scholarly journals SYNTHESIS OPTIMIZATION OF 6-NITRO-3,4-DIHYDROQUINAZOLINE-4-ONE

2020 ◽  
Vol 63 (7) ◽  
pp. 48-53
Author(s):  
Mirjalol E. Ziyadullaev ◽  
Rixsibay K. Karimov ◽  
Gulnora V. Zukhurova ◽  
Asqar Sh. Abdurazakov ◽  
Shamansur Sh. Sagdullaev
Keyword(s):  
13C Nmr Spectroscopy ◽  
Process Conditions ◽  
Mathematical Planning ◽  
Steep Ascent ◽  
Synthesis Conditions ◽  
Dinitro Derivative ◽  
Higher Temperature ◽  
Temperature Time ◽  
Main Factor

A method for the synthesis of the substance 6-nitro-3,4-dihydroquinazolin-4-one has been developed. Quantitative determination of the target product was carried out spectrophotometrically using an SF-46 instrument. As a solvent, 0.1 mol/l HCl was used. A 0.1 mol/l hydrochloric acid solution was used as a comparison solution. The optical density of the standard and test samples was measured at a wavelength of 254 nm. The synthesis conditions of 6-nitro-3,4-dihydro-quinazolin-4-one were studied. The structure of the obtained product was studied by IR, Mass, 1H, 13C NMR spectroscopy, and the structure of the synthesized compound was also established. The main factors that influence the process of producing 6-nitro-3,4-dihydroquinazolin-4-one are identified. The process is optimized by the method of mathematical planning of the experiment. A mathematical model is drawn up. And the regression equation is calculated. A steep ascent along the response surface was carried out and optimal process conditions were found: temperature, time, quantitative ratio of the starting materials. It has been established that the main factor affecting the nitration process of 3,4-dihydroquinazolin-4-one is the temperature of 40 ºC and the reaction time is 4.5 h. Note that at a higher temperature, according to the analysis, a significant amount of dinitro derivative is formed, as a reaction byproduct.   

SOME DIRECTIONS IN THE MODIFICATION OF AZOLES

2020 ◽  
Vol 5 (443) ◽  
pp. 85-91
Author(s):  
Ibrayev M.K., ◽  
◽  
Takibayeva A.T., ◽  
Fazylov S.D., ◽  
Rakhimberlinova Zh.B., ◽  
...  
Keyword(s):  
13C Nmr Spectroscopy ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
Active Compounds ◽  
Synthesis Conditions ◽  
Alkaloid Cytisine ◽  
Azole Ring ◽  
Cyclic Compounds ◽  
New Compounds ◽  
Derivatives Of

This article presents studies on the targeted search for new derivatives of azoles, such as benzthiazole, 3,5-dimethylpyrazole, 1,3,4-oxadiazole-2-thione, 1,3,4-thiadiazole. The possibility of combining in one molecule of the azole ring with other cyclic compounds: the alkaloid cytisine, morpholine, furan and some arenes has been studied. To obtain new compounds, the reactions of bromination, acylation, and interaction with isothiocyanates were studied. Optimal synthesis conditions were studied for all reactions. It was found that the reaction of 4-bromo-3,5-dimethylpyrazole with isothiocyanates, in contrast to the previously written derivatives of anilines, takes a longer time and requires heating the reaction mixture. The combination of a pirasol fragment with halide substituents often results in an enhanced therapeutic effect. The synthesized 2-bromine-N-(6-rodanbenzo[d]thiazole-2-yl)acetamide, due to the alkylbromide group, is an important synth in the synthesis of new benzthiazole derivatives. Its derivatives combine in one molecule the rest of rhodanbenzthiazole with alkaloid cytisine and biogenic amine morpholine and are potentially biologically active compounds, since the molecule structure contains several pharmacophoric fragments: benzthiazole and alkaloid (amine) heterocycles, rhodane and urea groups. The mechanism of formation of 1,3,4-oxadiazole-2-tyons from hydrazides under action on them by carbon disulfide was studied and assumed. It was shown that dithiocarbamates in acidic medium decompose with the release of hydrogen sulfide and the formation of highly reactive isothiocyanate group. Then, intra-molecular cyclization occurs, with the formation of end products - 1,3,4-oxadiazole-2-thions. The structures of the synthesized compounds were studied by 1H and 13C NMR spectroscopy. All synthesized substances are potentially biologically active compounds, since they contain several pharmacophore fragments in their structure.

