Abstract New, non-imidazole histamine H 3 receptor antagonists were prepared and in vitro tested as H 3 receptor antagonists measured as the electrically evoked contraction of the guinea-pig jejunum. The 2-(1-piperidinyl)-and 2-(1-pyrrolidinyl) benzothiazoles show no or very poor activity; 2-[1-(4-amino) piperidinyl]-and 2-(1, 2-ethanediamino)-and 2-(1, 3- propanediamino) derivatives of benzothiazole possess weak activity at H 3 receptors, ...
