| Abstract
| - Hindered amino acids have been introduced into peptide chains by coupling N-(Cbz- and Fmoc-α-aminoacyl)benzotriazoles with amino acids, wherein at least one of the components was sterically hindered,to provide compounds 3a−e, (3c +3 c‘), 5a−d, (5a + 5a‘), 6a−c, (6b + 6b‘), 8a−c, 9a−e, 10a−d, and(10a + 10a‘) in isolated yields of 41−95% with complete retention of chirality as evidenced by NMRand HPLC analysis. The benzotriazole activation methodology is a new route for the synthesis of stericallyhindered peptides. (Note: compound numbers written within brackets represent diastereomeric mixturesor racemates; compound numbers without brackets represent enantiomers.)
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