120060-93-7Relevant academic research and scientific papers
Formation of Non-Natural α,α-Disubstituted Amino Esters via Catalytic Michael Addition
Teegardin, Kip A.,Gotcher, Lacey,Weaver, Jimmie D.
, p. 7239 - 7244 (2018)
The enolate monoanion of amino esters is explored, and the first catalytic Michael addition of α-amino esters is demonstrated. These studies indicate that the acidity of the αC-H is the primary factor determining reactivity. Thus, polyfluorophenylglycine amino esters yield novel α-amino esters in the presence of a catalytic amount of a guanidine-derived base and Michael acceptors. Reactivity requires an acidic N-H, which is accomplished using common protecting groups such as N-Bz, N-Boc, and N-Cbz. Calculations and labeling experiments provide insight into the governing principles in which a key C-to-N proton transfer occurs, resulting in an expansion of the scope to include a number of natural amino esters. The study culminates with a late-stage functionalization of peptidic γ-secretase inhibitor, DAPT.
Nitrogen-Doped Carbon Enables Heterogeneous Asymmetric Insertion of Carbenoids into Amines Catalyzed by Rhodium Nanoparticles
Kobayashi, Shū,Masuda, Ryusuke,Yamashita, Yasuhiro,Yasukawa, Tomohiro
supporting information, p. 12786 - 12790 (2021/05/07)
Development of stable heterogeneous catalyst systems is a crucial subject to achieve sustainable society. Though metal nanoparticles are robust species, the study of asymmetric catalysis by them has been restricted because methods to activate metal nanopa
Determination of Chemical and Enantiomeric Purity of α-Amino Acids and their Methyl Esters as N-Fluorenylmethoxycarbonyl Derivatives Using Amylose-derived Chiral Stationary Phases
Islam, Md. Fokhrul,Adhikari, Suraj,Paik, Man-Jeong,Lee, Wonjae
, p. 332 - 338 (2019/04/13)
Liquid chromatographic enantiomer separation and simultaneous determination of chemical and enantiomeric purity of α-amino acids and their methyl esters as N-fluorenylmethoxycarbonyl (FMOC) derivatives was performed on three covalently bonded type chiral stationary phases (CSPs) derived from amylose derivatives. The enantiomer separation of α-amino acid esters as N-FMOC derivatives was better than that of the corresponding acids, especially for CSP 1 and 2. Chemical impurities as the corresponding racemic acids present in several commercially available racemic amino acid methyl esters were observed to be 0.49–17.50%. Enantiomeric impurities of several commercially available L-amino acid methyl esters were found to be 0.03–0.58%, whereas chemical impurities as the corresponding racemic acids present in the same analytes were found to be 0.13–13.62%. This developed analytical method will be useful for the determination of chemical and enantiomeric purity of α-amino acids and/or esters as N-FMOC derivatives using amylose-derived CSPs.
SIMULTANEOUS USE OF N-Fmoc AND OTmse PROTECTIVE GROUPS IN THE SYNTHESIS OF PEPTOLYTIC SENSITIVE PEPTIDES
Vanfleteren, L.,Anteunis, M. J. O.
, p. 505 - 518 (2007/10/02)
The combined use of Fmoc (fluorenylmethoxycarbonyl) as N-protection and Tmse (trimethylsilylethyl) as O-protection during demanding fragment condensation mediated by Bop-Cl (N,N'-bis(3-oxo-2-oxazolidinyl)phosphinyl chloride) has been explored in the preparation of useful synthons that are sensitive to acidic and even basic hydrolyses.Stepwise deprotection by morfoline (Fmoc-deprotection) followed by F--mediated removal of Tmse results in a very effective peptide synthesis strategy, as exemplified by the preparation of i.a.Phg-MePhe-Thz.Similarly, combinations of N-Boc, O-Tmse peptide esters are also possible that allow the preparation of +H2-MePhe-Thz-OTmse (via Boc-MePhe-Thz-OTmse) without competitive DKP formation.
