Synthesis of 3-Substituted 2,1-Benzisoxazoles by the Oxidative Cyclization of 2-Aminoacylbenzenes with Oxone

Abstract

An efficient approach to the synthesis of 2,1-benzisoxazoles through direct construction of the N–O bond by the chemoselective oxidation of 2-aminoacylbenzenes with Oxone is described. This alternative methodology is characterized by its simple and transition-metal-free conditions and good functional group compatibility utilizing Oxone as a green oxidant instead of hypervalent iodine compounds. Moreover, this new procedure simplifies the number of steps compared to the previously reported procedure by circumventing the use of 2-azido-substituted aryl ketones

On Route to Diverse Nitrogen‐Bridged Polyhetero‐cycles with an N(acyl), N(aryl)‐acetal Core

“…2‐cyanobenzaldehyde 1 and anilines 2 a‐c were commercially available and used without further purification. Anilines 2 d , [27] 2 e , [28] 2 f , [ 29] 2 g , [30] 2 h , [31a] 2 i , [31b] 2 j , [31c] 2 k , [31d] and 2 l [31b] were prepared according to the reported procedures and gave spectra and analytical data as reported.…”

Advances in transition metal-catalyzed C–H amination strategies using anthranils

“…The protocol worked with a variety of anthranils with both N-benzoylpyrrolidines and isoquinolone derivatives. The presence of a free halogen-atom was beneficial for further transformation (25)(26)(27).…”

“…25 (v) Recently, Arcadi and co-authors reported a chemoselective oxidation cyclization of 2-aminoacyl benzene with oxones for the synthesis of 3-substituted anthranils. 26…”

Formation of Synthetically Versatile 2-Aminobenzophenones from Readily Accessed Acyl Hydrazides

“…Compounds bearing this structure have displayed desirable pharmacological use as antimitotic, 1 antitumor, 2 and antiproliferative 3 agents, as well as skeletal muscle relaxants. 4 2-Aminobenzophenones are also useful starting materials for the synthesis of a wide variety of fine chemicals such as acridones, 5 quinolines, 6−8 quinazolines, 9−11 quinolinones, 12 quinoxalinones, 13 fluorenones, 14 benzisoxazoles, 15 indazoles, 16 indoles, 17 2-quinazolinones, 18 benzothiophenes, 19 diaryldibenzodiazocines, 20 and (perhaps most noteworthy) benzodiazepines. 21−24 As such, various methodologies for the synthesis of 2-aminobenzophenones and their derivatives have been developed, including (i) Friedel–Crafts acylation of para-substituted anilines; 25,26 (ii) reaction of 2-aminobenzaldehydes with aryl Grignard reagents followed by oxidation with CuCl 2 ; 27 (iii) Pd-catalyzed addition of arylboronic acids 28 or sodium arylsulfinates 29 to 2-aminobenzonitriles; (iv) Pd-catalyzed C–H bond coupling of ortho-directed anilines; 30 and (v) aryl insertion into the C–N of amides 31 or imides.…”