排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
Pinelopi Voulgari Dimitrios Alivertis Konstantinos Skobridis 《Helvetica chimica acta》2021,104(11):e2100066
Osimertinib, a third generation potent and specific EGFR inhibitor is an important drug against many forms of cancer. It was synthesized by an improved and highly efficient protocol, revisiting the classical synthetic process and modifying parameters, such as solvents, temperature, reagents, and reaction time. A cost-effective, environmentally friendly methodology for the synthesis of osimertinib was established, which gave shorter reaction times, saved labor by eliminating purification steps through column chromatography, and enhanced yields. Four of the seven steps in total, were proceeded quantitatively or almost quantitatively (ca. 98 %). This synthetic protocol provides a very high overall yield, up to 68 %. In addition, the entire approach enables the preparation of osimertinib analogues and could be extended in the synthesis of other structurally similar bioactive compounds. 相似文献
2.
It has been proved that the electrolysis parameters strongly influence the structural properties of nickel electrodeposits,
mainly the crystalline growth, preferred orientation and surface morphology. To determine the structural characteristics of
nickel and composite nickel matrix electrocoatings, prepared under either direct current or pulse current conditions, the
electron microscopy techniques have proved very important tools. In particular, investigation of the distribution and percentage
of microparticles incorporated in the metallic matrix during preparation of nickel composite electrocoatings demands the use
of techniques such as energy dispersion spectroscopy (EDS) or image analysis. 相似文献
3.
Manuel Cordova Pinelopi Moutzouri Bruno Simões de Almeida Daria Torodii Prof. Lyndon Emsley 《Angewandte Chemie (International ed. in English)》2023,62(8):e202216607
The resolution of proton solid-state NMR spectra is usually limited by broadening arising from dipolar interactions between spins. Magic-angle spinning alleviates this broadening by inducing coherent averaging. However, even the highest spinning rates experimentally accessible today are not able to completely remove dipolar interactions. Here, we introduce a deep learning approach to determine pure isotropic proton spectra from a two-dimensional set of magic-angle spinning spectra acquired at different spinning rates. Applying the model to 8 organic solids yields high-resolution 1H solid-state NMR spectra with isotropic linewidths in the 50–400 Hz range. 相似文献
4.
Asimina Voulgari Vasiliki A. Gatselou Foteini A. Kappi Tatiana G. Choleva George Z. Tsogas Athanasios G. Vlessidis 《International journal of environmental analytical chemistry》2017,97(12):1163-1177
This work describes the development of a new green solid-phase extraction approach, which is based on the use of low-cost extraction discs composed of plain filter papers that are covered with a synthetic wax-like coating. The filter papers are printed in a commercial solid ink printer, which dispenses a synthetic wax-like ink on the surface of the paper, to cover the hydrophilic cellulose fibre matrix with an interface of lipophilic domains where non-polar analytes can partition through hydrophobic interactions. The modified paper filters were used to extract hydrophobic organic compounds from water samples following the customary procedure of solid-phase extraction without sorbent preconditioning and needless of high-vacuum sources. As a proof-of-concept application, a series of non-polar organic UV filters were used as model analytes to optimise the extraction parameters and evaluate the performance of the method in spiked water samples. Based on this principle, a new sample preparation platform with low environmental footprint has been developed that enables extraction to be carried out using low-cost, environmental benign and non-toxic conventional materials. The advantages and disadvantages of the method, alongside with its future prospects towards the development of custom-made ‘printed extraction kits’, are envisioned and discussed. 相似文献
5.
Fotini Orfanou Sotiris Michaleas Dimitra Benaki Olga Galanopoulou Afrodite Voulgari Ekaterini Antoniadou-Vyza 《Journal of inclusion phenomena and macrocyclic chemistry》2009,64(3-4):289-297
Oxolinic acid (OXA) is a first-generation quinolone antibacterial agent, known to cause drug induced photosensitivity. In the present work its photoinduced degradation was monitored under simulated solar irradiation. The effect of photoprotecting agents on OXA stability was also assessed by drug complexation with hydroxypropyl-β-cyclodextrin (HPβCD). The complex was studied by UV-Vis and 1H (2D) NMR Spectroscopy. A photostability indicating chromatographic method was developed and validated. Because OXA is insoluble in acidic solutions, and because an acidic solvent is necessary for successful chromatographic separation, a procedure was developed to pre-treat the sample. This method is suitable for the separation of degradation products from OXA and from each other. The method was also evaluated in the presence of HPβCD, in order to ensure that inclusion complexation did not generate inaccuracies. Investigation of OXA photodegradation profiles confirms first order kinetics and acceleration at higher initial sample concentrations. A 94% photostabilization upon complexation with HPβCD was achieved. Furthermore, molecular self association phenomena were determined by self titration experiments, using 1H NMR Spectroscopy and suggestions were made for the photostabilization mechanism of cyclodextrins. 相似文献
6.
