Synthesis of indole–cycloalkyl[b]pyridine hybrids via a four-component six-step tandem process

Abstract

The one-pot four-component reaction of 3-(1H-indol-3-yl)-3-oxopropanenitriles, aromatic aldehydes, cycloalkanones and ammonium acetate occurred via a six-step tandem Knoevenagel condensation–nucleophilic addition to carbonyl–Michael addition–N-cyclization–elimination–air oxidation sequence to afford structurally intriguing indole–cycloalkyl[b]pyridine-3-carbonitrile hybrid heterocycles in excellent yields.

Synthesis of pyrimidine-6-carbonitriles, pyrimidin-5-ones, and tetrahydroquinoline-3-carbonitriles by new superb oxovanadium(V)-[5,10,15,20-tetrakis(pyridinium)-porphyrinato]-tetra(tricyanomethanide) catalyst via anomeric based oxidation

“…Suggested reaction mechanism for the synthesis of 4-(aryl)-2-(1 H -indol-3-yl)-5,6,7,8-tetrahydroquinoline-3-carbonitriles 10 was showed in Fig. 10 30 . At the start, [(VO)TPP][(TCM) 4 ] activates the carbonyl group of the aldehyde 2 .…”

“…Triazolopyrimidines and tetrahydroquinolines were synthesized by using numerous approaches and catalysts such as thiamine hydrochloride (VB 1 ) 23 , Nafion-H 24 , phthalhydrazide-MCM-41 (P-MCM-41) 25 , boric acid under aqueous micellar medium 26 , [DABCO](SO 3 H) 2 Cl 2 and [DABCO](HSO 3 ) 2 (HSO 4 ) 2 27 , DBU 28 , microwave irradiation 29 , etc. [30][31][32][33][34][35][36][37][38][39] .…”

Chemistry of 3-cyanoacetyl indoles: synthesis, reactions and applications: a recent update

“…The one-pot four-component reaction of 3-(1 H -indol-3-yl)-3-oxopropanenitriles 1, aromatic aldehydes, cycloalkanones and ammonium acetate reported via a six-step tandem Knoevenagel condensation-nucleophilic addition to carbonyl-Michael addition- N -cyclization-elimination-air oxidation sequence to afford structurally intriguing indole–cycloalkyl[ b ]pyridine-3-carbonitrile hybrid heterocycles 53–56 in 80–95% yields in refluxing EtOH for 2 h ( Scheme 21 ). 55 …”

Ketones as strategic building blocks for the synthesis of natural product-inspired compounds

“…positions 4-6 = H), [39][40][41][42][43][44] or bearing specific substituents and substitution patterns. [45][46][47][48][49][50][51][52][53][54][55][56] In the former case, an operationally straight-forward Au-catalysed annulation of unfunctionalised pyridine rings to ketones was described by Arcadi, which proceeded by reacting ketones with propargylamine (Scheme 3a). 42 Pyridines were fused to a range of ketones including alicyclic ketones, acetophenones, and aromatisation of the resulting dihydropyridine, to give the pyridine products.…”