Author: Jessica.F

Stone, Sarah published the artcilePulse-exposure toxicity of ammonia and propoxur to the tropical copepod Acartia sinjiensis, Recommanded Product: N-Methylformamide, the main research area is Acartia ammonia toxicity risk assessment; Crustacean; Episodic; Intermittent; Marine; Time-averaged concentration.

Toxicity risk assessments of short-term discharges of contaminated waters to the aquatic environment have shown that receptor organisms can tolerate higher pulse-exposure than continuous-exposure concentrations of some contaminants. However, these observations are influenced by the mode of toxicity of the contaminants present and the concentration-time profile of the exposure. For common metal contaminants, the time-weighted average concentration (TAC) of the exposure has been useful for predicting risk of toxicity to multiple species, including the tropical, euryhaline copepod Acartia sinjiensis. To increase our understanding of the application and limitations of the TAC approach, the present study examined how varied pulse-exposure durations affect the toxicity of fast-acting contaminants, ammonia, and the common pesticide propoxur to this copepod species. Copepod larvae were exposed under continuous-exposure conditions (all life stages from eggs to nauplii to copepodites exposed) and as 6- and 18-h pulse exposures applied during the most sensitive life stage only (24-h-old nauplii) within 78-h tests. Larval development ratio and population size were assessed as test endpoints. Generally, increased exposure duration resulted in increased toxicity. Trends observed for ammonia and propoxur were slightly different for larval development and population size. Larvae tolerated greater concentrations of contaminants in a 6-h pulse (higher 10% effect concentration) than in an 18-h pulse, or a continuous 78-h exposure, whereas toxicity responses converged for the 18- and 78-h exposures. Continuous toxicity thresholds were always protective of pulse exposures, providing a conservative toxicity threshold for all durations of pulse exposures. Although generalizations for predictions of risk based on TACs are frequently effective for common metal contaminants, the TAC approach was not effective for ammonia and propoxur. Environ Toxicol Chem 2021;00:1-11. 2021 SETAC.

Environmental Toxicology and Chemistry published new progress about Acartia sinjiensis. 123-39-7 belongs to class amides-buliding-blocks, name is N-Methylformamide, and the molecular formula is C2H5NO, Recommanded Product: N-Methylformamide.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics

Exner, Jessica published the artcileElectronic effects in profluorescent benzotriazinyl radicals: a combined experimental and theoretical study, HPLC of Formula: 7465-88-5, the main research area is profluorescent benzotriazinyl radical preparation styryl trapping product; absorption photoluminescence EPR g factor quantum chem calculation.

The synthesis, photophys. characterization, and quantum chem. calculations of a series of benzotriazinyl radicals I (R1, R2, R3 = H, OMe, CN) and their styryl radical trapping products II are presented. The benzotriazinyl radicals are non-luminescent but surprisingly the corresponding styryl radical trapping products exhibit high fluorescence quantum yields (up to 60% in some cases), making them highly valuable probes or labels. Addnl., the influence of the substitution pattern on the optical properties of the radical trapping products was observed exptl. and interpreted by means of quantum chem. calculations Specific substitution patterns showed a bathochromic shift compared to the unsubstituted compound Computationally, it was shown that this substitution pattern leads to a stronger energetic stabilization of the LUMO than the HOMO. Anal. of the influence of the substitution pattern on the optical properties showed a bathochromic shift in several examples, which was interpreted by means of quantum chem. calculations

Physical Chemistry Chemical Physics published new progress about Absorption spectra. 7465-88-5 belongs to class amides-buliding-blocks, name is 4-Methoxy-N-phenylbenzamide, and the molecular formula is C14H13NO2, HPLC of Formula: 7465-88-5.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics

Munoz, Maria M. published the artcileEquilibrium solubility and apparent specific volume at saturation of sodium sulfadiazine in some aqueous cosolvent mixtures at 298.2 K, Safety of N-Methylformamide, the main research area is sodium sulfadiazine equilibrium solubility aqueous cosolvent mixture elec conductivity.

