Process for preparing tiotropium bromide

摘要

The present invention relates to a novel process for the preparation of tiotropium bromide there is provided a process for preparing tiotropium bromide comprising (i) reacting scopine oxalate with diethylamine in an inert solvent to form scopine; (ii) reacting scopine and methyl di-(2-dithienyl)glycoIate (MDTG) in the presence of an inorganic base, and in an inert solvent to form N-demethyltiotropium; (iii) reacting N-demethyltiotropium with bromomethane in an inert solvent to form tiotropium bromide; (iv) crystallizing tiotropium bromide in a mixture of methanol and acetone, and optionally thereafter, (v) micronizing the tiotropium bromide so formed.