- Synthesis and biological activity of peptide proline-boronic acids as proteasome inhibitors
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On the basis of the application of proline-boronic acid as pharmacophore in the kinase inhibitors and our previous research results, using proline-boronic acid as warhead, two series of peptide proline-boronic acids, dipeptide proline-boronic acids (I) and tripeptide proline-boronic acids (II), were designed and synthesized. All the synthesized compounds were first evaluated for their biological activity against MGC803 cell, and then, the best compound II-7 was selected to test its anti-tumor spectrum on six human tumor cell lines and proteasome inhibition against three subunits. The results indicated that series II have much better biological activities than series I. The compound II-7 exhibited not only excellent biological activities with IC50 values of nM level in both cell and proteasome models, but also much better subunit selectivity. Thus, proline-boronic acid as warhead is reasonable in the design of proteasome inhibitors.
- Han, Liqiang,Wen, Yanzhao,Li, Ridong,Xu, Bo,Ge, Zemei,Wang, Xin,Cheng, Tieming,Cui, Jingrong,Li, Runtao
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p. 4031 - 4044
(2017/07/05)
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- Amino acid derivatives
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Compounds of the formula STR1 wherein R1 is alkoxycarbonyl, aralkoxycarbonyl, alkanoyl, cycloalkylcarbonyl, aralkanoyl, aroyl, heterocyclylcarbonyl, alkylsulphonyl, arylsulphonyl, monoaralkylcarbamoyl, cinnamoyl or α-aralkoxycarbonylaminoalkanoyl and R2 is hydrogen or R1 and R2 together with the nitrogen atom to which they are attached represent a cyclic imide group of the formula STR2 in which P and Q together represent an aromatic system; R3 is alkyl, cycloalkyl, aryl, aralkyl, heterocyclylalkyl, cyanoalkyl, alkyl- sulphinylalkyl, carbamoylalkyl or alkoxycarbonylalkyl or, when n stands for zero, R3 can also represent alkylthioalkyl or, when n stands for 1, R3 can also represent alkylsulphonylalkyl; R4 is alkyl, cycloalkyl, cycloalkylalkyl, aryl or aralkyl; R5 is hydrogen and R6 is hydroxy or R5 and R6 together represent oxo; R7 and R8 together represent a trimethylene or tetramethylene group which is optionally substituted by hydroxy, alkoxycarbonylamino or acylamino or in which one --CH2 -- group is replaced by --NH--, --N(alkoxycar- bonyl)--, --N(alkyl)-- or --S-- or which carries a fused cycloalkane, aromatic or heteroaromatic ring; and R9 is alkoxycarbonyl, monoalkylcarbamoyl, monoaralkylcarbamoyl, monoarylcarbamoyl or a group of the formula STR3 in which R10 and R11 each represent alkyl; and their pharmaceutically acceptable acid addition salts inhibit proteases of viral origin and can be used as medicaments for the treatment or prophylaxis of viral infections. They can be manufactured according to generally known procedures.
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- Synthesis and Conformation of Aromatic Cyclic Dipeptides. Cyclo(phenylalanyl)2, Cyclo(1-naphthylalanyl)2, and Cyclo(2-naphthylalanyl)2
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Cyclic dipeptides of aromatic amino acids, cyclo(L-phenylalanyl)2, cyclo(L-1-naphthylalanyl)2, and cyclo(L-2-naphthylalanyl)2 were synthesized and subjected to spectroscopic analyses using 1H NMR, absorption, circular dichroism (CD), fluorescence, and fluoroscence-detected circular dichroism (FDCD).The 1H NMR data suggested that the 2,5-piperazinedione rings of the three cyclic dipeptides are in planar or nearly planar bowsplitboat-type conformation.The aromatic side groups of cyclo(1- and 2-naphthylalanyl)2's were found to take asymmetric configurations, one naphthyl group being folded onto the 2,5-piperazinedione ring, the order being unfolded.Strong exciton couplet was observed in CD spectra of the three compounds.The signs of the exciton splitting were opposite in the two naphthyl cyclic dipeptides.Fluorescence spectra of the two naphthyl cyclic dipeptides showed no excimer emission.The absence of strong interchromophoric interaction in the lowest excited state was also suggested by the virtual coincidence of CD spectrum with FDCD spectrum.From the above spectroscopic data, probable conformations were proposed for the naphthyl cyclic dipeptides.
- Egusa, Syun,Takagi, Jun,Sisido, Masahiko,Imanishi, Yukio
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p. 2195 - 2202
(2007/10/02)
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