✍ Scribed by Richard A. Bunce; Takahiro Nago
No coin nor oath required. For personal study only.
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A tandem Michael‐S~N~Ar annulation reaction has been developed for the synthesis of 1‐alkyl‐2,3‐dihydro‐4(1__H__)‐quinolinones. Success in the reaction followed expected electronic effects for the final S~N~Ar ring closure. Treatment of doubly activated 1‐(2‐fluoro‐5‐nitrophenyl)‐2‐propen‐1‐one with primary amines in N,N‐dimethylformamide at 50°C for 24 h provided 2,3‐dihydro‐4(1__H__)‐quinolinones in 67–78% yields. Singly activated 1‐(2‐fluorophenyl)‐2‐propen‐1‐one reacted similarly, but failed to undergo the final ring closure with hindered or aromatic amines. Finally, 1‐(2‐fluoro‐5‐methoxyphenyl)‐2‐propen‐1‐one, with one activating and one deactivating group on the ring, gave only simple 1,4‐addition products. J. Heterocyclic Chem., (2009).
📜 SIMILAR VOLUMES
## Abstract An efficient synthesis of (±)‐2‐aryl‐2,3‐dihydro‐4(1__H__)‐quinolinones has been developed from chalcones prepared from 2′‐nitroacetophenone and a series of substituted benzaldehydes. The cyclization sequence is initiated by reduction of the nitro group under dissolving metal conditions
## Abstract magnified image A synthesis of ester‐ and ketone‐substituted (±)‐1‐alkyl‐6‐nitro‐1,2,3,4‐tetrahydroquinolines has been developed from 2‐pentenoates and 2‐penten‐1‐ones substituted at C5 by a 2‐fluoro‐5‐nitrophenyl group. The cyclization involves an S~N~Ar reaction followed by a Michael
## Abstract magnified image Treatment of 2‐fluoro‐5‐nitrobenzyl bromide with active methylene compounds in the presence of excess potassium carbonate in acetone leads to the formation of highly functionalized 4__H__‐1‐benzopyrans by a tandem S~N~2‐S~N~Ar reaction sequence. The reaction works well
## Abstract magnified image A tandem reductive amination‐S~N~Ar reaction has been applied to the synthesis of (±)‐1,2‐dialkyl‐5‐nitro‐2,3‐dihydro‐1__H__‐indoles. Treatment of a series of 2‐fluoro‐5‐nitrobenzyl ketones with primary amines and sodium cyanoborohydride in methanol at room temperature