Pyridazinone derivatives and the preparation thereof.

摘要

Novel 3(2H)-pyridazinone derivatives which, in their free acid form, are 4-halogenated-5-mercapto-3(2H)-pyridazinones having a straight or branched C2 to C6 alkyl substituent in the 2-position of their structure. These products are made by interaction of a corresponding 4,5-di-halogenated-3(2H)-pyridazinone with a hydrosulfide, preferably in aqueous solution. The direct product of this interaction is usually a salt, from which the free acid form can be obtained by acidification. The products are useful as intermediates for the production of insecticidal, acaricidal, nematicidal and fungicidal products for agricultural and horticultural use. Preferred compounds are 2-tertiary-butyl-4-chloro-5-mercapto-3(2H)-pyridazinone and 3-tertiary-butyl-4-bromo-5-mercapto-3(2H)-pyridazinone.