- JM-PHOS ligands: Second-generation phosphine oxazolines for asymmetric catalysis
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(formula presented) A small library of phosphine oxazollne ligands 2 was prepared and tested in palladium-mediated allylation processes (reactions 1 and 2). They were found to be superior to the first-generation ligands 1 and as effective as the well-know
- Hou, Duen-Ren,Burgess, Kevin
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- Expeditious synthesis of enantiopure, orthogonally protected bis-α-amino acids (OPBAAs) and their use in a study of Nod1 stimulation
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A convenient approach towards the synthesis of orthogonally protected chiral bis-a-amino acids (OPBAAs) is described. The key transformations include: (1) a highly stereoselective conjugation (alkylation) of the Sch?llkopf bislactim ethers and oxazolidinyl alkyl halides to build a backbone skeleton; and (2) our orthogonal protection strategy. A series of enantiopure OPBAAs bearing a variety of alkyl chain as a spacer; two stereogenic centers; and three protecting groups were prepared as examples. These versatile molecules were applied to the synthesis of biologically interesting di- or tri-peptide analogues, including chiral iE-meso-DAP and A-iE-meso-DAP, for the study of Nod1 activation in the innate immune response.
- Chen, Po-Ting,Lin, Cheng-Kun,Tsai, Chih-Ju,Huang, Duen-Yi,Nien, Fu-Yao,Lin, Wan-Wan,Cheng, Wei-Chieh
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- β-Hydroxy- A nd β-Aminophosphonate Acyclonucleosides as Potent Inhibitors of Plasmodium falciparum Growth
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Malaria is an infectious disease caused by a parasite of the genus Plasmodium, and the emergence of parasites resistant to all current antimalarial drugs highlights the urgency of having new classes of molecules. We developed an effective method for the synthesis of a series of β-modified acyclonucleoside phosphonate (ANP) derivatives, using commercially available and inexpensive materials (i.e., aspartic acid and purine heterocycles). Their biological evaluation in cell culture experiments and SAR revealed that the compounds' effectiveness depends on the presence of a hydroxyl group, the chain length (four carbons), and the nature of the nucleobase (guanine). The most active derivative inhibits the growth of Plasmodium falcIParum in vitro in the nanomolar range (IC50 = 74 nM) with high selectivity index (SI > 1350). This compound also showed remarkable in vivo activity in P. berghei-infected mice (ED50 ~0.5 mg/kg) when administered by the IP route and is, although less efficient, still active via the oral route. It is the first ANP derivative with such potent antimalarial activity and therefore has considerable potential for development as a new antimalarial drug.
- Cheviet, Thomas,Wein, Sharon,Bourchenin, Gabriel,Lagacherie, Manon,Périgaud, Christian,Cerdan, Rachel,Peyrottes, Suzanne
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- A stereocontrolled synthetic route to anti-β-amino alcohols
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A physiologically indispensable β-amino hydroxy functionality has been constructed with complete anti-stereoselectivity by intramolecular iodoamidation of (Z)-olefinic homoallylic trichloroacetimidates 4-6, 18, 20, 30 and 32, which comprise bulky substituents at the vinylic positions.
- Kang, Sung Ho,Hwang, Yu Sang,Youn, Joo-Hack
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- Design and synthesis of a novel site-directed reducing agent for the disulfide bond involved in the acetylcholine binding site of the AChoR
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The 2-trimethylammonioethyloxycarbonylamino-1,4-butanedithiol 7 was synthesized and tested as a site-directed reducing agent for the disulfide bond involved in the acetylcholine binding site of the AChoR, which was then specifically labeled by an undecagold cluster.
