The Influence of Different Carbonate Ligands on the Hydrolytic Stability and Reduction of Platinum(IV) Prodrugs

2022 ◽  
Author(s):  
Shu Chen ◽  
Ka-Yan Ng ◽  
Qiyuan Zhou ◽  
Houzong Yao ◽  
Zhiqin Deng ◽  
...  
Keyword(s):  
Hydrolytic Stability ◽  
Hydroxyl Group ◽  
Synthetic Method ◽  
Bioactive Ligands

Pt(IV) complexes bearing axial carbonate linkages have drawn much attention recently. A synthetic method behind it allows to attach the hydroxyl group of bioactive ligands to the available hydroxyl group...

Simple, Efficient, and Selective Synthesis of Phthaloylserine and Phthaloylthreonine

2015 ◽  
Vol 1088 ◽  
pp. 363-366
Author(s):  
Yu Ting Liu ◽  
Si Meng Song ◽  
Da Wei Yin ◽  
Dan Chen
Keyword(s):  
Amino Acids ◽  
Phthalic Anhydride ◽  
Side Reaction ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
Synthetic Method ◽  
Selective Synthesis ◽  
Protection Method ◽  
Amino Protection

An amino protection method was developed in which phthalic anhydride was used as the amino protection group, N,N-dimethylformamide (DMF) as solvent, L-threonine and L-serine with hydroxyl groups in side chain as the protected amino acids.The structures of products were confirmed by IR、1H NMR and 13C NMR. It is an efficient and simple protection method of amino acids with a hydroxyl group in the side chain.In addition, the synthetic method avoids the side reaction and significantly improves reaction yields(over 90%).

scholarly journals Aspects of Nucleic Acid Structure and Function

2020 ◽  
pp. 31-40
Author(s):  
Sosale Chandrasekhar
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Genetic Code ◽  
Rna World ◽  
Hydrolytic Stability ◽  
Trna Synthetase ◽  
Hydroxyl Group ◽  
Effect Of Temperature ◽  
Structural Basis ◽  
Trna Synthetases

Despite decades of intense study, certain physico-chemical aspects of the nucleic acids–the genetic repository of life–remain enigmatic. Thus, solutions of DNA are apparently constituted of varying amounts of double and single-stranded forms, with melting studies being inconclusive about the effect of temperature on the composition. Consequently, this casts doubt on current estimates of the thermodynamic stability of the base pairs. However, the overwhelming stability of the Watson-Crick model is adumbrated by a kinetic analysis of the action of DNA polymerase, microscopic reversibility indicating that polymerase action is kinetically controlled, whereas proof reading-excision is thermodynamically controlled. The structural basis for the differing roles played by DNA and RNA in the sustenance and propagation of life also remains to be clarified. It appears that formation of the RNA double helix is sterically inhibited by the 2’ ribose hydroxyl group, which is also relatively inaccessible to external base, thus enhancing hydrolytic stability. The in vivo conformation of RNA is likely determined by the requirements of its appointed biological role, the large size of tRNAs being particularly significant in possibly leading to enhanced specificity in its interaction with the corresponding tRNA synthetase. The proclivity of RNA generally to remain single stranded may indeed be the reason for the existence of viruses as stable RNA-protein complexes. The preeminent role of nucleic acids as “genetic guardians” is, however, blurred by the fact that the translation of the genetic code is contingent on the action of the various tRNA synthetases. This implies that the genetic code is manifested via codon-anticodon specificity only by the involvement of protein molecules that are unique to each codon-anticodon pair. This has intriguing implications for the origin and evolution of the genetic code, possibly indicating that the tRNA synthetases are a relic of prebiotic protein-nucleic acid hybrids (thus also raising doubts about the RNA world hypothesis).

scholarly journals Simple Synthesis of 17-β-O-hemisuccinate of Stanozolol for Immunoanalytical Methods