Natural abundance 13C-NMR spectroscopy for the quantitative determination of fecal fat

2003 ◽  
Vol 36 (7) ◽  
pp. 505-510 ◽  
Author(s):  
P Kunz ◽  
B Künnecke ◽  
I Kunz ◽  
H Lengsfeld ◽  
M von Kienlin
Keyword(s):  
Nmr Spectroscopy ◽  
Quantitative Determination ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Natural Abundance ◽  
Fecal Fat

The Perchloric Method for the Determination of Sulfur in Rubber

1934 ◽  
Vol 7 (4) ◽  
pp. 730-735
Author(s):  
Ernest Kahane
Keyword(s):  
Nitric Acid ◽  
Perchloric Acid ◽  
Organic Substance ◽  
Present Author ◽  
General Idea ◽  
Organic Substances ◽  
Gutta Percha ◽  
Higher Temperature ◽  
As If

Abstract The problem of the determination of sulfur in rubber has been dealt with extensively in the literature, and it seems as if discussions and descriptions of new technic are nowhere nearly ended yet. The determination is so essential, and its rapid and precise execution is of such importance in industrial technic, that efforts in this direction should not be regarded as wasted. In 1926 and in 1927 Le Caoutchouc et La Gutta-Percha contained two articles in which the present author discussed the conditions of the determination of sulfur in rubber and then proposed the use of a new oxidizing mixture, not mentioned previous to that time, which involved the destruction of organic substances by perchloric acid. This method consisted simply in the attack on a 1-gram sample of rubber by 10 cc. of nitric acid (d. 1.39) and 5 cc. of perchloric acid (d. 1.61). Upon heating, attack by the nitric acid takes place, and this is followed by evaporation of the excess nitric acid, then at a little higher temperature there is an attack by the perchloric acid, which oxidizes the rest of the organic substance completely. This publication was concerned much more, in the determination of sulfur by the perchloric method, with the general idea of the destruction of organic substances than it was with the precise details of carrying it out. The technic had been studied somewhat superficially, as is shown by the text of the article itself.

Effect of Temperature on Column Bioleaching of a Refractory Gold Ore

2013 ◽  
Vol 825 ◽  
pp. 352-355 ◽  
Author(s):  
Zeng Ling Wu ◽  
Zhong Sheng Huang ◽  
Ren Man Ruan ◽  
Shui Ping Zhong ◽  
Brenda K.C. Chan
Keyword(s):  
Sulfide Oxidation ◽  
Effect Of Temperature ◽  
Low Grade ◽  
Key Factors ◽  
Gold Extraction ◽  
Gold Ores ◽  
Fraction Distribution ◽  
Higher Temperature ◽  
Liberation Analysis ◽  
Main Factor

Low-grade, finely disseminated refractory sulfide gold ores associated with high arsenic are ubiquitous resources all over the world. Since heap bio-oxidation is an economic and promising biotechnology to recover gold, low grade, high organic carbon and arsenic bearing gold ores from Zhesang Mines in China were chosen for this purpose to study the key factors that would affect biooxidation. Pyrite and arsenopyrite (particle size 0.002-0.22 mm) were the main minerals from Mineral Liberation Analysis (MLA). Column biooxidation and cyanidation of mineral size < 10 mm were evaluated for its potential for gold extraction. Results showed that temperature was the main factor influencing sulfide oxidation. 58-67 % of sulfide was oxidized at 35-45°C after > 240 days of biooxidation with mixed mesophiles, while higher sulfide-S dissolution (77%) was obtained at 60°C. Sulfide-S fraction distribution revealed higher mineral decomposition, finer fractions and eventually higher sulfide oxidation at 60°C. Jarosite and scorodite were found from the residues at 60°C by SEM and EDX, which implies higher temperature accelerated arsenic precipitation. No elemental sulfur was detected during the biooxidation at 35-60°C. After bio-oxidation, column cyanidation was successfully demonstrated recovery of gold from the residues, with gold extraction rate reaching 66%.

