Synthesis of β-Amino Acids: 2-(1H-Benzotriazol-1-yl)-1,1,3,3-tetramethyluronium Tetrafluoroborate (TBTU) for Activation of Fmoc-/Boc-/Z-α-Amino Acids
摘要:
A new and efficient method for the homologation of urethane protected alpha-amino acids to its beta-homomers by the Arndt-Eistert method using TBTU as a coupling agent is described. Several Fmoc-/Boc-/Z-protected alpha-amino diazoketone derivatives have been obtained as crystalline solids in good yield. The method is found to be rapid and stereospecific.
Cyclic β-Tetra- and Pentapeptides: Synthesis through On-Resin Cyclization and Conformational Studies by X-Ray, NMR and CD Spectroscopy and Theoretical Calculations
作者:Frank Büttner、Anna S. Norgren、Suode Zhang、Samran Prabpai、Palangpon Kongsaeree、Per I. Arvidsson
DOI:10.1002/chem.200500249
日期:2005.10.21
The solution-phase synthesis of the simplest cyclic beta-tetrapeptide, cyclo(beta-Ala)4 (4), as well as the solid-phase syntheses through side chain anchoring and on-resin cyclization of the cyclic beta3-tetrapeptide cyclo(-beta3hPhe-beta3hLeu-beta3hLys-beta3hGln-) (14) and the first cyclic beta3-pentapeptide cyclo(-beta3hVal-beta3hPhe-beta3hLeu-beta3hLys-beta3hLys-) (19) are reported. Extensive computational