- Electron transfer through the hydrogen-bonded interface of a β-turn- forming depsipeptide
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Hydrogen-bonding networks are believed to play an important role in electron-transfer pathways in a protein medium. A porphyrin-quinone donor- acceptor compound with a depsipeptide bridge which forms a β-turn has been synthesized to study hydrogen bond-mediated electron transfer. The placement of the donor and acceptor has been chosen to favor electron transfer through the hydrogen bond interface of the β-turn. Use of ester linkages also allows control of the hydrogen-bonding pattern within the β-turn-forming depsipeptide. Infrared spectroscopy in the amide A (NH stretch) and amide I (carbonyl stretch) regions indicates that the β-turn conformation is about 85% populated in dichloromethane and essentially completely disrupted in dimethyl sulfoxide at 296 K. The electron-transfer rate constant, k(et), was evaluated using the singlet excited-state lifetimes of the porphyrin in the presence and absence of an electron acceptor. The lifetimes were obtained using time-correlated single-photon-counting fluorescence spectroscopy. Very fast electron transfer (k(et) = (1.1 ± 0.1) x 109 s-1) was observed in the presence of the β-turn conformation. When the β-turn structure was disrupted using the solvent DMSO, electron transfer was no longer competitive with the intrinsic fluorescence emission. Analysis of the data in terms of Marcus theory and the pathway model for electronic coupling yielded a value for the hydrogen bond coupling decay factor, ε(hb), of 0.8 ± 0.4, which is of the same order of magnitude as the theoretically predicted value of 0.36.
- Williamson, David A.,Bowler, Bruce E.
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- Comparison of enantioselective reductions using bead and monolith 'disk' polymer formulations of CBS catalysts
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Two polymer-supported versions of the Corey, Bakshi, and Shibata (CBS) catalyst were prepared and examined. Polymeric beads, with the auxiliary bound in pendant and crosslinked fashion, were prepared utilizing an improved procedure based upon earlier work. Optimization of a procedure for ketone reduction gives results that match those in solution. Attempted reuse gave mixed results. For comparison purposes, CBS functionalized monoliths were formed and tested but performed poorly.
- Varela, Michael C.,Dixon, Seth M.,Price, Michael D.,Merit, Jeffrey E.,Berget, Patrick E.,Shiraki, Saori,Kurth, Mark J.,Schore, Neil E.
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- Psychrophilin E, a new cyclotripeptide, from co-fermentation of two marine alga-derived fungi of the genus Aspergillus
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Chemical investigation of the mycelial extract of a mixed culture of two marine alga-derived fungal strains of the genus Aspergillus has yielded one new cyclotripeptide, psychrophilin E (1), the recently reported oxepin-containing alkaloids, protuboxepin A (2) and oxepinamide E (3), together with three other polyketide derivatives (4-6). The chemical structure and relative and absolute configurations of psychrophilin E (1) were unambiguously established based on HRMS, 1D, 2D NMR and chiral-phase HPLC analysis of its hydrolysate. All the isolated compounds were assessed for their anti-proliferative activity against four different human cancer cell lines and some of them revealed selective activities. 2014
- Ebada, Sherif S.,Fischer, Thomas,Hamacher, Alexandra,Du, Feng-Yu,Roth, Yoen Ok,Kassack, Matthias U.,Wang, Bin-Gui,Roth, Eckhard H.
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- Synthesis of pyrrolo- and pyrido[1,2-a]xanthene [1,9-de]azepines: A study of the azepine ring construction
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(Chemical Equation Presented) Pentacyclic pyrrolo- and pyrido[1,2-a] xanthene[1,9-de]azepines were synthesized in various oxidation states by assembling the azepine ring following two strategies: 7-endo-trig cyclization of the aryl radical derived from a γ-methylene lactam and cyclodehydration of aldehydes. Other strategies examined (Heck reaction and intramolecular acylation) did not afford azepines, but six-membered nitrogenated rings.
- De La Fuente, M. Carmen,Dominguez, Domingo
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- Diastereoselective hydrogenation of a tricyclic α,β -dehydrodipeptide
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An unsaturated diketopiperazine derivative with a tricyclic α, β-dehydrodipeptide structure was isolated as a reaction intermediate in the hydrogenation of pyrazine-2-(methyl-(S)-prolinecarboxamide). The diastereoselective hydrogenation of this dehydrodipeptide was studied using various noble metals (Pd, Pt, Rh, and Ru) supported on charcoal. The hydrogenation over Pd, Rh, and Ru catalysts proceeded with a high diastereoselectivity (71-79%), and the diastereomer with the (S)-configuration on both chiral carbon atoms was formed preferentially. The reaction rates and diastereoselectivities of the hydrogenation over the Pd, Rh, and Ru catalysts were similar, while the platinum catalyst was much less active and selective (48% d.e.). The obtained results were compared with those of the hydrogenation of pyrazine-2-(methyl-(S)-prolinecarboxamide); two different pathways for the hydrogenation of this molecule were suggested. In one path, cyclization already occurs after hydrogenation to the tetrahydropyrazine molecule, and in the other path cyclization occurs after full hydrogenation of the pyrazine molecule.
- Kukula, Pavel,Prins, Roel
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- Synthesis of new mono- and bisorganophosphorus proline derivatives with P–C–N moieties
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The various methods of aminomethylation of some PH-acids with proline and their derivatives are investigated. The numerous derivatives of proline and corresponding phosphonates, phosphonites, phosphinates, and phosphorane with proline moieties are presented.
- Prishchenko, Andrey A.,Livantsov, Mikhail V.,Novikova, Olga P.,Livantsova, Ludmila I.,Petrosyan, Valery S.
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- Synthesis and properties of novel chiral ionic liquids from L-proline
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A novel class of chiral ionic liquids with chiral cations directly derived from natural l-proline has been synthesized and their physical properties such as melting point, thermal degradation, and specific rotation have been characterized. Further, their potential use in chiral recognition was demonstrated by studying interactions with racemic Mosher's acid salt. CSIRO 2008.
- Gao, Hong-Shuai,Hu, Zhi-Guo,Wang, Jian-Ji,Qiu, Zhao-Fa,Fan, Feng-Qiu
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- Diastereoselective Synthesis of Fluorine-Containing Pyrrolizidines via Triphenylcarbenium Tetrafluoroborate-Promoted Carbofluorination of N-3-Arylpropargylpyrrolidine-Tethered Tertiary Allylic Alcohols
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Inexpensive and air stable triphenylcarbenium tetrafluoroborate efficiently promoted the carbofluorination of N-arylpropargylpyrrolidines bearing a tertiary allylic alcohol tether at the 2-position of the pyrrolidine ring to provide 1-isobutenyl-2-(fluoro(phenyl)methylenylhexahydro-1H-pyrrolizidines in a stereoselective fashion. When subjected to bis(trifluoromethane)sulfonamide, the same substrates underwent cycloisomerization reaction within minutes to generate 1-isobutenyl-2-benzoylhexahydro-1H-pyrrolizidines with excellent stereoselectivity.
