4-Hydroxybenzaldehyde → p-Octyloxycarbonyloxybenzaldehyde

To a solution of 4-hydroxybenzaldehyde (II) (16 g, 0.181 mol) dissolved in dry pyridine (100 ml) was added nonyl chloroformate (24.7 g, 0.119 mol) to react these together, followed by sufficiently agitating the reaction mixture, allowing it to stand overnight, adding toluene (100 ml) and water (100 ml), washing the mixture with 6N-hydrochloric acid, then with 2N-NaOH aqueous solution, further with water until the washing water became neutral, distilling off toluene to obtain 4-nonyloxycarbonyloxyaldehyde (IV) (33.2 g), dissolving this product (20.5 g, 0.07 mol) in acetic acid (60 ml), dropwise adding to the resulting solution being agitated, a solution of anhydrous chromic acid (14 g, 0.140 mol) dissolved in water (11 ml) and acetic acid (17 ml), while keeping the temperature of the system at 30° C. or lower, keeping the inner temperature at 40° C. on a water bath for 4 hours after completion of the reaction, cooling the resulting material, adding water (300 ml), filtering deposited crystals, washing the crystals with water and recrystallizing from ethanol to obtain 4-nonyloxycarbonyloxybenzoic acid (V) (7 g) having a melting point of 118.8°~120.4° C., adding to this product (7 g, 0.028 mol), thionyl chloride (6 g, 0.050 mol), heating the mixture under reflux for one hour, and distilling off excess thionyl chloride to obtain 4-nonyloxycarbonyloxybenzoic acid chloride (VI) (7.5 g).