Bromo-3-thienyl-magnesium is an intermediate used in the synthesis of 7-[(Hydroxy-2-thienyl-3-thienylacetyl)oxy]-9,9-dimethyl-3-Oxa-9-azoniatricyclo[3.3.1.02,4]nonane Bromide (H962025), which is an impurity in the synthesis of Tiotropium Bromide (T444850), a muscarinic receptor antagonist. Bronchodilator.