Biological effect of some new pyridazine derivatives on wheat in germination experiments

Abstract

Pyridazine  compounds  have  an  intense  biological  activity,  being  used  as  anticancer, antituberculosis,  antihypertensive,  antifungal,  or  antimicrobial  agents.  Nevertheless,  some  of  them might  be  noxious  persistent  compounds  to  the  environment.  Therefore,  several  studies  to  test  the biologic effect of some new pyridazine derivatives have been done using simple experiments of wheat germination. The germination percentage, shoot and root length, fresh weights, as well as free amino acid  content  varied  as  a  function  of  concentration  and  structure  of  each  investigated  compound. Triplicate of 50­seed samples of wheat were treated with 5∙10 –3 molar solutions of both pyridazinium bromides  (2a­c)  and  the  corresponding  cycloadducts  (4­9)  for  1  hour.  After  a  7­day  period  of germination  in  the  presence  of  the  investigated  compound,  the  wheat  plantlets  were  cut  from  the seeds. The total height (H) of the lots and the weight (W) of the seedlings, as well as the free amino acids were measured. Among the pyridazine derivatives, the fluorine­containing 6a proved to be the most toxic, whereas another fluorinated compound, 9a, exhibited even a slight stimulatory action on the  germination  process.  All  the  other  tested  compounds  displayed  a  large  variety  of  biological activities.