66617-58-1Relevant academic research and scientific papers
Transition Metal-Free N-Arylation of Amino Acid Esters with Diaryliodonium Salts
Kervefors, Gabriella,Kersting, Leonard,Olofsson, Berit
supporting information, p. 5790 - 5795 (2021/03/08)
A transition metal-free approach for the N-arylation of amino acid derivatives has been developed. Key to this method is the use of unsymmetric diaryliodonium salts with anisyl ligands, which proved important to obtain high chemoselectivity and yields. The scope includes the transfer of both electron deficient, electron rich and sterically hindered aryl groups with a variety of different functional groups. Furthermore, a cyclic diaryliodonium salt was successfully employed in the arylation. The N-arylated products were obtained with retained enantiomeric excess.
Catalytic Transfer Hydrodebenzylation with Low Palladium Loading
Yakukhnov, Sergey A.,Ananikov, Valentine P.
supporting information, p. 4781 - 4789 (2019/09/16)
A highly-efficient catalytic system for hydrodebenzylation reaction is described. The cleavage of O-benzyl and N-benzyl protecting groups was performed using an uncommonly low palladium loading (0.02–0.3 mol%; TON up to 5000) in a relatively short reaction time. The approach was used for a variety of substrates including pharmaceutically important precursors, and gram-scale deprotection reaction was shown. Transfer conditions together with easy-to-make Pd/C catalyst are the key features of this debenzylation scheme. (Figure presented.).
A novel route towards cycle-tail peptides using oxime resin: Teaching an old dog a new trick
Bérubé, Christopher,Borgia, Alexandre,Voyer, Normand
supporting information, p. 9117 - 9123 (2019/01/03)
Two anabaenopeptins, Schizopeptin 791 and anabaenopeptin NZ825, have similar structural features and have been synthesized via a novel acid-catalyzed head-to-side-chain concomitant cyclization/cleavage reaction on oxime resin. The methodology gave rapid access to the anabaenopeptin scaffold by taking advantage of a combined solid-phase/solution-phase synthetic strategy. Also, as side-products of the synthesis, large C2-symmetric 38-member cyclic peptides ring bearing two endocyclic lysine side-chains were isolated, constituting a novel cyclic peptide scaffold.
Fluorinated epoxyketone-based compounds and uses thereof as proteasome inhibitors
-
Page/Page column 67, (2016/09/28)
The present application relates to novel fluorinated epoxyketone-based compounds, compositions comprising these compounds and their use, in particular for the treatment of diseases, disorders or conditions mediated by proteasome inhibition, in particular, the present application includes compounds of Formula I, and compositions and uses thereof.
Self-Assembly of Tetraphenylalanine Peptides
Mayans, Enric,Ballano, Gema,Casanovas, Jordi,Díaz, Angélica,Pérez-Madrigal, Maria M.,Estrany, Francesc,Puiggalí, Jordi,Cativiela, Carlos,Alemán, Carlos
, p. 16895 - 16905 (2015/11/16)
Three different tetraphenylalanine (FFFF) based peptides that differ at the N- and C-termini have been synthesized by using standard procedures to study their ability to form different nanoassemblies under a variety of conditions. The FFFF peptide assembles into nanotubes that show more structural imperfections at the surface than those formed by the diphenylalanine (FF) peptide under the same conditions. Periodic DFT calculations (M06L functional) were used to propose a model that consists of three FFFF molecules defining a ring through head-to-tail NH3+?-OOC interactions, which in turn stack to produce deformed channels with internal diameters between 12 and 16 ?. Depending on the experimental conditions used for the peptide incubation, N-fluorenylmethoxycarbonyl (Fmoc) protected FFFF self-assembles into a variety of polymorphs: ultra-thin nanoplates, fibrils, and star-like submicrometric aggregates. DFT calculations indicate that Fmoc-FFFF prefers a parallel rather than an antiparallel β-sheet assembly. Finally, coexisting multiple assemblies (up to three) were observed for Fmoc-FFFF-OBzl (OBzl = benzyl ester), which incorporates aromatic protecting groups at the two peptide terminals. This unusual and noticeable feature is attributed to the fact that the assemblies obtained by combining the Fmoc and OBzl groups contained in the peptide are isoenergetic. Variety show! Three different tetraphenylalanine-based peptides that differ at the N- and C-termini have been synthesized by using standard procedures to study their ability to form different nanoassemblies (e.g., nanotubes, see figure) under a variety of conditions.
Chiral recognition of carboxylates by a static library of thiourea receptors with amino acid arms
Ulatowski, Filip,Jurczak, Janusz
, p. 4235 - 4243 (2015/05/13)
Chiral recognition is based on a large network of very subtle interactions whose outcome is difficult to predict. A combinatorial approach is therefore the most suitable to search for the most efficient receptor and obtain a structure-enantioselectivity correlation. We synthesized a set of 12 receptors constructed with 1,9-diaminoantracene and α-amino acid esters, linked via thiourea groups. The association constants and enantioselectivities for the complexes with mandelate and N-acetylphenylalanine were determined by competitive NMR titrations. Association constants quite regularly depend on the substituents in the receptor structure, but the distribution of enantioselectivities across the library could not easily be rationalized.