- Yeh, Ming-Chang P.,Chen, Hsiao-Feng,Huang, Yu-Ya,Weng, Yu-Ting
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- Conformational analysis and intramolecular interactions of l -proline methyl ester and its N -acetylated derivative through spectroscopic and theoretical studies
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This work reports a detailed study regarding the conformational preferences of l-proline methyl ester (ProOMe) and its N-acetylated derivative (AcProOMe) to elucidate the effects that rule their behaviors, through nuclear magnetic resonance (NMR) and infrared (IR) spectroscopies combined with theoretical calculations. These compounds do not present a zwitterionic form in solution, simulating properly amino acid residues in biological media, in a way closer than amino acids in the gas phase. Experimental 3JHH coupling constants and infrared data showed excellent agreement with theoretical calculations, indicating no variations in conformer populations on changing solvents. Natural bond orbital (NBO) results showed that hyperconjugative interactions are responsible for the higher stability of the most populated conformer of ProOMe, whereas for AcProOMe both hyperconjugative and steric effects rule its conformational equilibrium.
- Braga, Carolyne B.,Ducati, Lucas C.,Tormena, Claudio F.,Rittner, Roberto
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- A novel 2 H -azirin-3-amine as a synthon for a sulfur-containing dipeptide segment
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Starting with tetrahydro-2H-thiopyran-4-carboxylic acid and methyl prolinate, the novel 2H-azirin-3-amine [S]-N-(1-aza-6-thiaspiro[2.5]oct-1-en-2- yl)proline methyl ester was synthesized. In reactions with benzoic acid, thiobenzoic acid and Boc-valine, respectively, its usefulness as a synthon for the dipeptide [S]-N-[(4-aminotetrahydro-2H-thiopyran-4-yl)carbonyl]proline in peptide synthesis was demonstrated.
- Stoykova, Svetlana A.,Linden, Anthony,Heimgartner, Heinz
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- Diastereomeric atropisomers from a chiral diyne by cobalt(I)-catalyzed cyclotrimerization
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The reaction of new, chiral, proline-based naphthyl diynes with different nitriles through a key [2+2+2] cycloaddition reaction step catalyzed by Co I-olefin complexes under thermal and photochemical conditions gave diastereomeric atropisomers in good yield and nearly 1:1 ratios. Facile chromatographic separation of the naphthyl tetrahydroisoquinolines gave access to both pure and stable diastereomeric atropisomers. The deprotection and direct functionalization of the methyl-or methoxymethyl-protected 2-naphthyl position of the atropisomers were investigated. The configuration of the formed atropisomers was assigned from results of X-ray studies and circular dichroism spectroscopy.
- Fischer, Fabian,Jungk, Phillip,Weding, Nico,Spannenberg, Anke,Ott, Holger,Hapke, Marko
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- Aldehyde-based racemization in the dynamic kinetic resolution of N-heterocyclic α-amino esters using Candida antarctica lipase A
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The present research introduces approaches for the dynamic kinetic resolution of the methyl esters of proline and pipecolic acid. As the result, a method was developed which is based on the acylation of the secondary amino group of the amino esters with vinyl butanoate by Candida antarctica lipase A. In the optimized method, acetaldehyde as a racemizing agent is released in situ from vinyl butanoate in the presence of triethylamine, allowing ca. 90% of the racemic proline and 70% of the pipecolic acid methyl esters to be acylated in the forms of highly enantiopure (ee=97%) butanamides with the S-absolute configurations.
- Liljeblad, Arto,Kiviniemi, Anu,Kanerva, Liisa T.
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- A transition metal-catalyzed enyne metathesis for the preparation of pyrrolizidine alkaloid core: Application towards the total synthesis of stemaphylline
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In this paper, we disclose an efficient route for the synthesis of pyrrolizidine alkaloid core and its application towards the total synthesis of stemaphylline. The key pyrrolizidine core was achieved with Ru-carbene catalyzed ring closing enyne metathesis (RCEM). The effect of different types and amounts of Ru-carbene catalysts, solvents and temperature were systematically studied. The advantage of this method includes the construction of pyrrolizidine alkaloid core in a single operation.
- Kumar, Praveen,Rahman, Md. Ataur,Haque, Ashanul,Singh Yadav, Jhillu
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supporting information
(2021/03/03)
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- London Dispersion Interactions Rather than Steric Hindrance Determine the Enantioselectivity of the Corey–Bakshi–Shibata Reduction
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The well-known Corey–Bakshi–Shibata (CBS) reduction is a powerful method for the asymmetric synthesis of alcohols from prochiral ketones, often featuring high yields and excellent selectivities. While steric repulsion has been regarded as the key director of the observed high enantioselectivity for many years, we show that London dispersion (LD) interactions are at least as important for enantiodiscrimination. We exemplify this through a combination of detailed computational and experimental studies for a series of modified CBS catalysts equipped with dispersion energy donors (DEDs) in the catalysts and the substrates. Our results demonstrate that attractive LD interactions between the catalyst and the substrate, rather than steric repulsion, determine the selectivity. As a key outcome of our study, we were able to improve the catalyst design for some challenging CBS reductions.
- Eschmann, Christian,Song, Lijuan,Schreiner, Peter R.
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supporting information
p. 4823 - 4832
(2021/02/01)
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- AN ORAL PHARMACEUTICAL COMPOSITION FOR ALPHA- AMYLASE INHIBITION
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The present invention relates to an oral pharmaceutical composition of synthesized amino acid derivative which is inhibitor of alpha-amylase. In particular, the invention refers to the use of the composition for the treatment of diabetes mellitus type II. The said composition is in the form of a liquid, gel, pill, capsule or tablet.
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Paragraph 0033-0034
(2021/02/12)
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- Tetrahydropyrido [3, 4-d] pyrimidine derivative and medical application thereof
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The invention relates to a compound as shown in a general formula (I) or a stereoisomer, a deuterated compound, a solvate, a prodrug, a metabolite, a pharmaceutically acceptable salt or eutectic crystal thereof, an intermediate and a preparation method thereof, and application of the compound in preparation of drugs for treating diseases related to KRas-G12C activity or expression quantity.
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Paragraph 0273; 0277; 0314-0318
(2021/03/06)
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- Modular Synthesis of Alkenyl Sulfamates and β-Ketosulfonamides via Sulfur(VI) Fluoride Exchange (SuFEx) Click Chemistry and Photomediated 1,3-Rearrangement
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Herein, we report a synthesis of medicinally relevant β-ketosulfonamides via a photomediated 1,3-rearrangement of alkenyl sulfamates. This protocol tolerates a wide array of sensitive functional groups including alkenes, alkynes, and nitrogen-based heterocycles. Additionally, this work provides a general approach toward alkenyl sulfamates via a two-step Sulfur(VI) Fluoride Exchange (SuFEx) sequence capitalizing on SO2F2 as a linchpin to efficiently couple readily available ketones and amines without a large excess of either partner.
- Sousa E Silva, Felipe Cesar,Doktor, Katarzyna,Michaudel, Quentin
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supporting information
p. 5271 - 5276
(2021/07/20)
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- X-ray Structure-Guided Discovery of a Potent, Orally Bioavailable, Dual Human Indoleamine/Tryptophan 2,3-Dioxygenase (hIDO/hTDO) Inhibitor That Shows Activity in a Mouse Model of Parkinson’s Disease
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Human indoleamine 2,3-dioxygenase 1 (hIDO1) and tryptophan 2,3-dioxygenase (hTDO) have been closely linked to the pathogenesis of Parkinson’s disease (PD); nevertheless, development of dual hIDO1 and hTDO inhibitors to evaluate their potential efficacy against PD is still lacking. Here, we report biochemical, biophysical, and computational analyses revealing that 1H-indazole-4-amines inhibit both hIDO1 and hTDO by a mechanism involving direct coordination with the heme ferrous and ferric states. Crystal structure-guided optimization led to23, which manifested IC50values of 0.64 and 0.04 μM to hIDO1 and hTDO, respectively, and had good pharmacokinetic properties and brain penetration in mice.23showed efficacy against the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse motor coordination deficits, comparable to Madopar, an anti-PD medicine. Further studies revealed that different from Madopar,23likely has specific anti-PD mechanisms involving lowering IDO1 expression, alleviating dopaminergic neurodegeneration, reducing inflammatory cytokines and quinolinic acid in mouse brain, and increasing kynurenic acid in mouse blood.
