Application of substituted 2-(trimethylsilyl)ethyl esters to suppress diketopiperazine formation
摘要:
The use of differently substituted 2-(trimethylsilyl)ethyl esters for C-terminal protection in peptide synthesis has been investigated. While the use of the unsubstituted 2-(trimethylsilyl)ethyl ester resulted in a substantial amount of diketopiperazine at the dipeptide stage, use of the corresponding methyl-substituted silyl ester gave a significant reduction of this undesired pathway. Both esters could be deprotected by fluoride-induced cleavage under mild conditions. (C) 2004 Elsevier Ltd. All rights reserved.
DOI:
10.1016/j.tetlet.2004.03.054
作为产物:
描述:
magnesium,methanidyl(trimethyl)silane,bromide 在
(CH3)2CO 作用下,
以
not given 为溶剂,
以52%的产率得到trimethylsilyl-2-methyl-2-hydroxypropane
参考文献:
名称:
Preparation and Reactions of α-Halo Derivatives of Certain Tetra-substituted Hydrocarbon Silanes. Grignard Syntheses of Some Silyl Compounds1
The rearrangement of (2-hydroxyalkyl)silanes with thionyl chloride and phosphorous tribromide
作者:A.J. Bourne、A.W.P. Jarvie
DOI:10.1016/s0022-328x(00)80272-7
日期:1970.9
The addition of phosphorous tribromide or thionyl chloride to compounds of the type R3SiCH2CD2OH (where R3 = Me3, PhMe2, Ph2Me or Ph3) gave rise to approximately the same proportion of the α-deuteriated product R3SiCH2CD2X and the β-deuteriated product R3SiCD2CH2X in all cases. Fragmentation accompanied the rearrangement, the yields of breakdown products R3SiX, decreased with successive phenyl substitution
将三溴化磷或亚硫酰氯添加到R 3 SiCH 2 CD 2 OH类型的化合物(其中R 3 = Me 3,PhMe 2,Ph 2 Me或Ph 3)中,得到的氘代α的比例大致相同乘积R 3 SICH 2 CD 2 X和β-氘代乘积R 3 SICD 2 CH 2 X在所有情况下。碎片伴随重排,分解产物的收率R 3SiX随硅上的连续苯基取代而降低,并且用(2-羟乙基-2,2- d 2)三苯基硅烷Ph 3 SiCH 2 CD 2 OH几乎没有观察到分解。
Deoxymetalation reactions.the mechanisms of deoxysilylation of mono-trimethylsilyl-and bis-trimethylsilyl-substituted alcohols and a comparison to the mechanism of deoxystannylation and deoxyplumbylation
作者:Dennis D. Davis、Henry M. Jacocks
DOI:10.1016/s0022-328x(00)93462-4
日期:1981.2
trimethylsilyl group, and a mechanism involving a hyper- conjugatively-stabilized carbocation intermediate is proposed. In contrast, the deoxymetalationreactions of the triphenyltin-, triphenyllead-, and iodomercury-analogs exhibits very different structure-reactivity relationships and have been described as proceeding through concerted E2-like or bridge-ion mechanisms. These mechanistic regimes are