Object-oriented synthetic approach toward angular and linear fused pyrazoloquinolines of biological importance with InCl3catalyst

1H-Pyrazolo[3,4-b]quinolines: Synthesis and Properties over 100 Years of Research

This paper summarises a little over 100 years of research on the synthesis and the photophysical and biological properties of 1H-pyrazolo[3,4-b]quinolines that was published in the years 1911–2021. The main methods of synthesis are described, which include Friedländer condensation, synthesis from anthranilic acid derivatives, multicomponent synthesis and others. The use of this class of compounds as potential fluorescent sensors and biologically active compounds is shown. This review intends to summarize the abovementioned aspects of 1H-pyrazolo[3,4-b]quinoline chemistry. Some of the results that are presented in this publication come from the laboratories of the authors of this review.

A review on the synthesis of heteroannulated quinolones and their biological activities

The quinoline scaffold has become an important construction motif for the development of new drugs. The quinolones and their heteroannulated derivatives have high importance due to their diverse spectrum of biological activities as antifungal, anti-inflammatory, anti-diabetes, anti-Alzheimer's disease, antioxidant and diuretic activities. This review summarizes the various new, efficient and convenient synthetic approaches to synthesize diverse quinolone-based scaffolds and their biological activities. We also dealt with the important mechanism, the route and type of reactions of the obtained products. The biological activities of some heteroannulated quinolones were also discussed.

Biologically active perspective synthesis of heteroannulated 8-nitroquinolines with green chemistry approach

A new class of pyrazolo[4,3-c]quinoline (5a-i, 7a-b) and pyrano[3,2-c]quinoline (9a-i) derivatives were designed and synthesized in moderate to good yields by microwave conditions. To enhance the yield of pyrano[3,2-c]quinoline derivatives, multicomponent one-pot synthesis has been developed. The synthesized compounds were identified by spectral and elemental analyses. Compounds 9a and 9i showed good antibacterial activity against Gram-positive and Gram-negative bacterial strains. All of the new compounds exhibited weak to moderate antioxidant activity, compound 9d exerted significant antioxidant power. The cytotoxicity of these compounds were also evaluated against MCF-7 (breast) and A549 (Lung) cancer cell lines. Most of the compounds displayed moderate to good cytotoxic activity against these cell lines. Compound 9i was found to be significantly active in this assay and also induced cell death by apoptosis. Molecular docking studies were carried out using EGFR inhibitor in order to determine the molecular interactions.

Dehydrogenative [2 + 2 + 1] Heteroannulation Using a Methyl Group as a One-Carbon Unit: Access to Pyrazolo[3,4-c]quinolines

A practical and straightforward access to pyrazolo[3,4-c]quinolines by molecular sieve mediated dehydrogenative [2 + 2 + 1] heteroannulation of N-(o-alkenylaryl)imines with aryldiazonium salts is described using a sp(3)-hybrid carbon atom as a one-carbon unit. The reaction enables the formation of three new chemical bonds, a C-C bond and two C-N bonds, in a single reaction and features simple operation and excellent functional group tolerance.