. . . . . . "thanol, propanol, iso-propanol, butanol, iso-butanol and tert-butanol, and if appropriate in the presence of a base, where in the case in which compounds of the formula (V) are employed, inorganic bases, in particular alkali metal or alkaline earth metal carbonates such as sodium carbonate, potassium carbonate or calcium carbonate, and organic bases, for example pyridine or triethylamine, are suit" .