Synthesis of Hexahydrobenzo[b]pyrimido[4,5-h][1,6]naphthyridines via an Intramolecular Hetero-Diels−Alder Reaction

The Intramolecular Povarov Tool in the Construction of Fused Nitrogen-Containing Heterocycles

Nitrogen heterocycles are part of the structure of natural products and agents with important biological activity, such as antiviral, antibiotic, and antitumor drugs. For this reason, heterocyclic compounds are one of today's most desirable synthetic targets and the Povarov reaction is a powerful synthetic tool for the construction of highly functionalized heterocyclic systems. This process involves an aromatic amine, a carbonyl compound, and an olefin or acetylene to give rise to the formation of a nitrogen-containing heterocycle. This review illustrates advances in the synthetic aspects of the intramolecular Povarov reaction for the construction of intricate nitrogen-containing polyheterocyclic compounds. This original review presents research done in this field, with references to important works by internationally relevant research groups on this current topic, covering the literature from 1992 to 2022. The intramolecular Povarov reactions are described here according to the key processes involved, using different combinations of aromatic or heteroaromatic amines, and aliphatic, aromatic, or heteroaromatic aldehydes. Some catalytic reactions promoted by transition metals are detailed, as well as the oxidative Povarov reaction and some asymmetric intramolecular Povarov processes.

Synthesis and Anticancer Properties of Functionalized 1,6-Naphthyridines

The burgeoning interest in synthesis and biological applications of 1,6-naphthyridines reflects the importance of 1,6-naphthyridines in the synthetic as well as medicinal chemistry fields. Specially, 1,6-naphthyridines are pharmacologically active, with variety of applications such as anticancer, anti-human immunodeficiency virus (HIV), anti-microbial, analgesic, anti-inflammatory and anti-oxidant activities. Although collective recent synthetic developments have paved a path to a wide range of functionalized 1,6-naphthyridines, a complete correlation of synthesis with biological activity remains elusive. The current review focuses on recent synthetic developments from the last decade and a thorough study of the anticancer activity of 1,6-naphthyridines on different cancer cell lines. Anticancer activity has been correlated to 1,6-naphthyridines using the literature on the structure-activity relationship (SAR) along with molecular modeling studies. Exceptionally, at the end of this review, the utility of 1,6-naphthyridines displaying activities other than anticancer has also been included as a glimmering extension.

Construction of hybrid polycyclic quinolinobenzo[a]phenazinone architectures using solid-state melt reaction (SSMR)

An efficient and versatile protocol for the synthesis of hybrid polycyclic quinolinobenzo[a]phenazinones has been developed under SSMR condition via intramolecular domino Knoevenagel-hetero-Diels-Alder reaction involving the generation of two new six membered fused rings and three contiguous stereogenic centers.