18-Membered cyclic esters derived from glycolide and lactide: preparations, structures and coordination to sodium ions
- OSU
From reactions between glycolide or lactide (4 equiv.) with 4-dimethylaminopyridine, DMAP (1 equiv.) and NaBPh4 (1 equiv.) in benzene at 70 C the cyclic ester adducts (CH{sub 2}C(O)O){sub 6}NaBPh{sub 4} and (CHMeC(O)O){sub 6}NaBPh{sub 4} are formed respectively. The structures of the salts Na[(S,R,S,R,S,R)-(CH{sub 3}CHC(O)O){sub 6}]{sub 2}BPh{sub 4} {center_dot} CH{sub 3}CN and (CH{sub 2}C(O)O){sub 6}NaBPh{sub 4} {center_dot} (CH{sub 3}CN){sub 2} are reported. The cyclic esters were separated by chromatography and the structures of (CH{sub 2}C(O)O){sub 6}, (S,R,R,R,R,R)-(CHMeC(O)O){sub 6} and (S,S,R,R,R,R)-(CHMeC(O)O){sub 6} were determined. The {sup 1}H and {sup 13}C NMR data are reported for one of each of the six enantiomers of (CHMeC(O)O){sub 6} and the two meso isomers. The mechanism for the formation of these 18-membered rings is discussed in terms of an initial reaction between DMAP and NaBPh{sub 4} in hot benzene that produces NaPh and DMAP:BPh{sub 3} in the presence of the monomer lactide. The cyclic esters (CHMeC(O)O){sub 6} can also be obtained from the reaction between polylactide, PLA, in the presence of DMAP and NaBPh{sub 4}. The cyclic esters 3-methyl-1,4-dioxane-2,5-dione and 3,6,6-trimethyl-1,4-dioxane-2,5-dione undergo similar ring enlarging reactions to give cyclic 18-membered ring esters as determined by ESI-MS.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1007611
- Journal Information:
- Dalton T., Vol. 42, Issue 2007
- Country of Publication:
- United States
- Language:
- ENGLISH
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