CYCLIC POLYESTERS .1. PREPARATION BY A NEW SYNTHETIC METHOD, USING POLYMER-SUPPORTED REAGENTS

A new method of synthesizing cyclic polyesters is described, using pol ymer-supported reactions. This method involves the attachment of omega -bromocarboxylate anions to the surface of an ion-exchange resin, foll owed by polymerization and cyclization by inter- and intramolecular al kylation reactions, respectively. The polymerization reaction results in the formation of oligomeric chain polyester molecules that remain b ound to the resin by the carboxylate anion end group. The cyclization reaction results in the detachment of the cyclic product from the resi n support. The cyclic polyester (CH2)10CO.O!x obtained was divided in to a series of sharp fractions using preparative g.p.c. and each fract ion was examined by analytical g.p.c. The cyclic nature of the polyest er product was established by n.m.r. spectroscopy and by fast atom bom bardment (f.a.b.) mass spectrometry. The f.a.b. mass spectrum of a fra ction showed a series of spectral lines corresponding to (CH2)10CO.O! x with x=2-7. The cyclic products were directly compared with analogou s linear polymers.