Current Organic Chemistry - Online First

The Stemona alkaloids are a unique class of naturally occurring alkaloids with pyrrolo[1,2-a]azepine or a pyrido[1,2-a]azepine skeleton. These alkaloids exhibit a wide range of bioactivities, including antitubercular, antibacterial, antifungal, and anthelmintic properties. The complex and interesting structure of Stemona alkaloids has attracted the attention of chemists, and numerous studies on the total synthesis of Stemona alkaloids have been published over the years. Some review articles on the total synthesis of these alkaloids have appeared in the literature. However they are quite outdated or do not describe steps in details. This article aims to give a comprehensive review on total synthesis of Stemona alkaloids. In addition, several considerable studies on formal synthesis of Stemona alkaloids have also been included.

The Boyland-Sims peroxydisulfate oxidation is a highly effective method for the introduction of a hydroxyl function into aromatic amines. The simplicity of the process, as well as the absence of the need to protect sensitive functional groups, are the reaction's defining characteristics. Nevertheless, the low yield of the target products restricts the practical application of the reaction. The present study investigates the peroxydisulfate oxidation of aniline under modified conditions of the Boyland-Sims reaction. The yield and ratio of ortho- and para-aminophenols formed in the oxidation of aniline were found to depend on the reaction conditions. Previous studies on this reaction have been conducted at ambient temperature. It was determined that these temperature conditions are inadequate for the complete oxidation of aniline. It was found that increasing the temperature to 45°C resulted in a twofold increase (up to 35%) in the yield of reaction products, which, however, remains inadequate for the practical application of the reaction. Consequently, modifications to the Boyland-Sims reaction conditions were proposed. These comprised the use of metallophthalocyanine catalysts or a second oxidizing agent, hydrogen peroxide. Both modifications enabled a substantial augmentation in the yield of reaction products, ortho- and para-aminophenols. In the presence of metallophthalocyanines, the yield of intermediate 2(4)-aminophenylsulfates increased to 54-85%. Among the studied catalysts, cobalt phthalocyanine proved to be the most active. Its addition allowed increasing the yield of 2(4)-aminophenylsulfates up to 85%, while the ratio of ortho- and para-aminophenols in the mixture was shifted towards the para-isomer, with a ratio of 1:7. However, the utilization of a combination of two oxidizing agents, ammonium persulfate and hydrogen peroxide, led to the unexpected formation of para-aminophenol as the predominant reaction product, accompanied by the presence of trace amounts of the ortho-isomer.

Ind recent years, the indole core has emerged as a highly favored scaffold in drug research. Although indole was first shown to be an anticancer agent in vinca alkaloids, it also continued to exhibit many activities with various mechanisms in other diseases, such as diabetes, HIV, Alzheimer's, and hyperlipidemia. Indole derivatives have proved that they deserve researchers’ attention due to their biochemical diversity in plenty of plants, bacteria, animals, marine organisms, and humans, as well as the fact that they are used to synthesize several FDA-approved drugs. The main review’s objective is to compile a comprehensive listing of almost all reported pharmacological activities from 2011 to 2025, with the structure-activity relationship of potentially active compounds. It also highlights several green approaches and recent indole and indole derivative synthesis trends.

Nickel-metallaphotoredox catalysis has emerged as a groundbreaking approach in organic synthesis research over the last decade. It integrates the accessibility of the redox states of inexpensive, earth-abundant nickel to capture carbon-centred radicals with the ability of photoredox catalysts (PCs) to mediate single-electron transfer (SET) or energy transfer (ET) for efficient, selective, and sustainable transformations. Advances in catalyst design, reaction optimization, and mechanistic understanding have unlocked a wide range of cross-coupling protocols, enabling previously inaccessible or less efficient C-C bond formations. This progress opens new possibilities for innovative applications in pharmaceuticals, materials science, and beyond. This mini-review focuses on advancements in the last three years in the formation of challenging C(sp³)-C(sp³) and C(sp³)-C(sp²) bonds, both in two-component and three-component systems, featuring a broad substrate scope, with chemo-, regio-, and stereo-selectivity under mild conditions. Although mechanistic studies have been conducted for some systems, and kinetic isotope effects have been probed for others, detailed investigations using computational methods to understand the molecular interactions are lacking or sometimes fail to indicate a general trend of the catalytic mechanism. The discovery of novel approaches to open-shell radical species, which dictate reactivity and selectivity, will be of utmost importance in developing new reactions. These advances will enrich all areas of chemical sciences and create numerous opportunities for interdisciplinary research.

Monoterpene glycosides are important active ingredients in many commonly used traditional Chinese medicines. Based on their different aglycones, monoterpene glycosides are primarily classified into five types: acyclic monoterpene glycosides, monocyclic monoterpene glycosides, bicyclic monoterpene glycosides, tricyclic monoterpene glycosides, and iridoid glucosides. These compounds exhibit significant medicinal efficacy, including antioxidant, anti-cancer, anti-tumor, anti-hypertensive, anti-diabetic, antibacterial, and anti-inflammatory properties. However, there have been few reviews published on monoterpene glycosides. This paper systematically summarizes and analyzes the classification, structural characteristics, and bioactivity of monoterpene glycosides, based on research conducted over the past 20 years on those isolated from natural products, thereby providing a scientific basis for the exploitation of monoterpene glycosides. The chemical structures and activities of monoterpene glycosides were obtained from well-known and widely utilized databases, including Web of Science, Science Direct, Google Scholar, PubMed, and CNKI, through the application of various search terms.

