Merging Directed C−H Activations with High-Throughput Experimentation: Development of Predictable Iridium-Catalyzed C−H Aminations Applicable to Late-Stage Functionalization

Herein, we report an iridium-catalyzed directed C−H amination methodology developed using a high-throughput experimentation (HTE)-based strategy, applicable for the needs of automated modern drug discovery. The informer library approach for investigating accessible directing group chemical space for the reaction, in combination with functional group tolerance screening and substrate scope investigations, allowed for the generation of an empirical predictive model to guide future users. Applicability to late-stage functionalization of complex drugs and natural products, in combination with multiple deprotection protocols leading to the desirable aniline matched pairs, serve to demonstrate the utility of the method for drug discovery. Finally reaction miniaturization to a nano molar range highlights the opportunities for more sustainable screening with decreased material consumption.

THE QUALITY OF THE MEAT OF THE ABERDEEN ANGUS BULL CALVES DEPENDING ON THE BODY TYPE

Проведен анализ качественных характеристик мясной продуктивности бычков абердин ангусской породы в зависимости от типов телосложения. Научно-хозяйственный опыт проводился в одном из хозяйств Карачаево-Черкесской Республики в 2020—2021 годах. Из потомства быков крупного (I группа) и мелкого типа (II группа) абердин ангусской породы было сформировано 2 группы по 14 голов. По окончании контрольного выращивания провели контрольный убой бычков в 18-месячном возрасте. Установлено, что бычки I группы достоверно (Р<0,01) превосходили по живой массе аналогов II группы. Молодняк I группы имел более высокую (на 31,4 кг) предубойную массу и более тяжелые туши по сравнению с бычками II группы на 28,3 кг (Р<0,01). По убойной массе бычки I группы превосходили сверстников II на 26,5 кг (Р<0,01), а по убойному выходу — соответственно на 1,98 абс.%. При обвалке молодняка I группы было получено мякоти больше на 9,9 кг (Р<0,01) по сравнению с данными по обвалке туш бычков II группы. Химический анализ различных проб мяса показал, что туши бычков I группы содержали несколько меньше жира по сравнению с тушами молодняка II группы, как общего количества в средних пробах, так и внутримышечного в пробах из мускулов. Различия между группами по другим показателям были незначительными. Наибольшее количество жира было в отрубах, дающих лучшие сорта мяса, — бедренном и спинно-грудном, несколько меньше содержалось в лопаточной части, дающей мясо второго сорта. По влагосвязывающей способности, цвету и нежности мяса различий между группами не обнаружено. The analysis of the qualitative characteristics of the meat productivity of the Aberdeen Angus bull calves, depending on the body types, is carried out. Scientific and economic experience was conducted in one of the farms of the Karachay-Cherkess Republic in 2020-2021. From the offspring of large (group I) and small type bulls (group II) of the Aberdeen Angus breed, 2 groups of 14 heads were formed. At the end of the control cultivation, a control slaughter of steers was carried out at the age of 18 months. It was found that the bulls of group I were significantly (P<0.01) superior in live weight to the analogues of group II. The young animals of group I had a higher pre-slaughter weight (by 31.4 kg) and heavier carcasses compared to the steers of group II by 28.3 kg (P<0.01). According to the slaughter weight, the bulls of the first group exceeded the peers of the second by 26.5 kg (P<0.01), and according to the slaughter yield — by 1.98 abs.%, respectively. When deboning young animals of the first group, more pulp was obtained by 9.9 kg (P<0.01) compared with the data on deboning the carcasses of bulls of the second group. Chemical analysis of various meat samples showed that the carcasses of group I steers contained slightly less fat compared to the carcasses of young animals of group II, both total in average samples and intramuscular in muscle samples. The differences between the groups on other indicators were insignificant. The greatest amount of fat was in the cuts that give the best varieties of meat — femoral and dorso-thoracic, slightly less was contained in the scapular part, which gives the second grade meat. No differences were found between the groups in terms of the moisture binding ability, color and tenderness of the meat.

Low Temperature Resistance Increase for Bitumen by Compounding with Tar

In this paper, a conventional road bitumen with penetration grade 100–130 is compounded with tar in order to obtain bitumen with improved low temperature resistance. The low temperature (at −24 °C, −30 °C and −36 °C) resistance of the virgin bitumen and the compounded one is evaluated by testing on a bending beam rheometer. It was found that the optimum compounding (20% of tar by weight) decreases the stiffness essentially (from 18% to 34%), i.e., it increases the low temperature resistance of the bitumen. The stiffness decreases in the compounded bitumen can be explained by quantitative variations in its group chemical composition and molecular fragments. Group chemical composition has been determined by the method of absorption chromatography, and the fragments of molecules are identified by NMR-spectroscopy.

Technological methods of increasing the meat productivity of sheep in late lambing periods

The purpose of the research was to develop a method for increasing the meat productivity of sheep under various housing systems. Methods. All studies were conducted according to generally accepted methods. The experimental population of rams of the control and experimental groups was kept until the age of 3 months together with ewes on the pasture (suckling period) with further weaning at the age of 3 months. Further, the rams were divided according to the technologies of keeping: the control group – pasture (graziery), and the experimental group – indoor maintenance (fattening) up to 4 months of age, followed by control slaughter. Monthly weighing of the experimental young rams livestock was carried out. Results. The research work showed that the use of this technological method significantly contributed in increasing average gain and live weight, respectively, by 6.6 % (20 g) and 5.7 % (2.3 kg) and as a result, slaughter weight – by 9.2 % (1.6 kg) in young rams from the experimental group in comparison with analogues of the control group. Chemical, amino acid and microstructural analyses of samples of the longissimus of the livestock showed that the specimens of the young rams of the experimental group had the best food and market advantages. The efficiency of using this technological method is also confirmed by the calculated economic indicators – the difference in the level of profitability was 7.9 % in favor of the rams of the experimental group. The scientific novelty of the research work is a detailed study of the indicators of meat productivity under the influence of this technological method with the justification of its application and the introduction of both scientific and practical contributions to the development of sheep farming.

