- N-Terminal Selective C?H Azidation of Proline-Containing Peptides: a Platform for Late-Stage Diversification
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A methodology for the C?H azidation of N-terminal proline-containing peptides was developed employing only commercially available reagents. Peptides bearing a broad range of functionalities and containing up to 6 amino acids were selectively azidated at the carbamate-protected N-terminal residue in presence of the numerous other functional groups present on the molecules. Post-functionalizations of the obtained aminal compounds were achieved: cycloaddition reactions or C?C bond formations via a sequence of imine formation/nucleophilic addition were performed, offering an easy access to diversified peptides.
- Allouche, Emmanuelle M. D.,Simonet-Davin, Rapha?l,Waser, Jerome
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supporting information
(2022/02/25)
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- L-Proline derived nitrogenous steroidal systems: An asymmetric approach to 14-azasteroids
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An efficient chiral pool approach using l-proline to access 14-azasteroids under mild reaction conditions has been described. The key step involves the intramolecular SN2′ cyclization reaction for the construction of critical C-ring in the nitrogen impregnated steroidal architectures bearing unsaturation at Δ9(11) position. In the endeavour to synthesize some new congeners, the remote electronic impact of the electron donating groups in A ring and heteroatoms like oxygen in B ring, on the propensity of C-ring cyclization was also observed.
- Singh, Ritesh,Panda, Gautam
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p. 19533 - 19544
(2013/10/22)
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- TRIAZINE KINASE INHIBITORS
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The invention provides compounds of formula I and pharmaceutically acceptable salts thereof. The formula I compounds inhibit tyrosine kinase activity thereby making them useful as anticancer agents.
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Page/Page column 57
(2010/08/08)
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- Design, construction and properties of peptide N-terminal cap templates devised to initiate α-helices. Part 2. Caps derived from N-[(2S)-2-chloropropionyl]-(2S)-Pro-(2S)-Pro-(2S,4S)-4-thioPro-OMe
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Recently, we designed 12-membered macrocyclic template caps to entrain peptides into α-helical structures, based on the covalent connection of the first and fourth residues of proline containing tetrapeptides. It was not possible to complete the synthesis of the templates from the acyclic precursors and it appeared that the generation of large molecular dipoles, caused by aligning the carbonyl groups, prevented reaction. While this work was in progress, Kemp's group published the structure of a 12-membered macrocyclic triproline template designed to initiate an α-helix that was very similar in structure to one of our own targets. However, the compound failed to cyclise in a conformation required for α-helix initiation and one or more carboxamide dipoles were not aligned. Here we provide a detailed conformational analysis of the system and test two methods for forcing the acyclic precursor into the macrocyclic conformation required for helix initiation. The first is the destabilisation of unwanted conformations in the transition state for cyclisation, and the second is the stabilisation of the favoured transition state structure through the introduction of a hydrogen-bonding interaction. Both strategies were unsuccessful and the reasons are discussed. A successful strategy which does not require the carbonyl dipoles to align in the transition state is presented in the following paper.
- Lewis, Arwel,Wilkie, John,Rutherford, Trevor J.,Gani, David
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p. 3777 - 3793
(2007/10/03)
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