Synthesis of fragment 8–12 of the natural sequence of ACTH

Two new variants of the synthesis of the pentapeptide 8–12 of the natural sequence of ACTH are presented. In some stages, the trimethylsilyl group was used as temporary protection of the carboxy group of the amino component. The final and intermediate compounds were obtained with good yields, were distinguished by chromatographic homogeneity, and were characterized by their angles of optical rotation, melting points, and electrophoretic behavior. Their purity was checked by TLC and by high-pressure liquid chromatography. Some physicochemical characteristics (angles of optical rotation, melting points, chromatographic mobilities) of the compounds obtained are given.