Carbostyril derivatives, process for producing the same and cardiotonic compositions containing the same

摘要

Novel carbostyril derivatives and their pharmaceutically acceptable salts represented by the formula (I) <IMAGE> wherein R1 is a hydrogen atom, a lower alkyl group, a lower alkenyl group, a lower alkynyl group or a phenyl-lower alkyl group; R2 and R3 may be the same or different and each is a lower alkyl group which may have one hydroxy group or one halogen atom as the substituent, or a phenyl-lower alkyl group which may have 1 to 3 substituents selected from the group consisting of a lower alkoxy group and a halogen atom on the phenyl ring, or said phenyl-lower allkyl group may have a lower alkylenedioxy group as the substituent on the phenyl ring; further R2 and R3 may form, together with the adjacent nitrogen and without an additional hetero-atom, a 5-or 6 membered saturated heterocyclic ring which may have a lower alkyl group or a phenyl-lower alkyl group as the substituent; the carbon-carbon bond between 3- and 4-positions in the carbostyril skeleton being a single or double bond. The derivatives are useful as the active ingredient in cardiotonic compositions.