Thiadiazole derivative, process for producing it and agricultural and horticultural fungicide using it as an active ingredient

A 1,2,5-thiadiazole derivative represented by the following formula [III]:

• ##STR11## wherein X and Y are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, a nitro group, a trifluoromethyl group, a carboxyl group, an alkoxycarbonyl group having from 2 to 5 carbon atoms, a naphthyl group or a tetrahydronaphthyl group;
• and
• A represents an alkyl group having from 1 to 6 carbon atoms, --C(.dbd.O)OR.sup.1, --C(.dbd.O)NR.sup.2 R.sup.3, a phenyl group which may be substituted by at least one of an alkyl group having from 1 to 6 carbon atoms and an alkoxy group having from 1 to 4 carbon atoms, --CHR.sup.4 C(.dbd.O)R.sup.5 or --C(.dbd.O)R.sup.6,
• in which R.sup.1 represents an alkyl group having from 1 to 6 carbon atoms;
• R.sup.2 and R.sup.3 are the same or different and each represents a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms;
• R.sup.4 represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms;
• R.sup.5 represents an alkoxy group having from 1 to 4 carbon atoms or an amino group which may be substituted by at least one of an alkyl group having from 1 to 4 carbon atoms and a phenyl group which may be substituted by at least one halogen atom;
• and
• R.sup.6 represents an alkyl group having from 1 to 6 carbon atoms.

An agricultural and horticultural fungicide comprising a 1,2,5-thiadiazole derivative represented by the following formula [III] as an active ingredient:

• ##STR12## wherein X and Y are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, a nitro group, a trifluoromethyl group, a carboxyl group, an alkoxycarbonyl group having from 2 to 5 carbon atoms, a naphthyl group or a tetrahydronaphthyl group;
• and
• A represents an alkyl group having from 1 to 6 carbon atoms, --C(.dbd.O)OR.sup.1, --C(.dbd.O)NR.sup.2 R.sup.3, a phenyl group which may be substituted by at least one of an alkyl group having from 1 to 6 carbon atoms and an alkoxy group having from 1 to 4 carbon atoms, --CHR.sup.4 C(.dbd.O)R.sup.5 or --C(.dbd.O)R.sup.6,
• in which R.sup.1 represents an alkyl group having from 1 to 6 carbon atoms;
• R.sup.2 and R.sup.3 are the same or different and each represents a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms;
• R.sup.4 represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms;
• R.sup.5 represents an alkoxy group having from 1 to 4 carbon atoms or an amino group which may be substituted by at least one of an alkyl group having from 1 to 4 carbon atoms and a phenyl group which may be substituted by at least one halogen atom;
• and
• R.sup.6 represents an alkyl group having from 1 to 6 carbon atoms.