9-Amino-4,5-diazafluorene-9-carboxylic Acid (Daf), a New Cα,α-Disubstituted Glycine Containing a Spatially Constrained Bipyridine-Like Ligand for Transition Metals − Synthesis and Evaluation of Peptide-Coupling Conditions at itsC- andN-Termini
作者:Jean-Paul Mazaleyrat、Karen Wright、Michel Wakselman、Fernando Formaggio、Marco Crisma、Claudio Toniolo
DOI:10.1002/1099-0690(200105)2001:10<1821::aid-ejoc1821>3.0.co;2-9
日期:2001.5
method. Coupling of Boc-Ala-OH at the N-terminus of Daf could also be performed by the mixed anhydride method. However, coupling of the crowded Aib residue required the use of Boc-Aib-NCA. Daf, a new Cα,α-disubstituted glycine, is the first α-amino acid containing a rigid bipyridine ligand in a totally controlled spatial disposition relative to the Cα atom.
N-苄基-4,5-二氮杂芴-9-亚甲基胺的阴离子与氯甲酸甲酯或苄酯酰化,然后进行酸性水解,生成 9-氨基-4,5-二氮杂芴-9-甲酸甲酯(H- Daf-OMe) 和苄酯 (H-Daf-OBzl)。在 60 °C 下用 Boc2O 进行 Nα-保护得到 Boc-Daf-OMe 和 Boc-Daf-OBzl,其皂化或氢解导致完全脱羧。然而,酯官能团的肼解提供了 Boc-Daf-NHNH2,它通过酰叠氮化物方法与 H-Ala-OMe 有效偶联。Boc-Ala-OH 在 Daf 的 N 端偶联也可以通过混合酸酐方法进行。然而,拥挤的 Aib 残基的偶联需要使用 Boc-Aib-NCA。Daf,一种新的 Cα,α-二取代甘氨酸,