Patent GB-880015-A (GB)
Title: New tetrahydro-dioxopyridazines and process for their manufacture
IPC: C07D403/04
Filed: 1958-03-31
Abstract: The invention comprises 1-phenyl-3,6-dioxo-1,2,3,6-tetrahydropyridazines which contain in the 2-position a C1-6 alkyl group and in the 4-position a free or substituted amino group (especially a di-C1-6 alkyl-amino, pyrrolidino, piperidino, morpholino or piperazino group) and in which the phenyl radical is unsubstituted or is mono-substituted by a halogen atom, a C1-6 alkyl or alkoxy radical or a nitro or free amino group, the acid addition salts of such of these compounds as are basic, and quaternary ammonium compounds derived from such of them as are tertiary amines (but excluding 1-phenyl - 2 - methyl - 4 - dimethylamino - 3,6 - dioxo-1,2,3,6-tetrahydropyridazine and its acid addition salts); the preparation of the foregoing compounds by the action of ammonia or a primary or secondary amine on the corresponding compounds not containing the 4-amino substituent but containing a halogen atom in the 4- or 5-position, followed, if desired, by reduction of any nitro substituent in the 1-phenyl radical to NH2 and/or conversion of a resulting tertiary amine into a quaternary ammonium compound and/or a resulting base into an acid addition salt or a resulting acid addition salt into the free base; and pharmaceutical preparations containing the products (see Group VI).  In the preparation of the compounds, the amino group enters the 4-position irrespective of the position of the halogen atom it replaces, and it is also possible to combine this replacement with the preparation of the starting material, by reacting excess of the amine or ammonia with a 1-phenyl-4,5-dihalo-3,6-dioxo-1,2,3,4,5,6-hexahydropyridazine. Specification 880,016 is referred to.ALSO:Pharmaceutical preparations, useful as antipyretic, analgesic and sedative-hypnotic agents, comprise, in association with an inert pharmaceutical carrier, 1 - phenyl - 3,6 - dioxo - 1,2,3,6-tetrahydropyridazines which contain in the 2-position a C1-6 alkyl group and in the 4-position a free or substituted amino group and in which the phenyl radical is unsubstituted or is monosubstituted by a halogen atom, a C1-6 alkyl or alkoxy radical or a nitro or free amino group, or the acid addition salts (e.g. hydrohalides, sulphates, nitrates, phosphates, thiocyanates, acetates, propionates, oxalates, malates, citrates, tartrates, benzoates, methane-, ethane-, hydroxyethane-, benzene- or toluene-sulphonates, salicylates or p-aminosalicylates) of such of these compounds as are basic, or quaternary ammonium compounds (e.g. halides, sulphates or arylsulphonates) derived from such of them as are tertiary amines (but excluding 1-phenyl-2-methyl - 4 - dimethylamino - 3,6 - dioxo - 1,2,3,6-tetrahydropyridazine and its acid addition salts).  The preparations may take the form of tablets, dragees, salves, creams, solutions, suspensions or emulsions.  They may be sterilized and/or may contain preserving, stabilizing, wetting or emulsifying agents, salts for regulating the osmotic pressure, buffers, or other therapeutically valuable substances (e.g. antibacterial or antivirus substances). Specification 880,016 is referred to.