a) Preparation of 4,4'-bis(hydroxy-methyl)biphenyl. In a 2-liter flask equipped with a mechanical stirrer, condenser, addition funnel and heating bath, 789 mg (20.8 mmol) of LiAlH4 was dissolved in 150 ml of anhydrous THF (tetrahydrofuran). A solution of 7.5 g (27.7 mmol) of 4,4'-bis(methoxycarbonyl)biphenyl dissolved in 500 ml of anhydrous THF was heated to 50 °C under an inert atmosphere and added dropwise to the above mixture over 1 hour. After the dropwise addition, stirring was continued at 50 °C for 30 minutes. Subsequently, the reaction mixture was cooled to room temperature and 15 ml of THF/H2O (80:20) mixture was carefully added to quench the excess LiAlH4. The reaction mixture was filtered through a Septum G2 filter and the precipitate was washed with ethanol (3 x 100 ml). The filtrate and washings were combined and evaporated to dryness under vacuum in a heating bath at 40 °C. The residue was redissolved in 100 ml of hot acetone (50 °C), filtered to remove insoluble matter, dried with anhydrous Na2SO4 and evaporated again to dryness. Finally 5.74 g of 4,4'-bis(hydroxymethyl)biphenyl was obtained in 96.6% molar yield.
