51211-55-3Relevant academic research and scientific papers
Molecular capture and conformational change of diketopiperazines containing proline residues by epigallocatechin-3-O-gallate in water
Ishizu, Takashi,Tokunaga, Miku,Fukuda, Moeka,Matsumoto, Mana,Goromaru, Takeshi,Takemoto, Soushi
, p. 585 - 589 (2021/06/06)
The addition of an aqueous solution of diketopiperazine cyclo(Pro-Xxx) (Xxx: amino acid residue) to an aqueous solution of (?)-epigallocatechin-3-O-gallate (EGCg) led to precipitation of the complex of EGCg and cyclo(Pro-Xxx). The molecular capture abilities of cyclo(Pro-Xxx) using EGCg were evaluated by the ratio of the amount of cyclo(Pro-Xxx) included in the precipitates of the complex with EGCg to that of the total cyclo(Pro-Xxx) used. Stronger hydrophobicity of the side chain of the amino acid residue of cyclo(Pro-Xxx) led to a higher molecular capture ability. Furthermore, the molecular capture ability decreased when the side chain of the amino acid residue had a hydrophilic hydroxyl group. When diketopiperazine cyclo(Pro-Xxx), excluding cyclo(D-Pro-L-Ala), was taken into the hydrophobic space formed by the three aromatic A, B, and B′ rings of EGCg, and formed a complex, their conformation was maintained in the hydrophobic space. Based on nuclear Overhauser effect (NOE) measurement, the 3-position methyl group of cyclo(D-Pro-L-Ala) in D2O was axial, whereas that of cyclo(L-Pro-L-Ala) was equatorial. When cyclo(D-Pro-L-Ala) was taken into the hydrophobic space of EGCg and formed a 2:2 complex, its 3-position methyl group changed from the axial position to the equatorial position due to steric hindrance by EGCg.
1-Ethyl 2-halopyridinium salts, highly efficient coupling reagents for hindered peptide synthesis both in solution and the solid-phase
Li, Peng,Xu, Jie-Cheng
, p. 8119 - 8131 (2007/10/03)
1-Ethyl-2-halopyridinium salts, BEP, FEP, BEPH and FEPH, were synthesized and proved to be very effective for the synthesis of hindered peptides containing N-methylated or C(α),C(α)-dialkylated amino acid residues. HPLC monitoring of model reactions indicated that these pyridinium salts demonstrated higher reactivities, lower racemization than the commonly used halogenated uronium and phosphonium salts. The efficiency of these pyridinium type coupling reagents was further proved by the synthesis of a series of hindered oligopeptides and active esters with good yields and convenient workup. The 8-11 tetrapeptide fragment of Cyclosporin A (CsA) and the pentapeptide moiety of Dolastatin 15 were also successfully synthesized using these pyridinium salts. The efficiency of these pyridinium type coupling reagents for SPPS was also demonstrated by the solid-phase synthesis of the extremely hindered 8-11 peptide segment of CsA and the linear undecapeptide of CsO. The mechanism of the pyridinium salt mediated coupling reactions was also studied by 1H NMR, IR and HPLC. It was proposed that the major reactive intermediates were the corresponding acyl halide and acyloxypyridinium salts of the N-protected amino acid or peptide. (C) 2000 Elsevier Science Ltd.
Highly Potent and Selective Heptapeptide Antagonists of the Neurokinin NK-2 Receptor
McElroy, Andrew B.,Clegg, Stephen P.,Deal, Martyn J.,Ewan, Georg B.,Hagan, Russell M.,et al.
, p. 2582 - 2591 (2007/10/02)
Incorporation of D-Pro9 into substance P related peptides is known to enhance neurokinin NK-2 receptor agonist potency and selectivity with respect to other neurokinin receptors.We now report that replacement of D-Trp9 by D-Pro9
Dipeptide derivatives and antihypertensive drugs containing them
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, (2008/06/13)
There are disclosed dipeptide derivatives represented by the general formula: STR1 wherein R1 is a radical selected from the group consisting of alkyl, aralkyl and aryl groups optionally containing one or more substituent groups, R2 is a radical selected from the group consisting of hydrogen atoms and alkyl, aralkyl and aryl groups optionally containing one or more substituent groups, R3 is a radical selected from the group consisting of hydrogen atoms and alkyl, aralkyl and aryl groups optionally containing one or more substituent groups, R4 is a radical selected from the group consisting of hydrogen atoms and alkyl, aralkyl and aryl groups optionally containing one or more substituent groups, and R5 is a radical selected from the group consisting of hydroxyl, amino, hydroxyamino, alkyloxy, aralkyloxy, aryloxy, alkylamino, aralkylamino, arylamino, alkyloxyamino, aralkyloxyamino, aryloxyamino, acylamino and sulfonylamino groups, which alkyloxy, aralkyloxy and aryloxy groups optionally containing one or more substituent groups; wherein R3 may be combined with R2 or R4 to form an alkylene bridge optionally containing one or more oxygen atoms, sulfur atoms and nitrogen atoms and optionally containing one or more substituent groups. However, certain dipeptide derivatives within the above general formula are excluded from the invention. The dipeptide derivatives are useful for the treatment of hypertension.
