Synthesis and characterization of linear and cyclic endothelin peptides on PEGylated poly(O-benzyl ether) dendrimeric supports

- Poly(ethylene glycol) (PEG) grafted poly(O-benzyl ether) dendrimers for polymer assisted reaction is presented here.
- PEG having different chain lengths (PEG400 and PEG1500) have been grafted to G3 and used.
- The efficiency of supports were checked by synthesizing linear and disulphide bonded endothelin peptides.

Synthesis and evaluation of poly(ethylene glycol) grafted poly(O-benzyl ether) dendrimers for polymer assisted organic reaction is presented here. Initially a cross-linked polymer Polystyrene-Poly(ethyleneglycol)dimethacrylate-Vinylbenzylchloride (PS-PEGDMA-VBC) was synthesized by radical suspension polymerization. 1,3,5-tris(hydroxymethyl)benzene dendron was prepared by the reduction of trimesic acid using LiAlH4. Dendrimers were generated on 2 mol% cross-linked resin by repetitive Williamson etherification and thionyl chloride reactions. The dendrimer was cleanly and efficiently prepared up to third generations (G3) and each stage of reaction was quantitatively and qualitatively analyzed. Poly(ethylene glycol) having different chain lengths (400 Da and 1500 Da) were grafted to G3 generation and tested for various physico-chemical properties. The utility of supports were checked by synthesizing linear as well as disulfide bonded endothelin peptides in high yield and purity by standard Fmoc method.

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