Process for producing antifungal oyridazinone derivatives

Abstract

Compounds of formula (I): ##STR1## [wherein R.sup.1 and R.sup.3 represent hydrogen or halogen atoms, R.sup.2 represents a hydrogen or halogen atom or a lower alkyl or alkoxy group (provided R.sup.1, R.sup.2 and R.sup.3 are not simultaneously hydrogen), represents a single or double carbon-carbon bond and, where it is a single bond, R.sup.4 represents a group of formula --SR.sup.5 (wherein R.sup.5 represents an optionally substituted alkyl, phenyl, aralkyl or pyridyl group or a lower alkenyl group) and, where it is a double bond, R.sup.4 represents hydrogen] can be prepared by reacting a compound of formula (II): ##STR2## with a compound of formula R.sup.6 H [where R.sup.6 represents a group --SR.sup.5, a group --SR.sup.7 (where R.sup.7 represents a group of formula ##STR3## and Y represents oxygen or sulphur, R.sup.8 and R.sup.9 represent lower alkoxy groups and R.sup.10 represents a lower alkoxy, lower alkyl or phenyl group), a methoxy group or a halogen atom] to give a compound of formula (IV): ##STR4## or, where R.sup.6 represents a methoxy group, a methyl ester thereof; reacting this compound with hydrazine to give a compound of formula (V): ##STR5## and, if necessary, treating the compound of formula (V) with an acid or a base to produce the compound of formula (VI). All of the compounds of formula (I) are valuable antifungal agents and compounds of formula (V) where R.sup.6 represents a group of formula --SR.sup.5 are novel compounds.