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Aim. To develop the efficient method for the synthesis of 3-aryl-3-trifluoromethyl-2,3-dihydro-1H-pyrrolizin-1-ones as promising scaffolds in design of bioactive compounds. Results and discussion. It has been shown that condensation of 3-amino-3-aryl-4,4,4-trifluorobutanoic acid methyl esters with 2,5-dimethoxytetrahydrofuran is a convenient synthetic approach to 4,4,4-trifluoro-3-aryl-3-(1H-pyrrol-1-yl)methylbutanoic acid methyl esters converted to 3-aryl-3-trifluoromethyl-2,3-dihydro-1H-pyrrolizin-1-ones by the intramolecular Friedel-Crafts reaction. Experimental part. By the interaction of 3-amino-3-aryl-4,4,4-trifluorobutanoic acid methyl esters with 2,5-dimethoxytetrahydrofuranin acetic acid at 70 оC 4,4,4-trifluoro-3-aryl-3-(1H-pyrrol-1-yl)methylbutanoic acid methyl esters were obtained and subsequently cyclized into 3-aryl-3-trifluoromethyl-2,3-dihydro-1H-pyrrolizin-1-ones upon treatment with boron tribromide in dichloromethane at room temperature. The structures of the compounds synthesized were confirmed by LCMS, IR and NMR (1H, 13C, 19F) spectroscopic methods. Conclusions. An efficient two step protocol for the synthesis of 3-aryl-3-trifluoromethyl-2,3-dihydro-1H-pyrrolizin-1-ones has been developed. It includes transformation of 3-amino-3-aryl-4,4,4-trifluorobutanoic acid methyl esters into the corresponding 3-(1H-pyrrol-1-yl) derivatives and their further intramolecular cyclization.

The article presents a mineralogical, petrographic, and geochemical characterization of the rare earth mineralization of the Kotlyarivka ore occurrence, which was discovered by drill hole 114 in the south-western part of the Krynychky plagiogranite-migmatite dome during geological exploration of the southern part of the Verkhivtseve greenstone structure and its granitoid framing. Rare earth elements (REE) are critically important minerals for many countries, including EU, USA, Canada, and Australia, and other developed countries. The Ukrainian Shield is one of the largest REE metallogenic provinces in Europe. In particular, the Middle Dnipro megablock is a prospective but under-explored region for the discovery of new REE deposits. Its prospects are associated with subalkaline and alkaline Mesoarchaean granitoids and metasomatites of the Tokivske, Mokra Moskovka, and Demuryno complexes. Comprehensive studies of core samples from primary and weathered rocks of the Kotlyarivka occurrence have revealed that monazite is the mine mineral concentrator of REE and yttrium. It was determined that monazite underwent two main stages of alterations: endogenic hydrothermal-metasomatic and hypergenic associated with weathering crust formation. Other minerals, such as apatite, zircon, and leucoxene, also contain lanthanides and yttrium. The findings highlight the critical need for the development of the mineral resource base for REE, involving the re-evaluation of known deposits and the search for new ones. This usually requires scientific support and modern laboratory equipment to accurately determine the composition and genetic features of productive mineralization. Despite some challenges, such as the limited number of samples available for study, the research provided new important data that contributed to the understanding rare earth elements mineralization in the studied Kotlyarivka occurrence and the Middle Dnipro region as a whole. Continuing such studies and conducting comprehensive full-scale research on REE mineralization in the Central Dnipro region will yield high theoretical and practical results.