The main objective of this research was to determine and correlate the equilibrium solubility of sodium sulfadiazine in several {cosolvent (1) + water (2)} mixtures at 298.2 K. Cosolvents were formamide, N-methylformamide, N,N-dimethylformamide, DMSO, N-methyl-2-pyrrolidone, 1,4-dioxane, and methanol. Classical shake-flask method was used to determine isothermal solubility Drug concentration measurements were performed by means of elec. conductivity determinations after adequate aqueous dilutions Solubility of sodium sulfadiazine decreases non-linearly with the addition of cosolvent to water in almost all mixtures compositions The Jouyban-Acree and Jouyban-Acree-Abraham models correlate the solubility values with the mixtures composition for all cosolvent systems. Furthermore, the apparent sp. volume of this drug at saturation was also calculated from d. and mixtures compositions

Physics and Chemistry of Liquids published new progress about Dielectric constant. 123-39-7 belongs to class amides-buliding-blocks, name is N-Methylformamide, and the molecular formula is C2H5NO, Safety of N-Methylformamide.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics

Gaudin, Theophile published the artcileA molecular contact theory for simulating polarization: application to dielectric constant prediction, Application of N-Methylformamide, the main research area is mol contact theory polarization dielec constant prediction.

Microscopic polarization in liquids, which is challenging to account for intuitively and quant., can impact the behavior of liquids in numerous ways and thus is ubiquitous in a broad range of domains and applications. To overcome this challenge, in this work, a mol. contact theory was proposed as a proxy to simulate microscopic polarization in liquids In particular, mol. surfaces from implicit solvation models were used to predict both the dipole moment of individual mols. and mutual orientations arising from contacts between mols. Then, the calculated dipole moments and orientations were combined in an anal. coupling, which allowed for the prediction of effective (polarized) dipole moments for all distinct species in the liquid As a proof-of-concept, the model focused on predicting the dielec. constant and was tested on 420 pure liquids, 269 binary organic mixtures (3792 individual compositions) and 46 aqueous mixtures (704 individual compositions). The model proved to be flexible enough to reach an unprecedented satisfactory mean relative error of about 16-22% and a classification accuracy of 84-90% within four meaningful classes of weak, low average, high average and strong dielec. constants The method also proved to be computationally very efficient, with calculation times ranging from a few seconds to about ten minutes on a personal computer with a single CPU. This success demonstrates that much of the microscopic polarization concept can be satisfactorily described based on a simple mol. contact theory. Moreover, the new model for dielec. constants provides a useful alternative to computationally expensive mol. dynamics simulations for large scale virtual screenings in chem. engineering and material sciences.

Physical Chemistry Chemical Physics published new progress about Dielectric constant. 123-39-7 belongs to class amides-buliding-blocks, name is N-Methylformamide, and the molecular formula is C2H5NO, Application of N-Methylformamide.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics

Honorio, Gabriel published the artcileNonlinear electrical and rheological spectroscopies identify structural and supramolecular relaxations in a model peptide, Recommanded Product: N-Methylformamide, the main research area is model peptide structural supramol relaxations deconvolution elec rheol spectroscopy.

Supercooled liquid secondary amides display an elec. absorption peak characterized by an almost Debye-like shape, indicative of a close-to-exponential polarization response. This response, believed to be supramol. in nature, is so enormously intense that the amide’s structural process, contributing only a few percent to the total relaxation strength, is hard to resolve reliably using standard dielec. spectroscopy. To overcome this issue, nonlinear dielec. spectroscopy involving field-induced structural recovery and temperature-induced phys. aging, was applied near the calorimetric glass transition of a mixture of N-methylformamide and N-ethylacetamide. Without the need to rely on cumbersome deconvolution procedures, it is thus demonstrated that the supramol. response is by a factor of 6 slower than the structural relaxation. Conversely, in linear rheol. experiments only the structural relaxation could be resolved, but not the supramol. one. However, medium-amplitude oscillatory shear experiments carried out at 160 K do reveal the supramol. process. Hence, the combination of linear and nonlinear mech. measurements corroborates the dielec. uncovered spectral separation of the two processes.

