One-pot synthesis of pyrrolo[1,2-a]quinoxaline and pyrrolo[1,2-a]pyrazine derivatives via the three-component reaction of 1,2-diamines, ethyl pyruvate and α-bromo ketones

Synthetic Methods of Quinoxaline Derivatives and their Potential Anti-inflammatory Properties

Quinoxaline molecule has gathered great attention in medicinal chemistry due to its vide spectrum of biological activities and has emerged as a versatile pharmacophore in drug discovery and development. Its structure comprises a bicyclic ring of benzopyrazine and displays a range of pharmacological properties, including antibacterial, antifungal, antiviral, anticancer, and antiinflammatory. This study aims to summarize the different strategies for the synthesis of quinoxalines and their anti-inflammatory properties acting through different mechanisms. Structure-activity relationships have also been discussed in order to determine the effect of structural modifications on anti-inflammatory potential. These analyses illuminate critical structural features required for optimal activity, driving the design and synthesis of new quinoxaline analogues with better antiinflammatory activities. The anti-inflammatory properties of quinoxalines are attributed to their inhibitory action on the expression of several inflammatory modulators such as cyclooxygenase, cytokines, nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and p38α Mitogen Activated Protein Kinase (p38α MAPK). Activators of nuclear factor erythroid 2-related factor 2 (NRF2) and agonistic effect on opioid receptors have also been discussed. Hence, this study may provide a future template for the design and development of novel quinoxaline derivatives acting through different molecular targets as potential anti-inflammatory agents with better efficacy and safety profiles.

A Review of the Synthetic Strategies toward Dihydropyrrolo[1,2-a]Pyrazinones

Dihydropyrrolo[1,2-a]pyrazinone rings are a class of heterocycles present in a wide range of bioactive natural products and analogues thereof. As a direct result of their bioactivity, the synthesis of this privileged class of compounds has been extensively studied. This review provides an overview of these synthetic pathways. The literature is covered up until 2020 and is organized according to the specific strategies used to construct the scaffold: fusing a pyrazinone to an existing pyrrole, employing a pyrazinone-first strategy, an array of multicomponent reactions and some miscellaneous reactions.

One-Pot Synthesis of Thiazolo[3,4-a]Quinoxalines from 1,2-Diamines, Aryl Isothiocyanates and Ethyl Bromopyruvate

Some hitherto unreported thiazolo[3,4- a]quinoxaline derivatives have been synthesised in excellent yields via a one-pot, three-component reaction of benzene-1,2-diamines, ethyl bromopyruvate and aryl isothiocyanates in MeCN, for the first time. The protocol avoids the use of any catalysts or chromatographic separations and provides a wide range of novel thiazolo[3,4- a]quinoxalines.

Synthesis of pyrrolo[1,2-a]quinoxalines via copper or iron-catalyzed aerobic oxidative carboamination of sp3C–H bonds

We developed an aerobic oxidative carboamination of sp³C–H bonds with 2-(1H-pyrrol-1-yl)anilines for synthesis of pyrrolo[1,2-a]quinoxalines.

One-Pot, Green and Efficient Synthesis of Pyrrolo[1,2-α]Quinoxalines in Water

A variety of pyrrolo[1,2-α]quinoxaline derivatives were synthesised via the reaction of 1,2-diamines with dibenzoylacetylene and dialkyl acetylenedicarboxylates in the presence of ethyl bromopyruvate in water. This novel, eco-friendly approach offers an easy, efficient, and mild synthesis of pyrrolo[1,2-α]quinoxaline derivatives in good yields.

Efficient assembly of quinoxaline derivatives from benzene-1,2-diamines, dialkyl acetylenedicarboxylates and ninhydrin

The hitherto unreported, highly functionalized alkyl 2-(2-hydroxy-1,3-dioxo-2,3-dihydro-1H-inden-2-yl)-2-(3-oxo-3,4-dihydroquinoxalin-2-yl)acetate derivatives 4 have been synthesized in excellent yields via a one-pot three-component reaction of benzene-1,2-diamines, dialkyl acetylenedicarboxylates, and ninhydrin under mild conditions.

Ambient temperature synthesis of β,β′-fused nickel(ii) pyrrolo[1,2-a]pyrazinoporphyrins via a DBSA-catalyzed Pictet–Spengler approach

Synthesis of novel β,β′-fused nickel(ii) pyrrolo[1,2-a]pyrazinoporphyrins is accomplished for the first time at ambient temperature via a DBSA-catalyzed Pictet–Spengler approach.