Side-product formation during cyclization with HBTU on a solid support.
Side-product formation during cyclization with HBTU on a solid support.
复制标题
HBTU 在固体载体上环化期间形成副产物。
DOI：
10.1111/j.1399-3011.1994.tb00393.x
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Aldrich,JV
中科院分区：
文献类型：
--
作者：
Story,SC;Aldrich,JV
The coupling reagent 2‐(1H‐benzotriazol‐1‐yl)‐1,1,3,3‐tetramethyluronium hexafluorophosphate (HBTU) was used in an attempt to prepare a highly strained 10‐membered lactam ring on a solid support via side‐chain to side‐chain cyclization of the adjacentα, γ‐diaminobutyric (Dab) andd‐glutamic acid residues in [Dab2,d‐Glu3,Leu5]enkephalinamide. This attempted cyclization failed, however, and yielded linear products instead. Characterization by mass spectrometry, amino acid analysis, peptide sequencing and NMR indicated that the major products were the tetramethylguanidinium (Tmg) derivatives [Dab(Tmg)2,d‐Glu3,Leu5]‐enkephalinamide and the corresponding dimeric linear Tmg‐containing peptide which resulted from the transfer of the tetramethyluronium moiety from HBTU to the amino side chain of Dab. The formation of these tetramethylguanidinium side products during cyclization reactions limits HBTU's usefulness for the formation of lactams.
