Zanotti G, Birr C, Wieland T
Int J Pept Protein Res. 1978 Oct;12(4):204-16. doi: 10.1111/j.1399-3011.1978.tb02888.x.
L-3a-Hydroxy-1.2.3.3a.8.8a-hexahydropyrrolo [2,3-b-]-indole-2-carboxylic acid (Hpi), obtained from L-tryptophan by oxidation with peroxyacetic acid (Savige, 1975), after introduction of the Boc-residue at N-1, is coupled with various glycine peptides of S-trityl-L-cysteine to give the Hpi-peptides 6(a-f). By treatment with absolute trifluoroacetic acid these peptides are converted by an intramolecular thiolysis to the monocyclic thioethers 7(a-f). Two of them, 7e and 7f, can be subjected to a second cyclization by the mixed anhydride method thus yielding the bicyclic tryptathionine heptapeptide 8e and octapeptide 8f. In their structures the bicyclic molecules resemble the mushroom phallotoxins and amatoxins, respectively. They show CD spectra closely related to the naturally occurring bicyclic peptides thus indicating conformational similarities. The CD spectra of the other cyclic peptides synthesized are also presented and discussed.
L-3a-羟基-1.2.3.3a.8.8a-六氢吡咯并[2,3-b-]吲哚-2-羧酸（Hpi）由L-色氨酸用过氧乙酸氧化制得（萨维奇，1975年），在N-1位引入Boc残基后，与S-三苯甲基-L-半胱氨酸的各种甘氨酸肽偶联，得到Hpi-肽6（a - f）。用无水三氟乙酸处理这些肽，通过分子内硫解将它们转化为单环硫醚7（a - f）。其中两个，7e和7f，可以通过混合酸酐法进行第二次环化，从而得到双环色氨酸七肽8e和八肽8f。在其结构中，双环分子分别类似于蘑菇毒伞肽和鹅膏毒素。它们的圆二色光谱与天然存在的双环肽密切相关，从而表明构象相似性。还给出并讨论了合成的其他环肽的圆二色光谱。
