Facil and one-pot synthesis of novel N-alkylated derivatives of S-lactic hydrazones under green conditions and study of their antibacterial properties

A new family of N-alkylated derivatives of S-lactic hydrazones have been synthesized under solvent-free and ambient temperature. Products furnished by a one-pot and three-component reaction of S-lactic hydrazide, various benzaldehydes, and acrylic esters in the presence of tetrabutylammonium bromide (TBAB) and 1,4-diaza-bicyclo[2,2,2]octane (DABCO). Not using of organic solvents during this reaction was an important feature that led to develop an economic approach. The reaction was failed with fumaric esters owing steric effects. Also, the investigation of the position of hydroxyl group in S-lactic hydrazones indicated that the OH group in S-lactic hydrazide is responsible to reduce the time reaction. N-alkylated S-lactic hydrazone 5a was crystallized and single crystal-XRD structure analysis was performed. This result, together with other NMR spectroscopic data analysis, allowed precisely confirm the structure of this compound. The structure of other products were determined by 1H NMR, 13C NMR, CHN, and IR spectral data. Additionally, according to the analysis of the products’ antibacterial activity, some compounds exhibit antibacterial properties.