- Catalytic dehydrative peptide synthesis with gem-diboronic acids
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Alkane-gem-diboronic acids have emerged as versatile organoboron catalysts for dehydrative amidation of α-Amino acids. A phenol-substituted multiboron catalyst with a B-C-B structure outperformed simple arylboronic acids in the condensation of α-Amino acids with suppressed epimerization of electrophiles. gem-diboronic acid catalysis were compatible with various O, N, and S-functionalized α-Amino acids bearing N-protecting groups including common carbamates used in peptide synthesis (Boc, Cbz, Fmoc). N-Trifluoroacetyl protection enabled an unprecedented catalytic dehydrative peptide synthesis at room temperature. Preliminary mechanistic studies revealed carboxylate-binding nature of gem-diboronic acids, orthogonal to the activation of carboxylic acids by arylboronic acids. The distinctive reactivity of the gem-diboronic acids would open prospects for mild catalytic peptide condensation.
- Michigami, Kenichi,Sakaguchi, Tatsuhiko,Takemoto, Yoshiji
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p. 683 - 688
(2020/01/02)
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- Macrocyclic inhibitors of the PD-1/PD-L1 and CD80(B7-1)/PD-L1 protein/protein interactions
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The present disclosure provides novel macrocyclic peptides which inhibit the PD-1/PD-L1 and PD-L1/CD80 protein/protein interaction, and thus are useful for the amelioration of various diseases, including cancer and infectious diseases.
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Page/Page column 703
(2016/05/09)
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- Immunomodulators
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The present disclosure provides novel macrocyclic peptides which inhibit the PD-1/PD-L1 and PD-L1/CD80 protein/protein interaction, and thus are useful for the amelioration of various diseases, including cancer and infectious diseases.
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Paragraph 0688; 0689
(2016/08/29)
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- SYNTHESIS OF DIAZOKETONES DERIVED FROM α-AMINO ACIDS; PROBLEM OF SIDE REACTIONS
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Optimum conditions of synthesis of eight diazoketones derived from optically active N-(t-butyloxycarbonyl)- and N-benzyloxycarbonylamino acids have been described.The problem of formation of by-products during Arndt-Eistert synthesis of β-homoamino acids at the stage of reaction of mixed anhydride with a weak nucleophile-diazomethane - has been discussed.
- Plucinska, Krystyna,Liberek, Bogdan
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p. 3509 - 3518
(2007/10/02)
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- ENZYMIC SYNTHESIS OF OLIGOPETIDE - VI. THE MECHANISTIC FEATURES OF PEPSIN-CATALYSED PEPTIDE SYNTHESIS
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The dipeptide Z-Phe-Phe-OBzl and tripeptide Z-Phe-Phe-Phe-OBzl were synthesized by pepsin catalysis from the incubation of Z-Phe and Phe-OBzl in the reaction solution.The yield ratio of two peptides in relation to reaction time was investigated by HPLC.Another example: The tripeptide Z-Phe-Leu-Phe-OBzl and tetrapeptide Z-Phe-Leu-Phe-Phe-OBzl were also synthesized concurrently from Z-Phe-Leu and Phe-OBzl by pepsin catalysis.These results may have important implication for the transpeptidation of pepsin.But, according to the report of Pellegrini and Luisi, the dipeptide, Z-Ph-Phe-OBzl, synthesized by pepsin catalysis was not contaminated with the tripeptide,Z-Phe-Phe-Phe-OBzl, and the yield was high.In order to investigate the discrepancies between our observation and those reported by Pellegrini and Luisi, a mechanism by which pepsin synthesizes the dipeptide, Z-Phe-Phe-OBzl, and tripeptide, Z-Phe-Phe-Phe-OBzl, is proposed and supporting data demonstrated by HPLC analysis.
- Tseng, Min-Jen,Wu, Shih-Hsiung,Wang, Kung-Tsung
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- ASYMMETRIC TRANSFORMATION OF AMINO ACIDS IN N-SALICYLIDENE AMINO ACYL-L-ISOLEUCINATOCOPPER(II)
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A new asymmetric transformation of amino acids was described.Thus, when N-salicylidene-D-alanyl-, D-phenylalanyl-, or D-phenyl-glycyl-L-isoleucinatocopper(II) was incubated at pH 8.5 and 80 deg C, the resulting mixture at equilibrium contained a complex of L-L-dipeptide in the contents of 63-76percent.The epimerization of dipeptides is based on the enhanced activity of N-terminal amino acids through complex formation.
- Harada, Kaoru,Shiono, Katsuji,Nomoto, Shinya
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p. 1271 - 1274
(2007/10/02)
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