Formation of Acridones by Ethylene Extrusion in the Reaction of Arynes with β-Lactams and Dihydroquinolinones

Abstract

N-Unsubstituted β-lactams react with a molecule of aryne by insertion into the amide bond to form a 2,3-dihydroquinolin-4-one, which subsequently reacts with another molecule of aryne to form an acridone by extrusion of a molecule of ethylene. 2,3-Dihydroquinolin-4-ones react under the same reaction conditions to afford identical results. This is the first example of ethylene extrusion in aryne chemistry.

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3+ + 2]-cycloaddition/rearrangement reactions

“…The required N -acylated 2,3-dihydro-4(1 H )-quinolones 6 were generally prepared following a literature method with the acid-catalysed Fries rearrangement of N -arylazetidin-2-ones of the general form 4 [43–44]. As illustrated in Scheme 1, the preparation starts from the related anilines 1 which were acylated with 3-bromopropionyl chloride ( 2 ) to afford amides 3 .…”

Ruthenium‐Pincer‐Catalyzed Hydrogenation of Lactams to Amino Alcohols

“…The combined organic phase was dried over anhydrous Na 2 SO 4 .A fter filtration, the filtrate was concentrated under reduced pressure and the resulting residue was purified by using silica gel chromatography (eluent: hexane/EtOAc) to provide the desired product. 1-Phenylazetidin-2-one [23] 3-Bromopropanoyl chloride (13 mmol) was added dropwise to a suspension of aniline (10 mmol) and K 2 CO 3 (13 mmol) in dichloromethane (10 mL) at 0 8C. The mixture was stirred at 0 8Cf or 15 min, then allow to warm to RT for another 3h.T he reaction was quenched with water and extracted three times with EtOAc.…”

Transition-Metal-Free Synthesis of Benzo-Fused Five- and Six-Membered Heterocycles Employing Arynes

“…The reaction took place via the extrusion of a molecule of ethylene [87]. The reaction took place via the extrusion of a molecule of ethylene [87].…”

“…SCHEME 61 Synthesis of 9-methylenexanthene and 9-hydroxy 9-phenylxanthene [84]. SCHEME 63 Reaction of aryne with dihydroquinolinones [87]. employing N-arylbenzamides as the coupling partner for arynes, instead of o-halobenzamides, resulted in the formation of acridines when the reaction was carried out in the presence of TBAT in toluene followed by BF 3 ·Et 2 O treatment.…”