170 research outputs found
From amines to (form)amides: a simple and successful mechanochemical approach
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
Adsorption and release of sulfamethizole from mesoporous silica nanoparticles functionalised with triethylenetetramine
Mesoporous silica nanoparticles (MSN) were synthesised and functionalised with tri-ethylenetetramine (MSN-TETA). The samples were fully characterised (transmission electron mi-croscopy, small angle X-ray scattering, Fourier transform infrared spectroscopy, thermogravimetric analysis, zeta potential and nitrogen adsorption/desorption isotherms) and used as carriers for the adsorption of the antimicrobial drug sulphamethizole (SMZ). SMZ loading, quantified by UVâVis spectroscopy, was higher on MSN-TETA (345.8 mg gâ1) compared with bare MSN (215.4 mg gâ1) even in the presence of a lower surface area (671 vs. 942 m2 gâ1). The kinetics of SMZ adsorption on MSN and MSN-TETA followed a pseudo-second-order model. The adsorption isotherm is described better by a Langmuir model rather than a Temkin or Freundlich model. Release kinetics showed a burst release of SMZ from bare MSN samples (k1 = 136 hâ1) in contrast to a slower release found with MSN-TETA (k1 = 3.04 hâ1), suggesting attractive intermolecular interactions slow down SMZ release from MSN-TETA. In summary, the MSN surface area did not influence SMZ adsorption and release. On the contrary, the design of an effective drug delivery system must consider the intermolecular interactions between the adsorbent and the adsorbate
Mechanochemistry Frees Thiourea Dioxide (TDO) from the âVeilsâ of Solvent, Exposing All Its Reactivity
The synthesis of nitrogen-based heterocycles has always been considered essential in developing pharmaceuticals in medicine and agriculture. This explains why various synthetic approaches have been proposed in recent decades. However performing as methods, they often imply harsh conditions or the employment of toxic solvents and dangerous reagents. Mechanochemistry is undoubtedly one of the most promising technologies currently used for reducing any possible environmental impact, addressing the worldwide interest in counteracting environmental pollution. Following this line, we propose a new mechanochemical protocol for synthesizing various heterocyclic classes by exploiting thiourea dioxide (TDO)'s reducing proprieties and electrophilic nature. Simultaneously exploiting the low cost of a component of the textile industry such as TDO and all the advantages brought by a green technique such as mechanochemistry, we plot a route towards a more sustainable and eco-friendly methodology for preparing heterocyclic moieties
A Visible-Light Driven Esterification of Aldehydes Catalyzed by VOSO4
An esterification of the C-H bond of aldehydes promoted by oxidovanadium(IV) sulfate, (VOSO4)-O-IV, is reported. The process is mediated by visible-light, is carried out at room temperature, in absence of additives and using H2O2 as a benign oxidant. VOSO4 is a commercially available, earth-abundant metal (EAM(s)) salt, that does not require to be prepared. This report opens intriguing perspectives for the extended application of vanadium salts toward halogenation processes as well as for C-H activations and gives a contribution in the field of earth-abundant metals based-catalysis
Mechanochemistry: New Tools to Navigate the Uncharted Territory of âImpossibleâ Reactions
Mechanochemical transformations have made chemists enter unknown territories, forcing a different chemistry perspective. While questioning or revisiting familiar concepts belonging to solution chemistry, mechanochemistry has broken new ground, especially in the panorama of organic synthesis. Not only does it foster new âthinking outside the boxâ, but it also has opened new reaction paths, allowing to overcome the weaknesses of traditional chemistry exactly where the use of well-established solution-based methodologies rules out progress. In this Review, the reader is introduced to an intriguing research subject not yet fully explored and waiting for improved understanding. Indeed, the study is mainly focused on organic transformations that, although impossible in solution, become possible under mechanochemical processing conditions, simultaneously entailing innovation and expanding the chemical space
Identifying Neurobiological Markers in ObsessiveâCompulsive Disorder: A Study Protocol for a Cross-Sectional Study in Subgroups of Differing Phenotype
Obsessiveâcompulsive disorder (OCD) represents a frequent and highly disabling mental
disorder. Past attempts to characterize different disease subgroups focused on the time of onset
(late vs. early onset), presence of insight (poor insight), and post-infectious forms (pediatric acuteonset neuropsychiatric syndrome, PANS). Each subgroup may be associated with a differing impact
on cognition, functioning, sleep quality, and treatment response profile. Certain lines of evidence
suggest brain-derived neurotrophic factor (BDNF) levels may differ between individuals living with
OCD as compared with controls, but there is a lack of evidence on the variation of BDNF levels
in OCD subgroups. Lastly, the potential of assessing inflammatory states, electroencephalogram,
and polysomnography to characterize these subtypes has been hardly explored. Estimates of drugresistance rates indicate that 20% and up to 65% of affected adults and up to 35% of the pediatric
population may not benefit from pharmacological treatments. At least part of the variability in
treatment response could depend on the underlying biological heterogeneity. In the present project,
we aim to increase the accuracy in characterizing the phenotypical and biological signature for the
different OCD subtypes through clinical, cognitive, and sleep markers, along with other possible
markers that may be biologically plausible
Detection of genetic variation using dual-labeled peptide nucleic acid (PNA) probe-based melting point analysis
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