- Kessler, Pascal
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- Selective, Modular Probes for Thioredoxins Enabled by Rational Tuning of a Unique Disulfide Structure Motif
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Specialized cellular networks of oxidoreductases coordinate the dithiol/disulfide-exchange reactions that control metabolism, protein regulation, and redox homeostasis. For probes to be selective for redox enzymes and effector proteins (nM to μM concentrations), they must also be able to resist non-specific triggering by the ca. 50 mM background of non-catalytic cellular monothiols. However, no such selective reduction-sensing systems have yet been established. Here, we used rational structural design to independently vary thermodynamic and kinetic aspects of disulfide stability, creating a series of unusual disulfide reduction trigger units designed for stability to monothiols. We integrated the motifs into modular series of fluorogenic probes that release and activate an arbitrary chemical cargo upon reduction, and compared their performance to that of the literature-known disulfides. The probes were comprehensively screened for biological stability and selectivity against a range of redox effector proteins and enzymes. This design process delivered the first disulfide probes with excellent stability to monothiols yet high selectivity for the key redox-Active protein effector, thioredoxin. We anticipate that further applications of these novel disulfide triggers will deliver unique probes targeting cellular thioredoxins. We also anticipate that further tuning following this design paradigm will enable redox probes for other important dithiol-manifold redox proteins, that will be useful in revealing the hitherto hidden dynamics of endogenous cellular redox systems.
- Becker, Katja,Busker, Sander,Felber, Jan G.,Maier, Martin S.,Poczka, Lena,Scholzen, Karoline,Theisen, Ulrike,Thorn-Seshold, Julia,Thorn-Seshold, Oliver,Zeisel, Lukas,Arnér, Elias S. J.,Brandst?dter, Christina
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supporting information
p. 8791 - 8803
(2021/06/27)
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- Synthesis of Aminomethylene- gem-bisphosphonates Containing an Aziridine Motif: Studies of the Reaction Scope and Insight into the Mechanism
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A broad range of N-carbamoylaziridines were obtained and then treated by the diethyl phosphonate anion to afford α-methylene-gem-bisphosphonate aziridines. Study of the reaction's scope and additional experiments indicates that the transformation proceeds via a new mechanism involving the chelation of lithium ion. This last step is crucial for the reaction to occur and disfavors the aziridine ring-opening. A phosphonate-phosphate rearrangement from a α-hydroxybisphosphonate aziridine intermediate is also proposed for the first time. This reaction provides a simple and convenient method for the synthesis of a highly functionalized phosphonylated aziridine motif.
- Cheviet, Thomas,Peyrottes, Suzanne
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p. 3107 - 3119
(2021/02/05)
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- Enantioselective Hydrogenation of Racemic α-Arylamino Lactones to Chiral Amino Diols with Site-Specifically Modified Chiral Spiro Iridium Catalysts
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A protocol for highly enantioselective hydrogenation of racemic α-arylamino lactones with catalysis by site-specifically modified chiral spiro iridium complexes has been developed. With the optimized catalyst, racemic α-arylamino-γ-lactones and α-arylamino-δ-lactones could be hydrogenated to the corresponding chiral 2-amino diols with good to excellent enantioselectivities.
- Gu, Xue-Song,Yu, Na,Yang, Xiao-Hui,Zhu, An-Te,Xie, Jian-Hua,Zhou, Qi-Lin
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supporting information
p. 4111 - 4115
(2019/06/07)
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- DITHIOAMINE REDUCING AGENTS
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Dithioamine reducing agents useful for the reduction of disulfide bonds. The reducing agents of this invention are useful, for example, to reduce disulfide bonds, particularly in proteins, or to prevent the formation of disulfide bonds, particularly in proteins and other biological molecules. Reducing agents of this invention can be employed to regulate protein function in proteins in which a sulfhydryl group is associated with biological activity. Reducing agents of this invention can prevent inactivation of a given protein or enhance activation of a given protein or other biological molecule in vitro and/or in vivo. Reducing agents of this invention can prevent or reduce oxidation of cysteine residues in proteins and prevent the formation of reduced activity protein dimers (or other oligomers). Reducing agents of this invention are useful and suitable for application in a variety of biological applications, particularly as research and synthetic reagents.
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Paragraph 00160; 00161
(2013/08/28)
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- DITHIOAMINE REDUCING AGENTS
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Dithioamine reducing agents useful for the reduction of disulfide bonds. The reducing agents of this invention are useful, for example, to reduce disulfide bonds, particularly in proteins, or to prevent the formation of disulfide bonds, particularly in proteins and other biological molecules. Reducing agents of this invention are useful and suitable for application in a variety of biological applications, particularly as research and synthetic reagents. The invention provides S-acylated dithioamines which can be selectively activated reducing agents by removal of the S-acyl groups enzymatically or chemically. The invention further provides dithiane precursors of thioamino reducing agents. The invention provides dithioamine reducing agents, S-acylated dithioamines and dithianes which are immobilized on surfaces, including among others, glass, quartz, microparticles, nanoparticles and resins.
