Synthesis of 1-alkyl-3-dialkylaminoalkylamine[1]benzo-thieno[2,3-b]pyrazin-2(1H))-ones and their ability to antagonize KCl-induced contractions

Summary A series of 1-alkyl-3-dialkylaminoalkylamino[1]benzothieno[2,3- b ]pyrazin-2(1 H ))-ones 5 was synthes was synthesized. Some of these compounds showed appreciable inhibition towards KCl-induced contractions in isolated rat aortic rings. The results obtained showed that, although this activity appears at higher concentrations than with caroverine, used as reference standard, this new tricyclic system could be considered as a nucleus with potential calcium antagonistic activity.