616-34-2Relevant articles and documents
Sequential photo-addition of glycine methyl-ester to [60]fullerene
Skanji, Rym,Ben Messaouda, Mhamed,Zhang, Yongmin,Abderrabba, Manef,Szwarc, Henri,Moussa, Fathi
, p. 2713 - 2718 (2012)
While direct photo-addition of glycine-methyl-esters (GME) to [60]fullerene (C60) can yield a complex product mixture, only a fulleropyrrolidine (FP) mono-adduct has been characterized and the mechanism remains to be ascertained. We show here that visible light irradiation of a mixture of C 60 and GME in the presence of oxygen is a direct route to synthesize sequentially higher FP poly-adducts through an unprecedented cyclization-deamination mechanism. Each step of this mechanism leads to a FP adduct involving the correlated addition of two GME radicals and the departure of an ammonia molecule.
Participation of C-H Protons in the Dissociation of a Proton Deficient Dipeptide
Koirala, Damodar,Mistry, Sabyasachy,Wenthold, Paul G.
, p. 1313 - 1323 (2017)
The dissociation of anionic dipeptides Phe*Gly and GlyPhe*, where Phe* refers to sulfonated phenyl alanine, has been investigated by using ion trap mass spectrometry. The dipeptides undergo collision-induced dissociation (CID) to give the same products, indicating that they rearrange to a common structure before dissociation. The rearrangement does not occur with the dipeptide methyl esters. The structures of the b2 ions were investigated to determine the effect that having a remote, anionic site has on product formation. Comparison with the CID spectra for authentic structures shows that the b2 ion obtained from GlyPhe* has predominantly a diketopiperazine structure. The CID spectra for the Phe*Gly b2 ion and the authentic oxazolone are similar, but differences in intensity suggest a two-component mixture. Isotopic labeling studies are consistent with the formation of two products, with one resulting from loss of a non-mobile proton on the Gly α-carbon. The results are attributed to the formation of an oxazole and oxazolone enol product. Electronic structure calculations predict that the enol structure of the Phe*Gly b2 ion is lower in energy than the keto version due to intramolecular hydrogen bonding with the sulfonate group. [Figure not available: see fulltext.].
Single Electron Transfer-Induced Selective α-Oxygenation of Glycine Derivatives
Císa?ová, Ivana,Jahn, Ullrich,K?nig, Burkhard,Moser, Johannes,Venugopal, Navyasree,Vojtí?ková, Margaréta
supporting information, (2021/11/03)
Modification of amino acids is an important strategy in organic and bioorganic chemistry. In contrast to common side-chain functionalization, backbone modification is much less explored. Especially glycine units seem to be attractive and versatile since a wide range of functionality can be potentially introduced. We report here oxidative modification of glycinates that are stable and enable further functionalization. Selective glycinate enolate oxidation by TEMPO or a FeCp2PF6/TEMPO reagent combination provides stable alkoxyamines in good to excellent yields. The methodology is expanded to glycine-containing dipeptides demonstrating selective oxygenation at the glycine unit. The orthogonal reactivity potential of oxygenated glycines for transformation to other amino acid derivatives is explored.
Synthesis and evaluation of antitumor activities of 4-selenopyrimidine derivatives
Shi, Mingxing,Wang, Libo,Zhang, Long,Wang, Kexin,Zhang, Hualin,Wang, Yajing,Li, Chang,Han, Weina
, p. 96 - 116 (2020/10/22)
Pyrimidine antimetabolic agents are the essential drugs in treatment of various tumors. Novel synthesis and biological evaluation of the pyrimidine derivatives incorporating selenium element and amino acid carrier as potential antitumor agents have not been tried and studied. Based on the biological significance of pyrimidine structure, these two additional elemental fragments maybe enhance the antitumor effect and reduce toxic side effects of pyrimidine agents. The aim of this paper is to synthesis a series of 4-selenopyrimidine derivatives in order to find more potent lead compounds against cancer. In this study, 12 new 4-selenopyrimidine derivatives that are unstable in acidic solutions but very stable in alkaline and neutral solutions avoiding light were synthesized, and the antitumor activities on HepG2 cell lines of these compounds were evaluated by MTT assay. The results have shown that these compounds could reduce the proliferation of HepG2 cells in a dose-dependent fashion, and the inhibitory activity of compounds a6 was greater than that of positive control 5-fluorouracil (5-FU), the IC50 for a6 was 3.63 μM. In the comprehensive analysis of the structure–activity relationship, we could draw the antitumor effect of selenouracil derivatives is stronger than those of selenothymine derivatives. These results suggest that the substituent groups of selenium element and amino acid on the pyrimidine derivatives are vital for their antitumor activities on HepG2 cells.