Method for preparing tiotropium salts

A compound of formula 3

• wherein
• R is a group selected from N-imidazolyl, N-triazolyl, —O—C(═NR′)—NHR″, —O—SO2-phenyl, —O—SO2-phenyl-methyl, —O—SO2—R′—O—CO—C(methyl)3, —O—CO-phenyl-NO2, chlorine, bromine, —N3 and —O—(P═O)R′″, where
• R′ denotes C1-C4-alkyl or C3-C6-cycloalkyl;
• R″ denotes C1-C4-alkyl, C3-C6-cycloalkyl, C1-C4-alkylene-N(C1-C4-alkyl)2;
• R′″ denotes C1-C4-alkyl, —O—C1-C4-alkyl, phenyl or —O-phenyl;
• R1 and R2, which may be identical or different, represent methyl, ethyl, propyl, butyl or phenyl, wherein phenyl may optionally be substituted by one or more C1-C4-alkyl groups.