A facile protocol for the preparation of 5-alkylidene and 5-imino substituted hydantoins from N,N′-disubstituted parabanic acids

[3+2]-Cycloaddition of Nitrile Imines to Parabanic Acid Derivatives—An Approach to Novel Spiroimidazolidinediones

“…In many publications, data on the formation of isomeric products I and II ( Scheme 2 ) as a result of the reaction of diphenyl thiourea and oxalyl chloride were presented implicitly [ 17 , 21 , 22 ], and we could not find a clear methodology that allows us to obtain exclusively isomer II . By conducting reactions of various thioureas with oxalyl chloride, we found that a thiazolidine-type product ( I ) was formed very easily.…”

“…In a recent work by S.H. Ungoren [ 17 ], it has been shown that the interaction of N,N-disubstituted parabanic acids with aryliminophosphoranes leads to the formation of 5-imino-substituted hydantoins with a good yield. Among the data available in the literature on the chemical properties of 5-substituted hydantoins in the 1,3-dipolar cycloaddition reactions, we found no examples of the interaction of some 1,3-dipoles and an exocyclic bond C=N of such compounds.…”

Green Synthesis of 1,3‐Dibenzylimidazolidine‐2,4,5‐triones by Oxidation of Hexabenzylhexaazaisowurtzitanes

“…H 2 O 2 /AcOH mixture is equivalent to peracetic acid which is a strong and benign oxidizing agent. The advantages of this procedure over previously reported ones (which have made use of an unsafe reagent such as oxalyl chloride or the highly toxic trimethylsilyl chloride ) are that it is highly efficient and sustainable using a cheap, easily available, green, and non‐toxic environmentally friendly reagent for defragmentation of HBIW and its derivatives. In short, while highly expensive 1,3‐dibenzylimidazolidine‐2,4,5‐trione has been previously prepared from urea and oxalyl chloride, it was shown that this compound and its analogues could be synthesized from corresponding HBIW derivatives.…”

“…Imidazolines are biologically active pharmacophores and synthetic intermediates in medicinal chemistry . Another member of this family is imidazolidine‐2,4,5‐trione (commonly known as parabanic acid) and its derivatives; they are used in preparation of alkylidene and imino‐substituted hydantoins by their reactions with Wittig reagents . Parabanic acid has a pronounced herbicidal action, controlling the growth of unwanted plants.…”

“…Although parabanic acid, the main skeleton of the titled compounds, is produced as a byproduct during synthesis of 1,1‐diamino‐2,2‐dinitroethylene (DADE) as an energetic material , few processes have been published for the preparation of substituted parabanic acid and its derivatives, for example, reaction of trimethylsilyl cyanide with aryl isocyanates and the reaction of urea derivatives with oxalyl chloride .…”