Nissan Chemical Industries Limited

Mitsuaki Hirotsuka

Keizo Tanikawa

Ken-ichi Shikada

Akira Saito

Takehisa Iwama

Yoshimasa Kamikawaji

Yoichiro Fujita

Akiko Yamamoto

Benzimidazole compound

A 3(2H)-pyridazinone derivative of the formula (I) its salt, a process for its production and a pharmaceutical composition containing it. ##STR1## wherein each of R.sup.1, R.sup.2 and R.sup.3 which are independent of one another, is a hydrogen atom or a C.sub.1-4 alkyl group, X is a chlorine atom or a bromine atom, Y.sup.1 is a hydrogen atom, a halogen atom, a nitro group, an amino group or a C.sub.1-4 alkoxy group, Y.sup.2 is a hydrogen atom, a halogen atom, a hydroxyl group, a C.sub.1-4 alkyl group or a C.sub.1-4 alkoxy group, A is a C.sub.1-5 alkylene chain which may be substituted by a hydroxyl group, B is a carbonyl group or a methylene chain which may be substituted by a C.sub.1-4 alkyl group, and each of R.sup.4 and R.sup.5 which are independent of each other, is a C.sub.1-4 alkyl group, or R.sup.4 is a hydrogen atom and R.sup.5 is --Z--Ar (wherein Z is a C.sub.1-5 alkylene chain, and Ar is an aromatic 6-membered ring which may contain a nitrogen atom), or R.sup.4 and R.sup.5 together form a C.sub.2-6 cyclic alkylene group, or R.sup.4 and R.sup.5 form together with the adjacent nitrogen atom a 4-substituted piperazine ring of the formula: ##STR2## wherein R.sup.6 is a C.sub.1-4 alkyl group.

Pyridazinone derivatives with pharmaceutical activity

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Funabashi, Japan

Mitsuaki Hirotsuka