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Reactive oxygen species (ROS) have been implicated in numerous pathological processes and their homeostasis facilitates the dynamic balance of intracellular redox states. Among ROS, hypobromous acid (HOBr) has a high similarity to hypochlorous acid (HOCl) in both chemical and physical properties, whereas it has received relatively little attention. Meanwhile, selective recognition of endogenous HOBr suffers great challenges due to the fact that the concentration of this molecule is much lower than that of HOCl. Fluorescence-based detection systems have emerged as very important tools to monitor biomolecules in living cells and organisms owing to distinct advantages, particularly the temporal and spatial sampling for in vivo imaging applications. To date, the development of HOBr-specific fluorescent probes is still proceeding quite slowly, and the research related to this area has not been systematically summarized. In this review, we are the first to review the progress made so far in fluorescent probes for selective recognition and detection of HOBr. The molecular structures, sensing mechanisms, and their successful applications of these probes as bioimaging agents are discussed here in detail. Importantly, we hope this review will call for more attention to this rising field, and that this could stimulate new future achievements.

Angiogenesis is an important and interesting scientific subject in the area of malignant tumours. Current research importance and interest are directed in connection to blood microvessels in cancer cell proliferation, tumour growth, and metastasis. Tyrosine kinases have been intensely implicated as therapeutic targets that affect the angiogenic process in tumour growth. In the last decades, targeting angiogenesis has led to achievements in the therapy of different carcinomas by different mechanisms, such as the utilization of anti-angiogenic small molecule receptor tyrosine kinase inhibitors. In the current review, we aim to track the advancements in the total synthesis of three receptor tyrosine kinase inhibitors (pazopanib, regorafenib and lenvatinib). This review surveys different synthetic routes for these three approved drugs (pazopanib, regorafenib and lenvatinib) which were previously published as patents (2014–2021). The purity of medicines is a very important factor during manufacturing so we have decided to review the purification process of these anticancer medicines as well. It should be noted that the different patents may have reported some procedures with different yields and purities for the synthesis of desired drug and their intermediates. In order to simplify the understanding of the contents of this review article, only the best results reported in each of these patents are reported for the synthesis of desired drug and their intermediates. Graphical abstract

The fusion of heterocycles onto an anthraquinone scaffold represents a promising strategy to optimize anticancer activity. This study has the aim to synthesize and characterize novel anthra[1,2-b]furan compounds based on the natural product aloe-emodin. Six novel anthra[1,2-b]furans bearing phenyl, n-hexane, and methoxy carbonyl substituents were synthesized starting from aloe-emodin. The synthetic route employed involved acetyl protection of aloe-emodin, electrophilic aromatic halogenation, subsequent Castro–Stephens coupling, spontaneous intramolecular cyclization, and deprotection of hydroxyl groups. These newly synthesized compounds were evaluated for their cytotoxic activity against various cancer cell lines, including lung adenocarcinoma (A5492), colorectal carcinoma (HCT116), hepatocellular carcinoma (HepG2), ovarian cancer (Skov3), and breast cancer (MCF-7), using the CCK8 assay. The anthra[1,2-b]furan derivative 10c, which contains a methoxy carbonyl group, demonstrated excellent potency against lung (A549) and breast (MCF-7) cancer cell lines, with IC50 values of 0.49 and 2.91 µM, respectively. This preliminary cytotoxic finding shows compound 10c as a promising hit for further investigations towards a promising lead compound.

This review focuses on the synthesis of polyheterocyclic structures with a variety of medicinal and optoelectronic applications, starting from readily available 4,5,6,7-tetrahydroindol-4-one analogs. First, routes toward the 4,5,6,7-tetrahydroindol-4-one starting materials are summarized, followed by synthetic pathways towards polyheterocyclic structures which are categorized based on the size and attachment point of the newly formed (hetero)cyclic ring.

