| abstract |
Ketene O,N-acetals of the formula I ##STR1## where R 1 is tertiary alkyl of 4 to 6 carbon atoms, R 2 is hydrogen, R 3 is phenyl which is unsubstituted or substituted by halogen, alkoxy, alkyl, phenyl, phenoxy, cyano, nitro or trifluoromethyl and ##STR2## is a triazole, pyrazole, benzimidazole or imidazole radical, are prepared by a process in which a ketene O,O-acetal of the formula II ##STR3## where R 1 , R 2 and R 3 have the above meanings and R 4 is phenyl which is unsubstituted or substituted by halogen, alkoxy, alkyl, phenyl, phenoxy, cyano, nitro or trifluoromethyl, is reacted with a compound of the formula ##STR4## where ##STR5## has the above meanings, at elevated temperatures. |