The synthesis of new methyleneoxyamino derivatives of 1-propylthioheptane via the condensation of 1-propanethiol, secondary amines, and formaldehyde was performed. The structure of the synthesized compounds was established by elemental analysis and IR and (1)H NMR spectroscopy. The compounds were tested as antimicrobial additives for lubricating oils; it was found that they effectively suppress the vital activity of microorganisms.