Triazolinedione-based methods for peptide cyclization and efforts toward the total synthesis of (-)-Biotin

Chapter 1 presents the development of a triazolinedione-based, tyrosine-selective method to cyclize short- to medium-sized peptides. The development of efficient conditions to prepare precursor ‘urazole' peptides is discussed. Preliminary efforts to oxidize and cyclize urazole peptides are discussed, along with efforts to apply this cyclization method toward antimicrobial peptide structural enhancement and stabilization. In Chapter 2, a total synthesis of (-)-biotin (unnatural) is discussed in detail. As part of a collaborative mirror-image synthetic biology study with the Kay Laboratory in the Department of Biochemistry, I am working to obtain practical quantities of mirrorimage biotin, (-)-biotin. We follow and discuss a previously reported total synthesis of (+)- biotin by Seki and coworkers in 2004. Detailed experimental information and spectral data are presented. This effort is ongoing.