Heterocyclylbenzonitriles

A heterocyclylbenzonitrile of formula (I) ##STR72## in which R.sup.1 represents hydrogen or halogen,

• R.sup.2 represents hydrogen, or represents formyl, or represents alkyl, alkenyl, alkinyl, alkoxy, alkylcarbonyl, alkoxycarbonyl or alkylsulphonyl having in each case 1 to 6 carbon atoms and which may be substituted in each case by halogen, cyano, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.4 -alkoxy-carbonyl, or represents cycloalkyl, cycloalkylalkyl, cycloalkylcarbonyl or cycloalkylsulphonyl having 3 to 6 carbon atoms in the individual cycloalkyl moieties and, which may have 1 to 4 carbon atoms in the alkyl moiety and which may be substituted in each case by halogen, cyano or C.sub.1 -C.sub.4 -alkyl, or represents phenylmethyl, phenylcarbonyl, naphthylcarbonyl, phenylmethylcarbonyl, phenoxycarbonyl, phenylsulphonyl, naphthylsulfonyl or phenylmethylsulphonyl, which may be substituted in each case by halogen, cyano, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -halogenoalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -halogenoalkoxy or C.sub.1 -C.sub.4 -alkoxycarbonyl,
• R.sup.3 represents alkyl, alkenyl or alkinyl having in each case 1 to 10 carbon atoms and which may be substituted in each case by halogen, cyano or C.sub.1 -C.sub.4 -alkoxy, or represents cycloalkyl or cycloalkylalkyl having 3 to 8 carbon atoms in the cycloalkyl moiety and, which may have 1 to 4 carbon atoms in the alkyl moiety and which may be substituted in each case by halogen, cyano or C.sub.1 -C.sub.4 -alkyl, or represents aryl or arylalkyl having 6 or 10 carbon atoms in the aryl moiety and 1 to 4 carbon atoms in the alkyl moiety and which may be substituted in each case by halogen, cyano, nitro, carboxyl or carbamoyl, by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -alkylsulphinyl or C.sub.1 -C.sub.4 -alkylsulphonyl which may be substituted in each case by fluorine or chlorine, or by dimethylaminosulphonyl, diethylaminosulphonyl, dimethylaminocarbonyl or diethylaminocarbonyl, or by C.sub.1 -C.sub.4 -alkoxy-carbonyl which may be substituted in each case by halogen, methoxy or ethoxy, or by phenyl, phenyloxy or phenylthio which may be substituted in each case by halogen, cyano, methyl, methoxy, trifluoromethyl or trifluoromethoxy, and
• Het represents ##STR73## which is bonded via N wherein,
• Q represents oxygen or sulphur.