Soluble non-cross-linked poly(norbornene) supports for peptide synthesis with minimal reagents
Naganna, Nimmashetti,Madhavan, Nandita
, p. 11549 - 11557 (2015/02/19)
Solid-phase peptide synthesis has been an attractive method for synthesizing peptides because it is quick and can be automated. The heterogeneous reaction medium in solid-phase peptide synthesis necessitates the use of large equivalents of reagents to drive the reactions to completion. Peptide synthesis using soluble, yet isolable, supports is an attractive alternative to solid-phase peptide synthesis. Reported herein is a soluble poly(norbornene)-derived support containing multiple attachment sites for high loading capacities and solubilizing oligoether/alkyl groups. The Ala-attached support has been used to synthesize tri- to octapeptides in 28 to 97% yields using only 1.2 equiv of amino acids and coupling reagents. The acyclic hexapeptide precursor to natural product segatalin A was synthesized in 41% yield on the support using one-eighth of the equivalents of coupling reagents compared to that in reported procedures. The support could be recovered in up to 98% yield after peptide synthesis, and the recovered support was utilized to synthesize tri- and tetrapeptides that contain amino acids other than Ala at the C-terminus in ca. 80% yields.
Ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o -NosylOXY): A recyclable coupling reagent for racemization-free synthesis of peptide, amide, hydroxamate, and ester
Dev, Dharm,Palakurthy, Nani Babu,Thalluri, Kishore,Chandra, Jyoti,Mandal, Bhubaneswar
, p. 5420 - 5431 (2014/07/08)
Ubiquitousness of amide and ester functionality makes coupling reactions extremely important. Although numerous coupling reagents are available, methods of preparation of the common and efficient reagents are cumbersome. Those reagents generate a substantial amount of chemical waste and lack recyclability. Ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o-NosylOXY), the first member of a new generation of coupling reagents, produces byproducts that can be easily recovered and reused for the synthesis of the same reagent, making the method more environmentally friendly and cost-effective. The synthesis of amides, hydroxamates, peptides, and esters using this reagent is described. The synthesis of the difficult sequences, for example, the islet amyloid polypeptide (22-27) fragment (with a C-terminal Gly, H-Asn-Phe-Gly-Ala-Ile-Leu-Gly-NH 2) and acyl carrier protein (65-74) fragment (H-Val-Gln-Ala-Ala-Ile- Asp-Tyr-Ile-Asn-Gly-OH), following the solid-phase peptide synthesis (SPPS) protocol and Amyloid β (39-42) peptide (Boc-Val-Val-IIe-Ala-OMe), following solution-phase strategy is demonstrated. Remarkable improvement is noticed with respect to reaction time, yield, and retention of stereochemistry. A mechanistic investigation and recyclability are also described.
Design, synthesis and biological evaluation of potent azadipeptide nitrile inhibitors and activity-based probes as promising anti-Trypanosoma brucei agents
Yang, Peng-Yu,Wang, Min,Li, Lin,Wu, Hao,He, Cynthia Y.,Yao, Shao Q.
supporting information; experimental part, p. 6528 - 6541 (2012/07/13)
Trypanosoma cruzi and Trypanosoma brucei are parasites that cause Chagas disease and African sleeping sickness, respectively. There is an urgent need for the development of new drugs against both diseases due to the lack of adequate cures and emerging drug resistance. One promising strategy for the discovery of small-molecule therapeutics against parasitic diseases has been to target the major cysteine proteases such as cruzain for T. cruzi, and rhodesain/TbCatB for T. brucei. Azadipeptide nitriles belong to a novel class of extremely potent cysteine protease inhibitors against papain-like proteases. We herein report the design, synthesis, and evaluation of a series of azanitrile-containing compounds, most of which were shown to potently inhibit both recombinant cruzain and rhodesain at low nanomolar/picomolar ranges. A strong correlation between the potency of rhodesain inhibition (i.e., target-based screening) and trypanocidal activity (i.e., whole-organism-based screening) of the compounds was observed. To facilitate detailed studies of this important class of inhibitors, selected hit compounds from our screenings were chemically converted into activity-based probes (ABPs), which were subsequently used for in situ proteome profiling and cellular localization studies to further elucidate potential cellular targets (on and off) in both the disease-relevant bloodstream form (BSF) and the insect-residing procyclic form (PCF) of Trypanosoma brucei. Overall, the inhibitors presented herein show great promise as a new class of anti-trypanosome agents, which possess better activities than existing drugs. The activity-based probes generated from this study could also serve as valuable tools for parasite-based proteome profiling studies, as well as bioimaging agents for studies of cellular uptake and distribution of these drug candidates. Our studies therefore provide a good starting point for further development of these azanitrile-containing compounds as potential anti-parasitic agents. Copyright
Selective esterifications of primary alcohols in a water-containing solvent
Wang, Yong,Aleiwi, Bilal A.,Wang, Qinghui,Kurosu, Michio
supporting information, p. 4910 - 4913,4 (2012/12/12)
Oxyma and an oxyma derivative, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-cyano-2-(hydroxyimino)acetate (5b), displayed a remarkable effect on selective esterifications of primary alcohols. A wide range of carboxylic acids could be esterified with primary alcohols by using EDCI, NaHCO3, and Oxyma or Oxyma derivative 5b in 5% H2O-CH3CN. Oxyma derivative 5b is particularly useful, since it could be removed after the reaction via a simple basic or an acidic aqueous workup procedure.
