Efficient and Green Method for the Synthesis of 1,5‐Benzodiazepine and Quinoxaline Derivatives in Water

Reusable nano-catalyzed green protocols for the synthesis of quinoxalines: an overview

Heterocyclic compounds are very widely distributed in nature and are essential for life activities. They play a vital role in the metabolism of all living cells, for example, vitamins and co-enzyme precursors thiamine, riboflavin etc. Quinoxalines are a class of N-heterocycles that are present in a variety of natural and synthetic compounds. The distinct pharmacological activities of quinoxalines have attracted medicinal chemists considerably over the past few decades. Quinoxaline-based compounds possess extensive potential applications as medicinal drugs, presently; more than fifteen drugs are available for the treatment of different diseases. Diverse synthetic protocols have been developed via a one-pot approach using efficient catalysts, reagents, and nano-composites/nanocatalysts etc. But the use of homogeneous and transition metal-based catalysts suffers some demerits such as low atom economy, recovery of catalysts, harsh reaction conditions, extended reaction period, expensive catalysts, the formation of by-products, and unsatisfactory yield of products as well as toxic solvents. These drawbacks have shifted the attention of chemists/researchers to develop green and efficient protocols for synthesizing quinoxaline derivatives. In this context, many efficient methods have been developed for the synthesis of quinoxalines using nanocatalysts or nanostructures. In this review, we have summarized the recent progress (till 2023) in the nano-catalyzed synthesis of quinoxalines using condensation of o-phenylenediamine with diketone/other reagents with plausible mechanistic details. With this review, we hope that some more efficient ways of synthesizing quinoxalines can be developed by synthetic chemists.

InCl3: A Versatile Catalyst for Synthesizing a Broad Spectrum of Heterocycles

This review deals with the recent applications of the indium trichloride (InCl₃) catalyst in the synthesis of a broad spectrum of heterocyclic compounds. Over the years, a number of reviews on the applications of InCl₃-catalyzed organic synthesis have appeared in the literature. It is evident that InCl₃ has emerged as a valuable catalyst for a wide range of organic transformations due to its stability when exposed to moisture and also in an aqueous medium. The most attractive feature of this review is the application of the InCl₃ catalyst for synthesizing bioactive heterocyclic compounds. The study of InCl₃-catalyzed organic reactions has high potential and better intriguing aspects, which are anticipated to originate from this field of research.

Eco-friendly approach to access of quinoxaline derivatives using nanostructured pyrophosphate Na2PdP2O7 as a new, efficient and reusable heterogeneous catalyst

In the present study, we report the synthesis of various quinoxaline derivatives from direct condensation of substituted aromatic 1,2-diamine with 1,2-dicarbonyl catalyzed by nanostructured pyrophosphate Na₂PdP₂O₇ as a new highly efficient bifunctionalheterogeneous catalyst. The quinoxaline synthesis was performed in ethanol as a green and suitable solvent at ambient temperature to afford the desired quinoxalines with good to excellent yields in shorter reaction times. Many Quinoxaline derivatives were successfully synthesized using various 1,2-diketones and 1,2-diamines at room temperature. Catalyst reusability showed that the Na₂PdP₂O₇ catalyst exhibited excellent recyclability without significant loss in its catalytic activity after five consecutive cycles.

Review on the Synthesis of Pyrazine and Its Derivatives

Pyrazine is a kind of natural product which can be found in plants, animals, insects, marine organisms andmicroorganisms. The main function of pyrazine in living organisms is used as flavor of the raw foods. Pyrazine and its derivatives were also produced in industries mainly for fragrance, flavor and pharmaceutical applications. This review describes the historical development of pyrazine including the discovery and synthesis, to the recent synthetic approach of pyrazinium. In general, six synthetic approaches namely condensation reaction, ring closure, metal catalysis, green reaction, Maillard reaction and acid catalyst on N-substitution have been reviewed in this paper. The first five approaches are mainly aimed for the substitution at 2, 3, 5 and 6 positions in pyrazine ring, whereas the last approach is specifically for 1 and 4 positions in pyrazine. Keywords: Diazine, pyrazine, and Maillard reaction

Synthesis of substituted pyrazines from N-allyl malonamides

Synthesis of highly substituted pyrazines from geminal diazides via thermal or copper-mediated cyclization and modification of the obtained pyrazines.

Magnetic Fe3O4 Nanoparticles as New, Efficient, and Reusable Catalysts for the Synthesis of Quinoxalines in Water

A novel, environmentally friendly procedure has been developed for the synthesis of quinoxaline derivatives in the presence of magnetic Fe3O4 nanoparticles. The reaction between 1,2-diamines and 1,2-dicarbonyl compounds was carried out in water to afford quinoxaline derivatives in high yield. The catalyst can be recovered by the use of an external magnet and reused for five cycles with almost consistent activity.

Gallium (III) triflate-catalyzed synthesis of heterocycles: quinoxalines, 1,5-benzodiazepines and their fluorinated derivatives

Background: The quinoxaline nucleus is a part of several antibiotics, such as echinomycin, levomycin and actinomycin, which are known to inhibit the growth of Gram-positive bacteria and are active against various transplantable tumors. Benzodiazepines are important classes of heterocycles that draw significant interest from the pharmaceutical industry because of their prominent therapeutic value, such as antiviral, antibacterial, anti-inflammatory, antiprotozoaval properties and also as kinase inhibitors. They have also been evaluated as anticancer, anthelmintic, antifungal and insecticidal agents. Results & conclusion: Quinoxalines, benzodiazepines and their fluorinated derivatives have been prepared in excellent yields from the corresponding diamines and diketones using gallium (III) triflate as an efficient and environmentally friendly catalyst, due to its stability, recyclability and minimal toxicity.