- Ning, Xiang-Li,Li, Yu-Zhi,Huo, Cui,Deng, Ji,Gao, Cheng,Zhu, Kai-Rong,Wang, Miao,Wu, Yu-Xiang,Yu, Jun-Lin,Ren, Ya-Li,Luo, Zong-Yuan,Li, Gen,Chen, Yang,Wang, Si-Yao,Peng, Cheng,Yang, Ling-Ling,Wang, Zhou-Yu,Wu, Yong,Qian, Shan,Li, Guo-Bo
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supporting information
p. 8303 - 8332
(2021/06/30)
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- Transition Metal-Free N-Arylation of Amino Acid Esters with Diaryliodonium Salts
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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.
- Kervefors, Gabriella,Kersting, Leonard,Olofsson, Berit
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supporting information
p. 5790 - 5795
(2021/03/08)
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- Continuous flow heterogeneous catalytic reductive aminations under aqueous micellar conditions enabled by an oscillatory plug flow reactor
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Despite the fact that continuous flow processing exhibits well-established technical advances, aqueous micellar chemistry, a field that has proven extremely useful in shifting organic synthesis to sustainable water-based media, has mostly been explored under conventional batch-based conditions. This is particularly because of the fact that the reliable handling of slurries and suspensions in flow has been considered as a significant technical challenge. Herein, we demonstrate that the strategic application of an oscillatory plug flow reactor enables heterogeneous catalytic reductive aminations in aqueous micellar media enhancing mass transport and facilitating process simplicity, stability and scalability. The micellar flow process enabled a broad range of substrates, including amino acid derivatives, to be successfully transformed under reasonably mild conditions utilizing only very low amounts of Pd/C as a readily available heterogeneous catalyst. The preparative capabilities of the process along with the recyclability of the heterogenous catalyst and the aqueous reaction media were also demonstrated. This journal is
- ?tv?s, Sándor B.,Buchholcz, Balázs,Darvas, Ferenc,Kappe, C. Oliver,Novák, Zoltán,Sipos, Gellért,Wernik, Michaela
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supporting information
p. 5625 - 5632
(2021/08/16)
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- Stereoretentive N-Arylation of Amino Acid Esters with Cyclohexanones Utilizing a Continuous-Flow System
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The N-arylation of chiral amino acid esters with minimal racemization is a challenging transformation because of the sensitivity of the α-stereocenter. A versatile synthetic method was developed to prepare N-arylated amino acid esters using cyclohexanones as aryl sources under continuous-flow conditions. The designed flow system, which consists of a coil reactor and a packed-bed reactor containing a Pd(OH)2/C catalyst, efficiently afforded the desired N-arylated amino acids without significant racemization, accompanied by only small amounts of easily removable co-products (i. e., H2O and alkanes). The efficiency and robustness of this method allowed for the continuous synthesis of the desired product in very high yield and enantiopurity with high space-time yield (74.1 g L?1 h?1) and turnover frequency (5.9 h?1) for at least 3 days.
- Ichitsuka, Tomohiro,Komatsuzaki, Shingo,Masuda, Koichiro,Koumura, Nagatoshi,Sato, Kazuhiko,Kobayashi, Shū
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supporting information
p. 10844 - 10848
(2021/05/31)
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- Design and Synthesis of 56 Shape-Diverse 3D Fragments
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Fragment-based drug discovery is now widely adopted for lead generation in the pharmaceutical industry. However, fragment screening collections are often predominantly populated with flat, 2D molecules. Herein, we describe a workflow for the design and synthesis of 56 3D disubstituted pyrrolidine and piperidine fragments that occupy under-represented areas of fragment space (as demonstrated by a principal moments of inertia (PMI) analysis). A key, and unique, underpinning design feature of this fragment collection is that assessment of fragment shape and conformational diversity (by considering conformations up to 1.5 kcal mol?1 above the energy of the global minimum energy conformer) is carried out prior to synthesis and is also used to select targets for synthesis. The 3D fragments were designed to contain suitable synthetic handles for future fragment elaboration. Finally, by comparing our 3D fragments with six commercial libraries, it is clear that our collection has high three-dimensionality and shape diversity.
- Atobe, Masakazu,Blakemore, David C.,Bond, Paul S.,Chan, Ngai S.,De Fusco, Claudia,Downes, Thomas D.,Firth, James D.,Hubbard, Roderick E.,Jones, S. Paul,Klein, Hanna F.,O'Brien, Peter,Roughley, Stephen D.,Vidler, Lewis R.,Waddelove, Laura,Whatton, Maria Ann,Wheldon, Mary C.,Woolford, Alison J.-A.,Wrigley, Gail L.
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supporting information
(2020/07/13)
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- Discovery of γ-Lactam alkaloid derivatives as potential fungicidal agents targeting steroid biosynthesis
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Biological control of plant pathogens is considered as one of the green and effective technologies using beneficial microorganisms or microbial secondary metabolites against plant diseases, and so microbial natural products have played important roles in the research and development of new and green agrochemicals. To explore the potential applications for natural γ-lactam alkaloids and their derivatives, 26 γ-lactams that have flexible substituent patterns were synthesized and characterized, and their in vitro antifungal activities against eight kinds of plant pathogens belonging to oomycetes, basidiomycetes, and deuteromycetes were fully evaluated. In addition, the high potential compounds were further tested using an in vivo assay against Phytophthora blight of pepper to verify a practical application for controlling oomycete diseases. The potential modes of action for compound D1 against Phytophthora capsici were also investigated using microscopic technology (optical microscopy, scanning electron microscopy, and transmission electron microscopy) and label-free quantitative proteomics analysis. The results demonstrated that compound D1 may be a potential novel fungicidal agent against oomycete diseases (EC50 = 4.9748 μg·mL-1 for P. capsici and EC50 = 5.1602 μg·mL-1 for Pythium aphanidermatum) that can act on steroid biosynthesis, which can provide a certain theoretical basis for the development of natural lactam derivatives as potential antifungal agents.
- Cao, Xiufang,Huang, Daye,Huang, Wenbo,Ke, Shaoyong,Song, Di,Wang, Shuangshuang
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p. 14438 - 14451
(2020/12/23)
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- Chiral binaphthalene-aza-polycyclic ligand and preparation method thereof
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The invention discloses a chiral binaphthalene aza-polycyclic ligand and a preparation method thereof. The ligand has the following structure. The preparation method comprises the following steps: (1)by taking 1, 1 '-binaphthalene 2, 2'-diphenol as a raw material, carrying out methyl protection, Tf2O protection, methylation, aromatic ring substitution and bromination reaction to obtain a 2-bromomethyl -2'-methoxy 1, 1'-binaphthalene derivative (compound V); (2) starting from aza-polycyclic carboxylic acids such as L -or D-proline, L -or D-2-piperidinecarboxylic acid, L- or D-acridine -acid and the like, carrying out derivatization to obtain various amino alcohols (compounds B); and (3) coupling the compound V and the compound B under an alkaline condition and a catalyst, and removing a protecting group to obtain the binaphthalene aza-polycyclic chiral ligand L. The ligand has central chirality and axial chirality at the same time, and can obtain higher reaction activity and enantioselectivity in asymmetric catalytic reaction. The ligands are simple to prepare, raw materials are easy to obtain, and the ligands have important significance for asymmetric synthesis.
