Synthesis and Antimicrobial Activities of Some New 3-(Chlorophenylethyl)-, 3-(Chlorophenylethenyl)-Isocoumarins and their Dihydro Derivatives

The bioactive 3-(chlorophenylethyl)- and 3-(chlorophenylethenyl)-isocoumarins were synthesized by the condensation of simple homophthalic acid with 3-chlorophenylpropionoyl chlorides and chlorocinnamoyl chlorides, respectively. Alkaline hydrolysis of these isocoumarins gave the respective keto-acids. (dl)-3,4-Dihydroisocoumarins were obtained by the reduction of the keto-acids to racemic hydroxyl-acids, followed by cyclodehydration using acetic anhydride. These compounds were tested for their antimicrobial and cytotoxicity (Brine shrimp lethality) bioassay. Bioassay indicated that some compounds show good antimicrobial activities and positive lethality.