Center for Natural Products Research, Chengdu Institute of Biology, Chinese Academy of Sciences, 610041, Chengdu, People's Republic of China.
Amino Acids. 2009 Oct;37(4):603-7. doi: 10.1007/s00726-008-0179-6. Epub 2008 Oct 5.
L-beta-Haloalanines are physiologically active unnatural amino acids and they are useful intermediates for the synthesis of natural and unnatural amino acids, S-linked glycopeptides, and lanthionines. In general L-beta-haloalanines were prepared predominantly from L-serine via functional group transformation. Here we reported an alternative approach for the preparation of L-beta-haloalanines via halogenation of protected L-cysteine esters which was obtained from L-cysteine or L-cystine, respectively. The mercapto group of protected L-cysteine esters was efficiently transformed to halo groups by triphenylphosphine/N-halosuccinimides. It has been proved to be a versatile desulfurization strategy via this functional group transformation.
L-β-卤代氨基酸是具有生理活性的非天然氨基酸，它们是合成天然和非天然氨基酸、S-连接糖肽和内硫氨酸的有用中间体。一般来说，L-β-卤代氨基酸主要是通过 L-丝氨酸的官能团转化来制备的。在这里，我们报道了一种通过保护的 L-半胱氨酸酯的卤化来制备 L-β-卤代氨基酸的替代方法，这些酯分别是从 L-半胱氨酸或 L-胱氨酸获得的。三苯基膦/N-卤代琥珀酰亚胺可以有效地将保护的 L-半胱氨酸酯的巯基转化为卤代基团。通过这种官能团转化，已经证明它是一种通用的脱硫策略。
