoamides via base-promoted decarboxylative reaction of α-oxocarboxylic acids with tetraalkylthiuram disulfides has been established.

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.