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Paragraph 0108; 0135-0138
(2021/01/11)
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- Synthesis and photophysics of benzazole based triazoles with amino acid-derived pendant units. Multiparametric optical sensors for BSA and CT-DNA in solution
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Herein we report the synthesis of a series of amino acid-derived triazoles by an organocatalytic cycloaddition reaction between azides and carbonyl compounds, catalyzed by a simple amine. These compounds present absorption maxima located in the UV-B ascribed to fully spin and symmetry allowed electronic transitions and a main fluorescence emission in the UV-A (~380 nm) with a relatively large Stokes shift (5700 cm?1). No significant solvatochromism was observed in both ground and excited states. Unexpectedly, the benzoxazole derivatives presented much higher fluorescence quantum yield values (40–80%) of compared to the sulfur analogues (3–6%). In addition, the DNA binding assays indicated that these compounds presented strong interaction with CT-DNA, which could be attributed to π-stacking and intermolecular hydrogen-bonding. The interaction of the benzazoles with bovine serum albumin (BSA) was also investigated, where a suppression mechanism was observed. In each case, docking was performed to better understand the observed interactions.
- Debia, Natalí P.,Rodríguez, Juan J.P.,da Silveira, Carolina H.,Chaves, Otavio A.,Iglesias, Bernardo A.,Rodembusch, Fabiano S.,Lüdtke, Diogo S.
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- Reductive Alkylation of Amines with Carboxylic Ortho Esters
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We have demonstrated for the first time that carboxylic ortho esters could be used as an alkylating agent in the reductive alkylation of amines. A variety of amines, including amino acid esters, were alkylated affording mono-alkylated products with high selectivity in practical to high yields using standard heterogeneous catalysts. By applying acyclic ortho esters alkylation was completed at room temperature. (Figure presented.).
- Kadyrov, Renat,Moebus, Konrad
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supporting information
p. 3352 - 3357
(2020/07/04)
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- Basicities and Nucleophilicities of Pyrrolidines and Imidazolidinones Used as Organocatalysts
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The Br?nsted basicities pKaH (i.e., pKa of the conjugate acids) of 32 pyrrolidines and imidazolidinones, commonly used in organocatalytic reactions, have been determined photometrically in acetonitrile solution using CH acids as indicators. Most investigated pyrrolidines have basicities in the range 16 aH aH aH 12.6) and the 2-imidazoliummethyl-substituted pyrrolidine A21 (pKaH 11.1) are outside the typical range for pyrrolidines with basicities comparable to those of imidazolidinones. Kinetics of the reactions of these 32 organocatalysts with benzhydrylium ions (Ar2CH+) and structurally related quinone methides, common reference electrophiles for quantifying nucleophilic reactivities, have been measured photometrically. Most reactions followed second-order kinetics, first order in amine and first order in electrophile. More complex kinetics were observed for the reactions of imidazolidinones and several pyrrolidines carrying bulky 2-substituents, due to reversibility of the initial attack of the amines at the electrophiles followed by rate-determining deprotonation of the intermediate ammonium ions. In the presence of 2,4,6-collidine or 2,6-di-tert-butyl-4-methyl-pyridine, the deprotonation of the initial adducts became faster, which allowed the rate of the attack of the amines at the electrophiles to be determined. The resulting second-order rate constants k2 followed the correlation log?k2(20 °C) = sN(N + E), where electrophiles are characterized by one parameter (E) and nucleophiles are characterized by the two solvent-dependent parameters N and sN. In this way, the organocatalysts A1-A32 were integrated in our comprehensive nucleophilicity scale, which compares n-, -, and σ-nucleophiles. The nucleophilic reactivities of the title compounds correlate only poorly with their Br?nsted basicities.
- An, Feng,Maji, Biplab,Min, Elizabeth,Ofial, Armin R.,Mayr, Herbert
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supporting information
p. 1526 - 1547
(2020/02/04)
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- Anti-tumor diazo dicyclic apoptosis protein inhibitor
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The invention provides a novel apoptosis protein inhibitor or pharmaceutically acceptable salts and isomers as well as preparation methods thereof and a pharmaceutical composition. The definition of each group is shown in the description. The invention further provides application of the compound and pharmaceutically acceptable salts and isomers thereof to preparation of medicines for treating IAP(Immimmunosuppressive Acidic Protein) related diseases. The compound disclosed by the invention has high binding affinity to XIAP, cIAP1 and cIAP2 proteins, has an excellent inhibiting effect on cellgrowth in MDA-MB-231 breast cancer and PC-3 pancreatic cancer cell lines, and also has high medicinal value and wide market prospects.
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Paragraph 0092-0094
(2019/08/01)
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- Novel chiral amine oxide ligand and preparation method thereof
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The invention provides a novel chiral amine oxide ligand and a preparation method thereof. The method uses a simple amino acid or an amino acid derivative as a raw material, the raw material is modified, the modified material reacts with substances such as a coupling agent and an alkali, and therefore the pincher configuration chiral ligand compound is obtained, that is, the chiral amine oxide ligand. The chiral amine oxide ligand provided by the invention has a structure of a non-simple linear chain, has a soft skeleton in the molecular structure, contains a recognition gene containing heteroatoms such as oxygen or nitrogen, and can well coordinate with a series of metals and realize high enantioselectivity and high reactivity in a non-symmetric reaction; and the preparation method is simple, the steps are few, and the raw materials are cheap and easy to obtain.
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Paragraph 0086; 0090; 0091; 0092; 0093; 0094
(2019/05/15)
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- Chiral urea-based ligand and preparation method thereof
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The invention discloses a chiral urea-based ligand and a preparation method thereof. The preparation method comprises the following steps: step 1, dissolving a chiral amine and isocyanate or isothiocyanate into an organic solvent according to a molar ratio of 1:(1-1.2), and performing full mixing; and step 2, performing a reaction at a temperature of -5 DEG C to 35 DEG C for 1-18 h, and performingcolumn chromatography purification to obtain the desired chiral urea-based ligand. The chiral urea-based ligand obtained by the method has a non-simple linear chain in the molecular structure and a soft skeleton in the molecular structure; the chiral urea-based ligand can utilizes multiple hydrogen-bond interaction of the urea structure to activate an electrophilic reagent or a nucleophilic reagent to improve the catalytic performance; and the chiral urea-based ligand has high enantioselectivity and high reactivity in an asymmetric reaction, the preparation method is simple, the steps are few, and the raw materials are cheap and easy to obtain.
