Synthesis of protected peptides with the sequence 8-13-1-3 and 4-13-1-3 of mycobacillin and their analogs.

We have synthesized both a protected nonapeptide of the mycobacillin 8-13-1-3 amino acid sequence and a protected tridecapeptide of the 4-13-1-3 sequence, which are a fragment and a open chain analog of this antibiotic, respectively. Some of their analogs with a reversed configuration of the amino acids at fixed positions have also been synthesized. The nonapeptides were obtained by coupling partially protected mycobacillin fragments with the sequence 8-10 and 11-13-1-3 while the tridecapeptides were synthesized by coupling partially protected fragments 4-7 and 8-13-1-3.