Rare-metal granite pegmatites of the lithium-cesium-tantalum (LCT) type are widely distributed in Early Precambrian Greenstone belts worldwide, including the Canadian and Australian shields. However, the Middle Dnipro Granite-Greenstone region, which includes a lot of greenstone belts such as Sura, Verkhivtseve, Konka, Sofiivka, Chortomlyk, etc., remains insufficiently studied in terms of these pegmatites. This article presents previously unpublished data on the pegmatites of the Sura and Verkhivtseve greenstone structures or belts, obtained through a meticulous study, analysis, and reinterpretation of repository and archive materials. It reveals their geological-structural setting, distribution limits, mineralogical and geochemical characteristics, and their connection with granite complexes and massifs. Furthermore, the article outlines the prospects for rare-metal mineralization in these pegmatites. Pegmatites within the Sura greenstone structures or belts were discovered on its northern flank within the Karnaukhivka synclinal branch, associated with the ultramafic massif of the same name. Over 60 pegmatite veins were encountered during the 1961 exploration for silicate nickel, with most veins intruding serpentinized ultrabasites. The extension of the veins aligns with the general extension of the Karnaukhivka ultramafic massif, and their average length ranges from 150 to 250 m. The majority of the pegmatite bodies likely dip subvertically and exhibit a zonal structure comprising aplite, multi-grained granite, pegmatoid, blocky quartz, and microcline. The northwestern part of the Sura greenstone structures or belts presents a promising Pravda-Karnaukhivka pegmatite field. The Verkhivtseve greenstone stroctures or belts displays a complex block structure, suggesting the presence of deeply eroded pegmatite-bearing blocks. Isolated bodies of pegmatites have been found on the southeastern flank of the structure, primarily within the Shmakove branch and its surrounding granitoids. A series of pegmatite and aplite veins with anomalous contents of rare metals and rare earth elements are localized in plagiogranites of Sura, granites of Demuryne, and plagiomigmatites of Dnipropetrovsk complexes. The highest niobium content of 0.048% and tantalum content of 0.005% were determined in drill-hole 0151. These pegmatite-bearing greenstone formations in the Shmakove branch and the associated granitoids are designated as the Hrushivka-Rudytsynske pegmatite field. Specialized prospecting for rare-metal mineralization associated with pegmatites within the Pravda-Karnaukhivka and Hrushivka-Rudytsynske pegmatite fields is recommended.

Nowadays, there has significantly increased the interest of industry in rare metal mineralization in pegmatites, which determines their importance as raw materials for “critical elements” Ta, Nb, Li, Be, Sn, Y, TR, etc., and thus there is a need to re-evaluate the known and newly-found deposits of rare metal pegmatites. A detailed comprehensive scientific analysis of the available materials on pegmatites of the East-Ukrainian pegmatitе province (Middle Dnipro and Western Azov) with the development of effective criteria and characteristics of hidden mineralization has to precede the production of costly geological exploration works. Due to the special genetic position of pegmatites in the chain of endogenous processes, their unique mineralogical-petrographic, geochemical and metallogenic properties and ability to form within well-defined structures and rock complexes, it is possible to identify very promising areas, with a detailed scientific analysis of areas. There is considered geological and structural setting and granitoid magmatism of the East-Ukrainian pegmatite region, which determine the specialization of pegmatite associations and the pegmatite fields and belts formed by them. Three pegmatite-­generating stages of development of the pegmatite region are singled out. It is shown that all rare metal pegmatites of the region are associated with the third – gra­nite-greenstone – stage. The analysis of the geological position and structure of two deposits of rare metals (Shevchenko – lithium; Kruta Balka – lithium, tantalum and niobium) was also carried out, and the structural position of the existing ore occurrences and mineralization points of rare metal pegmatites was taken into account. Based on geological data on these deposits and ore occurrences using previous developments reflected in the literature, the most important search criteria and characteristics of rare metal pegmatites of the East-Ukrainian pegmatite region are shown. Taking into account the above, there are given recommendations for scientific analysis of the territory with the compilation of general forecast maps of the territory and detailed maps of perspective structures in the scale of 1:10 000–1:25 000 with analysis of geological structure and reflection of pegmatite-bearing structures, plicative failure of their strata; study of physical, physico-thermal, chemical and mineralogical properties of rocks with the development of classification of rocks according to the possibility of occurrence of pegmatite bodies in them. Primarily, it is recommended to carry out prospect evaluation survey within the clusters of rare metal pegmatites – Voskresenka, Voskresenka-2, Mokri Yaly, Golubi Skeli, Sadovе in the Western Azov and Komendantivka and Zhovtе in the Middle Dnipro region, as well as detailed mapping of the Hulyaipole pegmatite cluster in the south of the Sofiivka structure.

