Synthesis, antimicrobial evaluation and QSAR studies of propionic acid derivatives

A series of Schiff bases ( 1 – 17 ) and esters ( 18 – 24 ) of propionic acid was synthesized in appreciable yield and characterized by physicochemical as well as spectral means. The synthesized compounds were evaluated in vitro for their antimicrobial activity against Gram-positive bacteria Staphylococcus aureus , Bacillus subtilis , Gram negative bacterium Escherichia coli and fungal strains Candida albicans and Aspergillus niger by tube dilution method. Results of antimicrobial screening indicated that besides having good antibacterial activity, the synthesized compounds also displayed appreciable antifungal activity and compound 10 emerged as the most active antifungal agent (pMIC ca and pMIC an = 1.93). The results of QSAR studies demonstrated that antibacterial, antifungal and overall antimicrobial activities of synthesized propionic acid derivatives were governed by the topological parameters, Kier’s alpha first order shape index ( κα 1 ) and valence first order molecular connectivity index ( 1 χ v ).