Formation of 1‐(2‐hydroxyphenyl)‐4‐ and 4,5‐substituted 4‐imidazolin‐2‐ones in the reaction of 3‐[2(hydroxyimino)alkyl]‐2‐benzoxazolones with sodium dithionite

Methods for the synthesis of 1-substituted 1H-imidazol-2(3H)-ones

“…[100][101][102] The interaction of 4,5-diphenyloxazol-2(3H)-one (66a) with primary amines 13 gave the respective 1-substituted 4,5-diphenyl-1H-imidazol-2(3H)-ones 1, with subsequent formation of intermediates AK and AL (Scheme 75). 100 When benzyl-and cyclohexylamines 13f,g were used in the reaction, small amounts of N,N'-disubstituted ureas 4c,d were also isolated from the reaction mixture, apparently formed by transamination of the intermediate β-oxourea AK.…”

“…102 It was assumed that the oxime 67 was initially reduced to imine АP. The intermediate AP could not be isolated, as it underwent a rapid recyclization by nucleophilic attack of imino group at the carbonyl carbon with cleavage of the С(2)-О bond in the oxazole ring.…”

Oximes of five-membered heterocyclic compounds with two heteroatoms 2. Reactions and biological activity (Review)

“…The reaction of benzoxazoline oximes 100 with Na 2 S 2 O 4 in 1% aqueous sodium hydroxide leads to the formation of the imidazolines 101 with yields of 50-89%[140].…”

3-(2-Oxopropyl)-2(3H)-benzoxazolone

“…The title compound is an important intermediate for the preparation of 3,4-and 3,4,5-substituted 1-(2-hydroxy-phenyl)imidazolin-2-ones [1,2] and 6-methyl-4-(2-hydroxyphenyl)-1,2,4-triazin-3-ones [3]. According to literature data, the product 3 is prepared from 2(3H)-benzoxazolone with commercially unavailable bromoacetone in abs.…”