Synthesis and evaluation of in vitro antiviral activity of novel phenoxy acetic acid derivatives

Several substituted phenoxy acetic acid derived pyrazolines were synthesized by the reaction between 2-4-[3-(2,4-dihydroxyphenyl)-3-oxo-1- propenyl]-2-methoxyphenoxy acetic acid and substituted acid hydrazides and were tested for their in vitro cytotoxicity and antiviral activity. None of the compounds showed any specific antiviral activity [50% antivirally effective concentration (EC50) ≥ 5-fold lower than minimum cytotoxic concentration]. The most cytotoxic of the series was 2-4-[3-(2,4-dihydroxyphenyl)-1-(2- hydroxybenzoyl-4,5-dihydro-1H-5-pyrazolyl]-2-methoxyphenoxyacetic acid (3j), with a minimum cytotoxic concentration of 0.16 μg/mL in human embryonic lung (HEL) cells.