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Paragraph 0074; 0075; 0076; 0077
(2019/07/04)
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- Catalytic Mechanism Study on the 1,2- and 1,4-Transfer Hydrogenation of Ketimines and β-Enamino Esters Catalyzed by Axially Chiral Biscarboline-Based Alcohols
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Axial N-O alcohols, which have two large carboline moieties connected to the axis were synthesized and used in catalytic enantioselective 1,2- and 1,4-transfer hydrogenations of total 26 ketimines and β-enamino esters. Excellent levels of enantioselectivity ranging from 91% to 99% were achieved by using catalyst (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide. Interestingly, a mixture of (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide and (aR)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide was also able to provide high enantioselectivities up to 95% that is the same as that using pure (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide. A plausible catalytic mechanism was suggested and total four kinds of transition states (TS) including almost 60 TS structures were investigated using density functional theory (DFT) with different basis sets such as 6-311G(2d,p). The predicted activation energy data are consistent with the experimental results. (Figure presented.).
- Dong, Mengxian,Wang, Jie,Wu, Shijie,Zhao, Yang,Ma, Yangyang,Xing, Yongfei,Cao, Fei,Li, Longfei,Li, Zhenqiu,Zhu, Huajie
-
supporting information
p. 4602 - 4610
(2019/08/30)
-
- Efficient synthesis of methyl (S)-4-(1-methylpyrrolidin-2-YL)-3-oxobutanoate as the key intermediate for tropane alkaloid biosynthesis with optically acitve form
-
Methyl (S)-4-(1-methylpyrrolidin-2-yl)-3-oxobutanoate has been synthesized for enzymatic studies on cyclization enzymes during cocaine biosynthesis in Erythroxylum coca plants. During the present new synthesis, L-proline was first protected with Cbz group and reduced to chiral amino alcohol, which were then followed by Swern oxidation, Wittig reaction and decarboxylative condensation. At the last step, N-methylamino acid precursor was treated with 1,1'-carbonyldiimidazole followed by reacting with methyl potassium malonate to give the 3-oxobutanoate in 54% overall yield. This new strategy has proven to avoid obvious racemization of the L-proline chiral center during the synthesis. In addition, six of the eight synthesis steps were performed via GAP chemistry/technology without the use of column chromatography for purification.
- Katakam, Nanda Kumar,Seifert, Cole W.,D'Auria, John,Li, Guigen
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p. 604 - 613
(2019/08/01)
-
- Tetrazole as a Replacement of the Electrophilic Group in Characteristic Prolyl Oligopeptidase Inhibitors
-
4-Phenylbutanoyl-aminoacyl-2(S)-tetrazolylpyrrolidines were studied as prolyl oligopeptidase inhibitors. The compounds were more potent than expected from the assumption that the tetrazole would also here be a bioisostere of the carboxylic acid group and the corresponding carboxylic acids are at their best only weak inhibitors. The aminoacyl groups l-prolyl and l-alanyl gave potent inhibitors with IC50 values of 12 and 129 nM, respectively. This was in line with typical prolyl oligopeptidase inhibitors; however, we did observe a difference with N-methyl-l-alanyl, which gave potent inhibitors in typical prolyl oligopeptidase inhibitors but not in our novel compound series. Furthermore, all studied 4-phenylbutanoyl-aminoacyl-2(S)-tetrazolylpyrrolidines decreased α-synuclein dimerization at the concentration of 10 μM, also when they were only weak inhibitors of the proteolytic activity of the enzyme with an IC50 value of 205 μM. Molecular docking studies revealed that the compounds are likely to bind differently to the enzyme compared to typical prolyl oligopeptidase inhibitors represented in this study by 4-phenylbutanoyl-aminoacyl-2(S)-cyanopyrrolidines.
- Kilpel?inen, Tommi P.,Tyni, Jonna K.,Lahtela-Kakkonen, Maija K.,Etel?inen, Tony S.,My?h?nen, Timo T.,Wallén, Erik A. A.
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supporting information
p. 1635 - 1640
(2019/12/02)
-
- Lewis Acid Catalyzed Enantioselective Photochemical Rearrangements on the Singlet Potential Energy Surface
-
The oxadi-methane rearrangement of 2,4-cyclohexadienones to bicyclic ketones was found to proceed with high enantioselectivity (92-97% ee) in the presence of catalytic amounts of a chiral Lewis acid (15 examples, 52-80% yield). A notable feature of the transformation is the fact that it proceeds on the singlet hypersurface and that no triplet intermediates are involved. Rapid racemic background reactions were therefore avoided, and the catalyst loading could be kept low (10 mol %). Computational studies suggest that the enantioselectivity is determined within a Lewis acid bound singlet intermediate via a conical intersection. The utility of the method was demonstrated by a concise synthesis of the natural product trans-chrysanthemic acid.
- Leverenz, Malte,Merten, Christian,Dreuw, Andreas,Bach, Thorsten
-
supporting information
p. 20053 - 20057
(2019/12/30)
-
- Prolinamide functionalized polyacrylonitrile fiber with tunable linker length and surface microenvironment as efficient catalyst for Knoevenagel condensation and related multicomponent tandem reactions
-
A series of new prolinamide polyacrylonitrile fiber catalysts with tunable length of alkyl linker and different linker group were prepared by covalent bonding for the first time and well characterized by mechanical strength, FT-IR, XRD, EA, TGA, SEM and water contact angel. The catalytic activities of these fiber catalysts were evaluated in Knoevenagel condensation and one-pot Knoevenagel-Michael multicomponent tandem reactions to synthesize α, β-unsaturated nitrile and 2-amino-4H-chromene derivatives in water. The result show that the suitable linker length attaching amines to fiber matrix as well as the constructed hydrophobic microenvironment by linker group within the surface layers of fiber materials effectively promotes the reactions. In addition, the good swollen capacity of fiber in solvent ensure that the reaction proceed well. Fiber catalyst PANPA?2F modified by prolinamide with a C2 alkyl chain exhibited the best catalytic performance and can be easily recovered and reused for at least ten consecutive cycles without significant loss of catalytic activity and active sites leaching.
- Zhu, Hai,Xu, Gang,Du, Huimin,Zhang, Chenlu,Ma, Ning,Zhang, Wenqin
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p. 217 - 229
(2019/05/16)
-
- 2-PYRROLIDINE PHENYLHYDRAZIDES ANTIBACTERIAL AGENTS
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2-Pyrrolidine phenylhydrazides antibacterial agents The present invention relates to 2-pyrrolidine phenylhydrazide compounds of formula (I), which are selective antibacterials specifically agalnstAcineto barter baumannii.The invention also relates to their therapeutic use as antibacterials, to a process for their preparation and to pharmaceutical compositions containing them.
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Page/Page column 57
(2018/02/28)
-
- N-methyl-D-aspartate receptor modulators and methods of making and using same
-
Disclosed are compounds having enhanced potency in the modulation of NMDA receptor activity. Such compounds are contemplated for use in the treatment of diseases and disorders, such as learning, cognitive activities, and analgesia, particularly in alleviating and/or reducing neuropathic pain. Orally available formulations and other pharmaceutically acceptable delivery forms of the compounds, including intravenous formulations, are also disclosed.
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-
Page/Page column 79; 80
(2018/06/25)
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- NUCLEIC ACID CONJUGATES AND USES THEREOF
-
Provided herein are conjugates comprising targeting moieties such as sugars, folates and cell-penetrating peptides, which can be used for the improved delivery of agents (e.g., nucleic acids, such as oligonucleotides or mRNAs, or other agents) to cells. The invention provides conjugates and compounds comprising targeting moieties, methods for preparing the same, and intermediates useful in their preparation. In another aspect, the present invention provides formulations (e.g., pharmaceutical compositions) comprising the targetting moiety-containing conjugates and compounds. The present invention also provides methods for delivering agents (e.g., nucleic acids such as oligonucleotides or mRNAs) to a cell, methods for treating and/or preventing a disease or condition in a subject, and methods for modulating gene expression in a cell or a subject. Further, provided herein are kits comprising the conjugates, or formulations thereof; and kits for the preparation of conjugates described herein.
