Search For Methods Of Synthesis Research Articles

SYNTHESIS OF TERMINAL 2-ALKENYL(ALKYNYL)THIO-5-CYANO-6-(p-DIMETHYLAMINOPHENYL)PYRIMIDIN-4-ONES

Functionalized pyrimidines possess a wide spectrum of biological activity. In particular, they have antitumor, antiviral, and anticonvulsant activities, exhibit anti-inflammatory and analgesic effects, and they are inhibitors of aldose reductase, SecA ATPase, azide, and plant growth. The search for methods of synthesis of new functionalized and condensed pyrimidine derivatives is an urgent problem.
 Alkenyl-functionalized mono- and polycyclic pyrimidines are promise substrates for studying the regioselectivity of electroph ilic heterocyclization reactions under the influence of halogen-containing electrophilic agents, and halogen- and chalcogen-functionalized cyclization products showed high antibacterial, antifungal, and antimalarial activity. The introduction of new functional groups capable to modification into such alkenylpyrimidines can significantly affect their reactivity and change/enhance the biological activity of the halocyclization products. We proposed the synthesis of 2-alkenyl(alkynyl)thio derivatives of 5-cyano-6-(p-dimethylaminophenyl)-pyrimidin-4-one containing a cyano group labile to functionalization. As a result of alkylation of 2-thioxo-5-cyano-6-(p-dimethylaminophenyl)pyrimidin-4-one with unsaturated alkyl halides in an alkaline medium, the terminal alkenyl (allyl, methallyl) and alkynyl (propargyl) thioethers of cyanopyrimidine were obtained, promising for heterocyclization with halogen-containing electrophilic reagents .
 Keywords: 2-thioxo-5-cyano-pyrimidin-4-one; alkylation; alkenylthiopyrimidinone; alkynylthiopyrimidinone.

Statistical properties of derived signal systems

The search for effective methods of synthesis of discrete signals (sequences) that correspond to the potentially possible limiting characteristics of correlation functions and possess the necessary correlation, structural, ensemble properties remains an urgent problem. The authors have proposed a method for the synthesis of derivatives of signal systems, for which orthogonal signals are used as the initial ones, and nonlinear discrete complex cryptographic signals (CS) are used as generating signals. The synthesis of the latter ones is based on the use of random (pseudo-random) processes, including algorithms for cryptographic information transformation. Derivative signals synthesized in this way have improved (in comparison with linear signal classes) ensemble and correlation properties, while the statistical properties of such signal systems remain unexplored. The paper presents the results of testing derived signal systems using the tests defined in FIPS PUB 140 and NIST 800-22. Analysis of the results obtained allows us to assert that the statistical properties of this class of derived signals satisfy the requirements for pseudo-random sequences: unpredictability, irreversibility, randomness, independence of symbols, etc. In essence, such signals do not differ from random sequences. The use of the proposed class of derived signals will improve the performance of signal reception noise immunity, information security and secrecy of the ICS functioning.

Molten-Salt Synthesis of Metal Oxide Nanoparticles

The search for synthesis methods which are simple, green, reliable, scalable and generalizable for functional metal oxide nanoparticles has been an area of interest for many researchers in recent years. Because of its meritorious features including environmental friendliness, low cost, simple to operate, easy to scale-up, etc., molten-salt synthesis (MSS) method becomes an excellent bottom-up synthesis technique of nanomaterials with various chemical compositions and morphologies. In this talk, I will start with the status, potential and challenges of MSS for the synthesis of nanomaterials to give a concise flavor on the importance of synthesis on the properties and application of nanomaterials. I will discuss different aspects of MSS such as the role of used molten salt, the choice of desirable molten salt, the effect of various synthesis parameters, typical oxosalts and their electrochemical aspects. More importantly, I will cover the recent progress of MSS for inorganic metal oxide nanoparticles. Other than the nanomaterials of a few binary oxides synthesized by the MSS, I will highlight how the MSS method has been successful in synthesizing complex metal oxide nanoparticles, such as AMO2 delafossites, AMO3 perovskites, AM2O4 spinels, and A2M2O7 pyrochlores. Specifically, in the past few years, we have focused on the studies of lanthanide and actinide doped pyrochlore AIII 2MIV 2O7 nanoparticles (where A = trivalent rare earth ions, and M = Zr4+, Hf4+, etc.) useful for solid-state lighting, X-ray scintillators, thermometry, bioimaging, and radioactive waste containment. We have achieved substantial tunability of their particle size, crystal phase, and more importantly, luminescence properties. We have gained a clear understanding of the influences of synthesis conditions, particle morphology and composition on their photoluminescence and radioluminescence. Therefore, MSS opens a new avenue for making size and shape tunable nanomaterials for various catalytic, optoelectronic, magnetic and electrical applications.

Theoretical study of the structures of [M(18C6)](HFA)2 complexes (M = Ba, Sr, Pb, Cd, Mn; 18C6 = 18-crown-6; HFA = hexafluoroacetylacetonate anion)

The structures of the [M(18C6)]2+ cations (M = Ba, Sr, Pb, Cd, Mn) and their salts [M(18C6)](HFA)2 and [M(18C6)](NO3)2 have been calculated by the density functional theory method (in the B3LYP/6-311++G** + LanL2Dz approximation). Upon geometry optimization, the gas-phase structures of compounds of different composition have been calculated; for them, the strength of binding of the central cation to the crown ether (18C6) and the degree of structural similarity have been evaluated. The structure of the [NH4(18C6)]+ cation identified in a practical synthesis has also been considered. For metal cations acting as a central atom, NH4+ and [M(18C6)]2+ complex cations, as well as for intermediate and ultimate products [M(18C6)](NO3)2 and [M(18C6)](HFA)2 (M = Ba, Sr, Pb, Cd, Mn), the electronic chemical potential and Pearson hardness, which enables the consideration of the propensity of various reagents to interact with each other in terms of the empirical HSAB principle (hard with hard and soft with soft), have been evaluated. Comparison of the estimates with the properties of the synthesized compounds with M = Ba, Sr, and Pb makes it possible to preliminarily verify the applicability of this principle to the systems under consideration and predict some properties of isostructural analogues important in the search for methods of synthesis of [M(18C6)](HFA)2, where M = Cd and Mn. The possibility of establishing a correlation between the electron density of the system, stability, and hydrolytic activity of complexes has been shown.

NEW APPROACHES TO THE SYNTHESIS OF ORGANOPHOSPHORUS COMPOUNDS

Abstract The past two decades have brought us a snowballing development of organophosphorus chemistry. Indeed organophosphorus compounds have found wide practical application (in agriculture, petroleum industry, as drugs, etc.) and continue to afford promising objects for the study of theoretical matters such as tautomerism, ambiphilicity, ambidenticity, and other problems of organic chemistry. On the other hand, however impressive this progress may be, the search for new methods of synthesis, improving the known methods and forecasting new types of organophosphorus compounds remain as challenging problems as before.