Birch, Stewart, Kolasch & Birch
6-acylaminophenyl-5-alkyl-4,5-dihydro-3(2H)-pyridazinone compounds useful as blood pressure depressants, antithrombotic agents and in the treatment of heart disease
 This invention relates to pyridazinone derivatives of the general formula: ##STR1## [wherein R.sup.1 stands for a hydrogen atom or a lower alkyl group; R.sup.2 for a hydrogen atom or a lower alkyl group; and A for (i) a ring selected from a benzene ring, a furan ring, a thiophene ring and a pyridine ring (on which ring 1-3 substituents or atoms selected from amino groups, nitro groups, lower alkanoylamino groups, hydroxyl groups, lower alkanoyloxy groups, sulfamoyl groups and halogen atoms may be present), or (ii) a grouping of the formula: ##STR2## (wherein R.sup.3 stands for a hydrogen atom, a lower alkyl group, a phenyl(lower)alkyl, a hydroxyphenyl(lower)alkyl group, a lower alkylmercapto(lower)alkyl group, a benzylmercapto(lower)alkyl group, a guanidino(lower)alkyl group, a nitroguanidino(lower)alkyl group, an indolyl(lower)alkyl group, a carbamoyl(lower)alkyl group or a carboxy(lower)alkyl group, R.sup.4 for a hydrogen atom or a lower alkyl group, R.sup.5 for a hydrogen atom, a lower alkyl group, a lower alkanoyl group, a benzoyl or a benzyloxycarbonyl group, and R.sup.3 and R.sup.4 may be combined to form a grouping of the formula: ##STR3## which forms a ring), or (iii) a grouping of the formula: ##STR4## (wherein R.sup.6, R.sup.7 and R.sup.8 each stand for a hydrogen atom or a lower alkyl group, B is an oxygen atom or a sulfur atom, R.sup.9 stands for a hydrogen atom or a lower alkanoyl group, and n is 0 or 1)]. 
Mitsui Toatsu Kagaku Kabushiki Kaisha
C C C C C
C07D C07D C07D C07D C07D
inventional inventional inventional inventional inventional
Tsutomu Takuo Joji Hajime Takashi Yasuhito Nobuyuki
Katakami Nakano Kamiya Iizuka Nishina Tanaka Fukazawa