Process for preparing octreotide and derivatives thereof

The present invention relates to a novel synthesis of octreotide and derivatives thereof by solid phase peptide synthesis. In particular, the present invention relates to synthesize linear peptides, cleave from resin and the cyclization process for their preparation. This invention relates a process for preparing octreotide and derivatives thereof. The starting material, Thr(ol)(tBu)-2-chlorotrityl resin is coupled with the various amino acids. The straight peptide-resin of D-Phe-Cys(Trt)-Phe-D-Trp(Boc)-Lys(Boc)-Thr(tBu)-Cys(Trt)-Thr(ol)(tBu)-2-chlorotrityl resin or D-Phe-Cys(Trt)-Tyr(tBu)-D-Trp(Boc)-Lys(Boc)-Thr(tBu)-Cys(Trt)-Thr(ol)(tBu)-2-chlorotrityl resin was obtained. Cleavage of the peptide from the resin was achieved by strong acid solution. The cleaved peptide reacted with charcoal to give disulfide-containing peptide of