For the synthesis of magnesium orotate and due to the low solubility of both magnesium hydroxide and orotic acid, 50 mL H2O were heated up to 70 °C. Half of the magnesium hydroxide (total: 0.125 g, 2.16 mmol, 1 eq.) was added to the warm solution. Subsequently, small amounts of both orotic acid (total: 0.75 g, 4.31 mmol, 2 eq.) and the remaining magnesium hydroxide were added alternatingly. After heating the solution to 90 °C and stirring it for 30 min, it was stored in the fridge for crystallization. After one weekend, 0.70 g (1.46 mmol, 68 %) of a white microcrystalline material could be obtained after filtration and drying.
IR, NMR and PXRD analysis (presented in sections S2 and S4) confirmed the product to be magnesium orotate octahydrate.