One‐step synthesis of functional polymers by polycondensation: Polyesters with pendant hydroxyl side groups from potassium malate or tartrate and 1,4‐dibromobutane

Polyesters with pendant hydroxyl side groups such as (R,S)‐ and (S)‐poly(tetramethylene malate)s and (R,R)‐poly(tetramethylene tartrate)s of moderately high molecular weights were prepared by polycondensation, at 105°C in 1‐methyl‐2‐pyrrolidone for 16 to 80 h, from potassium malate or tartrate and 1,4‐dibromobutane. It was shown by a detailed analysis of the 1H and 13C NMR spectra of the prepared polyesters that no branching occurs in the course of the reaction. The nature of the end‐groups was also clearly established by NMR spectroscopy. The presence of large cycles in the final products cannot be completely excluded.