l-Proline-catalyzed one-pot synthesis of 2-aryl-2,3-dihydroquinolin-4(1H)-ones

(±)‐2‐Aryl‐2,3‐dihydro‐4(1H)‐quinolinones by a tandem reduction–Michael addition reaction

“…Using an alternative strategy, metathesis of 2‐alkynylanilines with aldehydes in the presence of an antimony pentafluoride‐methanol catalyst gave (±)‐2,3‐disubstituted‐2,3‐dihydro‐4(1 H )‐quinolinones [10] as cis–trans mixtures in 25–95% yields. Finally, condensation of 2′‐aminoacetophenone with various benzaldehydes in the presence of L ‐proline was reported as a potential route to chiral 2‐aryldihydroquinolinones [11], and although yields were in the 79–93% range, the asymmetric induction was poor (less than 10% enantiomeric excess). To date, there have been few reports detailing the synthesis of 2‐aryldihydroquinolinones from 2′‐nitrochalcones [12], and this is the route we sought to exploit.…”

Microwave-assisted Fe3O4 nanoparticles catalyzed synthesis of chromeno[1,6]naphthyridines in aqueous media

“…While a considerable number of naphthyridines fused with five-membered rings has been described in literature [13][14], corresponding derivatives condensed with six-membered heterocycles have been less investigated [15][16]. There are also few synthetic methods available in literature for the synthesis of chromeno [1,6]naphthyridines [17][18][19][20].…”

“…usage of corrosive catalysts [17], multistep process [18], high temperature, long reaction time, non-compatible solvent [19], low yields and unavailable starting materials [20]. Although, some strategically sound modifications have been documented [21] for upliftment of reaction condition, but somewhere down the line it still lack the versatility.…”

Use of Mesoporous Molecular Sieves in the Production of Fine Chemicals: Preparation of Dihydroquinolinones of Pharmaceutical Interest From 2′‐Aminochalcones

“…[9,10] The synthesis of 2,3-dihydro-4(1 H)-quinolinones is generally accomplished by the base or acid catalyzed intramolecular aza-Michael cyclization of substituted 2'-aminochalcones, through the nucleophilic attack of the amino group on the b-carbon of the enone function, which leads to the formation of six-membered heterocyclic systems( 6-endo-trigc yclization product) as predicted from Baldwin's rules (Scheme 1). [11] Basic homogene-ous catalysts such as piperidine,K OH, [12] l-proline, [13] as well as Brønsted andL ewis acids such as orthophosphoric acid in acetic acid, [7] PEG-400 (PEG = polyethylene glycol), [14] wet cyanuric chloride, [15] zinc chloride, [16] ytterbium(III) triflate (YbOTf) 3 in ionic liquid ([bmim]BF 4 ;b mim = 1-butyl-3-methylimidazolium) [17] or lithium tetrafluoroborate [18] have been used as catalysts for the cyclization of 2'-aminochalcones into quinolinones. However,m any of these homogeneous processes involvet he use of corrosive reagents, require large amountso fc atalyst, long reactiont imes, and high temperatures, giving, in most cases, low yields of products.…”