An Expeditious Copper‐Catalyzed Access to 3‐Aminoquinolinones, 3‐Aminocoumarins and Anilines using Sodium Azide

Abstract

An efficient copper-catalyzed in situ C-) À NH 2 bond formation to provide a range of 3-aminoquinolin-2(1H)-ones and 3-aminocoumarins from 3-bromoquinolinones and 3-bromocoumarins, respectively, has been achieved. The reaction conditions involve the use of copper powder as the catalyst, eco-friendly ethanol as the solvent in the presence of pipecolinic acid as the ligand and ascorbic acid as the additive. The efficiency of this practical method was demonstrated in the synthesis of various anilines.

Synthesis and biological evaluation of coumarin replacements of novobiocin as Hsp90 inhibitors

“…45, 46 Compounds 11 , 18 – 21 , 23 , 24 , were heated in a sealed tube with copper nanoparticles, azidotrimethyl silane, and amino ethanol in a solution of dimethyl acetamide to give anilines 25 – 31 . 46 The protecting groups on compounds 27 – 29 were exchanged from benzyl ethers to silyl ethers by hydrogenolysis on palladium/carbon and subsequent O-silylation with tert -butyldimethylsilyl chloride (TBSCl), which gave anilines 32 – 34 .…”

Palladium‐Catalyzed Coupling of 3‐Halo‐Substituted Coumarins, Chromenes, and Quinolones with Various Nitrogen‐Containing Nucleophiles

“…Amination of 7a was achieved by using 3,4,5‐trimethoxyaniline as the nucleophile in the presence of Pd(OAc) 2 as the catalyst and Xantphos as the ligand to give 11d in 60 % yield (Table 4, Entry 4). The synthesis of the 5‐aminocoumarin derivative 11e was achieved by the copper‐catalyzed C–N coupling reaction of substrate 7a with sodium azide as the amino source, according to our previously reported conditions 11. The reaction occurred rapidly in the presence of inexpensive copper powder as the catalyst and environmentally benign EtOH as the solvent, providing amino derivative 11e in a moderate yield (45 %; Table 4, Entry 5).…”

“…In contrast to the numerous applications of 3‐aminocoumarin derivatives, there are very few synthetic approaches to these compounds. To introduce a variety of amine substitutions at the 3‐position, the most common route is undoubtedly the N ‐functionalization of 3‐aminocoumarins,9 readily obtained from the reduction of 3‐nitrocoumarins 10 or by reaction of 3‐bromocoumarins with sodium azide under copper catalysis 11. An alternate route includes the condensation of salicylaldehydes with glycine derivatives 12,9a.…”

Organocatalyzed Enantioselective Michael Addition of 2‐Hydroxypyridines and α,β‐Unsaturated 1,4‐Dicarbonyl Compounds

“…[33] Compound 43 was prepared after converting the bromo-substituent of 42 to the amino-and then isoxazole-3-carboxamido-group. [34] Conclusion In summary, chiral N-substituted 2-pyridones were prepared by an enantioselective organocatalytic Michael reaction for the first time. The reaction condition is mild and easy to execute (10 mol% catalyst, 20°C, 48 h).…”

“…[33] Compound 43 was prepared after converting the bromo-substituent of 42 to the amino-and then isoxazole-3-carboxamido-group. [34]…”