The synthesis of 5-chloro-3-pyridylmethylene-2-indolinone is reported.
This compound was subjected to an in vivo cardiotonic assay with 10 a
nalogs whose synthesis and in vitro cardiotonic activity were previous
ly reported. All the compounds tested (except the 5-hydroxyindole deri
vative) showed significant positive inotropic activity. The 3-pyridyl
derivative without substituents at the indole system was the most acti
ve of the whole series.