4- imidazolidine-2,5-dione preparation

Preparation of 3-[5 -amino-(/Y-l-butyloxycarbonyl)- -pentanyl]-5-[(indol-3-yl) methyl]-imidazolidine 2,4-dione... 

Iinidazolidine-4,5-dione-2-thiones (26), also known as thioparabanic acids, can be prepared by beating thioureas with oxalyl chloride or diethyl oxalate. Cyanogen may also be used if the reactants are heated in the presence of acid. Stoffel and Ulrich and Sayigh have studied in detail the reaction of thioureas with oxalyl chloride and were able to isolate intermediate thiazolidine-4,5-diones (25) which on heating rearranged to the imidazolidine-4,5-dione-2-thiones (26). Thus, in the mechanism proposed by Stoffel, initial attack of the oxalyl chloride is on sulfur to form 24, which can cyclize to 25. Further heating then eauses rearrangement of 25 to 26. 

The same group prepared N-(/S-D-glucopyranosyl)oxazolidine-2,4-diones [146] and N-(/l-D-glucopyranosyl)imidazolidine-2,4-diones [147] by desulfurization-condensation of glucosyl isothiocyanate with a-hydroxyacids and J -substituted a-aminoacids, respectively, in the presence of silver triflu-oroacetate and triethylamine. 4-Glucosyl-l,2,4-oxadiazolidine-5-thiones were also prepared by reaction of protected glucosyl isothiocyanates with an ox-aziridine ring [148]. 

Imidazolidine-2,4-diones, generally called hydantoins, are prepared when urea and N-substituted ureas are used instead of amides in the amidocarbonylation. Carbonylation of cyclohexanecarboxaldehyde, and A,A-dimethylurea (4) in NMP using PdBr2 and PPh3 in the presence of LiBr and H2SO2 afforded the hydantoin 5 in 80% yield [3]. 

In a related piece of work, imidazolines have been prepared from A -chloro-N-phenyl amidines and enamines. (Scheme 79). Pyrazomycins have been synthesized by the Roche group, the key step being the preparation of the pyrazolone ring by the addition of toluene- -sulphonyl azide to the anion from diethyl acetone dicarboxylate (Scheme 80). Imidazolidines (201) have been prepared by the action of isocyanates and isothiocyanates with an aziridine ester a dipolar intermediate is implicated. Imidazolidine-4,5-diones have been prepared by the... 

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