1199-01-5Relevant articles and documents
Structures of b and a product ions from the fragmentation of argentinated peptides
Lee, Vicky W.-M.,Li, Hongbo,Lau, Tai-Chu,Siu, K. W. Michael
, p. 7302 - 7309 (1998)
Argentinated (silver-containing) oligopeptides fragment under low- energy collision conditions to yield abundant argentinated product ions. The structures of the [b2 - H + Ag]+ and [a2 - H + Ag]+ ions have been determined by means of tandem mass spectrometry and confirmed by comparison with synthesized derivatives of the candidate [b2 - H + Ag]+ ion structure. The [b2 - H + Ag]+ ion was found to be an N-argentinated oxazolone, which could subsequently form the [a2 - H + Ag]+ ion and other product ions after collision activation. Tripeptides containing proline as their second residue were observed to form a relatively less abundant [b2 - H + Ag]+ ion, which was postulated to be an argentinated ketene.
Room-Temperature Dual Fluorescence of a Locked Green Fluorescent Protein Chromophore Analogue
Chatterjee, Soumit,Ahire, Ketan,Karuso, Peter
, p. 738 - 749 (2020)
A structurally locked green fluorescent protein (GFP) chromophore with a phenyl group at C(2) of the imidazolone has been synthesized. Rotation around the exocyclic double bond is hindered, resulting in room-temperature fluorescence. The quantum yield in water is 500 times greater than that of unlocked analogues. Unlike the methyl-substituted analogue, the phenyl analogue exhibits a dual emission (cyan and red) that can be used for ultrasensitive ratiometric measurements and fluorescence microscopy. To explain this dual emission, DFT calculations were carried out along with fluorescence upconversion experiments. The Z-isomer was found to be emissive, while the origin of the dual emission was dependent on the phenyl group in the Z-isomer, which stabilizes the Franck-Condon state, resulting in a cyan fluorescence, while the zwitterionic tautomer fluoresces red. These results bring important new insights into the photophysics of the GFP chromophore and provide a new scaffold capable of dual emission with utility in biotechnology.
Reaction of 4-benzylidene-2-phenyloxazol-5(4H)-one with 3,4- dithio-toluene in the presece of triethylamine
Tikdari, Ahmad Momeni,Fozooni, Samieh
, p. 473 - 478 (2003)
Unsaturated oxazol-5(4H)-ones constitute an important class of synthon. In this paper we present our findings on the reaction of 4-benzylidene-2- phenyloxazol-5(4H)-one and 4-cyclohexylidene-2-phenyloxazol-5(4H)-one and 4-cyclohexylidene-2-phenyloxazol-5(4H)-one with 3,4-dithio-toluene in the presence of triethylamine. The intermediates can be isolated under nautral conditions. Base mediated reaction of 3,4-dithio toluene with 4-benzylidene-2-phenyloxazol-5(4H)-one in boiling benzene was unsuccessful but simple heating of these reactants at an elevated temperature give 2-benzamido-2-cyclohexyl-7-methyl-1,4-benzodithian-3-one.
Synthesis, cytotoxicity, and docking study of novel 1-naphthyl-5-aryl-1H-1,2,4-triazole-3-carboxamides
Zaki, Islam,Ramadan, Mohamed,Abdelrahman, Mostafa H.,Aly, Omar M.
, p. 1483 - 1496 (2017)
A new series of 1-naphthyl-5-aryl-1H-1,2,4-triazole-3-carboxamide derivatives were synthesized and structurally proved by 1H and 13C NMR along with high-resolution mass spectrometry. The cytotoxic activity of the newly synthesized compounds was evaluated. Compounds showed a pronounced inhibitory effect against cellular localization of tubulin. Flow cytometric analysis showed that Hep-G2 cells treated indicated a predominated growth arrest at the G2/M-phase compared to that of S-phase. Molecular modeling study using MOE program indicated that most of the target compounds showed good binding with the colchicine-binding site of β-subunit of tubulin with the binding free energy (?G) values of about 42?kJ/mol. Graphical abstract: [Figure not available: see fulltext.].
An eco-compatible access to diversified bisoxazolone and bisimidazole derivatives
Ahmed Arafa, Wael Abdelgayed,Abdel-Magied, Ahmed Fawzy
, p. 338 - 352 (2018)
An efficient, straight-forward and eco-friendly synthetic strategy for the assembly of novel bisoxazolones via a four-component, sequential reaction of dialdehydes, glycine, benzoyl chloride and acetic anhydride, using ultrasound radiation, is described. Additionally, a diverse group of new bisimidazoles has been synthesized in good yields by the sonication of diamines and (Z)-4-Arylidene-2-phenyloxazol-5(4H)-ones. These approaches have resulted in a number of successful routes for the facile synthesis of bis-oxazolone and bis-imidazole frameworks within minutes of irradiation. Excellent outcomes using these environmentally-friendly parameters make these synthetic schemes ideal, sustainable, green-chemistry procedures and provide simple access towards the preparation of bisheterocycles. Formula parented.
A novel route to 4-arylidene-2-phenyl-5(4H)-oxazolones
Kidwai,Kumar
, p. 451 - 453 (1998)
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A Facile Synthesis of 2-Aminopropane-1,2,3-tricarboxylic Acid and Its Symmetrical Dimethyl Ester
Nizovtsev, Alexey V.,Bovin, Nicolai V.
, p. 4428 - 4432 (2021/08/20)
A new convenient synthetic route to 2-aminopropane-1,2,3-tricarboxylic acid is described. The first two stages of the threestep synthesis are performed in a one-pot procedure and include the cyclization of hippuric acid with DCC followed by treatment with methyl bromoacetate to yield an alkylated oxazolone. Its hydrolysis with HCl provides 2-aminopropane-1,2,3-tricarboxylic acid as its HCl salt. Esterification of the resulting acid with methanol in the presence of thionyl chloride leads selectively to its symmetrical diester.
Silver-Promoted Direct Phosphorylation of Bulky C(sp2)-H Bond to Build Fully Substituted β-Phosphonodehydroamino Acids
Cao, Hao-Qiang,Liu, Hao-Nan,Liu, Zhe-Yuan,Qiao, Baokun,Zhang, Fa-Guang,Ma, Jun-An
supporting information, p. 6414 - 6419 (2020/09/02)
A general and practical cross-dehydrogenative coupling protocol between readily available trisubstituted α,β-dehydro α-amino carboxylic esters and H-phosphites is described. This C(sp2)-H phosphorylation reaction proceeds with absolute Z-selectivity promoted by silver salt in a radical relay manner. The bulky tetrasubstituted β-phosphonodehydroamino acids were obtained in grams and added new modules to the toolkit for peptide modifications.
