Water-soluble phenylpyridazine compounds and compositions containing the same

A phenylpyridazine compound having the formula (1):

• 47
• wherein:
• R1 is optionally substituted alkyl, or optionally substituted alkenyl;
• R2 and R3 each independently represents hydrogen or an alkyl, hydroxyalkyl, dihydroxyalkyl or alkynyl, or R2 and R3 are fused together with the adjacent nitrogen atom to form an optionally substituted, nitrogen-containing, saturated heterocyclic group;
• X, Y and Z each independently represents hydrogen or halogen, optionally substituted alkyl, alkoxy, alkylthio, alkylsulfinyl or alkylsulfonyl, or optionally substituted aryl;
• and
• n stands for a number of from 1 to 5;
• with the proviso that R2 and R3 are not hydrogen or the same C1-C3 alkyl groups at the same time when R1 is a benzyl group or a C1-C3 alkyl group;
• or a salt thereof