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2019
Author(s):  
Silvana Casati ◽  
Roberta Ottria ◽  
Pierangela Ciuffreda
Keyword(s):  
Room Temperature ◽  
Total Yield ◽  
Hydroxyl Group ◽  
Synthetic Method ◽  
Doping Agent ◽  
Novel Approach ◽  
The World ◽  
Hapten Design ◽  
Doping In Sports ◽  
The Common

The use of doping in sports is a global problem that affects athletes around the world. Among the different methods developed to detect doping agents in biological samples, there are antibody-based methods that need an appropriate hapten design. Steroids with a hydroxyl group can be converted to the corresponding hemisuccinates. A novel approach to the synthesis of 17β-O-hemisuccinate of the common doping agent stanozolol is described here. Acylation of stanozolol with methyl 4-chloro-4-oxobutyrate/4-dimethylaminopyridine, followed by mild alkaline hydrolysis with methanolic sodium hydroxide at room temperature, gave the simultaneous protection and deprotection of pyrazole-nitrogen atoms. The proposed new synthetic method allows the desired hemisuccinate derivative to be obtained in only two steps, and with a good total yield starting from stanozolol.

Detection method of combustion oscillation characteristics under strong noise background

2020 ◽  
Vol 21 (6) ◽  
pp. 612
Author(s):  
Yunkun Wei ◽  
Tianhong Zhang ◽  
Zhonglin Lin ◽  
Qi Xie ◽  
Yan Zhang
Keyword(s):  
Radiation Thermometry ◽  
Hydroxyl Group ◽  
Interference Signal ◽  
Engine Vibration ◽  
Combustion Technology ◽  
Lean Fuel ◽  
Combustion Oscillation ◽  
Aero Engines ◽  
Temperature Measurement System ◽  
Multispectral Radiation Thermometry

After the lean fuel premixed combustion technology is applied to aero engines, severe combustion oscillations will be cased and led to hidden safety hazards such as engine vibration, further energy waste and other problems. Therefore, it is increasingly important to actively control combustion oscillations. In this paper, a multispectral radiation thermometry (MRT) is used to analyze the hydroxyl group, which is a measurable research object in the combustion chamber of an aero engine, and to fit the functional relationship between the radiation intensity ratio and the temperature in different bands. The theoretical value of the error is <2%. At the same time, in order to solve the problem of weak detection signal and excessive interference signal, an improved frequency domain filtering method based on fast Fourier transform is designed. Besides, the FPGA platform is used to ensure the real-time performance of the temperature measurement system, and simulations and experiments are performed. An oscillating signal with an oscillation frequency of 315 Hz is obtained on the established test platform, and the error is only 1.42%.

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

Enhanced Hydrolytic Stability of Porous Boron Nitride via the Control of Crystallinity, Porosity and Chemical Composition

2018 ◽  
Author(s):  
Ravi Shankar ◽  
Sofia Marchesini ◽  
Camille Petit
Keyword(s):  
Boron Nitride ◽  
Hydrolytic Stability ◽  
Chemical Properties ◽  
Spectroscopic Techniques ◽  
High Porosity ◽  
Heat Treated Sample ◽  
Heat Treated ◽  
Treated Sample ◽  
Molecular Separations ◽  
High Degree

Porous boron nitride is gaining significant attention for applications in molecular separations, photocatalysis, and drug delivery. All these areas call for a high degree of stability (or a controlled stability) over a range of chemical environments, and particularly under humid conditions. The hydrolytic stability of the various forms of boron nitride, including porous boron nitride, has been sparingly addressed in the literature. Here, we map the physical-chemical properties of the material to its hydrolytic stability for a range of conditions. Using analytical, imaging and spectroscopic techniques, we identify the links between the hydrolytic instability of porous boron nitride and its limited crystallinity, high porosity as well as the presence of oxygen atoms. To address this instability issue, we demonstrate that subjecting the material to a thermal treatment leads to the formation of crystalline domains of h-BN exhibiting a hydrophobic character. The heat-treated sample exhibits enhanced hydrolytic stability, while maintaining a high porosity. This work provides an effective and simple approach to producing stable porous boron nitride structures, and will progress the implementation of the material in applications involving interfacial phenomena.<br>

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