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In connection with our studies on antibacterial compounds in the class of 5-dialkylaminomethylhydantoins against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) strains, some molecular modifications were attempted. The antibacterial activities of all of the synthesized hydantoin derivatives were evaluated. Among the hydantoin derivatives designed in this study, C₂-symmetrical twin-drug type compound (7) showed the highest level of antibacterial activity against S. aureus strain.

To find new antibacterial leads in the class of hydantoin derivatives, we carried out synthetic investigation and biological evaluation of the title hydantoin derivatives and related compounds. Among the hydantoin derivatives described in this article, compound 3o, in which a 2,6-dichlorophenyl ring was introduced at the N-3 position of the hydantoin nucleus, showed the highest levels of antibacterial activity against both Escherichia coli NBRC14237 (NIHJ) and Staphylococcus aureus ATCC6538P (gram-negative and gram-positive bacteria, respectively) strains.

The closure by cyclization with diethyl carbonate (EtO)(2)CO from aminoalcohols 1 as starting material can lead to the oxazolidinones 2a, b and 2c, respectively. In the reaction of trans-isomer (6) and (EtO)(2)CO, isolated products were also only 5-membered oxazolidinone derivative (7), containing its dehydrated derivative 8. The preferential formation of the 5-membered oxazolidinone ring system apparently indicated that this process (5-Exo-Trig ring closure) is more favorable than that of 6- or 7-membered ring derivative (3 or 9) by 6- or 7-Exo-Trig ring closure.

A conventional new route to the novel oxazolidin-2-one derivatives (3a-f) having two substituents on N-3 and C-4 in the oxazolidin-2-one ring was established with racemic beta-aminoalanine derivatives (1) as the key starting materials.