1738-87-0Relevant articles and documents
Thermodynamic and (1)H NMR Study of Proton Complex Formation of Histidine-containing Cyclodipeptides in Aqueous Solution
Arena, Giuseppe,Impellizzeri, Giuseppe,Maccarrone, Giuseppe,Pappalardo, Giuseppe,Sciotto, Domenico,Rizzarelli, Enrico
, p. 371 - 376 (2007/10/02)
A thermodynamic and (1)H NMR study of proton complex formation in aqueous solution of some L-histidine-containing cyclic L-dipeptides has been carried out.The enthalpic and entropic changes associated with protonation of the cyclodipeptides, obtained by potentiometric and calorimetric measurements, together with the (1)H NMR data and NOESY experiments, enable the role played by non-covalent interactions in proton complex formation to be assessed.In addition, a comparison with c(Gly-His) permits the influence of side-chain residues on the conformation of protonated species to be observed.
A Simple and Mild Esterification Method for Carboxylic Acids Using Mixed Carboxylic-Carbonic Anhydrides
Kim, Sunggak,Lee, Jae In,Kim, Youn Chul
, p. 560 - 565 (2007/10/02)
A simple and mild esterification method using mixed carboxylic-carbonic anhydrides has been developed.Simple aliphatic carboxylic esters are prepared in high yields by the reaction of acids with equimolar amounts of chloroformates (2,2,2-trichloroethyl chloroformate is an exception) and triethylamine in the presence of a catalytic amount of 4-(dimethylamino)pyridine.Although aromatic acids give a mixture of the ester, the acid anhydride, and the carbonate under normal conditions utilized in this study, it is found that increasing the amount of 4-(dimethylamino)pyridine drastically decreases the formation of the acid anhydride and the carbonate, affording a satisfactory yield of the ester.This method reaches a limit with sterically hindered acids and the formation of the acid anhydride and the carbonate is favored.
A New Method for the Preparation of Active Esters Using Di-2-pyridyl Carbonate
Kim, Sunggak,Ko, Young Kwan
, p. 473 (2007/10/02)
The use of di-2-pyridyl carbonate in the presence of a catalytic amount of 4-dimethylaminopyridine is found to be very effective in the preparation of various active esters.
ACTIVATION OF A CARBOXY GROUP BY DIALKYL PYROCARBONATES. SYNTHESIS OF SYMMETRICAL ANHYDRIDES AND ARYL ESTERS OF N-PROTECTED AMINO ACIDS USING DI-tert-BUTYL PYROCARBONATE AS CONDENSING REAGENT
Pozdnev, V. F.,Chernaya, M. Yu.
, p. 333 - 337 (2007/10/02)
It has been shown that di-tert-butyl pyrocarbonate can be used as a condensing reagent in the production of anhydrides and some aryl esters of carboxylic acids.The synthesis of anhydrides and of phenyl, p-nitrophenyl, β-naphtyl, and quinolin-8-yl esters of N-protected amino acids is described.
Psycho-pharmacological peptides
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, (2008/06/13)
The present invention relates to novel psycho-pharmacological active peptides and peptide derivatives of the formula: wherein R represents the amino acid residue L-Lys or L-Arg, R1 represents the amino acid residue L-Glu or L-Gln, B represents one of the following amino acid or peptide-radicals: L-Leu-OH, (α-dehydro)Leu-OH D-Leu-OH L-Leu-L-Phe-OH L-Leu-L-Phe-L-Lys-OH L-MeLeu-OH or the radical STR1 and A represents one of the following radicals or residues: hydrogen H-L-Glu Z1 -L-Glu Z2 -L-Ser-L-Glu- H-Q1 -L-Thr-L-Ser-L-Glu- Q2 -L-Thr-L-Ser-L-Glu- Z3 -Q1 -L-Thr-L-Ser-L-Glu- or H2 N-ALK-CO-L-Phe-Q1 -L-Thr-L-Ser-L-Glu- in which Z1 represents H-L-Ser, H-D-Ser, desamino-Ser, 2,3-dihydroxy propanoyl or H2 N-ALK-CO-, Z2 represents H-L-Thr, H-D-Thr, desamino-Thr, 2,3-dihydroxybutanoyl or H2 N-ALK-CO; Q1 represents L-Met, L-Met(O), L-Met (O2) or L-Leu Q2 represents H-D-Met, H-D-Met (O), H-D-Leu, H-D-Met (O2), desamino Met, desamino Met (O), desamino Met (O2), desamino Leu, 2-hydroxy-4-methylthiobutanoyl, 2-hydroxy-4-methylpentanoyl or the radical H2 N-ALK-CO, Z3 represents H-L-Phe, H-D-Phe, desamino Phe, 2-hydroxy-3-phenyl-propanoyl and H2 N-ALK-CO-, and ALK represents an alkylene or alkylidene group with 1-6 carbon atoms, as well as the functional derivatives thereof.