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(2013/08/28)
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- A potent, versatile disulfide-reducing agent from aspartic acid
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Dithiothreitol (DTT) is the standard reagent for reducing disulfide bonds between and within biological molecules. At neutral pH, however, >99% of DTT thiol groups are protonated and thus unreactive. Herein, we report on (2S)-2-amino-1,4-dimercaptobutane (dithiobutylamine or DTBA), a dithiol that can be synthesized from l-aspartic acid in a few high-yielding steps that are amenable to a large-scale process. DTBA has thiol pKa values that are ~1 unit lower than those of DTT and forms a disulfide with a similar E o′ value. DTBA reduces disulfide bonds in both small molecules and proteins faster than does DTT. The amino group of DTBA enables its isolation by cation-exchange and facilitates its conjugation. These attributes indicate that DTBA is a superior reagent for reducing disulfide bonds in aqueous solution.
- Lukesh III, John C.,Palte, Michael J.,Raines, Ronald T.
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supporting information; experimental part
p. 4057 - 4059
(2012/04/10)
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- Asymmetric michael additions of α-nitrocyclohexanone to aryl nitroalkenes catalyzed by natural amino acid-derived bifunctional thioureas
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A series of new thiourea catalysts prepared from natural amino acids have been applied in organocatalytic asymmetric Michael additions of α-nitrocyclohexanone to nitroalkenes. The resulting addition products are formed with excellent enantioselectivities (up to an er of 98:2) in good yields (up to 90%).
- J?rres, Manuel,Schiffers, Ingo,Atodiresei, Iuliana,Bolm, Carsten
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supporting information
p. 4518 - 4521
(2012/10/29)
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- Chemo-enzymatic synthesis of the azasugars 1,4-dideoxyallonojirimycin and 1,4-dideoxymannojirimycin
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The enzymatic resolution of the N-phenylacetyl derivative of racemic homoserine lactone with penicillin G acylase immobilized on Eupergit C gave (R)-(+)-α-amino-γ-butyrolactone and (S)-(-)-α-N- phenylacetamido-γ-butyrolactone in high enantiomeric purity (ee >99%) and 46-47% yields for each enantiomer. The enantiomers were converted into azasugars 1,4-dideoxyallonojirimycin and 1,4-dideoxymannojirimycin using Wittig olefination, catalytic ring-closing metathesis (RCM), and stereoselective dihydroxylation with OsO4 in 29% overall yield over 11 high yielding steps. Enzyme inhibition studies showed that 1,4-dideoxyallonojirimycin is a better β-glucosidase inhibitor (IC50 32.4 μM toward β-glucosidase from almonds) and a better β-galactosidase inhibitor (IC50 5.9 mM for β-galactosidase from Aspergillus oryzae) than 1,4-dideoxymannojirimycin (IC50 2.86 mM and 12.5 mM for β-glucosidase and β-galactosidase, respectively).
- Venkataiah, Mallam,Reddipalli, Gowrisankar,Jasti, Lakshmi Swarnalatha,Fadnavis, Nitin W.
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experimental part
p. 1855 - 1860
(2012/01/13)
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- Synthetic aromatic amino acids from a negishi cross-coupling reaction
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An N,O-protected, iodinated bishomoalanine derivative, safely available from glutamic acid, reacts with aryl halides in a Negishi reaction in high yields. From the coupling product, Fmoc-protected amino acids with aromatic and heteroaromatic side chains were generated in high yields by racemization-free procedures. These monomers could be used for solid-phase peptide synthesis. Georg Thieme Verlag Stuttgart.
- Suhartono, Marcel,Schneider, Angelika E.,Duerner, Gerd,Goebel, Michael W.
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experimental part
p. 293 - 303
(2010/03/30)
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- Hydrogenation of N-acylcarbamates and N-acylsulfonamides catalyzed by a bifunctional [Cp*Ru(PN)] complex
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Awakening of the Cp one: the bifunctional complex 1 facilitates the interaction with substrates bearing less electrophilic carbon atoms than ketones, epoxides, and imides. The title reaction was applicable to the reduction of Evans' asymmetric alkylation products to the chiral alcohols along with gtood recovery of the chiral oxazolidinone auxiliary. EWG=electron- withdrawing group.
