Classical and advanced chemical sciences
It has been found that 4-nitrophenylglyoxal reacts with N-alkoxy-N’-arylureas and N-alkoxy-N’-alkylureas in acetic acid medium with the selective formation of the diastereomers of the 3-alkoxy-1,5-diaryl-4,5-dihydroxyimidazolidin-2-ones and 3-alkoxy-1-alkyl-5-aryl-4,5-dihydroxyimidazolidin-2-ones with cis-orientation of OH-groups. The X-ray structural analysis of 3-propyloxy-4S,5S-4,5-dihydroxy-1-methyl-5-(4-nitrophenyl) imidazolidin-2-one and of 3-n-butyloxy-4S,5S-4,5-dihydroxy-1-(4-methylphenyl)-5-(4-nitrophenyl) imidazolidin-2-one has demonstrated this structural feature of these compounds.
Keywords: 4-Nitrophenylglyoxal, N-alkoxy-N’-arylureas, N-alkoxy-N’-alkylureas, 3-alkoxy-1,5-diaryl-4,5-dihydroxyimidazolidin-2-ones, 3-alkoxy-1-alkyl-5-aryl-4,5-dihydroxyimidazolidin-2-ones, synthesis, structure
Synthesis of benzimidazolo[2,3-b]quinazolinone derivatives has been reported in excellent yields by using silica-supported perchloric acid (HClO4-SiO2) as a mild and reusable heterogeneous catalyst. The procedure is simple, environmentally benign and has the advantage of high atom economy. Furthermore, the catalyst can be recovered and reused several times efficiently without substantial loss of catalytic activity.
Keywords: 2-Aminobenzimidazole; benzimidazolo[2,3-b]quinazolinones; heterogeneous catalyst; perchloric acid; silica
A novel, efficient, and high-yielding one-pot three-component method was developed for the synthesis of 2-(1H-benzo[d]oxazole-2-yl)-N-arylbenzamides by combining phthaldichloride with anilines and o-aminophenol in water without any external catalyst. The environmentally friendly procedure, easy operation and mild reaction conditions enable the tolerance of a wide scope of functionalities as well as high reaction efficiency.
Keywords: Water, phthaldichloride, anilines, o-aminophenol, 2-(1H-benzo[d]oxazole-2-yl)-N-arylbenzamides
Materials and environmental chemistry
This study discussed the behavior of ozone level observed in the atmospheric region of Campo Grande. To determine the best adjusted distribution to describe the ozone co-generation data for the year 2016 in Campo Grande were used 15 functions adjusted for this purpose; the performances of the distributions are evaluated using three test qualities, namely Kolmogorov- Smirnov, Anderson-Darling and Chi-Square test. Finally, the result of the fitted quality test is compared, it was observed that the generalized extreme value distribution provides a good fit for the whole year and the distributions Gamma 3P; lognormal 3P; weibull and Gamma 3P for the seasons of the year: winter, spring, summer, autumn, which are empirically proven to be the most appropriate distribution of data.
Keywords: ozone, probability distribution, fit quality tests
Synthesis of 3,4-dihydropyrimidin-2(1H)-one and 3,4-dihydropyrimidin-2(1H)-thione derivatives from aldehydes, ethyl acetoacetate and urea or thiourea using glycerol as an organo OH-acid, green and reusable catalyst is reported. The practical and simple protocol led to excellent yields of the dihydropyrimidin-2(1H)-one and thiones under mild reaction conditions and within short span of reaction times with easy reaction workup by maintaining excellent atom economy.
Keywords: Organic OH-acid, reusable catalyst, glycerol, dihydropyrimidin-2(1H)thione, dihydropyrimidin-2(1H)one
Theoretical and computational chemistry
In the given paper, two methods of calculating with high precision accuracy the chemical potential and the integrals of the type called the Fermi–Dirac of different indexes are presented. Our calculations are conclusive with already existing data. These data are essential not only in the study of the theory of solids but at the explanation of the experimental results of investigated transport phenomena in solids, namely, in semiconductors.
Keywords: Chemical potential, Fermi–Dirac integrals, Gauss–Legendre method