- -
-
Paragraph 00386
(2018/03/09)
-
- Enantioselective Intermolecular [2+2] Photocycloaddition Reaction of Cyclic Enones and Its Application in a Synthesis of (-)-Grandisol
-
The intermolecular [2+2] photocycloaddition of typical cyclic α,β-unsaturated enones, such as 2-cyclohexenone, with olefins was performed in moderate to good yields (42-82%) and with high enantioselectivity (82%-96% ee). An unusual substitution pattern at the chiral oxazaborolidine-AlBr3 Lewis acid complex that promotes the reaction was found to be crucial for the success of the reaction. The method was applied to the enantioselective synthesis of the monoterpene (-)-grandisol, which could be accomplished in six steps and with an overall yield of 13% starting from 3-methyl-2-cyclohexenone.
- Poplata, Saner,Bach, Thorsten
-
supporting information
p. 3228 - 3231
(2018/03/13)
-
- Synthesis of amphiphilic meso -tetrasubstituted porphyrin-L-amino acid and -heterocyclic conjugates based on m -THPP
-
Two series of amphiphilic meso-tetrasubstituted porphyrin conjugates based on 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (m-THPP) covalently linked to L-amino acids and heterocycles were synthesized efficiently in the context of a program targeting new photosensitizers for PDT. 5,10,15-Tris(3-hydroxyphenyl)-20-(3-oxyacetic acid)phenyl]porphyrin and the respective trihexyl ether derivatives were conjugated with polar and non-polar natural L-amino acids such as glycine, L-proline, and L-tyrosine via an amide bond linker using N,N,N′,N′-tetramethyl-O-(1H-benzotriazol-1-yl)uroniumhexafluorophosphate in diisopropylethylamine (HBTU/DIPEA). m-THPP was also conjugated with heterocyclic systems such as indole 3-acetic acid, 4-methylthiazole-5-carboxylic acid, and thiophene-2-carboxylic acid via ester linker using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride in N-hydroxysuccinamide or 1-hydroxybenzotriazole (EDCI, NHS or HOBt). The members of the two series were obtained in good yields and characterized by UV-vis, HRMS MALDI-TOF, 1H NMR and 13C NMR spectroscopy.
- Sweed, Ayman M. K.,Senge, Mathias O.,Atta, Sanaa M. Sh.,Farrag, Dalia S.,Abdel-Rahman, Abdel-Rahman H.,Shaker, Yasser M.
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p. 997 - 1009
(2018/09/12)
-
- Unlocking the potential of phenacyl protecting groups: CO2-based formation and photocatalytic release of caged amines
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Orthogonal protection and deprotection of amines remain important tools in synthetic design as well as in chemical biology and material research applications. A robust, highly efficient, and sustainable method for the formation of phenacyl-based carbamate esters was developed using CO2 for the in situ preparation of the intermediate carbamates. Our mild and broadly applicable protocol allows for the formation of phenacyl urethanes of anilines, primary amines, including amino acids, and secondary amines in high to excellent yields. Moreover, we demonstrate the utility by a mild and convenient photocatalytic deprotection protocol using visible light. A key feature of the [Ru(bpy)3](PF6)2-catalyzed method is the use of ascorbic acid as reductive quencher in a neutral, buffered, two-phase acetonitrile/water mixture, granting fast and highly selective deprotection for all presented examples.
- Speckmeier, Elisabeth,Klimkait, Michael,Zeitler, Kirsten
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p. 3738 - 3745
(2018/04/14)
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- Characterization and cytotoxicity evaluation of biocompatible amino acid esters used to convert salicylic acid into ionic liquids
-
The technological utility of active pharmaceutical ingredients (APIs) is greatly enhanced when they are transformed into ionic liquids (ILs). API-ILs have better solubility, thermal stability, and the efficacy in topical delivery than solid or crystalline drugs. However, toxicological issue of API-ILs is the main challenge for their application in drug delivery. To address this issue, 11 amino acid esters (AAEs) were synthesized and investigated as biocompatible counter cations for the poorly water-soluble drug salicylic acid (Sal) to form Sal-ILs. The AAEs were characterized using 1H and 13C NMR, FTIR, elemental, and thermogravimetric analyses. The cytotoxicities of the AAE cations, Sal-ILs, and free Sal were investigated using mammalian cell lines (L929 and HeLa). The toxicities of the AAE cations greatly increased with inclusion of long alkyl chains, sulfur, and aromatic rings in the side groups of the cations. Ethyl esters of alanine, aspartic acid, and proline were selected as a low cytotoxic AAE. The cytotoxicities of the Sal-ILs drastically increased compared with the AAEs on incorporation of Sal into the cations, and were comparable to that of free Sal. Interestingly, the water miscibilities of the Sal-ILs were higher than that of free Sal, and the Sal-ILs were miscible with water at any ratio. A skin permeation study showed that the Sal-ILs penetrated through skin faster than the Sal sodium salt. These results suggest that AAEs could be used in biomedical applications to eliminate the use of traditional toxic solvents for transdermal delivery of poorly water-soluble drugs.
- Moshikur, Rahman Md.,Chowdhury, Md. Raihan,Wakabayashi, Rie,Tahara, Yoshiro,Moniruzzaman, Muhammad,Goto, Masahiro
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-
- Unusual visible-light photolytic cleavage of tertiary amides during the synthesis of cyclolignans related to podophyllotoxin
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During the attempted photochemical cyclization of 2,3-bisbenzylidene-γ-hydroxybutyric acid cyclic amide ester, it was observed that a γ-butyrolactone ring was formed, which was concurrent with the release of the amine fragment from the amide. The process occurs with high yield giving rise to the formation of β-apopicropodophyllin and its regioisomer. Additional experiments confirmed the photochemical nature of this transformation, and that it is independent from the photocyclization of the benzylidene groups – a typical reactivity for the members of the fulgide family. In contrast to the latter UV-driven cyclization, the photochemical cleavage of the amide was proven to proceed under irradiation with visible light.
- Lisiecki, Kamil,Krawczyk, Krzysztof K.,Roszkowski, Piotr,Maurin, Jan K.,Budzianowski, Armand,Czarnocki, Zbigniew
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p. 6316 - 6328
(2017/10/06)
-
- Novel reversible methionine aminopeptidase-2 (MetAP-2) inhibitors based on purine and related bicyclic templates
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The natural product fumagillin 1 and derivatives like TNP-470 2 or beloranib 3 bind to methionine aminopeptidase 2 (MetAP-2) irreversibly. This enzyme is critical for protein maturation and plays a key role in angiogenesis. In this paper we describe the synthesis, MetAP-2 binding affinity and structural analysis of reversible MetAP-2 inhibitors. Optimization of enzymatic activity of screening hit 10 (IC50: 1?μM) led to the most potent compound 27 (IC50: 0.038?μM), with a concomitant improvement in LLE from 2.1 to 4.2. Structural analysis of these MetAP-2 inhibitors revealed an unprecedented conformation of the His339 side-chain imidazole ring being co-planar sandwiched between the imidazole of His331 and the aryl-ether moiety, which is bound to the purine scaffold. Systematic alteration and reduction of H-bonding capability of this metal binding moiety induced an unexpected 180° flip for the triazolo[1,5-a]pyrimdine bicyclic template.
