Industrial process for preparing tropenol

A process for preparing tropenol (I):

• optionally in the form of an acid addition salt thereof, said process comprising:
• reacting a compound of formula (II)
• wherein
• R denotes a group selected from C1-C4-alkyl, C2-C6-alkenyl and C1-C4-alkylene-phenyl, each of which may be substituted by hydroxy or C1-C4-alkoxy,
• optionally in the form of an acid addition salt thereof or a hydrate thereof, in a suitable solvent with a formamide-acetal of formula (III)
• wherein
• R′ denotes C1-C4-alkyl and R″ denotes a group selected from C1-C4-alkyl and C1-C4-alkylene-phenyl, to obtain a compound of formula IV
• wherein R and R″ are as defined above;
• decarboxylating the compound of formula (IV) to obtain an ester of formula (V)
• wherein R is as defined above;
• and saponifying the compound of formula (V) to obtain the compound of formula (I), which is optionally converted into an acid addition salt thereof by reaction with a suitable acid.