Patent ID: 7491824

Claim:
A process for preparing tiotropium salts of formula 1 wherein X − may represent an anion with a single negative charge, preferably an anion selected from among chloride, bromide, iodide, methanesulphonate or trifluoromethanesulphonate, wherein a compound of formula 2 wherein X − may have the meanings given above, is reacted in one step with a compound of formula 3 generated in situ wherein R is a group selected from N-imidazolyl, N-triazolyl, —O—C(═NR′)—NHR″, —O—SO 2 -phenyl, —O—SO 2 -phenyl-methyl, —O—SO 2 —R′—O—CO—C(methyl) 3 , —O—CO-phenyl-NO 2 , chlorine, bromine, —N 3 and —O—(P═O)R′″, where R′ denotes C 1 -C 4 -alkyl or C 3 -C 6 -cycloalkyl; R″ denotes C 1 -C 4 -alkyl, C 3 -C 6 -cycloalkyl, C 1 -C 4 -alkylene-N(C 1 -C 4 -alkyl) 2 ; R′″ denotes C 1 -C 4 -alkyl, —O—C 1 -C 4 -alkyl, phenyl or —O-phenyl; R 1 and R 2 , which may be identical or different, represent methyl, ethyl, propyl, butyl or phenyl, wherein phenyl may optionally be substituted by one or more C 1 -C 4 -alkyl groups, in a suitable solvent with the addition of a suitable base to yield a compound of formula 4 wherein the groups X − , R 1 and R 2 may have the meanings as given above, and without being isolated the compound of formula 4 is converted into the compound of formula 1 by reaction with a suitable acid or a suitable desilylating reagent while cleaving the silyl group.