Process for the preparation of imidates

A process for the preparation of compounds of the foumula I and salts or acid addition compounds thereof ##STR41## in which R denotes hydrogen, (C.sub.1 -C.sub.20)-alkyl, halogenated (C.sub.1 -C.sub.20)-alkyl with the exception of CF.sub.3, naphthyl, anthracenyl or phenyl or phenyl, anthracenyl or naphthyl, all three of which are monosubstituted or polysubstituted by halogen, hydroxyl, (C.sub.1 -C.sub.6)-alkyl, (C.sub.1 -C.sub.6)-alkylmercapto, (C.sub.1 -C.sub.6)-alkoxy, (C.sub.1 -C.sub.6)-alkylsulfonyl, (C.sub.1 -C.sub.6)-alkylsulfinyl or (C.sub.1 -C.sub.6)-alkylsulfonyloxy, it being possible for the above-mentioned alkyl-containing radicals to be halogenated, halogen, nitro, (C.sub.1 -C.sub.6 -alkoxy)-carbonyl, cyano, phenyl, phenylthio or phenoxy, it being possible for these three radicals to be substituted in turn by (C.sub.1 -C.sub.6)-alkyl, (C.sub.1 -C.sub.6)-halogenoalkyl, (C.sub.1 -C.sub.6)-alkoxy, (C.sub.1 -C.sub.6)-halogenoalkoxy, phenyl, heteroaryl or halogen;

• heteroaryl which can be substituted by (C.sub.1 -C.sub.6)-alkyl, (C.sub.1 -C.sub.6)-halogenoalkyl, (C.sub.1 -C.sub.6)-alkoxy, (C.sub.1 -C.sub.6)-halgenoalkoxy, phenyl, heteroaryl or halogen;
• phenoxy, phenylthio or phenylamino, it being possible for these three radicals to be substituted by (C.sub.1 -C.sub.6 )-alkyl, (C.sub.1 -C.sub.6)-halogenoalkyl, (C.sub.1 -C.sub.6)-alkoxy, (C.sub.1 -C.sub.6)-halogenoalkoxy, phenyl, hereroaryl or halogen;
• or (C.sub.3 -C.sub.7)-cycloalkyl which can be halogenated;
• halogen, hydroxyl, (C.sub.1 -C.sub.10)-alkoxy, mercapto, (C.sub.1 -C.sub.10)-alkylmercapto, amino, mono-(C.sub.1 -C.sub.10 -alkyl)-amino and di-(C.sub.1 -C.sub.10 -alkyl)-amino,
• R.sup.1 denotes (C.sub.1 -C.sub.12)-alkyl which can be monosubstituted or polysubstituted by halogen, nitro, (C.sub.1 -C.sub.4)-alkoxy or carboxyl, phenyl or naphthyl both of which can be monosubstituted or polysubstituted by (C.sub.1 -C.sub.6)-alkyl, (C.sub.1 -C.sub.6)-halogenoalkyl, (C.sub.1 -C.sub.6)-alkoxy, (C.sub.1 -C.sub.6)-halogenoalkoxy, phenyl, heteroaryl or halogen, (C.sub.3 -C.sub.6)-alkenyl, (C.sub.3 -C.sub.6)-alkinyl, (C.sub.5 -C.sub.6)-cycloalkyl or benzyl which can be substituted in the phenyl ring by (C.sub.1 -C.sub.6)-alkyl, (C.sub.1 -C.sub.6)-halogenoalkyl, (C.sub.1 -C.sub.6)-alkoxy, (C.sub.1 C.sub.6)-halogenoalkoxy, phenyl, heteroaryl or halogen, or heteroaryl which can be substituted by (C.sub.1 -C.sub.6)-alkyl, (C.sub.1 -C.sub.6)-halogenoalkyl, (C.sub.1 -C.sub.6)-alkoxy, (C.sub.1 -C.sub.6)-halogenoalkoxy or halogen, and X denotes oxygen or sulfur, which comprises reacting a nitrile of the formula II with a compound of the formula III
• R--C.tbd.N (II)
• R.sup.1 --XH (III)
• in the presence of anhydrous hydrofluoric acid, a perfluoroalkanecarboxylic acid, a perfluoroalkanesulfonic acid or a perfluorinated ion exchanger containing sulfonic acids, and converting the resulting salts of formula I. into the free imidates of formula I.