scholarly journals Structure-Acid Lability Relationship of N-alkylated α,α-dialkylglycine Obtained via a Ugi Multicomponent Reaction

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 197
Author(s):  
Iván Ramos-Tomillero ◽  
Marisa K. Sánchez ◽  
Hortensia Rodríguez ◽  
Fernando Albericio

Using the classical Ugi four-component reaction to fuse an amine, ketone, carboxylic acid, and isocyanide, here we prepared a short library of N-alkylated α,α-dialkylglycine derivatives. Due to the polyfunctionality of the dipeptidic scaffold, this highly steric hindered system shows an interesting acidolytic cleavage of the C-terminal amide. In this regard, we studied the structure-acid lability relationship of the C-terminal amide bond (cyclohexylamide) of N-alkylated α,α-dialkylglycine amides 1a–n in acidic media and, afterward, it was established that the most important structural features related to its cleavage. Then, it was demonstrated that electron-donating effects in the aromatic amines, flexible acyl chains (Gly) at the N-terminal and the introduction of cyclic compounds into dipeptide scaffolds, increased the rate of acidolysis. All these effects are related to the ease with which the oxazolonium ion intermediate forms and they promote the proximity of the central carbonyl group to the C-terminal amide, resulting in C-terminal amide cleavage. Consequently, these findings could be applied for the design of new protecting groups, handles for solid-phase synthesis, and linkers for conjugation, due to its easily modulable and the fact that it allows to fine tune its acid-lability.

2016 ◽  
Vol 14 (33) ◽  
pp. 7912-7919 ◽  
Author(s):  
Zihong Wan ◽  
Yu Li ◽  
Shaowei Bo ◽  
Ming Gao ◽  
Xuemeng Wang ◽  
...  

Monodisperse polyethylene glycols above 4000 Da, including the longest one to date (10 262 Da), can be prepared from oligoethylene glycol-containing ω-amino acids through solid phase synthesis.


2015 ◽  
Vol 9 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Dongxin Zhao ◽  
Li Ma ◽  
Kui Lu ◽  
Juan He

Ferulic acid was used as a common drug for cardia-cerebrovascular disease and leukopenia, but the application of ferulic acid was inhibited by the poor absorption and stability. The improvement of these defects can be realized by modifying ferulic acid by amino acids, because the amido bond can increase the bioavailability and therapeutic effect of some drugs based on the peptide transporter system of mammalian which can transport the peptidyl drugs. The peptidyl derivatives of ferulic acid, namely acetyl feruloyl tyrosine and acetyl feruloyl valyl tyrosine, were synthesized using Fmoc solid-phase synthesis method. The synthesized ferulic acid amide derivatives were purified by RP-HPLC, and characterized by IR, HNMR and ESI-MS. The results indicated that Fmoc solid phase synthesis was a convenient method for the amide bond modification of ferulic acid and the further property research on ferulic acid derivatives.


Author(s):  
A. G. Razina ◽  
V. A. Kazakov ◽  
A. A. Ashmarin ◽  
V. D. Kochakov

The Pb-Se film systems were obtained by solid-phase synthesis and investigated by Xray diffraction and X-ray photoelectron spectroscopy, electron Auger spectroscopy. It was found that the films are heterogeneous in structure and composition. To study the structural features under the influence of temperature, Raman spectra of samples at temperatures of 300 K and 373 K were investigated.


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