Esters, amides and substituted derivatives of cinnamic acid: synthesis, antimicrobial activity and QSAR investigations.

A series of esters (I(a-k)), substituted derivatives (II(a-d)) and amides (III(a-q)) of cinnamic acid were synthesized and evaluated as antibacterial and antifungal agents. All the derivatives belonging to the series I, II and III showed antimicrobial activity comparable to the standard. Compounds I(f) and II(c) proved to be the most effective compounds. Quantitative structure-activity relationship (QSAR) investigation with multiple linear regression analysis was applied to find a correlation between different calculated physicochemical parameters of the compounds and biological activity. The quantitative models relating the structural features of cinnamic acid derivatives I(a-k), II(a-d) and III(a-q) and their antimicrobial activity showed that Gram negative Escherichia coli and Candida albicans (fungus) were the most sensitive microorganisms.