10 gold deposits and more than 200 occurrences have already been discovered in Ukraine. They are located within the Carpathian-Crimean, Dnipro-Donetsk and Ukrainian Shield metallogenic provinces. The richest gold-bearing province is the Ukrainian Shield (USh). Its gold resources are estimated at least 2,400 tons. The main attention in the article is given to the Solone ore field (SOF), which is located within the Middle Dnipro subprovince of the USh pro­vince. Gold resources of SOF are about 1000 tons. We consider it is the most promising gold field for development, on the basis of next key factors: 1) gold mineralization is localized in high mineralized early Precambrian greenstone formations. Its analogue is the Porcupine gold field in Canada; 2) simple geological structure with a clear ore-caused and ore-control role of subvolcanic acidic rocks; 3) two medium-scale gold-molybdenum deposits, Serhiivka and Balka Zolota, have already been discovered, as well as Apollonivka, East-Apollonivka, Novyi, Tetyana’s, Doro­zhnyi, Rozrakhunkovyi, Central, Soniachnyi gold ore occurrences; 4) localization in the industrially developed Dnipro region, which includes world-class deposits of iron (Kryvyi Rih basin) and manganese (Nikopol basin), as well as deposits of national level – titanium, aluminum, etc.; 5) Serhiivka and Balka Zolota deposits are complex gold-molybdenum deposits. In addition, molybdenite contains a high content of Re and Os, which can be extracted as very expensive components; 6) buried alluvial gold placers are known in the Paleogene rocks of the sedimentary cover above primary ore deposits. In view of these favorable geological and economic circumstances, SOF has real prerequisites for the start of gold mining in the near future. Serhiivka deposit is the high priority target for development within the Solone ore field.

А new Vovchansk Uranium Ore district is allocated within the Orikhiv-Pavlohrad structural-metallogenic zone (SMZ) of the Azov metallogenic region. It is represented by Dibrova REE-U-Th deposit and a number of less studied ore occurrences. This deposit, according to ore mineralogy and age, geological and structural features, can be related to potassium-uranium metasomatite type. Dibrova deposit is considered to be possible analogue of mineralization of the Central Ukrainian Uranium Ore district. Among the main diagnostic characteristics of Dibrova deposit are: 1) location within the Mesoarchean trough-like structure superimposed on the Paleoarchean basement. 2) Spacial and genetic association with Paleoproterozoic two-feldspar granitoids of Dibrova type, which are considered to be related to Saltychia intrusive complex. 3) Regional and local faults, favorable for emplacement of numerous bodies of aplite-pegmatitic granitoids and associated intensive metasomatic alterations of rocks. The flexural fold was formed at the intersection of multidirectional faults, which is also favorable for ore mineralization. 4) Mineralization is confined to metasomatically altered aplite-pegmatites, less often to microcline quartzites of Dibrova suite. 5) K2O/Na2O ratio of ore-bearing granitoids reaches 3.5 and thorium-uranium ratio varies from 1.0 to 4.0. 6) Ores are composed by quartz (70–90 %) as predominant mineral and microcline. Minor minerals (up to 10–15 %) are represented by sillimanite, muscovite, biotite. 7) Accessory minerals include monazite, zircon, rutile, nasturan, brannerite, uraninite, molybdenite. 8) Among trace elements are niobium, lead, molybdenum, bismuth, copper, zinc and tin. Economic REE-U-Th mineralization was da­ted at 1.9–2.2 billion years. It is formed through circulation of hydrothermal-metasomatic fluids associated with the emplacement of Paleoproterozoic aplite-pegmatitic granites of the Dibrova type. Study of monazite and uraninite inclusions by the CHIME techniques confirms the Paleoproterozoic age of mineralization, 2085–2115 Ma. At the same time, the influence of Mesoarchean Yanvarske granitoids for the formation of REE mineralization during early pre-ore stage is not excluded.