Soft Matter published new progress about Dielectric constant. 123-39-7 belongs to class amides-buliding-blocks, name is N-Methylformamide, and the molecular formula is C2H5NO, Recommanded Product: N-Methylformamide.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics

Gregory, Kasimir P. published the artcileThe electrostatic origins of specific ion effects: quantifying the Hofmeister series for anions, Related Products of amides-buliding-blocks, the main research area is electrostatic origins specific ion effect Hofmeister anion.

Life as we know it is dependent upon water, or more specifically salty water. Without dissolved ions, the interactions between biol. mols. are insufficiently complex to support life. This complexity is intimately tied to the variation in properties induced by the presence of different ions. These specific ion effects, widely known as Hofmeister effects, have been known for more than 100 years. They are ubiquitous throughout the chem., biol. and phys. sciences. The origin of these effects and their relative strengths is still hotly debated. Here we reconsider the origins of specific ion effects through the lens of Coulomb interactions and establish a foundation for anion effects in aqueous and non-aqueous environments. We show that, for anions, the Hofmeister series can be explained and quantified by consideration of site-specific electrostatic interactions. This can simply be approximated by the radial charge d. of the anion, which we have calculated for commonly reported ions. This broadly quantifies previously unpredictable specific ion effects, including those known to influence solution properties, virus activities and reaction rates. Furthermore, in non-aqueous solvents, the relative magnitude of the anion series is dependent on the Lewis acidity of the solvent, as measured by the Gutmann Acceptor Number Analogous SIEs for cations bear limited correlation with their radial charge d., highlighting a fundamental asymmetry in the origins of specific ion effects for anions and cations, due to competing non-Coulombic phenomena.

Chemical Science published new progress about Coordination number. 123-39-7 belongs to class amides-buliding-blocks, name is N-Methylformamide, and the molecular formula is C2H5NO, Related Products of amides-buliding-blocks.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics

McClymont, Kyle S. published the artcileTotal Synthesis of (-)-Maximiscin, Computed Properties of 343338-28-3, the main research area is maximiscin enantioselective total synthesis.

A short, enantioselective synthesis of (-)-maximiscin (I), a structurally intriguing metabolite of mixed biosynthetic origin, is reported. A retrosynthetic anal. predicated on maximizing ideality and efficiency led to several unusual disconnections and tactics. Formation of the central highly oxidized pyridone ring through a convergent coupling at the end of the synthesis simplified the route considerably. The requisite building blocks could be prepared from feedstock materials (derived from shikimate and mesitylene). Strategies rooted in hidden symmetry recognition, C-H functionalization, and radical retrosynthesis played key roles in developing this concise route.

Journal of the American Chemical Society published new progress about C-H bond activation. 343338-28-3 belongs to class amides-buliding-blocks, name is (S)-2-Methylpropane-2-sulfinamide, and the molecular formula is C4H11NOS, Computed Properties of 343338-28-3.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics

Liang, Weixiong published the artcileOn the myth of ”red/near-IR carbon quantum dots” from thermal processing of specific colorless organic precursors, Recommanded Product: N-Methylformamide, the main research area is carbon quantum dot thermal processing organic precursor red nearIR.

