Herein, we describe a new strategy for the detection of reactive alkylating agents such as alkyl halides. These toxic compounds react with a FRET-based profluorescent probe, triggering a ...self-immolative elimination at room temperature, thus leading to a fluorescence signal.
A fluorogenic FRET probe allows efficient detection of toxic alkylating agents through a self-immolative reaction.
Radiosensitive compounds can be useful for the detection of radiations and also as prodrugs that can be activated during a radiotherapy. Herein we describe the use of benzothiazolines, which upon ...treatment with 137Cs produced γ‐irradiation in water give rise to fluorescent benzothiazoles and concomitant release of amines or carboxylic acids. In a proof of concept study, we showed that benzothiazolines may be used as new cleavable linkers that can be triggered upon irradiation.
Benzothiazolines in aqueous solutions are cleaved under irradiation with γ‐rays in a dose‐dependent manner, leading to the formation of fluorescent products. The study paves the way for the future use of benzothiazolines as radiation sensors or as prodrugs in the context of radiotherapy.
3-Aryltetronic acids were prepared in one step by treatment of a mixture of methyl arylacetates and methyl hydroxyacetates with potassium tert-butoxide, via tandem transesterification/Dieckmann ...condensation. Several mushroom or lichen pigments, vulpinic acids, were synthesized from 3-(4-methoxyphenyl)tetronic acid in three steps involving the reaction of the corresponding dianion with an α-ketoester and the dehydration of the tertiary alcohols obtained into mixtures of (E)- and (Z)-alkenes, which were converted under UV irradiation at 254 nm to natural (E)-isomers. Syntheses of pinastric acid, 4,4′-dimethoxyvulpinic acid, and the first synthesis of recently isolated methyl 3′,5′-dichloro-4,4′-di-O-methylatromentate were hence achieved in an efficient manner.
Potential metal chelators containing one or several acyltetronic acid moieties were prepared from cyclic or acyclic amines and polyamines, and from bis(phenols) by reaction with 1–4 equiv of ...3-bromoacetyltetronic acid in the presence of potassium carbonate. The affinity constants of the chelating agents for toxic metallic cations Cd2+, Cs+, and Pb2+ and for dimethylarsinic acid were measured, at pH 7.5 and 9.3. Compound 4, an acyclic triamine containing four acyltetronic moieties, was found to complex efficiently all the tested species.
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A study of the lithium ion conductor Li3x La2/3–x TiO3 solid solution and the surrounding composition space was carried out using a high throughput physical vapor deposition system. An optimum total ...ionic conductivity value of 5.45 × 10–4 S cm–1 was obtained for the composition Li0.17La0.29Ti0.54 (Li3x La2/3–x TiO3 x = 0.11). This optimum value was calculated using an artificial neural network model based on the empirical data. Due to the large scale of the data set produced and the complexity of synthesis, informatics tools were required to analyze the data. Partition analysis was carried out to determine the synthetic parameters of importance and their threshold values. Multivariate curve resolution and principal component analysis were applied to the diffraction data set. This analysis enabled the construction of phase distribution diagrams, illustrating both the phases obtained and the compositional zones in which they occur. The synthetic technique presented has significant advantages over other thin film and bulk methodologies, in terms of both the compositional range covered and the nature of the materials produced.
The natural mushroom pigment Norbadione A and three other pulvinic acids were shown by our group to display very efficient antioxidant properties by comparison with a collection of potent molecules ...including catechols, flavonoids, stilbenes, or coumarins. Despite numerous publications on robust and straightforward synthetic access to pulvinic acids by us and others, no report has been made to unravel the structure−activity relationships that govern the striking antioxidant activity. Herein is presented the synthesis of 18 diverse pulvinic acid derivatives and the study of their radical scavenging capacities by four different assays. The influence of each of the two phenyl rings, of their substituents and of the lateral chain on the antioxidant properties, was explored to reveal a simplified structure of excellent activity. These results, along with the absence of cytotoxicity, make the synthesized compounds interesting to evaluate for several biological activities and especially for anti-inflammatory effects and skin protection against UV induced oxidative stress.
Polyamidoximes (pAMD) are known to have strong affinities for uranyl cations. Grafting pAMD onto the surface of functionalized maghemite nanoparticles (MNP) leads to a nanomaterial with high ...capacities in the extraction of uranium from wastewaters by magnetic sedimentation. A diamidoxime (dAMD) specifically synthesized for this purpose showed a strong affinity for uranyl: Ka = 105 M-1 as determined by Isothermal Titration Calorimetry (nano-ITC). The dAMD was grafted onto the surface of MNP and the obtained sorbent (MNP-dAMD) was characterized. The nanohybrids were afterward incubated with different concentrations of uranyl and the solid phase recovered by magnetic separation. This latter was characterized by zeta-potential measurements, X-Ray Photoelectron Spectroscopy (XPS) and X-Ray Fluorescence spectroscopy (XRF), whereas the supernatant was analyzed by Inductively Coupled Plasma coupled to Mass Spectrometry (ICP-MS). All the data fitted the models of Langmuir, Freundlich and Temkin isotherms very well. These isotherms allowed us to evaluate the efficiency of the adsorption of uranium by MNP-dAMD. The saturation sorption capacity (qmax) was determined. It indicates that MNP-dAMD is able to extract up to 120 mg of uranium per gram of sorbent. Spherical aberration (Cs)-corrected High-Resolution Scanning Transmission Electron Microscopy (HRSTEM) confirmed these results and clearly showed that uranium is confined at the surface of the sorbent. Thus, MNP-dAMD presents a strong potential for the extraction of uranium from wastewaters.
The addition of the potassium salt of (R)-4-phenyl-2-oxazolidinone to dialkyl alkylidenemalonates under various conditions is reported. Very good diastereoselectivities (> 90% de) were obtained in ...several cases. Conversion of one of the adducts to the β-amino acid (S)-β-leucine was achieved in two straightforward steps.
A high‐throughput screening method has highlighted the marked antioxidant activity of some pulvinic acid derivatives (PADs) towards oxidation of thymidine, under γ and UV irradiation, and Fenton‐like ...conditions. Here, we report the synthesis of a series of new hydrophilic PADs and the evaluation of their radioprotective efficacy in cell culture. Using a cell‐based fluorescent assay, we show that some of these compounds have a pronounced ability to prevent cell death caused by radiation and to allow the subsequent resumption of proliferation. Thus, PADs may be considered as a novel class of radioprotective agents.
In pulvinic we trust? Norbadione A, a naturally occurring pulvinic acid, is known to exhibit radioprotective activity. We synthesized several hydrophilic derivatives and tested their radioprotective efficacy in cell cultures. Excellent protection and cell proliferation was observed several days following strong X‐ray irradiation, which suggests that pulvinic acid derivatives are a novel class of radioprotecting agents worth further evaluation.
Tetronic acid was converted in a few steps to an alkenyl iodide which served as a common precursor for several vulpinic acids (methyl pulvinates), bearing different Ar groups, and obtained via ...Suzuki–Miyaura cross-couplings.
Several vulpinic acids were synthesized in a few steps from a single precursor, the tetronic acid. This commercial compound was converted in a few steps to an iodide. Suzuki–Miyaura cross-couplings involving this common intermediate and various arylboronates allowed to gain access to several vulpinic acids (or methyl pulvinates). Among them, two natural products, vulpinic acid and pinastric acid, were prepared.
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