A new class of bactericidal agents against S. aureus, MRSA and VRE derived from bisindolylmethane

Bisindole Compounds-Synthesis and Medicinal Properties

The indole nucleus stands out as a pharmacophore, among other aromatic heterocyclic compounds with remarkable therapeutic properties, such as benzimidazole, pyridine, quinoline, benzothiazole, and others. Moreover, a series of recent studies refer to strategies for the synthesis of bisindole derivatives, with various medicinal properties, such as antimicrobial, antiviral, anticancer, anti-Alzheimer, anti-inflammatory, antioxidant, antidiabetic, etc. Also, a series of natural bisindole compounds are mentioned in the literature for their various biological properties and as a starting point in the synthesis of other related bisindoles. Drawing from these data, we have proposed in this review to provide an overview of the synthesis techniques and medicinal qualities of the bisindolic compounds that have been mentioned in recent literature from 2010 to 2024 as well as their numerous uses in the chemistry of materials, nanomaterials, dyes, polymers, and corrosion inhibitors.

Green and sustainable approaches for the Friedel-Crafts reaction between aldehydes and indoles

The synthesis of indoles and their derivatives, more specifically bis(indolyl)methanes (BIMs), has been an area of great interest in organic chemistry, since these compounds exhibit a range of interesting biological and pharmacological properties. BIMs are naturally found in cruciferous vegetables and have been shown to be effective antifungal, antibacterial, anti-inflammatory, and even anticancer agents. Traditionally, the synthesis of BIMs has been achieved upon the acidic condensation of an aldehyde with indole, utilizing a variety of protic or Lewis acids. However, due to the increased environmental awareness of our society, the focus has shifted towards the development of greener synthetic technologies, like photocatalysis, organocatalysis, the use of nanocatalysts, microwave irradiation, ball milling, continuous flow, and many more. Thus, in this review, we summarize the medicinal properties of BIMs and the developed BIM synthetic protocols, utilizing the reaction between aldehydes with indoles, while focusing on the more environmentally friendly methods developed over the years.

K2S2O8-glucose mediated oxidative coupling of alcohols with indoles for synthesis of Bis(indolyl)methanes in water

The use of inexpensive K2S2O8 in water at room temperature for synthesis of bis(indolyl)methanes (BIMs) from simple indoles and alcohols is reported. The key step involves the conversion of alcohols...

FeCl3·6H2O as a Mild Catalyst for Nucleophilic Substitution of Symmetrical Bis(indoyl)methanes

In this paper, unsymmetrical bis(indolyl)methane (BIM) and 3-alkylindole derivatives are smoothly synthesized from symmetrical BIMs with a variety of nucleophiles including heteroaromatic/aromatic compounds, allylsilane and alkynylsilane. FeCl₃·6H₂O is found to be a mild and highly effective catalyst for this nucleophilic substitution reaction in which N-methyl-2-phenylindole behaves as a good leaving group in the C_sp³-C_sp² bond cleavage reaction. The operational ease, nonexpensive and environmentally friendly catalyst, mild reaction conditions, broad functional group tolerance, and scalability of this reaction strategy are advantages of the present procedure.

Recent advances in indole dimers and hybrids with antibacterial activity against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA), one of the major and most dangerous pathogens in humans, is a causative agent of severe pandemic of mainly skin and soft tissue and occasionally fatal infections. Therefore, it is imperative to develop potent and novel anti-MRSA agents. Indole derivatives could act against diverse enzymes and receptors in bacteria, occupying a salient place in the development of novel antibacterial agents. Dimerization and hybridization are common strategies to discover new drugs, and a number of indole dimers and hybrids possess potential antibacterial activity against a panel of clinically important pathogens including MRSA. Accordingly, indole dimers and hybrids are privileged scaffolds for the discovery of novel anti-MRSA agents. This review outlines the recent development of indole dimers and hybrids with a potential activity against MRSA, covering articles published between 2010 and 2020. The structure-activity relationship and the mechanism of action are also discussed to facilitate further rational design of more effective candidates.

Synthesis of novel antiproliferative hybrid bis-(3-indolyl)methane phosphonate derivatives

An efficient synthetic methodology for the preparation of phosphorus substituted bis-(3-indolyl)methane through a double nucleophilic addition of indole derivatives to an in situ generated α-iminophosphonate is reported. In addition, bis-(3-indolyl)methane substrates showed in vitro cytotoxicity, inhibiting the growth of carcinoma human tumor cell lines A549 (carcinomic human alveolar basal epithelial cell) and SKOV03 (human ovarian carcinoma).

Synthesis of a Novel Type of 2,3'-BIMs via Platinum-Catalysed Reaction of Indolylallenes with Indoles

Optimisation, scope and mechanism of the platinum-catalysed addition of indoles to indolylallenes is reported here to give 2,3'-BIMs with a novel core structure very relevant for pharmaceutical industry. The reaction is modulated by the electronic properties of the substituents on both indoles, with the 2,3'-BIMs favoured when electron donating groups are present. Although simple at first, a complex mechanism has been uncovered that explains the different behaviour of these systems with platinum when compared with other metals (e.g. gold). Detailed labelling studies have shown Pt-catalysed 6-endo-trig cyclisation of the indollylallene as the first step of the reaction and the involvement of two cyclic vinyl-platinum intermediates in equilibrium through a platinum carbene, as the key intermediates of the catalytic cycle towards the second nucleophilic attack and formation of the BIMs.

Fe3O4@SiO2 supported aza-crown ether complex cation ionic liquids: preparation and applications in organic reactions

A series of aza-crown ether ionic liquids supported on magnetic Fe₃O₄@SiO₂ core–shell particles were designed, synthesized and characterized by elemental analysis, TEM, TG and FT-IR.