reactor next the reaction temperature was raised to 80 u00b0 c and the reaction was continued for 24 h with stirring the reactor was then cooled to room temperature and the reactants were added dropwise to 1000 ml saturated saline and stirred to precipitate a light yellow solid i e compound hpp a afterwards the synthesized compound hpp a was filtered washed with quantities of deionized water and dried at 80 u00b0 c in a vacuum oven to give 12 04 g of product hpp a with a yield of 92 which was then recrystallized with acetic anhydride to give 10 46 g of a light yellow product with a higher purity the yield is 80 and m p is 253 u00b0 c 1 h nmr and 13 c nmr spectra of the compound hpp a are shown in fig1 and 2a and 2 b respectively monomer hpp b was synthesized from starting material hpp a and hydrogen in solvent dmf and in the presence of catalyst pd c via the following steps 6 g of hpp a 0 10 g of pd c and 50 g of dimethylformamide dmf were first added to a 50 ml glass reactor and stirred purging and emptying were repeated three times with nitrogen and three times with hydrogen and the reaction was continued for 12 h under a controlled pressure of 3 5 kg cm 2 after reaction pd c was filtered off and the filtrate was added dropwise.