- Ito, Masato,Koo, Lee Wei,Himizu, Akio,Kobayashi, Chika,Sakaguchi, Ayaka,Ikariya, Takao
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scheme or table
p. 1324 - 1327
(2009/06/30)
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- Design, synthesis, and bioactivity of novel inhibitors of E. coli aspartate transcarbamoylase
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A series of inhibitors of the aspartate transcarbamoylase, an enzyme involved in pyrimidine nucleotide biosynthesis, has been synthesized. These inhibitors are analogues of a highly potent inhibitor of this enzyme, N-phosphonacetyl-l-aspartate (PALA). Analogues have been synthesized with modifications at the α- and β-carboxylates as well as at the aspartate moiety. The ability of these compounds to inhibit the enzyme was evaluated. These studies, with functional group modified PALA derivatives, showed that amide groups can be a useful substitute of the carboxylate in order to reduce the charge on the molecule, and indicate that the relative position of the functional group in the β-position is more critical than the nature of the functional group. Some of the molecules synthesized here are potent inhibitors of the enzyme.
- Eldo, Joby,Heng, Sabrina,Kantrowitz, Evan R.
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p. 2086 - 2090
(2007/10/03)
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- Efficient entry to polysubstituted pyrrolizidines, indolizidines and quinolizidines via a sequential reaction process
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A sequential SN2-Michael addition-Michael addition reaction process between ω-iodo-α,β-alkynoates and δ- or γ-amino α,β-unsaturated esters is developed, which affords polysubstituted pyrrolizidines, indolizidines or quinolizidines in good yield
- Ma, Dawei,Zhu, Wei
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p. 1181 - 1184
(2007/10/03)
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- IMPROVED PROCEDURE FOR THE PREPARATION OF (4S)- OR (4R)-2,2-DIMETHYL-4-(2-HYDROXETHYL)OXAZOLIDINE-3-CARBOXYLIC ACID ALKYL ESTERS
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The present invention is directed to a process for the preparation of (4S)- or (4R)-2,2-dimethyl-4-(2-hydroxethyl)oxazolidine-3-carboxylic acid alkyl esters. The invention is further directed to an intermediate product from which those alkyl esters may be obtained.
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Page/Page column 12-13
(2010/11/23)
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- Highly efficient approach to orthogonally protected (2S,4R)- and (2S,4S)-4-hydroxyornithine
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(Chemical Equation Presented) A concise stereoselective approach to both orthogonally protected (25,4A)- and (2S,4S)-4-hydroxyornithine, key constituents of the biphenomycin-and clavalanine-type antibiotics, respectively, has been developed. The approach is based on bis(oxazoline) copper(II)-complex-catalyzed diastereoselective Henry reactions of nitromethane with the homoserine-derived aldehyde 6. The synthesis of this versatile chiral building block has been markedly improved.
- Paintner, Franz F.,Allmendinger, Lars,Bauschke, Gerd,Klemann, Patricia
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p. 1423 - 1426
(2007/10/03)
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- 3-(Imidazolyl)-2-aminopropanoic acids
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Compounds according to formula (I) wherein n is 1-4, R1 is optionally substituted C1-6 alkyl, C2-6 alkenyl, or C2-6 alkynyl, Heterocycle, Aromatic heterocycle, Aryl or hydrogen and R2, R3,
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- New, optically active phosphine oxazoline (JM-phos) ligands: Syntheses and applications in allylation reactions
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Three different syntheses of the phosphine oxazoline systems 1 are presented. Two of these approaches are divergent routes designed to involve an advanced intermediate that can be transformed into several different end-products. The third is a shorter route specifically designed to facilitate preparations of these systems on a larger scale using minimal functional group protection. Overall, eight different phosphine oxazolines were prepared. These were screened in several palladium-mediated allylation reactions. They proved to be most useful for asymmetric alkylation of 3-acetoxy-1,3-diphenylpropene and less suitable/effective for the more challenging substrates (a pentenyl derivative and a cyclohexenyl system). X-ray crystallographic analysis of the complex [(η3-PhCHCHCHPh)Pd(1a)][PF6] led to the conclusion that the origins of asymmetric induction in these systems might be indirectly attributed to interaction of the oxazoline-phenyl substituent with the palladium and with an allyl-phenyl substituent. Finally, data is presented for allylation of a silylenolate of an N-acyl oxazolidinone; excellent enantioselectivities and yields were obtained.
