Malignant tumours are the second leading cause of death among working-age population; meanwhile, prevention and treatment of these diseases is hampered by the wide diversity of cell types that can become malignant or develop resistance to chemotherapy. Recent years have witnessed a considerable growth of the fascination with azolo[1,5-a]pyrimidines as a promising platform for developing antitumour agents; several drugs based on this platform are already in clinical trials or are used in practice. The present review, devoted to this platform, considers the diversity of oncogenic targets that are affected by azolo[1,5-a]pyrimidines and demonstrates their cytotoxic action against various types of cancer cells. The main focus is on the antitumour potential of azole[1,5-a]pyrimidines. Analysis of modern literature including 132 studies reveals the key structure–activity relationships and provides conclusions about the most promising substitution patterns in the heterocyclic system depending on the macromolecular target. The structures of the lead compounds are presented, and the cell lines most sensitive to azolopyrimidines are listed. The bibliography includes 196 references.
The search for non-metal photocatalysts is of considerable scientific and practical interest due to the growing environmental concerns associated with photocatalysis. Among such materials, graphitic carbon nitride (g-C3N4) undoubtedly holds the highest priority. The focus on this material has diverted attention of researchers from other polymorphs of carbon nitride, the solid phases of which, namely α, β, cubic, and pseudocubic phases, behave similarly to diamond-like structures (diamond, silicon nitrides, boron nitrides). These phases hold a considerable potential due to their structural features, both in a pure state and in composites. Although research into carbon nitride started with attempts to obtain and theoretically investigate dense carbon nitride phases, currently these phases are still least explored in terms of practical applicability; these issues are addressed only in few studies. The main challenge here lies in creating the special conditions required for the formation of dense phases. This review critically examines the structure, synthesis methods, product yields, and morphology of both dense and layered polymorphs of carbon nitride. The evolution of synthetic approaches to dense carbon nitride polymorphs is demonstrated, and results of theoretical studies of the band structure, along with the approximations employed, are analyzed. This review consolidates the fragmentary data on various C3N4 polymorphs and highlights the diversity of factors influencing their structure and morphology. Data on the potential use of dense carbon nitride phases and their composites, including application as photocatalysts, are also presented. The bibliography includes 144 references.
Mechanical recycling of high-density polyethylene (HDPE) is already being carried out on an industrial scale, while extrusion-based 3D printing still relies on a few polymers that are easier to print but clearly less sustainable. In the present review, we bring together the experimental literature of 2013–2026 on printing this polymer, following the whole chain from virgin resin or washed post-consumer waste to the finished part: melt rheology and the workable melt-flow-index window, crystallization kinetics as the origin of shrinkage and warpage, filament extrusion practice and quality control, validated printing windows and bed-adhesion strategies, and the mechanical performance of printed parts against injection-molded (IM) baselines. A number of studies report that, under optimized conditions, tensile strength and stiffness of the resulting products approach those of IM HDPE materials, although performance varies widely with grade, formulation, and print parameters; adequately stabilized recyclate has been shown to retain most of its mechanical performance over 3–5 processing cycles in the systems studied, which supports distributed recycling into filament. Original processing maps, schemes and comparative tables gather the scattered numerical windows into design guidance, while the barriers that remain, namely standardization, long-term durability data and equipment availability, are set out as research priorities. The bibliography includes 130 references.
The study of abiotic chemical reactions within living systems represents a transformative frontier in biomedical research, driven by the multidisciplinary integration, including synthetic biology, chemical biology, pharmacy and chemistry. The employment of bioorthogonal chemistry, and analogous methodologies facilitates the precise modulation of biological processes with high specificity, high fidelity and minimal off-target effects. This review systematically summarizes recent advances in the design and application of such in situ chemical reactions in living systems. A range of reaction types are introduced in the current review that have found significant application, including bioorthogonal transformations, cyanine-based photooxidation, in situ polymerization, and the like. A discussion of the mechanisms underlying these reactions and their key advantages are also comprehensively included. Subsequently, a generalization and summarization of representative biomedical applications is conducted, encompassing the domains of cellular behavior regulation, fluorescence imaging and antitumor therapy. Finally, we delineate the prevailing challenges and future directions for the development and translation of in situ chemical tools. The precise orchestration of chemistry in living environments holds great promise for unlocking novel diagnostic and therapeutic platforms, paving the way toward more effective and personalized treatments for complex diseases. The bibliography includes 134 references.
This review focuses on the current state of research in the synthesis of analogues of natural plant hormones cytokinins and their antagonists, anticytokinins. The review covers data published since the 1950s concerning the influence of the structure of these compounds on their phytohormonal activity in plant systems. For the first time, special attention is paid to the structural features that determine the emergence of the specificity toward the individual cytokinin receptors. Data on the structure and properties of the anticytokinins are updated for the first time in over 30 years. Based on the analysis performed, a number of recommendations are formulated and promising areas for the future research on the development of synthetic phytohormones are identified. This review will be useful both for chemists engaged in the synthesis and study of biologically active compounds and for plant physiologists and biochemists, as well as for specialists in agronomy. The bibliography includes 176 references.
