An effective La-complex-based probe ionization method is reported. Novel stable isotopically labeled probes containing the 15N-labeled 2,6-bis(oxazolin-2-yl)pyridine (pybox) ligand, succinimide-tetramethylpybox (NHS-TMpybox), maleimide-tetramethylpybox (Mal-TMpybox), and 4-(tetramethylpybox)-butyl bromoacetate (BrAc-TMpybox), have been synthesized and their value in analyzing large complex molecules has been studied. The value of the 15N-labeled pybox-La complex in ionizing various compounds, including bioactive peptides by cold-spray ionization mass spectrometry is emphasized.
The unexpected reactivity of 2,5-diketopiperazines under basic conditions, thanks to N-Boc activation, allows access to valuable pharmacological scaffolds, such as original statine derivatives. Toward this transannular rearrangement of activated lactams (TRAL), we report here the study of his lactam reactivity using [(15)N]-isotopic labeling. (C) 2007 Elsevier Ltd. All rights reserved.
Synthesis of <sup>15</sup>N-labeled heterocycles <i>via</i> the cleavage of C–N bonds of anilines and glycine-<sup>15</sup>N
作者:Jiwen He、Xingguo Zhang、Qiuqin He、Hao Guo、Renhua Fan
DOI:10.1039/d1cc01734a
日期:——
A nitrogen replacement process of anilines by glycine-15N via the cleavage of two C–N bonds for the synthesis of 15N-labeled aromatic heterocycles was reported.
一种通过甘氨酸-15N替代苯胺的氮替换过程,通过断裂两个C-N键合成15N标记的芳香杂环化合物。
Synthesis of DL-α-15N-tryptophan from 1-15N-hydantoin
DL-alpha-N-15-Tryptophan was prepared by the use of Al-Ni alloy as reducing agent from 1-N-15-hydantoin and indole-3-aldehyde via three steps and 1-N-15-hydantoin was prepared from N-15-glycine. The yield of 1-N-15-hydantoin based on N-15-glycine was 89.3% and the yield of DL-alpha -N-15-tryptophan based on 1-N-15-hydantoin was 84%, giving an over-all yield from N-15-glycine of 75%.