7.
Pinelopi C. Ioannou Evriklia S. Lianidou Dimitrios G. Konstantianos 《Analytica chimica acta》1995,300(1-3):237-241
A very simple, rapid and highly sensitive fluorimetric method for the determination of diflunisal in serum and urine is described. The method is based on the formation of a ternary complex between diflunisal, Tb3+ and EDTA in alkaline aqueous solutions. This complex exhibits very intense terbium ion luminescence with a main emission maximum at 546 nm when excited at 284 nm. Optimum conditions for the complex formation have been investigated. The detection limit for diflunisal is 2.4 μg 1−1, while the range of application is 0.01–6.00 mg 1−1. The method has been successfully applied for the determination of diflunisal in untreated human serum and urine samples. Analytical recoveries from serum and urine samples spiked with diflunisal were in the ranges of 96.8–101.2% and 98.0–102.0%, respectively. 相似文献
8.
Dr. Pinelopi Moutzouri Dr. Federico M. Paruzzo Bruno Simões de Almeida Dr. Gabriele Stevanato Prof. Lyndon Emsley 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(15):6294-6297
The typical linewidths of 1H NMR spectra of powdered organic solids at 111 kHz magic-angle spinning (MAS) are of the order of a few hundred Hz. While this is remarkable in comparison to the tens of kHz observed in spectra of static samples, it is still the key limit to the use of 1H in solid-state NMR, especially for complex systems. Here, we demonstrate a novel strategy to further improve the spectral resolution. We show that the anti-z-COSY experiment can be used to reduce the residual line broadening of 1H NMR spectra of powdered organic solids. Results obtained with the anti-z-COSY sequence at 100 kHz MAS on thymol, β-AspAla, and strychnine show an improvement in resolution of up to a factor of two compared to conventional spectra acquired at the same spinning rate. 相似文献
9.
Pinelopi Moutzouri Manuel Cordova Bruno Simões de Almeida Daria Torodii Lyndon Emsley 《Angewandte Chemie (International ed. in English)》2023,62(21):e202301963
One key bottleneck of solid-state NMR spectroscopy is that 1H NMR spectra of organic solids are often very broad due to the presence of a strong network of dipolar couplings. We have recently suggested a new approach to tackle this problem. More specifically, we parametrically mapped errors leading to residual dipolar broadening into a second dimension and removed them in a correlation experiment. In this way pure isotropic proton (PIP) spectra were obtained that contain only isotropic shifts and provide the highest 1H NMR resolution available today in rigid solids. Here, using a deep-learning method, we extend the PIP approach to a second dimension, and for samples of L-tyrosine hydrochloride and ampicillin we obtain high resolution 1H-1H double-quantum/single-quantum dipolar correlation and spin-diffusion spectra with significantly higher resolution than the corresponding spectra at 100 kHz MAS, allowing the identification of previously overlapped isotropic correlation peaks. 相似文献
10.
Pinelopi Moutzouri Federico M. Paruzzo Bruno Simes de Almeida Gabriele Stevanato Lyndon Emsley 《Angewandte Chemie (International ed. in English)》2020,59(15):6235-6238
The typical linewidths of 1H NMR spectra of powdered organic solids at 111 kHz magic‐angle spinning (MAS) are of the order of a few hundred Hz. While this is remarkable in comparison to the tens of kHz observed in spectra of static samples, it is still the key limit to the use of 1H in solid‐state NMR, especially for complex systems. Here, we demonstrate a novel strategy to further improve the spectral resolution. We show that the anti‐z‐COSY experiment can be used to reduce the residual line broadening of 1H NMR spectra of powdered organic solids. Results obtained with the anti‐z‐COSY sequence at 100 kHz MAS on thymol, β‐AspAla, and strychnine show an improvement in resolution of up to a factor of two compared to conventional spectra acquired at the same spinning rate. 相似文献