1,1-二氧杂萘[1,2- b ]噻吩-2-甲氧基羰基(α-Nsmoc)和3,3-二氧杂萘[ 2,1- b ]噻吩-2-甲氧基羰基(β-Nsmoc)氨基保护基†
摘要:
在Bsmoc相关的,基于萘噻吩砜基的氨基保护基的三个理论上可能的替代基团中,最易获得的两个衍生物α-和β-Nsmoc类似物已作为Bsmoc残基的替代品进行了研究。油性受保护的氨基酸或氨基酸氟化物。所有的萘系统均提供易于处理的固体氨基酸衍生物。用作引入α-Nsmoc保护基的关键试剂的中间体砜醇11很容易由α-四氢萘酮制备(方案1)。对应的β-类似物17类似地,在小规模上进行制备,但由于β-四氢萘酮的成本高,因此将罗丹宁与α-萘醛反应的替代途径用于大规模工作(方案2)。所有蛋白原氨基酸都转化为它们的α-和β-Nsmoc衍生物。脱保护研究表明,哌啶对脱保护的反应性依次为α-Nsmoc> Bsmoc>β-Nsmoc。1个1 H NMR实验表明,两个新系统的解封在机理上与先前为Bsmoc衍生物建立的解封在机理上相似,因为该反应是通过将迈克尔加成到α,β-不饱和砜系统的β-碳原子上而引发的。研究了α-
The 1,1-Dioxobenzo[b]thiophene-2-ylmethyloxycarbonyl (Bsmoc) Amino-Protecting Group
摘要:
Full details are presented for use of the Bsmoc amino-protecting group for both solid phase and rapid continuous solution syntheses. Application to the latter methodology represents a significant improvement over the corresponding Fmoc-based method for rapid solution synthesis due to the opportunity to use water or saturated sodium-chloride solution rather than an acidic phosphate buffer to remove all byproducts, with consequent cleaner phase separation and higher yields of the growing peptide. Comparison of the Bsmoc and Bspoc functions showed that the former, because of steric hindrance, does not suffer from the competitive or premature deblocking observed with the Bspoc system. Because of its incorporation of a styrene chromophore, resin loading of Bsmoc amino acids could be followed as has previously been shown for the Fmoc analogues. Applications of Bsmoc chemistry to peptide sequences incorporating the base sensitive Asp-Gly unit gave less contamination due to aminosuccinimide formation than comparable syntheses involving standard Fmoc chemistry because a weaker or less concentrated base could be used in the deblocking step. Experimental details are presented for building up peptides in solution via the continuous methodology. Deblockings involved the use of insoluble piperazino silica as well as the polyamine TAEA which simplified aqueous separation of the growing, but nonisolated peptide product, from excess acylating agent and other side products formed in the deblocking process. By the appropriate choice of base, one can act selectively at either site of a molecule which incorporates both beta-elimination and Michael acceptor sites as protective units (Bsmoc vs Fm and Fmoc vs Bsm).
1,1-Dioxonaphtho[1,2-<i>b</i>]thiophene-2-methyloxycarbonyl (α-Nsmoc) and 3,3-Dioxonaphtho[2,1-<i>b</i>]thiophene-2-methyloxycarbonyl (β-Nsmoc) Amino-Protecting Groups
作者:Louis A. Carpino、Adel Ali Abdel-Maksoud、Dumitru Ionescu、E. M. E. Mansour、Mohamed A. Zewail
DOI:10.1021/jo062397g
日期:2007.3.1
mechanistically similar to that previously established for the Bsmoc derivative in that the reaction is initiated by Michael addition to the β-carbon atom of the α,β-unsaturatedsulfone system. Application of α- and β-Nsmoc amino acids to the solid-phase synthesis of two model peptides was examined. An advantage of the α-Nsmoc system over the long-known Bsmoc system proved to be the milder conditions needed for
在Bsmoc相关的,基于萘噻吩砜基的氨基保护基的三个理论上可能的替代基团中,最易获得的两个衍生物α-和β-Nsmoc类似物已作为Bsmoc残基的替代品进行了研究。油性受保护的氨基酸或氨基酸氟化物。所有的萘系统均提供易于处理的固体氨基酸衍生物。用作引入α-Nsmoc保护基的关键试剂的中间体砜醇11很容易由α-四氢萘酮制备(方案1)。对应的β-类似物17类似地,在小规模上进行制备,但由于β-四氢萘酮的成本高,因此将罗丹宁与α-萘醛反应的替代途径用于大规模工作(方案2)。所有蛋白原氨基酸都转化为它们的α-和β-Nsmoc衍生物。脱保护研究表明,哌啶对脱保护的反应性依次为α-Nsmoc> Bsmoc>β-Nsmoc。1个1 H NMR实验表明,两个新系统的解封在机理上与先前为Bsmoc衍生物建立的解封在机理上相似,因为该反应是通过将迈克尔加成到α,β-不饱和砜系统的β-碳原子上而引发的。研究了α-
The 1,1-Dioxobenzo[<i>b</i>]thiophene-2-ylmethyloxycarbonyl (Bsmoc) Amino-Protecting Group
作者:Louis A. Carpino、Mohamed Ismail、George A. Truran、E. M. E. Mansour、Shin Iguchi、Dumitru Ionescu、Ayman El-Faham、Christoph Riemer、Ralf Warrass
DOI:10.1021/jo982140l
日期:1999.6.1
Full details are presented for use of the Bsmoc amino-protecting group for both solid phase and rapid continuous solution syntheses. Application to the latter methodology represents a significant improvement over the corresponding Fmoc-based method for rapid solution synthesis due to the opportunity to use water or saturated sodium-chloride solution rather than an acidic phosphate buffer to remove all byproducts, with consequent cleaner phase separation and higher yields of the growing peptide. Comparison of the Bsmoc and Bspoc functions showed that the former, because of steric hindrance, does not suffer from the competitive or premature deblocking observed with the Bspoc system. Because of its incorporation of a styrene chromophore, resin loading of Bsmoc amino acids could be followed as has previously been shown for the Fmoc analogues. Applications of Bsmoc chemistry to peptide sequences incorporating the base sensitive Asp-Gly unit gave less contamination due to aminosuccinimide formation than comparable syntheses involving standard Fmoc chemistry because a weaker or less concentrated base could be used in the deblocking step. Experimental details are presented for building up peptides in solution via the continuous methodology. Deblockings involved the use of insoluble piperazino silica as well as the polyamine TAEA which simplified aqueous separation of the growing, but nonisolated peptide product, from excess acylating agent and other side products formed in the deblocking process. By the appropriate choice of base, one can act selectively at either site of a molecule which incorporates both beta-elimination and Michael acceptor sites as protective units (Bsmoc vs Fm and Fmoc vs Bsm).