Carbon dots were originally found and reported as surface-passivated small carbon nanoparticles, where the effective surface passivation was the chem. functionalization of the carbon nanoparticles with organic mols. Understandably, the very broad optical absorptions of carbon dots are largely the same as those intrinsic to the carbon nanoparticles, characterized by progressively decreasing absorptivities from shorter to longer wavelengths. Thus, carbon dots are generally weak absorbers in the red/near-IR and correspondingly weak emitters with low quantum yields. Much effort has been made on enhancing the optical performance of carbon dots in the red/near-IR, but without meaningful success due to the fact that optical absorptivities defined by Mother Nature are in general rather inert to any induced alterations. Nevertheless, there were shockingly casual claims in the literature on the major success in dramatically altering the optical absorption profiles of ”carbon dots” by simply manipulating the dot synthesis to produce samples of some prominent optical absorption bands in the red/near-IR. Such claims have found warm receptions in the research field with a desperate need for carbon dots of the same optical performance in the red/near-IR as that in the green and blue. However, by looking closely at the initially reported synthesis and all its copies in subsequent investigations on the ”red/near-IR carbon dots”, one would find that the ”success” of the synthesis by thermal or hydrothermal carbonization processing requires specific precursor mixtures of citric acid with formamide or urea. In the study reported here, the systematic investigation included precursor mixtures of citric acid with not only formamide or urea but also their partially methylated or permethylated derivatives for the carbonization processing under conditions similar to and beyond those commonly used and reported in the literature. Collectively all of the results are consistent only with the conclusion that the origins of the observed red/near-IR optical absorptions in samples from some of the precursor mixtures must be mol. chromophores from thermally induced chem. reactions, nothing to do with any nanoscale carbon entities produced by carbonization.

Nanoscale Advances published new progress about Carbon quantum dots. 123-39-7 belongs to class amides-buliding-blocks, name is N-Methylformamide, and the molecular formula is C2H5NO, Recommanded Product: N-Methylformamide.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics

Hochstrasser, Denis F. published the artcileDevelopment of polyacrylamide gels that improve the separation of proteins and their detection by silver staining, Recommanded Product: N,N’-(Butane-1,4-diyl)diacrylamide, the main research area is protein separation gel electrophoresis crosslinker; silver staining protein detection crosslinker.

Background staining that is associated with Ag detection of proteins and nucleic acids in polyacrylamide gels was due mostly to the amide groups in methylenebisacrylamide, a commonly used gel crosslinker. To reduce this background staining, 8 existing crosslinking agents were tested; all were unsuitable. Six new crosslinking agents were synthesized and tested. Of these, diacrylylpiperazine provided increased phys. strength, improved electrophoretic separation of proteins, and Ag staining detection of proteins with reduced background stain.

Analytical Biochemistry published new progress about Biological staining. 10405-38-6 belongs to class amides-buliding-blocks, name is N,N’-(Butane-1,4-diyl)diacrylamide, and the molecular formula is C10H16N2O2, Recommanded Product: N,N’-(Butane-1,4-diyl)diacrylamide.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics

Dhawan, Sanjeev published the artcileHCl-mediated transamidation of unactivated formamides using aromatic amines in aqueous media, HPLC of Formula: 123-39-7, the main research area is secondary or tertiary amide green chemoselective preparation; aromatic hetero aryl amine formamide transamidation hydrochloric acid catalyst.

Transamidation protocol for the synthesize of secondary and tertiary amides R1R2NC(O)H [R1 = Ph, 2-HOC6H4, 3-BrC6H4, etc.; R2 = H, Me, Ph, etc.] from weakly nucleophilic aromatic and hetero-aryl amines with low reactive formamide derivatives, utilizing hydrochloric acid as catalyst was reported. This current acid mediated strategy was beneficial because it eliminated the need for a metal catalyst, promoter or additives in the reaction, simplifies isolation and purification Notably, this approach conventionally used to synthesize mols. on gram scales with excellent yields and a high tolerance for functional groups.

Synthetic Communications published new progress about Amidation catalysts. 123-39-7 belongs to class amides-buliding-blocks, name is N-Methylformamide, and the molecular formula is C2H5NO, HPLC of Formula: 123-39-7.

Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics