- A concise synthesis of (S)-(-)-3-(2-carboxy-4-pyrrolyl)-alanine
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A convergent synthesis of (S)-(-)-3-(2-carboxy-4-pyrrolyl)-alanine (CPA) 1, a non-proteinogenic amino acid is described starting from a commercially available dimethyl L-aspartate 2 in good overall yield. Copyright (C) 2000 Elsevier Science Ltd.
- Adamczyk, Maciej,Johnson, Donald D.,Reddy, Rajarathnam E.
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Read Online
- Visualizing the reaction cycle in an Iron(II)- and 2-(Oxo)-glutarate-dependent hydroxylase
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Iron(II)- and 2-(oxo)-glutarate-dependent oxygenases catalyze diverse oxidative transformations that are often initiated by abstraction of hydrogen from carbon by iron(IV)-oxo (ferryl) complexes. Control of the relative orientation of the substrate C-H and ferryl Fe-O bonds, primarily by direction of the oxo group into one of two cisrelated coordination sites (termed inline and offline), may be generally important for control of the reaction outcome. Neither the ferryl complexes nor their fleeting precursors have been crystallographically characterized, hindering direct experimental validation of the offline hypothesis and elucidation of the means by which the protein might dictate an alternative oxo position. Comparison of high-resolution X-ray crystal structures of the substrate complex, an Fe(II)-peroxysuccinate ferryl precursor, and a vanadium(IV)-oxo mimic of the ferryl intermediate in the L-arginine 3-hydroxylase, VioC, reveals coordinated motions of active site residues that appear to control the intermediate geometries to determine reaction outcome.
- Mitchell, Andrew J.,Dunham, Noah P.,Martinie, Ryan J.,Bergman, Jonathan A.,Pollock, Christopher J.,Hu, Kai,Allen, Benjamin D.,Chang, Wei-Chen,Silakov, Alexey,Bollinger, J. Martin,Krebs, Carsten,Boal, Amie K.
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Read Online
- A facile synthesis of (S)-gizzerosine, a potent agonist of the histamine H2-receptor
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A simple and direct approach for the synthesis of (S)-gizzerosine, an amino acid responsible for the disease, black vomit, and a potent histamine H2-receptor, has been developed in 10 steps and in 31% overall yield from l-aspartic acid. The key steps involved a two-carbon homologation of an l-aspartic acid semi-aldehyde and direct alkylation of unprotected histamine with a 6-hydroxynorleucine derivative.
- Fanning, Kate N.,Sutherland, Andrew
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Read Online
- Geometric changes around an N atom due to a urethane-type bis(tert-butoxycarbonyl) substituent
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Two crystal structures of urethane-protected derivatives of aspartic acid dimethyl ester are presented, namely dimethyl (2S)-2-[(tert-butoxycarbonyl) amino]butanedioate, C11H19NO6, and dimethyl (2S)-2-{bis[(tert-butoxycarbonyl]amino}butanedioate, C16H 27NO8. The geometry at the N atom is discussed and compared with similar structures. The analysis of singly and doubly N-substituted derivatives reveals an elongation of all bonds involving the N atom and conformational changes of the amino acid side chain due to steric interactions with two bulky substituents on the amino group.
- Wojewska, Dominika,Kluczyk, Alicja,Slepokura, Katarzyna
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- A short and efficient synthesis of (S)-(+)-2-(Hydroxymethyl)-6-piperidin-2- one
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A concise synthesis of (S)-(+)-2-(hydroxymethyl)-6-piperidin-2-one is described that employs l-aspartic acid as chiral pool starting material and Wittig reaction as the key step. Georg Thieme Verlag Stuttgart - New York.
- Upadhyay, Puspesh K.,Kumar, Pradeep
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- Total synthesis of a pyrrole lactone alkaloid, longanlactone
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The first asymmetric total synthesis of the natural pyrrole lactone longanlactone has been achieved. The key reactions, a Barbier propargylation and a Paal-Knorr pyrrole synthesis, have provided easy access to the target natural product from L-aspartic acid in six steps and 31 % overall yield. The C-4 epimer of the natural product and propionyllonganlactone have also been prepared by this strategy.
