How is Bis(2-hydroxyphenyl)methanone (CAS: 835-11-0) typically synthesized?

Bis(2-hydroxyphenyl)methanone is typically synthesized through the condensation of two equivalents of 2-hydroxybenzaldehyde using a coupling agent like triphenylphosphine in the presence of sodium hydroxide. This method provides good yield and selectivity. Other methods include the reaction of phenol with formaldehyde followed by oxidation, although this route is less common and less efficient.