- Heinrich, Timo,Buchstaller, Hans-Peter,Cezanne, Bertram,Rohdich, Felix,Bomke, J?rg,Friese-Hamim, Manja,Krier, Mireille,Kn?chel, Thorsten,Musil, Djordje,Leuthner, Birgitta,Zenke, Frank
-
p. 551 - 556
(2017/01/17)
-
- HETEROAROMATIC NMDA RECEPTOR MODULATORS AND USES THEREOF
-
Disclosed herein, in part, are heteroaromatic compounds and methods of use in treating neuropsychiatric disorders, e.g., schizophrenia and major depressive disorder. Pharmaceutical compositions and methods of making heteroaromatic compounds are provided. The compounds are contemplated modulate the NMDA receptor.
- -
-
Paragraph 00323
(2017/07/27)
-
- Design, synthesis, and evaluation of novel Akt1 inhibitors based on an indole scaffold
-
A new series of potential Akt1 inhibitors with indole scaffold were designed and synthesized. The antiproliferative activity against PC-3 cell line and enzyme inhibitory activity against Akt1 were evaluated. Among them, some compounds showed much more potent antiproliferative activity and stronger Akt1 inhibitory activity compared to the positive control of GSK690693. In particular, compound 19b exhibited the most potent inhibitory activity against Akt1 with inhibition rate of 70.3% at a concentration of 10?nm. Furthermore, compound 19b could dose dependently reduce the phosphorylation of the downstream GSK3β protein in the PC-3 cell line and displayed fivefold higher antiproliferative activity against PC-3 cell line with IC50 value of 3.1?±?0.1?μm than positive control (15.5?±?0.4?μm). Herein, compound 19b may serve as a promising lead for further optimization and development of novel Akt1 inhibitors based on an indole scaffold.
- Yang, Dezhi,Tong, Dongdong,Zhang, Qian,Wang, Yongtao,Sun, Jing,Zhang, Fenghe,Zhao, Guisen
-
p. 791 - 803
(2017/09/30)
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- Daclatasvir intermediate and preparation method thereof
-
The invention discloses a daclatasvir intermediate and a preparation method thereof. The preparation method comprises the following steps: in a solvent, under the effect of an organic alkaline, performing an esterification reaction on a compound shown as a formula D8 and a compound shown as a formula B2, so as to prepare a compound shown as a formula D10, wherein the esterification reaction is shown in the description, and the temperature of the esterification reaction is 20 DEG C-60 DEG C. When used to prepare daclatasvir, the daclatasvir intermediate has the characteristics of low cost, high yield, friendliness to environment, simple steps, mild reaction conditions and applicability to industrialized production. The preparation method for the daclatasvir intermediate is low in cost, high in yield, friendly to environment, simple in steps, mild in reaction conditions and suitable for industrialized production.
- -
-
Paragraph 0051; 0065; 0066; 0101; 0102; 0113; 0114
(2017/10/23)
-
- Preparation method for daclatasvir
-
The invention discloses a preparation method for daclatasvir. The preparation method comprises the following steps: in a solvent, performing a cyclization reaction on a compound shown as a formula D10 and ammonium acetate, so as to prepare the daclatasvir shown as a formula I, wherein the cyclization reaction is shown in the description. The preparation method for daclatasvir is low in cost, high in yield, friendly to environment, simple in steps, mild in reaction conditions and suitable for industrialized production.
- -
-
Paragraph 0076; 0077; 0112; 0113; 0124
(2017/10/22)
-
- Enantiomerically pure piperazines via NaBH4/I2reduction of cyclic amides
-
Enantiomerically pure (3S,7R,8aS)-3-phenyloctahydropyrrolo[1,2-a]pyrazine-7-ol, (3S,7R,8aS)-3-methyl octahydropyrrolo[1,2-a]pyrazine-7-ol, (3S,7R,8aS)-3-isopropyloctahydropyrrolo[1,2-a]pyrazine-7-ol and (3S,7R,8aS)-3-isobutyloctahydropyrrolo[1,2-a]pyrazine-7-ol 16d were synthesized via preparation of the corresponding cyclic amides from enantiomerically pure L-proline and hydroxyproline derivatives followed by reduction using sodium borohydride-iodine.
- Harish, Vagala,Periasamy, Mariappan
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p. 175 - 180
(2017/01/11)
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- The reactions of α-amino acids and α-amino acid esters with high valent transition metal halides: synthesis of coordination complexes, activation processes and stabilization of α-ammonium acylchloride cations
-
Titanium tetrachloride smoothly reacted with a selection of α-amino acids (aaH) in CH2Cl2 affording yellow to orange solid coordination compounds, 1a-d, in 70-78% yields. The salts [NHEt3][TiCl4(aa)], 2a-b, were obtained from TiCl4/aaH/NEt3 (aa = l-phenylalanine, N,N-dimethylphenylalanine), in 60-65% yields. The complex , 3, was isolated from the reaction of l-proline with NbCl5/NHiPr2, performed in CH2Cl2 at room temperature. The X-ray structure of 3 features a bridging (E)-1,2-bis(3,4-dihydro-2H-pyrrol-5-yl)ethene-1,2-diolate ligand, resulting from the unprecedented C-C coupling between two proline units. Unusually stable α-ammonium acyl chlorides were prepared by the reactions of PCl5/MCln (MCln = NbCl5, WCl6) with l-proline, N,N-dimethylphenylalanine, sarcosine and l-methionine. MX5 (M = Nb, Ta; X = F, Cl) reacted with l-leucine methylester and l-proline ethylester to give ionic coordination compounds, [MX4L2][MX6] (M = Nb, L = Me2CHCH2CH(NH2)CO2Me, X = F, 9; Cl, 11a; M = Nb, X = Cl, , 11c; Ta, 11d), in moderate to good yields. [NbCl5(Me2CHCH2CHNH3CO2Me)][NbCl6], 12, was isolated as a co-product of the reaction of NbCl5 with l-leucine isopropylester, and crystallographically characterized. The reaction of NbCl5 with l-serine isopropylester afforded NbCl3(OCH2CHNHCO2iPr), 13, in 66% yield. The activation of the ester O-R bond was observed in the reactions of l-leucine methyl ester with NbF5 and l-proline ethyl ester with MBr5 (M = Nb, Ta), these reactions proceeding with the release of EtF and EtBr, respectively. All the metal products were characterized by analytical and spectroscopic methods, while DFT calculations were carried out in order to provide insight into the structural and mechanistic aspects.
- Biancalana, Lorenzo,Bortoluzzi, Marco,Ferretti, Eleonora,Hayatifar, Mohammad,Marchetti, Fabio,Pampaloni, Guido,Zacchini, Stefano
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p. 10158 - 10174
(2017/02/15)
-
- Iminium Catalysis inside a Self-Assembled Supramolecular Capsule: Modulation of Enantiomeric Excess
-
The noncovalent combination of a supramolecular host with iminium organocatalysis is described. Due to cation–π interactions the reactive iminium species is held inside the host and reacts in this confined environment. The products formed differ up to 92 % ee from the control experiments without added host. A model rationalizing the observed difference is presented.
