Meeting organometallic chemistry with drug discovery: C H activation enabled discovery of a new ring system of 12H-Indazolo[2,1-a]cinnolin-12-ones with anti-proliferation activity

Metal-free Microwave-Assisted Azo-Povarov Reaction of N-Carbony Aryldiazenes with trans-Cyclooctene to access Ring-fused Cinnolines

“…C-H activation and functionalisation catalysed by stable rhodium(III) complexes have experienced a rapid development in recent years. Rh-catalysed cascade annulation reaction of azobenzenes with terminal alkynes for the preparation of indolo [1,2-b]cinnolines developed by Yuan et al, [11] annulation of Nphenylindazoles and diazo compounds for the synthesis of indazolo [2,1-a]cinnolines, [12] or the construction of pyrazolo [1,2-a]cinnolines through Rh-catalysed annulation of pyrazoline derivatives with sulfoxonium ylides improved by Liu, Wang et al, [13] are only a few representative examples recently reported. [14] Iridium is another noble metal successfully used in catalysed C-H activation reaction for the synthesis of cinnoline derivatives.…”

“…[14] Iridium is another noble metal successfully used in catalysed C-H activation reaction for the synthesis of cinnoline derivatives. [14c,15] However, alternative cost-effective transition metals, such as Pd [16] or Ru, [12,17] have become as appealing metal catalysts for C-H bond activation to build the cinnoline backbone.…”

“…Even though the typical merits that C-H bond activation offers for the preparation of cinnoline scaffolds, [11][12][13][14][15][16][17] such as a high regioselectivity, atom economy, and reaction stages, very recently, we have accomplished the first azo-version of the Povarov reaction (azo-Povarov reaction) involving Sc(OTf)3-catalysed [4 + 2] annulations of N-carbonyl aryldiazenes, acting as 4-electron donors, with cyclopentadiene [26] (Scheme 1C).…”

Reducing-Agent-Free Convergent Synthesis of Hydroxyimino-Decorated Tetracyclic Fused Cinnolines via RhIII-Catalyzed Annulation Using Nitroolefins

“…In this expedition, the directing group potential of indazolone and phthalazine-dione have been successfully explored in recent times by the groups of Gandhi, Perumal, Xu, Hou, Sakhuja, and Ruan for preparing functionally decorated fused indazolones/phthalazinones using alkynes, α-diazocarbonyl compounds, and α-carbonyl sulfoxonium ylides as coupling partners under Ir I , Ru II , and Rh III catalysis (Figure ). In particular, novel strategies for the synthesis of indazolo- and phthalazino-cinnolines have received prime interest due to the prevalence of cinnoline and cinnolone-fused heterocycles in several pharmacological active molecules displaying antiproliferative, antibacterial, antifungal, anti-inflammatory, and anticancer activities (Figure ).…”

“…Medicinally important fused and functionalized cinnolines and recently synthesized indazolo-/phthalazino-cinnolines under metal catalysis. − ,− , …”