How is 3,5-Dibromo-4-hydroxybenzaldehyde (CAS: 2973-77-5) typically synthesized?

3,5-Dibromo-4-hydroxybenzaldehyde (CAS: 2973-77-5) can be synthesized through the bromination of 4-hydroxybenzaldehyde followed by a selective reduction. Commonly, this involves the use of bromine in the presence of anhydrous hydrogen bromide or bromine and zinc powder. The reaction is typically carried out under anhydrous conditions to prevent side reactions. The yield is usually around 65-75%, and the product can be purified by recrystallization from ethanol.