- Reddy, Chada Raji,Reddy, Motatipally Damoder,Dilipkumar, Uredi
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- Substrate Engineering in Lipase-Catalyzed Selective Polymerization of d -/ l -Aspartates and Diols to Prepare Helical Chiral Polyester
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The synthesis of optically pure polymers is one of the most challenging tasks in polymer chemistry. Herein, Novozym 435 (Lipase B from Candida antarctica, immobilized on Lewatit VP OC 1600)-catalyzed polycondensation between d-/l-aspartic acid (Asp) diester and diols for the preparation of helical chiral polyesters was reported. Compared with d-Asp diesters, the fast-reacting l-Asp diesters easily reacted with diols to provide a series of chiral polyesters containing N-substitutional l-Asp repeating units. Besides amino acid configuration, N-substituent side chains and the chain length of diols were also investigated and optimized. It was found that bulky acyl N-substitutional groups like N-Boc and N-Cbz were more favorable for this polymerization than small ones probably due to competitively binding of these small acyl groups into the active site of Novozym 435. The highest molecular weight can reach up to 39.5 × 103 g/mol (Mw, D = 1.64). Moreover, the slow-reacting d-Asp diesters were also successfully polymerized by modifying the substrate structure to create a "nonchiral"condensation environment artificially. These enantiocomplementary chiral polyesters are thermally stable and have specific helical structures, which was confirmed by circular dichroism (CD) spectra, scanning electron microscope (SEM), and molecular calculation.
- Zhang, Yu,Xia, Bo,Li, Yanyan,Lin, Xianfu,Wu, Qi
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Read Online
- Synthesis of Imidazole and Histidine-Derived Cross-Linkers as Analogues of GOLD and Desmosine
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Amino acid derivatives with a central cationic heterocyclic core (e.g., imidazolium) are biologically relevant cross-linkers of proteins and advanced glycation end (AGE) products. Here, imidazolium-containing cross-linkers were synthesized from imidazole or histidine by N-alkylation employing aspartate- and glutamate-derived mesylates as key step. Biological investigations were carried out to probe the biocompatibility of these compounds.
- Sch?del, Nicole,Icik, Esra,Martini, Maike,Altevogt, Luca,Ramming, Isabell,Greulich, Andreas,Baro, Angelika,Bilitewski, Ursula,Laschat, Sabine
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supporting information
p. 2260 - 2268
(2021/03/04)
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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 and Biological Evaluation of a Library of AGE-Related Amino Acid Triazole Crosslinkers
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Three N-Boc-protected amino acids, l-serine, l-aspartic, and l-glutamic acid, were either converted into their methyl azidoalkanoates or various alkynes via Bestmann-Ohira strategy or via reaction with propargylamine and propargyl bromide, respectively. The Cu-catalyzed click reaction provided a library of amino acid based triazoles, which were further N-methylated to triazolium iodides or deprotected and precipitated as free amino acid triazole dihydrochlorides. The biological properties of all derivatives were investigated by cytotoxicity assay (against L929 mouse fibroblasts) and broth microdilution method (E. coli ΔTolC and S. aureus). First results reveal complete inactivity for triazolium iodides with cell viabilities and microbial growths nearly 100 %, indicating them as possible analogs of advanced glycation endproducts (AGEs).
