Here we report that chiral Mn(I) complexes are capable of H–P bond activation. This activation mode enables a general method for the hydrophosphination of internal and terminal α,β-unsaturated ...nitriles. Metal−ligand cooperation, a strategy previously not considered for catalytic H–P bond activation, is at the base of the mechanistic action of the Mn(I)-based catalyst. Our computational studies support a stepwise mechanism for the hydrophosphination and provide insight into the origin of the enantioselectivity.
NMR spectroscopy is a powerful spectroscopic tool that not only allows the determination of structures after synthesis, as usually explained to students of Organic Chemistry, but also is useful in ...many other fields such as medicine imaging, real-time industrial processes, material sciences, or metabolomics. In this experiment, students performed a ring-opening polymerization (ROP) reaction in the laboratory and, then, collected a series of 1D NMR spectra with the aim of determining the tacticity of the polymers formed and their number-average molecular weight. The deconvolution of 1H and 13C NMR experimental data was central in their learning process, and the consistence of the results obtained was validated within the literature. This exercise gave students skills on polymerization reaction processes, instrumental analysis, and determination and interpretation of NMR spectra in the use of deconvolution procedures along with the critical evaluation of the obtained results.
Here we report catalytic asymmetric hydrophosphination of α,β-unsaturated carbonyl derivatives using a chiral Mn(I) complex as a catalyst. Through H–P bond activation, various phosphine-containing ...chiral products can be accessed via hydrophosphination of various ketone-, ester-, and carboxamide-based Michael acceptors.
The health status of premature infants born 321-350 weeks' gestational age (wGA) hospitalized for RSV infection in the first year of life (cases; n = 125) was compared to that of premature infants ...not hospitalized for RSV (controls; n = 362) through 6 years. The primary endpoints were the percentage of children with wheezing between 2-6 years and lung function at 6 years of age. Secondary endpoints included quality of life, healthcare resource use, and allergic sensitization. A significantly higher proportion of cases than controls experienced recurrent wheezing through 6 years of age (46.7% vs. 27.4%; p = 0.001). The vast majority of lung function tests appeared normal at 6 years of age in both cohorts. In children with pulmonary function in the lower limit of normality (FEV1 Z-score -2; -1), wheezing was increased, particularly for cases vs. controls (72.7% vs. 18.9%, p = 0.002). Multivariate analysis revealed the most important factor for wheezing was RSV hospitalization. Quality of life on the respiratory subscale of the TAPQOL was significantly lower (p = 0.001) and healthcare resource utilization was significantly higher (p<0.001) in cases than controls. This study confirms RSV disease is associated with wheezing in 32-35 wGA infants through 6 years of age.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This work describes the catalytic activity of palladium( ii ) species in the cycloisomerization of alkynoic acids and their derivatives in aqueous media as well as in Deep Eutectic Solvents (DESs), ...with one of the lowest metal catalyst loadings reported so far in the literature. Different substrates such as terminal and internal alkynes or alkynyl sulfonylimides were studied, obtaining selectivity either to the cyclic compound or the hydrolysed keto derivative. This new system avoids the use of harmful solvents and employs very efficient and recoverable heterogeneous catalysts.
Lewis Acid Promoted Dearomatization of Naphthols Kulish, Kirill; Boldrini, Cosimo; Castiñeira Reis, Marta ...
Chemistry : a European journal,
December 4, 2020, Letnik:
26, Številka:
68
Journal Article
Recenzirano
Odprti dostop
Two‐step dearomative functionalization of naphthols promoted by Lewis acids and copper(I) catalysis was developed. Initially, Lewis acid complexation inverted the electronic properties of the ring ...and established an equilibrium with the dearomatized counterpart. Subsequent trapping of the dearomatized intermediate with organometallics as well as organophosphines was demonstrated and provided the corresponding dearomatized products.
A method to activate naphthols with Lewis acids (LA) is developed, stabilizing the non‐aromatic tautomer and leading to the formation of α,β‐unsaturated ketones. Organometallic addition catalyzed by CuI as well as addition of phosphines and hydrides are compatible with the presence of LA, yielding the corresponding dearomatized products. The procedure requires very mild reaction conditions and can be an important tool for organic synthesis.
