Mechanochemical synthesis of bismuth active pharmaceutical ingredients, bismuth(iii) gallate and bismuth citrate†

Organobismuth compounds have been known for centuries as substances of medical interest, and continue to be used in medicine today. Bismuth active pharmaceutical ingredients (APIs) are used as digestive aids, including in combating Helicobacter pylori, showing antiviral properties. Here we report the mechanochemical synthesis of bismuth gallate and bismuth citrate. In addition, we revisit the previously reported mechanochemical synthesis of bismuth(III) di- and trisalicylate. In the case of bismuth citrate, which has an unknown structure, we show that hydration induces a reversible transformation to a large (possibly cubic) unit cell.