Derivative of 1-phenyl-1,4-dihydro-3-hydroxy-4-oxopyridazine, its preparation and its application for therapy

PURPOSE: To obtain a new compd. useful for therapy of anxiety, asthma, rheumatoid inflammation, inflammatory diseases of digestive organs or colon and psoriasis. CONSTITUTION: This is a compd. of formula I [wherein X is a single or plural group selected from a 1-4C alkyl, an oxy-1-4C alkyl, a halogen and CF 3 ; R 1 is H or a 1-3C alkyl; R is H, a 1-4C alkyl or alkenyl, a 1-4C acyl, or formula II (in which (n) is 2-4; each of R 2 and R 3 is H, a 1-4C alkyl, a 1-4C alkylphenyl in which an aromatic nucleus may be substituted with a 1-3C alkyl, an oxy-1-3C alkyl, a halogen or CF 3 , or a methylaryl in which the aryl is 2-, 3- or 4-pyridyl or 2-quinolinyl)], such as 1-meta-trifluoromethylphenyl-1,4-dihydro-3-hydroxy-4- oxo-6-methyl-pyridazine. The compd. is obtained by treating a compd. of formula III with sodium nitrite in hydrochloric acid to obtain the compd. in which R is H, and then allowing the resultant compd. to react with a compd. of the formula RX (wherein X is a halogen). COPYRIGHT: (C)1993,JPO