This paper concerns the in silico studies of the influence of heterocyclic substituents as well as their protonated and deprotonated forms on the spectral characteristics of BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) dyes. Computational studies were carried out in order to reveal the most effective method of modeling of the spectral features of fluorescent BODIPY dyes. To perform these studies, the pyrrole and imidazole derivatives of BODIPY dyes were selected, and their spectral features were investigated with DFT and TD-DFT calculations. The calculations showed that the deprotonation of the substituents leads to a bathochromic shift of the calculated absorption wavelength, while the protonation (imidazole derivative) brings about a hypsochromic shift with respect to the neutral form of the dye. The calculated spectral characteristics, considering the influence of the solvent polarity (PCM model), were correlated with the ETN solvatochromic parameter. These correlations show that the increase in the solvent polarity causes a hypsochromic shift of the calculated absorption and emission wavelengths, whereas the bathochromic shift of the wavelengths is observed for the protonated form.

The objective of this review is to give an overview of the synthetic methods to prepare different indolo[3,2-b]carbazoles and similar systems with a potential use in electro-optical devices such as OLEDs (organic light emitting diode), OPVs (organic photovoltaic) and OFETs (organic field effect transistor). Some further modifications to the core units and their implications for specific applications are also discussed.

Designing new synthetic strategies for indazoles is a prominent topic in contemporary research. The transition-metal-catalyzed C–H activation/annulation sequence has arisen as a favorable tool to construct functionalized indazole derivatives with improved tolerance in medicinal applications, functional flexibility, and structural complexity. In the current review article, we aim to outline and summarize the most common synthetic protocols to use in the synthesis of target indazoles via a transition-metal-catalyzed C–H activation/annulation sequence for the one-step synthesis of functionalized indazole derivatives. We categorized the text according to the metal salts used in the reactions. Some metal salts were used as catalysts, and others may have been used as oxidants and/or for the activation of precatalysts. The roles of some metal salts in the corresponding reaction mechanisms have not been identified. It can be expected that the current synopsis will provide accessible practical guidance to colleagues interested in the subject.

BOPAM exhibits high fluorescence quantum yields, along with exceptional photostability, rendering it a promising platform for applications as fluorescence sensors. However, the development of BOPAM-based fluorophores with extended emission wavelengths remains limited, and the underlying mechanisms of fluorescence quenching via the population of dark twisted intramolecular charge transfer (1TICT) excited states are not yet fully understood. To address these gaps, we synthesized a series of BOPAM derivatives by incorporating electron-donating groups at the boron atoms and the phenyl rings of the BOPAM core. The introduction of bromide, phenyl, and naphthyl groups preserved the intrinsic locally excited (1LE) emission of BOPAM. In contrast, the incorporation of diphenylamine (BP-DA) and triphenylamine (BP-TA) moieties resulted in a red-shifted emission, attributed to an enhanced intramolecular charge transfer (ICT) process. Notably, in acetonitrile, BP-DA exhibited weak fluorescence originating from a 1TICT state, which was populated via the S2 → 1TICT transition. Furthermore, the emission observed from BP-TA was associated with a higher-lying excited state, likely the initially populated S2 state possessing a 1LE character. These findings not only introduce novel red-emissive BOPAM-based fluorophores, but also offer valuable insights into the role of the S2 state in governing fluorescence quenching mechanisms in BOPAM derivatives.

A metal-free protocol for the direct bis-arylation of 2,5-dichlorobenzoquinone with aryldiazonium salts is reported. The reactive salts are generated in situ and converted to radicals through irradiation with visible light. Reaction products precipitate from the solvent, eliminating the need for purification and thus providing a novel green method for the synthesis of versatile bis-electrophiles.

The present review narrates several reports which deal with the synthesis of fused 1,2,3-triazole containing scaffolds following a sequential multicomponent reaction (MCR)—intramolecular azide-alkyne cycloaddition (IAAC) approach. The reviewed reactions were cleverly designed so as to incorporate azide and alkyne functionalities in the MCR product which was then subjected to IAAC. The review is divided into two sections based on the number of components in the multicomponent reaction. We have aimed at a critical discussion and also have highlighted either advantages or disadvantages of each methodology.