The article is devoted to molybdenum mineralization of the Eastern flank of Au-Mo Serhiivka deposit, located in the Middle Dnipro megablock of the Ukrainian Shield (USh). The generalized description of mineralization is performed on such important questions: discovery and exploration history, structure and composition of the host rocks, metamorphic and metasomatic alteration of rocks, structural position and localization conditions of molybdenum mineralization, ore composition, description of major ore minerals, morphology of mineralization and the most widespread views about its genesis. Molybdenum ores were discovered and named East-Serhiivka occurrence for the first time in 1974, before the discovery of gold mineralization, which occurred in 1985. Serhiivka deposit consists of two Mesoarchaean volcanic-plutonic associations (VPA) of different composition: the early mafic and the late felsic. The Eastern flank of the deposit, where the molybdenum mineralization is concentrated, is a structural knot similar to the lying letter “T”. It is formed by complex joint of the sub-latitudinal Serhiivka and sub-meridional Solone subvolcanic bodies and the East-Serhiivka massif of plagiogranitoids of the late VPA, which intrude basic rocks of early VPA. Molybdenum mineralization is localized in linearly elongated zones with a chaotic network of thin quartz, carbonate-quartz veinlets and poor (2–5 %) sulfide impregnation, including molybdenite. About 20 vein-impregnated ore zones have been recovered with up to 100–150 m thickness and 0,01 to 0,3 %, sometimes more than 1 % average molybdenum grade. The ores are subdivided into two major mineral types: 1) quartz-molybdenite; 2) quartz-sulfide-gold-molybdenite. The main components of ores molybdenite and native gold are associated with pyrite, chalcopyrite, magnetite, occasionally – pyrrhotite, arsenopyrite, scheelite, bismuth telluride, silver and others. Typical non-metallic minerals are quartz, carbonate, feldspar, chlorite, amphibole, biotite, sericite. It is supposed hydrothermal-metamorphogenic genesis of molybdenum (and gold) ores. Molybdenite and gold are rarely detected in the same intersections, which indicates separate genesis of these minerals. According to the accepted classification molybdenum mineralization is systemized as linear stockwork. Molybdenum ores of Serhiivka deposit are mostly considered as independent, separate from gold mineralization, potentially workable mine. It is the most prospective one in the Middle Dnipro region, USh and Ukraine in general. We suggest a comprehensive approach to studying, resource and reserves evaluation of Serhiivka deposit, taking into account the potential of both molybdenum and gold mineralization, as well as concentrations of rhenium and osmium in molybdenite. Geological exploration on the base of this approach will increase investment prospects of Serhiivka gold-molybdenum deposit.

The most important molybdenum mineralization of the Middle Dnipro province is limited to the Mesoarchean (3,1–2,9 Ga) Greenstone belts or structure (GSS). These are next occurrences: East-Sergiivka, Solone in the Sura GSS and Gannivka (district “Chervona”) in the Kryvyi Rih GSS. They have spatial combining or closeness with well-known gold deposits and occurrences: East-Sergiivka and Solone occurrences are located on the Eastern flanks of the Sergiivka and Balka Zolota deposits, respectively, in the sublatitudinal ore-bearing zones. From the West to the East gold mineralization gradually changes to gold-molybdenum and molybdenum. Gannivka molybdenum and Zhovtіanka gold occurrences are adjacent and localized in the submeridional zone of the Kryvyi Rih-Kremenchuk fault, and not spatially combined. However, similar to the etalon Lobash deposit, they can be combined as elements of a common ore-generating system related to a submeridional-extended granite massif undiscovered by erosion. In the process of previously performed geological surveys and related research, these ore prospects were studied and evaluated separately for each type of minerals. It is proposed to carry out further geological research in the context of spatially and genetically combining of gold and molybdenum mineralization. First of all it concerns deposits and occurrences of Sura GSS, where it is rationally to place two complex gold-molybdenum deposits: Sergiivka and Balka Zolota. This approach, which involves carrying out mining and exploration works on a joint scientific and technical base for molybdenum and gold ores, will undoubtedly have good economic efficiency and, ultimately, substantially increase the investment attractiveness of one or another deposit, facilitate the early launch industrial exploitation.