- Microwave-assisted synthesis of the Sch?llkopf chiral auxiliaries: (3S)- and (3R)-3,6-dihydro-2,5-diethoxy-3-isopropyl-pyrazine
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A practical and efficient methodology for the laboratory scale preparation of Sch?llkopf's bis-lactim ether chiral auxiliaries (3S)- and (3R)-3,6-dihydro-2,5-diethoxy-3-isopropyl-pyrazine has been developed. The key step is the preparation of the 2,5-diketopiperazine derivative by microwave-assisted heating in water. The protocol avoids reactions at low temperature and the use of high boiling solvents. Only inexpensive and readily available starting materials are required. The bis-lactim ethers were produced in high yields on a multigram scale.
- Carlsson, Anna-Carin,Jam, Fariba,Tullberg, Marcus,Pilotti, ?ke,Ioannidis, Panos,Luthman, Kristina,Gr?tli, Morten
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Read Online
- Sila-substitution of the α-amino acid proline: Synthesis of rac- and (R)-4,4-Dimethyl-4-sila-proline ethyl ester
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In context with studies on silicon-containing α-amino acids and peptides, a strategy for the synthesis of the 4-sila-proline skeleton was developed. The synthesis of rac- and (R)-4,4-dimethyl-4-sila-proline ethyl ester [rac-2 and (R)-2] is described. Compounds rac-2 and (R)-2 (≥ 99% ee) were prepared by two-step syntheses, starting from 3,6-diethoxy-2,5-dihydropyrazine and (R)-3,6-diethoxy-2-isopropyl-2,5-dihydropyrazine, respectively.
- Handmann, Vera Iris,Merget, Markus,Tacke, Reinhold
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Read Online
- Stereostructure Clarifying Total Synthesis of the (Polyenoyl)tetramic Acid Militarinone B. A Highly Acid-Labile N-Protecting Group for Amides ?
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The 5S, 8′R, and 10′R configurations of militarinone B (3), which is a natural product from Paecilomyces militaris, should equal those in its biosynthetic precursor, militarinone C. The configuration at C-1′ emerged from syntheses of the militarinone B candidates 1′′S- and 1′′R-(5S,8′R,10′R)-3 from the building blocks 9, 11, 14, and 15a while introducing TMB as a more acid-labile N-protecting group for β-ketoamides than DMB. Comparisons of 1′′S- and 1′′R-(5S,8′R,10′R)-3 with natural militarinone B (3; reisolated from Nature) revealed identity versus distinctness.
- Drescher, Christian,Brückner, Reinhard
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p. 6194 - 6199
(2021/08/18)
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- Structure-Enabled Discovery of a Stapled Peptide Inhibitor to Target the Oncogenic Transcriptional Repressor TLE1
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TLE1 is an oncogenic transcriptional co-repressor that exerts its repressive effects through binding of transcription factors. Inhibition of this protein–protein interaction represents a putative cancer target, but no small-molecule inhibitors have been published for this challenging interface. Herein, the structure-enabled design and synthesis of a constrained peptide inhibitor of TLE1 is reported. The design features the introduction of a four-carbon-atom linker into the peptide epitope found in many TLE1 binding partners. A concise synthetic route to a proof-of-concept peptide, cycFWRPW, has been developed. Biophysical testing by isothermal titration calorimetry and thermal shift assays showed that, although the constrained peptide bound potently, it had an approximately five-fold higher Kd than that of the unconstrained peptide. The co-crystal structure suggested that the reduced affinity was likely to be due to a small shift of one side chain, relative to the otherwise well-conserved conformation of the acyclic peptide. This work describes a constrained peptide inhibitor that may serve as the basis for improved inhibitors.
- McGrath, Sally,Tortorici, Marcello,Drouin, Ludovic,Solanki, Savade,Vidler, Lewis,Westwood, Isaac,Gimeson, Peter,Van Montfort, Rob,Hoelder, Swen
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supporting information
p. 9577 - 9584
(2017/07/22)
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- The synthesis of methylated, phosphorylated, and phosphonated 3′-aminoacyl-tRNASec mimics
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The twenty first amino acid, selenocysteine (Sec), is the only amino acid that is synthesized on its cognate transfer RNA (tRNASec) in all domains of life. The multistep pathway involves O-phosphoseryl-tRNA: selenocysteinyl-tRNA synthase (SepSe
- Rigger, Lukas,Schmidt, Rachel L.,Holman, Kaitlyn M.,Simonovic, Miljan,Micura, Ronald
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supporting information
p. 15872 - 15878
(2014/04/03)
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- CYCLOPENTYL GLUTARAMIDES AND THEIR USE AS NEUTRAL ENDOPEPTIDASE INHIBITORS
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The invention relates to NEP inhibitors for treating cardiovascular disorders wherein R1 is C1-C6alkyl, C1-C6alkoxyC1-C3alkyl or C1-C6alkoxyC1-C
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- Synthesis of optically active ring-A substituted tryptophans as IDO inhibitors
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The first synthesis of optically active 7-methoxy-d-tryptophan as well as other ring-A substituted tryptophans is described.
- Li, Xiaoyan,Yin, Wenyuan,Sarma, P.V.V. Srirama,Zhou, Hao,Jun Ma,Cook, James M.
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p. 8569 - 8573
(2007/10/03)
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- A Strategy Towards the Stereoselective Synthesis of 5-Hydroxylysine
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A stereoselective synthesis of 5-hydroxylysine is described in which the α-stereogenic centre is generated by a Schoellkopf amino acid synthesis, and the ethanolamine structure is obtained via Sharpless aminohydroxylation from an olefin moiety. The reactions and their selectivities are studied.
- Loehr, Birgit,Orlich, Simone,Kunz, Horst
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p. 1139 - 1141
(2007/10/03)
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- Enantiospecific synthesis of 5-methoxy-D(+)- or L(-) tryptophan
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A method for the enantiospecific synthesis of 5-methoxy-D(+)-tryptophan 8 or the L(-)-optical antipode is described. This procedure can be scaled up and performed without the need for extensive chromatographic separations. It provides for the first time t
- Zhang,Cook
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p. 3883 - 3900
(2007/10/03)
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