Efficient access to pyrido[1,2-a]pyrimidines and imidazo[1,2-a]pyridines through Knoevenagel reaction/aza–ene addition/intramolecular cyclization

Efficient Synthesis of Highly Substituted N‐Arylamino quinolone‐based Pyrrolo[3,4‐b]pyridines and Pyrazolone‐based Pyrrolo[3,4‐b]pyridines Through a One‐Pot Three‐Component Reaction

“…In other derivatives, these diastereomers were not visible due to the absence of substitution in the ortho position. Based on the experimental results and the literatures, [29,30] a plausible mechanism for this process is proposed in Scheme 2.…”

“…[25] One of the most important and famous enamines for the synthesis of nitrogen-containing heterocycles is nitroketen aminals, [26] cyclic enamino ketones, [27] and αaminomaleimides, [28] which played an important role in this process. According to our knowledge, the three-component reaction of 2-chloroquinoline-3-carbaldehydes, malononitrile derivatives and enamines such as nitroketen aminals, cyclic enamino ketones to synthesize quinoline-based pyrido[1,2a]pyrimidines/imidazo[1,2-a]pyridines [29] and N-arylamino biquinoline derivatives have been previously reported. [16] Also, Ghandi et al reported the synthesis of quinoline-based 1,4dihydropyridines through a one-pot four-component condensation of 2-chloroquinoline-3-carbaldehydes, arylamines, acetylenedicarboxylates and malononitrile derivatives.…”

Regio- and Chemoselective Synthesis of 4,6-Dithia-1,2,9-triazaspiro[4.4]non-2-en-8-ones through an Ultrasound-Promoted One-Pot Sequential Pseudo-Five-Component Reaction

“…24,25,29,30 Similarly, thiazolidine derivatives also exhibit antiviral, anti-inflammatory, antifungal, antimicrobial, antibacterial, and anticancer activities. [31][32][33] The biological importance of the above heterocyclic compounds has encouraged research on the synthesis of quinoline derivatives [34][35][36][37] and spiro-hetero-cycles [38][39][40][41] through dipolar cycloaddition reactions 34,37,42 in order to generate spiro-heterocycles possessing thiadiazole, thiazolidine, and 2-chloroquinoline motifs.…”

Recent Strategies in Transition-Metal-Catalyzed Sequential C–H Activation/Annulation for One-Step Construction of Functionalized Indazole Derivatives

“…Nitrogen-based heterocyclic systems are commonly found in pharmaceutical agents and natural products, and they have been intensively explored as new bioactive products [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Among them, the indazoles [ 11 , 12 , 13 , 14 , 15 , 16 ] are favored by synthetic and medicinal chemists, as evidenced by their widespread abundance in pharmaceuticals and natural products.…”