Metal-free oxidative coupling of arylmethylamines with indoles: a simple, environmentally benign approach for the synthesis of 3,3'-bis(indolyl)methanes

Unlocking Diversity: From Simple to Cutting-Edge Synthetic Methodologies of Bis(indolyl)methanes

From a synthetic perspective, bis(indolyl)methanes have undergone extensive investigation over the past two to three decades owing to their remarkable pharmacological activities, encompassing anticancer, antimicrobial, antioxidant, and antiinflammatory properties. These highly desirable attributes have spurred significant interest within the scientific community, leading to the development of various synthetic strategies that are not only more efficient but also ecofriendly. This synthesis-based literature review delves into the advancements made in the past 5 years, focusing on the synthesis of symmetrical as well as unsymmetrical bis(indolyl)methanes. The review encompasses a wide array of methods, ranging from well-established techniques to more unconventional and innovative approaches. Furthermore, it highlights the exploration of various substrates, encompassing readily available chemicals such as indole, aldehydes/ketones, indolyl methanols, etc. as well as the use of some specific compounds as starting materials to achieve the synthesis of this invaluable molecule. By encapsulating the latest developments in this field, this review provides insights into the expanding horizons of bis(indolyl)methane synthesis.

Synthesis of Bis(3-indolyl)methanes Mediated by Potassium tert-Butoxide

The indole moiety is an important N-heterocycle found in natural products, and a key structural component of many value-added chemicals including pharmaceuticals. In particular, bis(3-indolyl)methanes (BIMs) are an important subgroup of indoles, composed of two indole units. Herein, we report the development of a simple method to access BIMs derivatives in yields of up to 77 % by exploiting a tBuOK-mediated coupling reaction of indoles and benzyl alcohols.

A Novel Method for the Syntheses of Imidazo-Thiadiazoles as Potential Antioxidants and Anti-Inflammatory Agents

BACKGROUND

A literature survey revealed that many imidazo-thiadiazole molecules were used as key intermediates for the development of novel drugs. The synthesized imidazo-thiadiazole derivatives were tested for their in vitro antioxidant and anti-inflammatory properties. The purpose of this research paper is to provide readers with information regarding diseases caused by free radicals.

OBJECTIVE

The objective of this study is to develop novel antioxidant and anti-inflammatory drugs.

METHODS

Imidazo-thiadiazole derivatives 5a-f were synthesized through cyclo-condensation reactions in two steps. First, the synthesis of 2-amino-thiadiazole derivatives from substituted aromatic carboxylic acids and thiosemicarbazide by using POCl₃ as a solvent as well as a catalyst was performed. In the next step, imidazo-thiadiazoles were prepared from 2-amino-thiadiazole derivatives with appropriate α-haloketones in the presence of polyethylene glycol-300 (PEG-300) as a green solvent. These imidazo- thiadiazole derivatives were prepared by using a novel method. The synthesized compounds were in vitro tested for their antioxidant and anti-inflammatory activities.

RESULTS

In vitro evaluation report showed that nearly all molecules possess potential antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), superoxide radical (SOR), and hydrogen peroxide (H₂O₂) radical scavenging activity. Most of the imidazo-thiadiazole derivatives have shown significant anti-inflammatory activity as compared to diclofenac sodium as a reference standard.

CONCLUSION

In the search for novel therapies to treat inflammation and oxidation, we have made efforts to develop anti-inflammatory and antioxidant agents with a preeminent activity. Imidazo-thiadiazoles 5a, 5e as well as 5f showed potential anti-inflammatory activity. All tested imidazo-thiadiazole deriv-atives (5a-f) showed potential antioxidant activity against one more radical scavenging species as com-pared to ascorbic acid as the reference standard. Thus, imidazo-thiadiazole derivatives constitute an interesting template for the design and development of new antioxidant as well as anti-inflammatory agents.

Simple practical method for synthesis of trisubstituted imidazoles: an efficient copper catalyzed multicomponent reaction

A rapid practical process has been developed for synthesis of 2,4,5-trisubstituted-imidazoles in excellent yields up to 95% from readily available starting materials. In this CuI catalyzed synthesis, trisubstituted imidazoles were afforded in short reaction times, wherein the substrate scope is well explored with benzoin as well as benzil reacting with different aldehydes in the presence of ammonium acetate as the nitrogen source.

A rapid practical process has been developed for synthesis of 2,4,5-trisubstituted-imidazoles in excellent yields up to 95% from readily available starting materials.