Hydrogenation of protected leucine enkephalin from a resin during solid phase synthesis

✍ Scribed by David A. Jones Jr.

• Publisher: Elsevier Science
• Year: 1977
• Tongue: French
• Weight: 228 KB
• Volume: 18
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)83092-6

✦ Synopsis

In the preceding paper,1 a description of the remwal of a peptide esterified to a polystyrene resin by means of catalytic hydrogenation was presented. This method is unique in the literature concerning solid phase peptide synthesis in that blocking groups derived frcmn A-butyl alcohol are left intact and the mild conditions minimize the concern of racemisation, which could be a problem in methods of peptide-resin cleavage utilizing basic reagents.

In order to further demonstrate the utility of this method, the synthesis of a biologically active compound was undertaken; specifically, one of the natural ligands for opiate receptors, leucine enkephalin (E), as described recently by Hughes end co-workersV2 Canpound (lb) was X-Tyr-Gly-Gly-Phe-Leu-OH g X=H 2 X=Boc3

removed frcnn the resin in 8% yield by hydrogenolysls in DMF, catalyzed by palladium black generated in situ from pUadium (II) acetate. _-After purification, the final yield of (lb) was 56$.

The synthesis was performed with the aid of a Schwartz-Mann peptide synthesizer. The carboxyl-terminal amino acid, Boc-Leu, was attached to the chloromethylated, 1% cross-linked resin by the method of Gisin.