Macromolecular synthesis from saccharic lactones. Polyaddition of D ‐glucaro‐ and D ‐mannaro‐ 1,4:6, 3‐dilactones with diisocyanates and hydrolyzability of the resulting polyurethanes having dilactone rings in the main chains

Polyaddition of saccharic acid dilactones prepared from D‐glucose and D‐mannitol, D‐glu‐caro‐, and D‐mannaro‐1,4:6,3‐dilactones (1 and 2, respectively), with hexamethylene di‐isocyanate (3a) and methyl (S)‐2,6‐diisocyanatocaproate (3b) was carried out by using dibutyltin dilaurate as a catalyst at 50, 25, and 0°C to give polyurethanes (4 and 5) having dilactone moieties in the main chains. The resulting polymers were found to decompose easily in phosphate buffers under neutral or slightly basic conditions (pH 7 or 8). Therefore, the polyurethanes may be used as novel degradable polymeric materials.