NOVEL BENZIMIDAZOLE DERIVATIVE, ITS PREPARATION AND PHARMACEUTICAL COMPOSITION THEREOF

摘要

NEW MATERIAL:A compound of formulaI[R<1> is lower alkyl, lower alkenyl, lower alkynyl or aryl; R<2> is H or lower alkyl; (n) is 2 or 3]and a salt thereof. EXAMPLE:1-[2-( Propargyloxy )ethyl]-2-( 4-methylhomopiperazino)benzimidazole difumarate. USE:An antihistaminic agent, exhibiting a strong antagonistic action on histamine, and useful for preventing and treating various allergic diseases due to the histamine with low toxicity. PROCESS:A novel substance of formula II is reacted with a compound of formula III or a compound of formula IV (R<4> is a protecting group easily eliminative by the catalytic reduction or acidic or basic conditions or lower alkyl) is reacted with a compound of formula V (X is halogen), and the protecting group is then eliminated to give the compound of formulaIwhen R<4> is the protecting group.