- Br?uer, Thomas M.,Zhang, Qi,Tiefenbacher, Konrad
-
supporting information
p. 7698 - 7701
(2016/07/07)
-
- SUBSTITUTED INDAZOLE COMPOUNDS, COMPOSITIONS THEREOF, AND METHODS OF TREATMENT THEREWITH
-
Provided herein are methods for treating and preventing malaria and/or Babesiosis, the methods comprising administering an effective amount of Indazole Compounds having the formulas: (I)[Formula (I) should be inserted here] or (II)[Formula (II) should be inserted here] wherein R1, R2, R3 and Y are as defined herein.
- -
-
Paragraph 00143
(2016/06/28)
-
- 6-AMINO QUINAZOLINE OR 3-CYANO QUINOLINE DERIVATIVES, PREPARATION PROCESS AND PHARMACEUTICAL USE THEREOF
-
The present disclosure relates to 6-amino quinazoline or 3-cyano quinoline derivatives, preparation processes and pharmaceutical compositions containing them. Specifically, the present disclosure relates to novel 6-amino quinazoline or 3-cyano quinoline derivatives presented by formula (I), or its tautomer, enantiomer, diastereomer, racemate or pharmaceutically acceptable salts thereof, or metabolite, metabolic precursor or prodrug thereof, and the uses for treatment especially for protein kinase inhibitors, in which each substitute group of general formula (I) is as defined in the specification.
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Page/Page column 56
(2016/10/08)
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- HtrA1 Proteolysis of ApoE in Vitro Is Allele Selective
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Apolipoprotein E (ApoE) belongs to a large class of proteins that solubilize lipids for physiological transport. Humans have three different APOE alleles, APOE e2, APOE e3, and APOE e4, and genetic studies identified ApoE4 as the strongest genetic risk factor for Alzheimer's disease (AD). People who are homozygous for ApoE4 (i.e., ApoE4/E4) are an order of magnitude more likely to develop late-onset AD (LOAD) than ApoE3/E3 carriers. Several differences between ApoE3 and ApoE4 may contribute to AD including the observation that ApoE4 is degraded to a greater extent than ApoE3 in the human brain. Experiments with high-temperature requirement serine peptidase A1 (HtrA1), which is found in the nervous system, demonstrate that HtrA1 is an allele-selective ApoE-degrading enzyme that degrades ApoE4 more quickly than ApoE3. This activity is specific to HtrA1, as similar assays with HtrA2 showed minimal ApoE4 proteolysis and trypsin had no preference between ApoE4 and ApoE3. HtrA1 has also been reported to cleave the tau protein (Tau) and the amyloid protein precursor (APP) to hinder the formation of toxic amyloid deposits associated with AD. Competition assays with ApoE4, ApoE3, and Tau revealed that ApoE4 inhibits Tau degradation. Thus, the identification of ApoE4 as an in vitro HtrA1 substrate suggests a potential biochemical mechanism that links ApoE4 regulation of AD proteins such as Tau.
- Chu, Qian,Diedrich, Jolene K.,Vaughan, Joan M.,Donaldson, Cynthia J.,Nunn, Michael F.,Lee, Kuo-Fen,Saghatelian, Alan
-
supporting information
p. 9473 - 9478
(2016/08/12)
-
- Synthesis of mono-and diphosphorus-substituted proline derivatives containing P–C–N fragments
-
Convenient methods for the synthesis of new types of mono-and diphosphorus-substituted proline derivatives containing P–C–N fragments were developed based on special pre-prepared proline-containing synthons. The corresponding organophosphorus acids including a proline fragment were also synthesized.
- Prishchenko,Livantsov,Novikova,Livantsova,Petrosyan
-
p. 1846 - 1854
(2017/03/22)
-
- Mechanistic interrogation of the asymmetric lithiation-trapping of N-thiopivaloyl azetidine and pyrrolidine
-
A fundamental mechanistic study of the s-BuLi/chiral diamine-mediated lithiation-trapping of N-thiopivaloyl azetidine and pyrrolidine is reported. We show that lithiated thiopivalamides are configurationally unstable at -78 °C. Reaction then proceeds via a dynamic resolution of diastereomeric lithiated intermediates and this accounts for the variable sense and degree of asymmetric induction observed compared to N-Boc heterocycles.
- Rayner, Peter J.,Smith, Joshua C.,Denneval, Charline,O'Brien, Peter,Clarke, Paul A.,Horan, Richard A. J.
-
supporting information
p. 1354 - 1357
(2016/01/25)
-
- New short and general synthesis of three key Maillard flavour compounds: 2-Acetyl-1-pyrroline, 6-acetyl-1,2,3,4-tetrahydropyridine and 5-acetyl-2,3-dihydro-4H-1,4-thiazine
-
A new general synthetic route towards three key Maillard flavour compounds, namely 2-acetyl-1-pyrroline, 6-acetyl-1,2,3,4-tetrahydropyridine and 5-acetyl-2,3-dihydro-4H-1,4-thiazine, was developed. The key step in the process is the methylenation reaction of azaheterocyclic carboxylic esters by means of dimethyltitanocene, giving rise to intermediate vinyl ethers which can be considered as excellent and stable precursors for the title compounds, as a simple acidic treatment of these precursors suffices to release the characteristic Maillard flavours.
- Deblander, Jurgen,Van Aeken, Sam,Adams, An,De Kimpe, Norbert,Abbaspour Tehrani, Kourosch
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p. 327 - 331
(2014/08/18)
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- New short and general synthesis of three key Maillard flavour compounds: 2-Acetyl-1-pyrroline, 6-acetyl-1,2,3,4-tetrahydropyridine and 5-acetyl-2,3-dihydro-4H-1,4-thiazine
-
A new general synthetic route towards three key Maillard flavour compounds, namely 2-acetyl-1-pyrroline, 6-acetyl-1,2,3,4-tetrahydropyridine and 5-acetyl-2,3-dihydro-4H-1,4-thiazine, was developed. The key step in the process is the methylenation reaction of azaheterocyclic carboxylic esters by means of dimethyltitanocene, giving rise to intermediate vinyl ethers which can be considered as excellent and stable precursors for the title compounds, as a simple acidic treatment of these precursors suffices to release the characteristic Maillard flavours.
- Deblander, Jurgen,Van Aeken, Sam,Adams, An,De Kimpe, Norbert,Abbaspour Tehrani, Kourosch
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p. 327 - 331
(2015/01/30)
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- PRO-DRUG FORMING COMPOUNDS
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Various prodrug compounds having the general structure: Active agent- (acid)-(linker) - SO2NR1R2 are described herein. Compounds having this general structure were shown to be more orally active than the unmodified parent molecule.
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Page/Page column 45; 46
(2015/02/02)
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- Chemoselective Intramolecular Functionalization of Methyl Groups in Nonconstrained Molecules Promoted by N-Iodosulfonamides
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Mechanistic evidence observed in Hofmann-L?ffler-Freytag-type reactions has been crucial to achieve the chemoselective functionalization of methyl groups under mild conditions. Radical-mediated methyl iodination and subsequent oxidative deiodination are the key steps in this functionalization, where iodine chemistry has a pivotal role on the formation of the C-N bond. The concepts of single hydrogen atom transfer (SHAT) and multiple hydrogen atom transfer (MHAT) are introduced to describe the observed chemoselectivity. (Chemical Equation Presented).
- Paz, Nieves R.,Rodríguez-Sosa, Dionisio,Valdés, Haydee,Marticorena, Ricardo,Melián, Daniel,Copano, M. Belén,González, Concepción C.,Herrera, Antonio J.
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supporting information
p. 2370 - 2373
(2015/06/02)
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