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In connection with our studies on antibacterial active compounds in the class of new oxazolidinones against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) strains, some molecular modifications were attempted. In this study, molecular modifications of 4-aminomethyloxazolidin-2-ones (3a) to the corresponding 4-acylaminomethyloxazolidin-2-one derivatives (3c–d) and preparations of the represented twin-drug type molecules (10–14) were investigated. Some additional 4-dialkylaminomethyloxazolidin-2-ones (2) were also synthesized. The synthesized compounds were evaluated for antibacterial activity with Gram-positive (S. aureus) and Gram-negative (E. coli) strains.

New 5-substituted hydantoins (III) and (IV) and symmetrical twin-drug type hydantoin derivatives (VII) are synthesized.

In connection with our studies on antibacterial active compounds in the class of new oxazolidinones against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) strains, some molecular modifications were attempted. In this study, molecular modifications of 4-aminomethyloxazolidin-2-ones (3a) to the corresponding 4-acylaminomethyloxazolidin-2-one derivatives (3c–d) and preparations of the represented twin-drug type molecules (10–14) were investigated. Some additional 4-dialkylaminomethyloxazolidin-2-ones (2) were also synthesized. The synthesized compounds were evaluated for antibacterial activity with Gram-positive (S. aureus) and Gram-negative (E. coli) strains.

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.

An efficient procedure for the preparation of 5-dialkylaminomethylhydantoins 3, which are easily obtained from cyclization of the corresponding urea derivatives 2 starting with beta-aminoalanines 1, is described. Methylenehydantoin and the corresponding 2-thio analogue (4a, 4b) were obtained from hydantoins 3a and 3b, respectively. Some new chemical properties of these hydantoin derivatives are reported.

Novel benzamide derivatives, N-[1-(aminocarbonyl)-2-(1-piperidinyl)ethyl]benzamides (4 and 5), were prepared from the reaction of β-piperidinoalanine (6) as the starting material.

New oxazolidin-2-ones (3), which mimic the clinically useful antibacterial agent (1) (Linezolid) were prepared by using a cyclization procedure with diethyl carbonate from aminoalcohol (7) starting with DL-serine methyl ester hydrochloride (4) and aromatic carboxylic acid derivatives (5).

The preparation of amide derivatives (4) by N-acylation of unprotected alpha-amino acids is easily achieved via readily available benzotriazolyl carboxylates (2a-d) or succinimidyl carboxylates (2e-f). These intermediates (2) are prepared from reaction of carboxylic acids (1) with 1-hydroxybenzotriazole (HO-Bt) or N-hydroxysuccinimide (HO-Su) in the presence of equimolar amounts of 1-ethyl-3-(3'-dimethylaminopropyl)carbodiimide hydrochloride (WSCI). The overall yields of the target compounds (4) were excellent, and this two-stage procedure could be applicable as an alternative procedure for one-pot reaction.

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 β-aminoalanine derivatives (1) as the key starting materials.