- Synthesis of a series of ω-dimethylaminoalkyl substituted ethylenediamine ligands for use in enantioselective catalysis
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The title compounds H2NCH((CH2)nNMe2)CH2NH2 L1-L4 (n = 1-4) are efficiently synthesized in enantiopure form. The commercial starting materials, l-asparagine, (S)-5-hydroxymethyl-2-pyrrolidinone, and (S)-6-(((benzyloxy)carbonyl)-amino)-2-((tert-butoxycarbonyl)amino)hexanoic acid, are elaborated in 6-9 standard steps to give L1 (18% overall), L2 (13%), L3 (36%) and L4 (38%) or the corresponding tris(hydrochloric acid) salts [H3NCH((CH2)nNHMe2)CH2NH3]3+ 3Cl-, which are preferable for long term storage. The sequences make use of isobutyl carbamate, Cbz, and Boc protecting groups and Hofmann type rearrangements; the dimethylamino groups are introduced at late stages, either via reductive dimethylations or nucleophilic displacements involving mesylates and HNMe2. L1-L4 chelate to [Co(en)2]3+ fragments to give octahedral complexes that catalyze numerous enantioselective reactions.
- Ghosh, Subrata K.,Ganzmann, Carola,Gladysz, John A.
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p. 1273 - 1280
(2015/11/09)
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- A multifaceted secondary structure mimic based on piperidine-piperidinones
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Minimalist secondary structure mimics are typically made to resemble one interface in a protein-protein interaction (PPI), and thus perturb it. We recently proposed suitable chemotypes can be matched with interface regions directly, without regard for secondary structures. Here we describe a modular synthesis of a new chemotype 1, simulation of its solution-state conformational ensemble, and correlation of that with ideal secondary structures and real interface regions in PPIs. Scaffold 1 presents amino acid side-chains that are quite separated from each other, in orientations that closely resemble ideal sheet or helical structures, similar non-ideal structures at PPI interfaces, and regions of other PPI interfaces where the mimic conformation does not resemble any secondary structure. 68 different PPIs where conformations of 1 matched well were identified. A new method is also presented to determine the relevance of a minimalist mimic crystal structure to its solution conformations. Thus dld-1-faf crystallized in a conformation that is estimated to be 0.91 kcal-mol-1 above the minimum energy solution state. Do we know, when designing a new peptidomimetic scaffold like the one shown, how it can resemble secondary structures? Design and modular synthesis of this elongated mimic is reported, and the structure is related to ideal and real structures at PPI interfaces.
- Xin, Dongyue,Perez, Lisa M.,Ioerger, Thomas R.,Burgess, Kevin
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p. 3594 - 3598
(2014/04/17)
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- Synthesis of chiral triamines and diamines from amino acids
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Selectively protected (2S)-1,2,6-triaminohexane 4 was prepared from L-lysine by reduction of the amino acid, replacement of the hydroxy group by an azido group and selective reduction. Following the same method vicinal diamines 11 and 13 bearing a third functional group were synthesized from L-glutamic acid.
- Kokotos, George,Markidis, Theodoros,Constantinou-Kokotou, Violetta
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p. 1223 - 1226
(2007/10/03)
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