The reaction of 5-(4-methoxyphenyl)furan-2,3-dione with urea in a 1:1 ratio when refluxed in a mixture of 1,2-dichloroethane-DMSO gives (Z)-N-carbamoyl-4-hydroxy-4-(4-methoxyphenyl)-2-oxobut-3-enamide in a good yield. This compound was fully characterized.

Literature data on the main preparative methods of synthesis of 5-arylfuran-2,3-diones have been considered. A new convenient protocol has been proposed for the synthesis of these compounds by heating 4-aryl-2,4-dioxobutanoic acids with acetyl bromide in anhydrous chloroform under reflux conditions. The structure of 5-(4-methoxyphenyl)furan-2,3-dione has been confirmed by X-ray analysis.

The description of preparative methods for the synthesis of 5- arylfuran- 2,3- diones by known methods is given, and a new convenient method for the synthesis of 5- arylfuran- 2,3- diones is described. The synthesis was performed by refluxing 4- aryl- 2,4- dioxobutanio acid with acetyl bromide. The structure of 5- (4- methoxyphenyl)furan- 2,3- dione is confirmed by X- ray.

5-Arylfuran-2,3-diones reacted with an equimolar amount of urea to give the corresponding aroylpyruvic acid ureides, (Z)-4-aryl- N-carbamoyl-4-hydroxy-2-oxobut-3-enamides which cyclized in DMSO solution to 5-(2-aryl-2-oxoethyl)-5-hydroxyimidazolidine-2,4-diones. The latter underwent dehydration in boiling acetic acid with the formation of 5-(2-aryl-2-oxoethylidene)imidazolidine-2,4-diones (hydantoins). The structure of the synthesized compounds was confirmed by X-ray analysis. Some derivatives exhibited antifungal activity against phytopathogenic fungi and are promising in terms of other kinds of biological activity.

The reaction of 5-(p-tolyl)furan-2,3-dione with thiourea in a 1:1 ratio when refluxed in 1,4-dioxane gives (Z)-N-carbamothioyl-4-hydroxy-2-oxo-4-(p-tolyl)but-3-enamide with a good yield. This compound was fully characterized.

The description of preparative methods for the synthesis of 5- arylfuran- 2,3- diones by known methods is given, and a new convenient method for the synthesis of 5- arylfuran- 2,3- diones is described. The synthesis was performed by refluxing 4- aryl- 2,4- dioxobutanio acid with acetyl bromide. The structure of 5- (4- methoxyphenyl)furan- 2,3- dione is confirmed by X- ray.