Dioxane-4-ones

These representative aliphatic polyesters are often used in copolymerized form in various combinations, for example, poly(lactide-co-glycolide) (PLGA) [66-68] and poly(lactide-co-caprolactone) [69-73], to improve degradation rates, mechanical properties, processability, and solubility by reducing crystallinity. Other monomers such as 1,4-dioxepan-5-one (DXO) [74—76], 1,4-dioxane-2-one [77], and trimethylene carbonate (TMC) [28] (Fig. 2) have also been used as comonomers to improve the hydrophobicity of the aliphatic polyesters as well as their degradability and mechanical properties. 

Kricheldorf HR, Damrau D-O (1998) Zn L-lactate-catalyzed polymerizations of 1,4-dioxan-2-one. Macromol Chem Phys 199 1089-1097... 

Dioxanes have been synthesized from l-O-allyl-l,2-diols by radical addition of per-fluoroalkyl iodides and subsequent nucleophilic cyclization.561 With sodium hydride, elimination occurs from iodides such as 1.3 other bases also give unsatisfactory results, whereas N-bromosuccinimide seems to be the reagent of choice for the cyclization to 1,4-dioxane 14. Similar results arc obtained with dibromodimethylhydantoin.561 Dihydrobenzofurans are synthesized by cyclodehydration utilizing the Vilsmeier reagent (chloromethylene)dimethylam-monium chloride is most practical.562 Nucleophilic aromatic substitution reactions with catechol derivatives also give the six-membered heterocycles.563 564 1.4-Dioxan-2-ones arc pre-... 

PDO = poly-1,4-dioxane-2-one PGA = polyglycolic acid PTMC = polytrimethylene-carbonate PCL = polycaprolactone PGL = poly(glycolid-lactide) PG = polyglycolide PDS = p-dioxanone PTMT = polytetramethylene terephthalate i-P = isotactice polypropylene PLG = poly(lactide-glycolide). Source Ingle (2003) Chu etal. (1997). 

Figure 1 Plot of ln([DX]eq/p) (where p= (Pn- )/Pn) on the reciprocal of the absolute temperature (eqn [7]). Bulk oligomerization of 1,4-dioxan-2-one (DX) initiated with a butan-1-ol/tin(ll) octoate mixture. ...

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