A simple and practical method has been developed for the synthesis of N-aryl/heteroarylphthalimides, bisphthalimides, 1,8-naphthalimides, and related derivatives. This method involves the reaction of various primary amines with different anhydrides, such as phthalic anhydride and 1,8-naphthalic anhydride, in the presence of a catalytic amount of mandelic acid in aqueous ethanol under reflux conditions. The use of less toxic solvents, excellent yields, shorter reaction times, elimination of column chromatographic purifications, and low-cost and naturally occurring catalysts are some of the major advantages of this developed protocol.

The use of micelles enables the resolution of a number of problems associated with the aggregation and reduction in photocatalytic activity of porphyrins. The formation of transport systems is impossible without information on the localization of porphyrins containing hydrophilic and hydrophobic parts in highly organized systems, such as liposomes or model systems–micelles. To solve the above issues, 5,10,15,20-tetra(3ʹ,4ʹ-dihydroxyphenyl)porphin (Por(OH)8), 5-(3ʹ,4ʹ-dihydroxyphenyl)-10,15,20-triphenylporphin (Por(OH)2), and 5-(3ʹ,4ʹ-dihydroxyphenyl)-10,15,20-tri(pyridinium-3ʹ-yl)porphine (PorN (OH)2) were synthesized, and their state was studied in aqueous media in the presence of an anionic surfactant in the premicellar region. It was found that the porphyrins are sedimentation-stable in the premicellar region, while in the micellar region, Por(OH)2 and PorN(OH)2 are localized inside SDS micelles. However, the peripheral substituents of PorN(OH)2 are oriented toward the “head” of the surfactant. Por(OH)8 is the worst isolated from water molecules of all the studied porphyrins, and can be located both on the surface and inside the micelle, orienting the OH groups toward the surface of the micelle, or the channels inside it. The results obtained can be used to design transport systems for the delivery of hydroxy-substituted porphyrin photosensitizers.

Heterocyclic compounds, which contain at least one heteroatom (e.g., nitrogen, oxygen, sulfur) within their ring structures, are crucial in pharmaceuticals and agrochemicals due to their bioactive properties. They serve as the core components of numerous drugs, including antibiotics, anticancer agents, and agrochemicals like pesticides. Given the increasing demand for these compounds, the need for efficient and sustainable synthetic methods has become paramount. Multicomponent reactions (MCRs) have emerged as a powerful tool for the rapid and efficient synthesis of heterocyclic frameworks. By combining three or more reactants in a single step, MCRs offer high atom economy, reduced waste, and simplified reaction protocols. Solid base catalysts have been extensively utilized to improve the sustainability of these reactions further. These catalysts, including metal oxides and supported alkali metals, provide several advantages: enhanced selectivity, ease of recovery and reuse, and minimal environmental impact. This review explores the diverse MCR strategies for heterocyclic synthesis using solid base catalysts. It highlights their role in promoting green chemistry by enabling scalable and environmentally benign processes. Key examples, such as the synthesis of imidazoles, pyridines, pyrans, pyrimidine, etc, are discussed, demonstrating these methods' efficiency and industrial relevance. Solid base catalysis ensures operational simplicity and aligns with sustainable chemistry goals, making it a cornerstone in modern heterocyclic synthesis.

Establishing the fundamental possibility of the existence of the heteroligand macrotetracyclic complexes of vanadium, chromium, manganese, and iron-containing in the inner coordination sphere phthalocyanine, oxygen (O^2-) and fluorine (F^-) ions and having general [MPc(O)F] formula (M= V, Cr, Mn, Fe), by using of quantum-chemical calculation of parameters of their molecular/electronic structures and thermodynamical characteristics. The molecular and electronic structures of the above-mentioned heteroligand macrotetracyclic chelates of 3d elements (M) of the type [MPc(O)F] (M= V, Cr, Mn, Fe) which are unknown at present, were theoretically investigated. Standard thermodynamic parameters of formation (standard enthalpy DH⁰f, 298, entropy S⁰f, 298, and Gibbs’s energy DG⁰f, 298) for these macrocyclic compounds were calculated, too. Identifying details of molecular and electronic structures of compounds indicated above. Density functional theory (DFT) model chemistries (B3PW91/TZVP and OPBE/TZVP) with a combination of the D3 version of Grimme’s dispersion. The data on the geometric parameters of the molecular structure of these complexes are presented; it was shown that MN4 chelate nodes, all metal-chelate and 6-membered non-chelate rings in each of these macrocyclic coordination compounds, are practically planar with a small deviation from coplanarity (not more 3^o); nonetheless, N4 grouping from donor nitrogen atoms and 5-membered non-chelate rings are strictly planar. Wherein, the bond angles between two donor nitrogen atoms and M atom are not equal to 90^o; a similar situation occurs for the bond angles between donor atoms N, M, and O or F (notwithstanding the bond angles formed by M, O, and F atoms are exactly 180°). Also, NBO analysis data and the values of the standard enthalpy, entropy, and Gibbs energy of the formation of these compounds were presented. Specific features of DFT calculated molecular and electronic structures of the heteroligand metal macrocyclic compounds have been discussed. It has been shown that good agreement between the parameters of molecular structures obtained by two various DFT model chemistries takes place. Also, it has been noted that predicting the possibility of the existence of exotic coordination compounds and modeling their molecular/electronic structures using modern quantum chemical calculations (and, in particular, using DFT of various levels) is a very useful tool for solving problems associated with such synthesis.