In situ ATR - FTIR spectroscopy of Hf(IV) tert butoxide adsorption on Si and Ge

2006 ◽  
Vol 917 ◽  
Author(s):  
Shilpa Dubey ◽  
Keijing Li ◽  
Harish Bhandari ◽  
Zheng Hu ◽  
C. Heath Turner ◽  
...  
Keyword(s):  
Hafnium Oxide ◽  
Density Functional ◽  
Substrate Surface ◽  
Surface Concentration ◽  
Bidentate Ligand ◽  
Initial Reaction ◽  
Process Conditions ◽  
Reaction Cell

AbstractHafnium oxide ultra thin films on Si (100) are being developed to replace thermally grown SiO2 gates in CMOS devices. In this work, a specially designed Attenuated Total Reflectance - Fourier Transform Infra Red Spectroscopy (ATR-FTIR) reaction cell has been developed to observe chemisorption of hafnium (IV) t-butoxide onto a Si and Ge ATR crystal heated up to 250°C and under 1 torr of vacuum to observe the initial reaction pathways and species on the substrate surface in real time and under typical process conditions. Chemisorption spectra were compared to spectra of the liquid precursor and to spectra generated by density functional theory (DFT) calculations of liquid, monodentate and bidentate absorbed precursor. An asymmetric stretching mode located at ~1017 cm-1 present in the chemisorbed spectra but not in the liquid spectra indicates that the adsorbed hafnium containing group is prevalent as a bidentate ligand according to calculations. Surface concentration of the chemisorbed species was dependant on the substrate temperature and precursor partial pressure allowing for determination of heats of adsorption which was 26.5 kJ/mol on Si.

Determination of the structural configuration of cresol–novolak resins by 13C NMR spectroscopy

1982 ◽  
Vol 27 (9) ◽  
pp. 3449-3454 ◽  
Author(s):  
J. A. Carothers ◽  
E. Gipstein ◽  
W. W. Fleming ◽  
T. Tompkins
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Structural Configuration

scholarly journals New methylphenylsiloxane resin based on alkoxysilanes

2019 ◽  
Vol 59 (7) ◽  
pp. 142-149
Author(s):  
Andrey M. Kontorov ◽  
Keyword(s):  
Kinematic Viscosity ◽  
Room Temperature ◽  
Raw Materials ◽  
Argon Atmosphere ◽  
29Si Nmr ◽  
Synthesis Conditions ◽  
Residual Functional ◽  
29Si Nmr Spectra ◽  
Hydroxy Groups

Currently interested in the reaction for producing oligosilsesquioxanes based on acidolysis alkoxysilanes. In this regard, the author was given the following tasks: development of optimal synthesis conditions; preparation of new methylphenylsiloxane resins with different properties. In this paper, the properties of new methylphenylsiloxane resins (MPR) with various radicals in silicon were studied. New IFSS were obtained by a new universal technology-acidolysis of a mixture of methyltriethoxysilane (MTEOS) and phenyltriethoxysilane (PTEOS) with various radicals, which are environmentally friendly raw materials. The obtained MPR were characterized by NMR spectroscopy on 1H and 29Si nuclei. Spectra were recorded at room temperature in deuteroacetone using Bruker AM-360 Fourier spectrometer. 29Si NMR spectra were measured using the pulse program "Inverse Gated Heteronuclear Decoupling". The content of residual functional groups (Si-OH, Si-OEt) in IFSS was determined by functional analysis methods. Determination of ethoxy groups and hydroxy groups was carried out by iodometric and aluminohydride method, respectively. Thermogravimetric analysis was performed on the device Derivatograph-H (firm Mom). TGA studies were carried out in the argon atmosphere and in the air at a heating rate of 10 ºC/min. Measurements of kinematic viscosity of 20 % and 50% by weight. toluene solutions of MPR were carried out at 20 °C on the viscometer HPV-2. The reaction acidolysis of methyltriethoxysilane and oligophenylenes is a convenient and versatile method for the synthesis of new heat-resistant resins methylphenylsiloxanes. In the course of the study, it was found that the resins obtained on the basis of organoalkoxysilanes are characterized by higher thermal and thermo-oxidative stability.

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