- Hou,Reibenspies,Burgess
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p. 206 - 215
(2007/10/03)
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- Radical cyclization in heterocycle synthesis. 7. Synthesis of chiral 2- substituted 5-amino-4-piperidinols via radical cyclization
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Oxime ether connected by a tether to formyl group, which is available from natural amino acid, efficiently cyclizes via stannyl radical addition- cyclization or SmI2-induced radical reaction to provide a new entry to asymmetric synthesis of 2-s
- Kiguchi, Toshiko,Okazaki, Miyuki,Naito, Takeaki
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p. 2711 - 2722
(2007/10/03)
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- An efficient conversion of chiral α-amino acids to enantiomerically pure 3-amino cyclic amines
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Enantiomerically pure 3-amino cyclic amines such as 3-amino pyrrolidine, 3-amino piperidine, and 2,3,4,5,6,7-hexahydro-1H-azepine have been synthesized in high yields from the optically active natural α-amino acids such as L-aspartic acid, L-glutamic acid, L-2-aminoadipic acid, and their enantiomers.
- Moon, Sung-Hwan,Lee, Sujin
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p. 3919 - 3926
(2007/10/03)
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- Practical synthesis of (S)-3-(p-nitrobenzyloxy-carbonylamino)pyrrolidine and its related compounds from L-aspartic acid
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An efficient method for the preparation of (S)-3-aminopyrrolidine derivatives was developed starting from L-aspartic acid, which involves an efficient formation of a pyrrolidine-ring from allylamine and a practical Pd/C-catalyzed cleavage of N-allyl prote
- Tomori, Hiroshi,Shibutani, Kuniko,Ogura, Katsuyuki
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p. 213 - 225
(2007/10/03)
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- Ortho-substituted benzofused macrocyclic lactams as zinc metalloprotease inhibitors
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The design and preparation of ortho-substituted benzofused macrocyclic lactams are described. The benzofused macrocyclic lactams were designed as neutral endopeptidase 24.11 (NEP) inhibitors. Docking studies were carried out in a model of thermolysin (TLN) using the MACROMODEL and QXP modeling programs to select suitable ring sizes. These studies predicted that the 11- , 12-, and 13-membered ring macrocyclic lactams would be active in both enzymes TLN and NEP. Good predictability of experimental results, within this series, of binding to thermolysin and to a lesser extent to NEP was observed. A visual comparison, docked at the active site of TLN, is presented for thiorphan, a 10-membered ring macrocycle and an 11-membered ring benzofused macrocyclic lactam. Potent inhibition of both NEP and thermolysin was obtained. The 11-membered ring macrocycle 25a is the most potent inhibitor from this series of compounds (TLN IC50 = 68 nM; NEP IC50 = 0.9 nM). The effects of prodrug 44b administered at 10 mg/kg po on plasma atrial natriuretic peptide (ANP) levels in conscious rats was greater than 200% over a 4 h period.
- Ksander, Gary M.,De Jesus, Reynalda,Yuan, Andrew,Ghai,Trapani,McMartin, Colin,Bohacek, Regine
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p. 495 - 505
(2007/10/03)
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- Copper(II) in Organic Synthesis. XI. Evaluation of the Ligand Architecture on the Efficiency of a Copper(II) Catalyst for Enantioselective Michael Reactions.
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Several bis-copper(II) complexes with chiral ligands derived from 2-substituted 2-(salicylideneamino)ethanols have been tested as catalysts of enantioselective Michael reactions.The degree of enantioselection is strongly affected by the architecture of the ligand.The best result (75percent e.e.) was obtained for a ligand having a substituent potentially suitable to induce the formation of a bis-tetradentate copper(II) complex with a square pyramidal coordination.
- Desimoni, Giovanni,Dusi, Guglielmo,Faita, Giuseppe,Quadrelli, Paolo,Righetti, PierPaolo
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p. 4131 - 4144
(2007/10/02)
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