Transformation of an Oligotrophic Sphagnum Bog during the Process of Rewetting

The vast peatlands of the European North of Russia were drained in the 20th century. Some of the drained areas were left without management and maintenance, which led to re-waterlogging. The current trend towards peatlands restoration requires an understanding of all the changes that have taken place in such ecosystems. The study aims to assess the changes in vegetation cover relative to changes in peat deposits in the rewetted oligotrophic bogs. The objects of research were located on the south-White Sea oligotrophic bogs. The studies were carried out using generally accepted geobotanical and geoecological methods in conjunction with the authors’ method for studying the group chemical composition of peat organic matter. The species diversity, structure and spatial distribution of the vegetation cover, the structure and composition of the peat, as well as the composition of the peat organic matter have been studied. It was shown that the transformation of an oligotrophic bog during the process of rewetting manifests itself in a significant change in the vegetation species diversity, somewhat reversible concerning ecologically tolerant species. Changes occurring in the peat deposit are irreversible. That limits the possibility of restoration of species of oligotrophic habitats to the initial state.

Prospects for surfactant peat derivatives

&lt;p&gt;Peat is a caustobiolith traditionally used as a renewable source of organic substances, in particular humic substances (HS). They are considered to have high biological activity and therefore are widely used in industry and agriculture.&lt;/p&gt;&lt;p&gt;Geoclimatic conditions have a significant impact on the peat accumulation process. Accordingly, peat from various regions differs in composition and physicochemical characteristics of the main components. This affects the properties of peat-based products.&lt;/p&gt;&lt;p&gt;The study of the group chemical composition of high-moor peat from different climatic regions (Western Siberia and the Belomor-Kuloy plateau) was performed according to the certified author&amp;#8217;s method. The study revealed that there are both similarities and a number of differences in peat group chemical composition. All samples showed the low ash-content (up to 3.5%) and the content of easily-hydrolyzable components is inversely proportional to the degree of peat decomposition. This is due to their greater bioavailability compared to other organic matter components. Despite the similar values of the bitumen content in the peat samples (3.5-4.2%), the composition and content of HS differ significantly: 26% and 13-15% for the peat samples from the Siberian region and the Belomor-Kuloy plateau respectively. The ratio of humic and fulvic acids in the peat samples are 3.8 and 1.8 that is consistent with differences in the degree of decomposition.&lt;/p&gt;&lt;p&gt;Humic substances macromolecules are diphilic, so they can show surface activity in solutions. By the Wilhelmy method it was found that for the adsorption of humic substances into the surface layer to an equilibrium state is required 16-20 hours. While the greatest changes (by 65-85%) occur during the first 30-60 minutes. The maximum depression of surface tension was 31.5-35.8 mN/m. This is characteristic of compounds with high molecular weight. The presence of bitumen components, which also have surface activity, in the HS solution, accelerates the achievement of adsorption equilibrium at the air&amp;#8211;water interface.&lt;/p&gt;&lt;p&gt;Based on the measuring of the surface tension the surface activity was determined. The surface activity characterizes the process of the surface layer formation of a surfactant solution at the air&amp;#8211;water interface with an infinite dilution. This parameter was calculated depending on HS solution concentration. The surface activity value of HS solutions extracted from Siberian peat is 2 2.1 N/ m*g that is 2 times higher than the HS solutions from the Belomor-Kuloy plateau. Removal of bitumens from the peat leads to an increase of the surface activity of HS solution from Siberian peat at twice it was before, but for Belomor-Kuloy plateau peat it decreases by 10%. The observed differences can be associated with the peculiarities of the composition of the bitumen. This trend has been confirmed by calculation of the critical micelle concentration and the measurement of the hydrodynamic sizes of particles in solutions using the dynamic light-scattering method.&lt;/p&gt;&lt;p&gt;It was revealed high surface activity of HS solution. So the range of their possible use could be extended (synthetic detergents, emulsifiers, etc.).&lt;/p&gt;&lt;p&gt;The reported study was funded by RFBR according to the research projects &amp;#8470; 20-35-90037, 18-05-60151, and 18-05-70087.&lt;/p&gt;

BITUMENS AND POLYMER BITUMENS - NANODISPERSE SYSTEMS

This work shows the data regarding the elemental and chemical group compositions of the road bitumens. The short characteristic has been shown for the components of the bitumens - the asphaltenes, the resins and the oils. The properties have been described for the bitumens on which they have the direct impact. The description is given for the micellar model of the bitumens from the point of view of the colloid chemistry. The analysis has been performed for the results of the study by other authors for the asphaltenes of a bitumen and an oil. The group chemical compositions are given for the bitumen of the grades BND 50/70, BND 70/100 and BND 100/130 produced by the plants of Kazakhstan. It has been shown that the content of the asphaltenes in them is from 15.8% to 24.3%; in most cases, the content of the asphaltenes is within the range of 20-25%, i.e. the asphaltenes nanoclusters are almost a fourth of the bitumen by weight. The brief description is given for the best known polymers used for the modification of the road bitumen: 1) the reactive polymers Elvaloy 4170 and Elvaloy AM; 2) the polymers of the group SBS - Kraton D 1192A, Calprene 501, SBS L 30-01 A, KUMHO KTR and Butonal NS 198. It is proposed to consider the bitumen and the polymer bitumen as the peculiar nanodisperse systems. The structures are described for the polymer bitumen nanodisperse systems occurring during the modification of the road bitumen with the polymers of the above two groups.