One-Pot Synthesis and Evaluation of Properties of Optically Active Poly(imide–urethane)s

Abstract

Abstract A new diacylazide 2 bearing two preformed imide rings and (S)-valine was prepared in three steps, starting from the reaction of 4,4′-carbonyldiphthalic anhydride with (S)-valine in refluxing glacial acetic acid, followed by treating 4,4′-carbonylbis[(S)-2′′-phthalimidovaline] (1) with ethyl chloroformate in the presence of triethylamine, and subsequently by a nucleophilic reaction with sodium azide. A novel family of optically active poly(imide–urethane)s (PIUs) with moderate inherent viscosities in the range 0.25–0.44 dL g−1 were prepared from diacylazide 2 and various aromatic diols in dry toluene under refluxing in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO, triethylenediamine) as a catalyst. The polycondensation reaction readily proceeded in desirable yields as one-pot reactions starting from 2 without separate synthesis of the corresponding diisocyanate. All of the resulting polymers were thoroughly characterized by spectroscopic methods and specific rotation. The PIUs exhibited an excellent solubility in a variety of polar solvents. Experimental results indicated that all the PIUs had glass-transition temperature between 179 and 218 °C, the decomposition temperature at 10% weight loss between 201 and 223 °C under nitrogen.