Abstract The direct functionalization of inert C(sp2)–H bonds represents a central and challenging objective in synthetic chemistry. Photoelectrocatalysis has recently ushered in a transformative paradigm for efficient C(sp2)–H bond functionalization. This graphical review highlights cutting-edge methodologies for the selective functionalization of C(sp2)–H bonds via the synergistic integration of electrochemistry and photochemistry. These advancements are classified into five main categories: C(sp2)–H bonds of heteroarenes; C(sp2)–H bonds of arenes; C(sp2)–H bonds of alkenes; C(sp2)–H bonds of alkenes/cyclization; and C(sp2)–H bonds of imines.

Abstract The encapsulation of squaraine dyes within a tetralactam macrocycle effectively mitigates their intrinsic limitations while maintaining favorable optical properties and improving both chemical and photochemical stability. However, the synthesis of such rotaxanes remains challenging due to the intricate balance of steric and electronic factors governing the macrocyclization. In this study, a series of rotaxanes derived from hemisquaraine dyes bearing primary and secondary amino groups was successfully synthesized using an oxocyclobutenolate template-assisted macrocyclization approach. Dyes with bulky tertiary amino groups, however, failed to undergo encapsulation. Upon encapsulation, the rotaxane systems in chloroform exhibited red-shifted absorption and emission bands, along with a substantial increase in fluorescence quantum yield. This enhancement is attributed to the restricted vibrational and rotational motions of the encapsulated dye. DFT calculations confirmed that all studied rotaxanes are thermodynamically viable, suggesting that the synthetic difficulties observed for tertiary amine derivatives arise from kinetic constraints. This hypothesis was supported by DFT calculations that simulated the macrocyclization process from the corresponding open-chain precursors. These calculations showed favorable energetics for hemisquaraine dyes that contain primary and secondary amino groups. In contrast, the significant steric effects of tertiary amino groups render the oxocyclobutenolate template-assisted macrocyclization energetically unfavorable.

Abstract A simple, efficient, and environmentally friendly methodology for the dibromination of anisoles using Fe(NO3)3·9H2O/FeBr3 at room temperature was developed. In general, anisoles bearing electron-donating or weak electron-withdrawing groups gave the dibrominated product in good to excellent yields, while anisoles bearing a strong electron-withdrawing group gave a high yield of the monobromination product. This protocol was also suitable for the bromination of 2- or 4-substituted substrates. Importantly, this protocol was also applicable for gram-scale synthesis. It is hopeful that this methodology will have great use in organic synthesis.

Abstract Ten 5-(arylsulfanyl), 5-(arylsulfinyl), and 5-(arylsulfonyl) derivatives of 1,3-oxazol-4-ylphosphonates and 1,3-oxazole-4-carbonitriles were synthesized and characterized using IR, 1H NMR, 13C NMR, 31P NMR spectroscopy, elemental analysis, and mass spectrometry. Their anticancer activity was assessed against NCI-60 human tumor cell lines using a single-dose assay. Diethyl [2-phenyl-5-(phenylsulfonyl)-1,3-oxazol-4-yl]phosphonate, diethyl [5-(4-chlorophenylsulfonyl)-2-(4-methylphenyl)-1,3-oxazol-4-yl]phosphonate, and 5-(4-methylphenylsulfonyl)-2-phenyl-1,3-oxazole-4-carbonitrile, which demonstrated the highest anticancer activity, were selected for five-dose screening. The two phosphonates showed selectivity (SIr > 3 by TGI and LC50) against most leukemia lines, while the 1,3-oxazole-4-carbonitrile derivative was selective against renal (63%), colon (57%), and breast cancer (50%). One compound demonstrated selectivity against the entire leukemia subpanel. A comparison analysis revealed that no standard drug exhibited a high degree of similarity to compounds across all potency vectors. This suggests that the molecular mechanisms may be unique. Possible targets such as cannabinoid receptor 2, adenosine A3 receptor, and cyclin-dependent kinase 2 have been proposed based on in silico studies. The parameters of druglikeness predicted by the ADMET analysis were within the rational range for all compounds. The two phosphonates are expected to be preferable for the development of antileukemia agents, while 5-(4-methylphenylsulfonyl)-2-phenyl-1,3-oxazole-4-carbonitrile is considered promising for agents targeting renal, colon, and breast cancers.

Abstract This graphical review addresses the functionalization of porphyrin derivatives. Simple porphyrin modifications (by introduction of an electron-withdrawing group, e.g., NO2, CO-R, into parent porphyrin system or complexation of the core ring with a highly electronegative unit, e.g., SnCl2) afford valuable intermediates in this area of chemistry. They are useful materials for further transformations, as such modifications increase the electrophilic character, thus allowing a broad spectrum of subsequent reactions. Such reactions are often utilized in the first steps of designed syntheses, leading to attractive and useful target porphyrin-like compounds featuring a high degree of complexity. In this regard, the vicarious nucleophilic substitution of hydrogen (VNS) has become one of the methods of choice. Specifically, it involves addition of a carbanion, bearing a leaving group X at the reactive center, to an electrophilic arene at positions occupied by hydrogen to form a σH-adduct. Subsequent base-induced β-elimination of HX then gives the product of nucleophilic substitution of hydrogen. This approach enables the synthesis of numerous porphyrins bearing up to ten new substituents on the meso-aryl rings (attached to positions 5, 10, 15, and 20) and up to six substituents at the β-positions. This graphical review is the first comprehensive account concerning VNS reaction in porphyrins.

