Site-selective incorporation of thioamide-linkages into a growing peptide

Synthesis of a Regular 24-membered Cyclodepsipeptide by Direct Amide Cyclization

“…According to GP 12,18,3,9,9,15,15,21,7,13,10,16,5,8,11,14,17,20, Dry HCl gas was bubbled through a solution of 15 (300 mg, 0.31 mmol) in toluene (30 mL) at 100 • C for 4.5 min. The mixture was then heated under reflux for 20 min while a gentle stream of dry HCl gas was bubbled through the solution.…”

“…Sterically demanding disubstituted amino acids have been incorporated into the linear precursors by the so-called 'azirine/oxazolone method' [16]. This particularly use- Scheme 1. ful approach has also been applied successfully in the syntheses of peptaibols [17], endothiopeptides [18], and conformationally restricted cyclic peptides [19].…”

Synthesis of Z‐Protected Aib‐ and Phe(2Me)‐Containing Pentapeptides and Their Crystal Structures

“…Later, it has been demonstrated that 13 C-NMR spectroscopy is a convenient method for distinguishing between the cis-and trans-conformation of the Xaa-Pro bond [31]. Typically, the chemical shifts of C(β)(Pro) and C(γ)(Pro) in cis-Xaa-Pro peptides are ca.…”

“…It has also been shown that the method can be adopted to solid-phase methodology [12]. Another modification allowed the synthesis of endothiopeptides containing Aib units [13][14][15][16].…”

A New 2H‐Azirin‐3‐amine as a Synthon for α‐Methyl Glutamate

“…A useful method for the introduction of such amino acids into peptides is the so-called 'azirine/oxazolone method' [1], which proved to be a convenient preparative access to such peptides. This strategy has been applied extensively in the synthesis of linear oligopeptides [2][3][4][5][6][7][8], endothiopeptides [9][10][11][12][13], conformationally restricted cyclic peptides [14][15][16][17], and cyclic depsipeptides [17][18][19][20][21][22][23][24][25][26] containing 2,2-disubstituted glycines.…”