New 1,3-diaryl-5-thioxo-imidazolidin-2,4-dione derivatives: synthesis, reactions and evaluation of antibacterial and antifungal activities

New cyanothioformamide derivative 1 was prepared by treatment of 3,5-dichlorophenyl isothiocyanate with potassium cyanide at room temperature. Cycloaddition of cyanothioformamide 1 with phenyl isocyanate as electrophile furnished the corresponding imidazolidine 2. Imine hydrolysis of 2 with ethanolic HCl produced the corresponding 4-thioxo-2,5-imidazolidinedione 3. This compound was used as key synthon for the preparation of a wide variety of new substituted imidazole compounds. Condensation of 3 with different types of hydrazine derivatives furnished new series of hydrazone 4a, b, thiosemicarbazone 5a, b and cyanoacetohydrazide 6 derivatives incorporating imidazolidine moiety. Finally, cyanoacetohydrazide 6 was used as intermediate for synthesizing new compounds. Evaluation of the antibacterial and antifungal activities for the synthesized compounds was carried out to probe their activities. Most of the tested compounds showed significant activities. The dione derivative 3 and the imidazolidine derivative 9a, which incorporates a chromene moiety, exhibited high activity near the reference drug against all tested organisms.