A new Y-based metal–organic framework (MOF) GR-MOF-6 with a chemical formula of {YL(DMF)2·(DMF)} n {H3L = 5-(4-carboxyphenyl)ethynyl isophthalic acid; DMF = N,N-dimethylformamide} has been prepared ...by a solvothermal route. Structural characterization reveals that this novel material is a three-dimensional MOF in which the coordination of the tritopic ligand to Y(III) metal ions leads to an intercrossing channel system extending over three dimensions. This material has proven to be a very efficient catalyst in the cyanosilylation of carbonyls, ranking second in catalytic activity among the reported rare earth metal-based MOFs described so far but with the lowest required catalyst loading. In addition, its electrophoretic behavior has been studied in depth, providing a zero-charge point between pH 4 and 5, a peak electrophoretic mobility of −1.553 μm cm V–1 s–1, and a ζ potential of −19.8 mV at pH 10.
The synthesis of different tetrahydroisoquinolines using choline chloride : ethylene glycol as a deep eutectic solvent (DES) and copper(ii) oxide impregnated on magnetite as a catalyst has been ...accomplished successfully. The copper catalyst amount is the lowest loading ever reported. The presence of DES showed to be essential since the reaction in the absence of this medium did not proceed. A direct proportional relationship was found between the conductivity of DES medium and the yield obtained. The DES and the catalyst could be reused up to ten times without any detrimental effect on the yield of the reaction, with the aerobic conditions making the protocol highly sustainable, where the only waste is water.
Recent introduction of monoclonal antibodies targeting immune checkpoints to harness antitumor immunity has revolutionized the cancer treatment landscape. The therapeutic success of immune checkpoint ...blockade (ICB)-based therapies mainly relies on PD-1/PD-L1 and CTLA-4 blockade. However, the limited overall responses and lack of reliable predictive biomarkers of patient´s response are major pitfalls limiting immunotherapy success. Hence, this reflects the compelling need of unveiling novel targets for immunotherapy that allow to expand the spectrum of ICB-based strategies to achieve optimal therapeutic efficacy and benefit for cancer patients. This review thoroughly dissects current molecular and functional knowledge of BTLA/HVEM axis and the future perspectives to become a target for cancer immunotherapy. BTLA/HVEM dysregulation is commonly found and linked to poor prognosis in solid and hematological malignancies. Moreover, circulating BTLA has been revealed as a blood-based predictive biomarker of immunotherapy response in various cancers. On this basis, BTLA/HVEM axis emerges as a novel promising target for cancer immunotherapy. This prompted rapid development and clinical testing of the anti-BTLA blocking antibody Tifcemalimab/icatolimab as the first BTLA-targeted therapy in various ongoing phase I clinical trials with encouraging results on preliminary efficacy and safety profile as monotherapy and combined with other anti-PD-1/PD-L1 therapies. Nevertheless, it is anticipated that the intricate signaling network constituted by BTLA/HVEM/CD160/LIGHT involved in immune response regulation, tumor development and tumor microenvironment could limit therapeutic success. Therefore, in-depth functional characterization in different cancer settings is highly recommended for adequate design and implementation of BTLA-targeted therapies to guarantee the best clinical outcomes to benefit cancer patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A new porous metal-organic framework (MOF) with the chemical formula Y
5
L
6
(OH)
3
(DMF)
3
·5H
2
O (
1
) (where L = 3-amino-4-hydroxybenzoate) has been prepared by a solvothermal procedure. The ...structural characterization reveals that this material consists of a robust three-dimensional metal-organic framework (MOF) grown with clusters formed by Y(
iii
) and hydroxide anions joined to one another by the ligand, giving rise to an open structure with interconnected microchannels with variable dimensions. This assembled set has shown to possess a fascinating catalytic activity for the cyanosilylation of a broad range of aldehydes and ketones with exceptional recyclability, a solvent-free medium, and one order of magnitude lower catalyst loading compared to all related lanthanide-based MOFs described so far in the literature.
A novel MOF has been synthesized, characterized, and applied in the cyanosilylation of aldehydes and ketones being the first example of an yttrium MOF able to catalyze this reaction.
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