27317-68-6Relevant articles and documents
Synthesis and conformational behavior of metallacyclicdipeptides derived from coordination of side chain alkynylamino acids to tungsten
Curran, Timothy P.,McTeague, T. Andrew,Nguyen, Vu D.,Yennie, Craig J.,Handali, Paul R.,Sanderson-Brown, Joseph P.,Dworsky, Zephyr D.
, p. 12 - 21 (2016)
Three dipeptides bearing alkynes on their side chains (9 (derived from dilysine), 14 (derived from dicysteine) and 17 (derived from diglycine)) were prepared and reacted with W(CO)3(dmtc)2 [dmtc = dimethyldithiocarbamate] to afford, respectively, three metallacyclicpeptides, 18, 19 and 20. The metallacyclicpeptides were characterized by HPLC, ES-MS, and 1H NMR. The conformational behavior of the alkynes about the tungsten center was assessed using 1H NMR. It was found that all three metallacyclicpeptides adopt multiple conformations of the alkynes relative to the tungsten. Both 18 and 19 appear to adopt all 8 possible conformations, while 20 adopts a limited number of conformations. The ability of the alkynes to equilibrate between the syn and anti conformations was assessed by examining the alkyne hydrogen resonances using variable temperature 1H NMR. It was found that the alkyne ligands in 18 and 19 will equilibrate between the syn and anti conformations. The alkyne hydrogen resonances in 18 coalesce to one signal around 343 K, while the alkyne hydrogen resonances in 19 do not completely coalesce even by 360 K. Complex 18 has a larger ring than complex 19, and the higher temperature of coalescence for 19 is attributed to its smaller ring size. In contrast, complex 20, which has the smallest ring size, cannot equilibrate between the syn and anti conformations, even at elevated temperatures. The results show that cyclic tungsten-bis(alkyne) complexes will form ring systems with ring sizes of approximately 10 atoms, that ring sizes of approximately 10 atoms are rigid, and that rigidity is lost as the ring size is increased.
Peptidic molecular brushes with enhanced chirality
Li, Wen,Zhang, Xiuqiang,Wang, Jue,Qiao, Xiao,Liu, Kun,Zhang, Afang
, p. 4063 - 4072 (2012/10/30)
Tethering oligopeptides through one end densely packed onto a linear polymer main chain will greatly reduce freedom of the peptide chains, which affords an easy access to investigate the secondary structure of peptides under constrained condition. Herein,
Iminosugar glycoconjugates
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Page/Page column 7, (2008/06/13)
The iminosugar conjugates according to the invention are N-alkylated 1,5-dideoxy-1,5-iminohexitol or 1,5-dideoxy-1,5-iminopentitol derivatives. The iminosugar component can be, for example, D-gluco-, L-ido-, D-galacto-, D-manno-, 2-acetamido-2-deoxy-D-gluco- or xylo-configuration. The N-substituent is a protected L-α-aminoacid derivative, showing L-lysine-like structural features. The linkage between the carbohydrate and the peptide component is not via the usual glycosidic position, but shows structural features of a very stable tertiary amine. Thus the linkage is very stable. These new compounds are synthesised by using catalytic intramolecular reductive amination of dicarbonyl sugars with partially protected amino acids. The process of intramolecular reductive amination itself is carried out using Pearlman's catalyst (Pd(OH)2/C) and H2 at ambient pressure and room temperature. The resulting accessible class of iminosugar conjugate compounds is represented by the general structure shown in Figure 4(c). The alkyl chain length parameter n can be freely chosen from n=0 upwards. Preferably n is between 0 and 10, and more preferably n is 2, 3, or 4. Residue R1 can be chosen from H, OH, or NHAc, with Ac being Acetyl. R2 can be H, OH, or NHAc. R3, R4, R5, R6 can be H or OH. R7 and R8 can be H, CH2OH CH3, COQH, or COOR with R being Alkyl or Aryl. R9 and R10 can be chosen from H, NH2, NHR, with R being a protective group, an amino acid, a peptide, or a protein. R11 can be OH, O-Alkyl, O-Aryl, NH2, N-Alkyl, N-Aryl, amino acid or peptide, connected via an amide bond.
