Synthesis, biological activity and electron impact of mass spectra of trisubstituted-2-thiohydantoins

3-[1-(2-Hydroxyphenyl)ethylideneamino]-2-thiohydantoin (2) was prepared via cyclization of 2-hydroxyacetophenone thiosemicarbazone (1) with ethyl chloroacetate in the presence of fused sodium acetate. The chemical behaviour of 2 towards acetic anhydride, arenediazonium chloride, aromatic aldehydes and hydrazine hydrate is described. The electron impact ionization mass spectra of compounds 2 and 3 show a strong molecular ion peak and a base peak of m/z 232 resulting from cleavage fragmentation. The molecular ion of compounds 4a, 4b, and 8 is a base peak of m/z 353,387 and 288, respectively. In contrast, compounds 5a and 5b show a base peak at m/z 336 and 370 resulting from fragmentation. Compounds 6a,b and 7a,b give a characteristic fragmentation pattern with a very stable fragment of m/z 326 and 350, respectively. Some of the synthesized compounds also exhibited antimicrobial activities.