The target monomer was prepared by firstly converting the
acid into the corresponding acid chloride, then condensing this
withp-cyanophenol. The acid (17.32 g, 0.059 mol) was stirred with thionyl chloride (35.7 g, 0.3 mol) in the presence of DMF
(2 drops) and 2,6-di-tert-butyl-4-methyl phenol (4.4 g, 0.02
mol). After ca. 25 min, by which time solution was achieved,
the excess thionyl chloride was removed by rotary evaporation
and high vacuum (1-2 h). The acid chloride residue was dis-
solved in anhydrous chloroform (30 mL), then added slowly
dropwise into a stirred solution of p-cyanophenol (7.03 g,
0.059 mol) and triethylamine (6.07 g, 0.06 mol) in chloroform
(20 mL) at 0??C. After the addition the mixture was stirred at
room temperature for 24 h and then chloroform (200 mL)
added. This solution was washed with water (50 mL) followed
by 2 N sodium hydroxide solution (3 x 50 mL) and water (2 x
50 mL). The organic layer was dried (MgSO,), evaporated,
then subjected to flash chromatography, using dichloro-
methane as both the solvent and the eluant. The monomer was
finally recrystallized from isopropanol and shown to be pure
by tlc. Yield: 16 g, 69%.
