The synthesis of a new cyclic ester, 3-benzyloxymethyl- 1,4-dioxane- 2,5-dione(3-BMG), was described, which is a precursor of a novel poly( α-hydroxy acid). As an important intermediate, 3-benzyloxy-glyceric acid (3-O-BGA) was obtined and first isolated as white needle crystal using 3-chloro-propandiol as starting material. Polymerization of 3- BMG was carried out in bulk at 140℃ with stannous 2-ethyl hexanoate [Sn(Oct)2] as catalyst. High molecular weight ofpolymer obtained indicates that the polymerization behavior of 3-BMG is similar to that of common lactides or lactones. 3-BMG can also be polymerized by the bimetallic (Al/Zn) alkoxide initiator. The resulting polymer undergoes hydrogenolysis at atmospheric pressure in the presence of a palladium on charcoal and the pendant benzyl group was removed completely. The glass transition temperature (Tg) of the polymer decreases after deprotection. And the deprotective polymer has melting temperature around 120℃. The data of water absorbing and contact angle determinations suggest that the hydrophility of the polymer was improved obviously after deprotection.

Key words: POLYESTER, DEGRADATION, RING OPEN POLYMERIZATION, HYDROGENOLYSIS, HYDROPHILICITY