Abstract Catalysis is a crucial tool for synthesizing many molecular scaffolds for various applications, including fuels, pharmaceuticals, fertilizers, fabrics, and fragrances. Different metal complexes of porphyrin and phthalocyanines have been developed as promising catalysts for various catalytic transformations under mild conditions, many of which mimic the action of cytochrome P450 enzymes. The efficiency and selectivity of porphyrins and phthalocyanine-based catalysts have been significantly enhanced by making their nanocomposites. Porphyrins and phthalocyanines have been modified with various nanomaterials such as metal nanoparticles, metal oxide nanoparticles, carbon-based nanomaterials, and nano-organic frameworks such as metal-organic frameworks and covalent-organic frameworks. Their photophysical and catalytic activities have been studied in various organic transformations. Herein, the formation of different nanocomposites of porphyrin and phthalocyanines has been summarized, and their chemical, electrochemical, and photocatalytic applications as catalysts in different organic transformations have been reviewed.1 Introduction2 Porphyrin and Phthalocyanine-Based Nanocomposites for Catalytic Applications2.1 Porphyrin and Phthalocyanine-Based Nanocomposites with Metal Nanoparticles2.2 Metal Oxide Nanoparticle Modified Porphyrin and Phthalocyanine Nanocomposites2.2.1 Nanoconjugates of Porphyrin and Phthalocyanine with Magnetic Nanoparticles2.2.2 Nanocomposites of Porphyrin and Phthalocyanine with Titanium Oxide Nanoparticles2.3 Porphyrin and Phthalocyanine-Based Nanocomposites with Carbon- Based Nanomaterials2.3.1 Porphyrin and Phthalocyanine Nanocomposites with Carbon Nanotubes2.3.2 Porphyrin/Phthalocyanine-Based Nanocomposites with Graphene Oxide2.3.3 Porphyrin and Phthalocyanine Nanocomposites with Graphitic Carbon Nitrite2.4 Porphyrin and Phthalocyanine-Based Nano-organic Frameworks3 Conclusion and Future Prospects

Abstract Hydrazide–hydrazone derivatives are prevalent in numerous bioactive compounds, showcasing a diverse array of biological effects including antibacterial, antitubercular, antifungal, anticancer, anti-inflammatory, anticonvulsant, antiviral, and antiprotozoal properties. Consequently, numerous medicinal chemists have undertaken the synthesis of various hydrazide–hydrazones, subjecting them to evaluation for their biological activities. Among these, antituberculosis activity stands out as a recurring focus in the scientific literature. This paper provides a comprehensive overview of research spanning the last 24 years (1999–2023), concentrating on the antituberculosis properties of hydrazide–hydrazone derivatives. The insights presented herein could serve as a valuable roadmap for the development of novel hydrazide–hydrazones with potential antimicrobial efficacy.

Abstract In recent years, there has been a notable surge in the utilization of microwave energy, leading to the emergence of innovative and groundbreaking methods across various branches of chemistry, including organic synthesis, materials science, heterocyclic chemistry, and medicinal chemistry. This comprehensive literature review delves into the microwave-assisted organic synthesis of specific heterocycles, illuminating its effectiveness in producing diverse molecules with heightened efficiency and selectivity. The review highlights the significant role of microwave irradiation as a potent method for constructing a wide range of compounds. Particular emphasis is placed on the impact of the technique on synthesizing various hybrids such as 1,2,3-triazole hybrids, coumarin hybrids, imidazopyridine hybrids, phenanthridines hybrids, carbene hybrids, and oxazole hybrids. This article is valuable as it offers insights into current synthetic procedures and trends in developing innovative medications utilizing heterocyclic compounds.1 Introduction2 Synthesis of 1,2,3-Triazole Hybrids3 Coumarin Hybrids4 Imidazo Pyridine Hybrids5 Phenanthridine Hybrids6 Carbene Hybrids7 Oxazole Hybrids8 Conclusion

Abstract A direct electrochemical amidation of xanthene was readily achieved under direct anodic oxidation. The reactivity of benzamides was significantly enhanced by the virtue of the solvent effect of hexafluoroisopropanol (HFIP). An obvious hydrogen bonding between HFIP and benzamide was detected, and the proton-coupled electron-transfer (PCET) effect was proposed for the enhancement effect of HFIP. In this transformation, a broad range of primary and secondary amides were readily used as amidating reagents, including l-proline-, naproxen-, and probencid-derived amides. We proposed a plausible reaction mechanism for this direct amidation based on the experimental observations.

Abstract Carbohydrates, traditionally known for their energy-providing role, have gained significant attention in drug discovery due to their diverse bioactivities and stereodiversity. However, pure carbohydrate molecules often exhibit limited bioactivity and suboptimal chemical and physical characteristics. To address these challenges, functional groups with bioactive scaffolds have been incorporated into carbohydrate to enhance their bioactivity and improve their overall properties. Among the various synthetic methods available, click chemistry has emerged as a powerful tool for the synthesis of carbohydrate-containing bioactive scaffolds, known as glycohybrids. Click chemistry offers several advantages, including high chemo- and regioselectivity, mild reaction conditions, easy purification, and compatibility with multiple functional groups. In the present review, we have emphasized the recent advances and most pertinent research on the development of 1,2,3-triazole-containing glycohybrids using the click reaction, their biological evaluations and the structure-activity relationship during 2017–2023. These newly synthesised glycohybrids could potentially be developed as new chemical entities (NCE) in pharmaceutical chemistry and may encourage the use of carbohydrates in drug discovery processes.1 Introduction2 CuAAC Click Chemistry Mediated Synthesis of Triazole-Based Glycohybrids and their Biological Activities3 Conclusions and Perspective