- Agelidis, Nektarios,Altevogt, Luca,Baro, Angelika,Bilitewski, Ursula,Bugdayci, Bakiye,Icik, Esra,Jolly, Anthony,L?ffler, Paul,Laschat, Sabine
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supporting information
(2020/09/01)
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- Selenolysine: A New Tool for Traceless Isopeptide Bond Formation
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Despite their biological importance, post-translationally modified proteins are notoriously difficult to produce in a homogeneous fashion by using conventional expression systems. Chemical protein synthesis or semisynthesis offers a solution to this problem; however, traditional strategies often rely on sulfur-based chemistry that is incompatible with the presence of any cysteine residues in the target protein. To overcome these limitations, we present the design and synthesis of γ-selenolysine, a selenol-containing form of the commonly modified proteinogenic amino acid, lysine. The utility of γ-selenolysine is demonstrated with the traceless ligation of the small ubiquitin-like modifier protein, SUMO-1, to a peptide segment of human glucokinase. The resulting polypeptide is poised for native chemical ligation and chemoselective deselenization in the presence of unprotected cysteine residues. Selenolysine's straightforward synthesis and incorporation into synthetic peptides marks it as a universal handle for conjugating any ubiquitin-like modifying protein to its target.
- Dardashti, Rebecca Notis,Kumar, Shailesh,Sternisha, Shawn M.,Reddy, Post Sai,Miller, Brian G.,Metanis, Norman
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supporting information
p. 4952 - 4957
(2020/04/07)
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- Two Distinct Mechanisms for C-C Desaturation by Iron(II)- and 2-(Oxo)glutarate-Dependent Oxygenases: Importance of α-Heteroatom Assistance
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Hydroxylation of aliphatic carbons by nonheme Fe(IV)-oxo (ferryl) complexes proceeds by hydrogen-atom (H?) transfer (HAT) to the ferryl and subsequent coupling between the carbon radical and Fe(III)-coordinated oxygen (termed rebound). Enzymes that use H?-abstracting ferryl complexes for other transformations must either suppress rebound or further process hydroxylated intermediates. For olefin-installing C-C desaturations, it has been proposed that a second HAT to the Fe(III)-OH complex from the carbon α to the radical preempts rebound. Deuterium (2H) at the second site should slow this step, potentially making rebound competitive. Desaturations mediated by two related l-arginine-modifying iron(II)- and 2-(oxo)glutarate-dependent (Fe/2OG) oxygenases behave oppositely in this key test, implicating different mechanisms. NapI, the l-Arg 4,5-desaturase from the naphthyridinomycin biosynthetic pathway, abstracts H? first from C5 but hydroxylates this site (leading to guanidine release) to the same modest extent whether C4 harbors 1H or 2H. By contrast, an unexpected 3,4-desaturation of l-homoarginine (l-hArg) by VioC, the l-Arg 3-hydroxylase from the viomycin biosynthetic pathway, is markedly disfavored relative to C4 hydroxylation when C3 (the second hydrogen donor) harbors 2H. Anchimeric assistance by N6 permits removal of the C4-H as a proton in the NapI reaction, but, with no such assistance possible in the VioC desaturation, a second HAT step (from C3) is required. The close proximity (≤3.5 ?) of both l-hArg carbons to the oxygen ligand in an X-ray crystal structure of VioC harboring a vanadium-based ferryl mimic supports and rationalizes the sequential-HAT mechanism. The results suggest that, although the sequential-HAT mechanism is feasible, its geometric requirements may make competing hydroxylation unavoidable, thus explaining the presence of α-heteroatoms in nearly all native substrates for Fe/2OG desaturases.
- Dunham, Noah P.,Chang, Wei-Chen,Mitchell, Andrew J.,Martinie, Ryan J.,Zhang, Bo,Bergman, Jonathan A.,Rajakovich, Lauren J.,Wang, Bo,Silakov, Alexey,Krebs, Carsten,Boal, Amie K.,Bollinger, J. Martin
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supporting information
p. 7116 - 7126
(2018/05/15)
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- Andrographolide compound, its pharmaceutical composition and application
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The invention discloses a andrographolide compound, preparation method thereof, and the application of the pharmaceutical composition. The invention of andrographolide compound (I), an isomer, prodrug, solvate or pharmaceutically acceptable salt has the following structure. The invention of andrographolide compound has good for the treatment of inflammatory diseases, the inflammatory diseases including but not limited to possible by bacteria, virus and the like caused by pathogens, caused by autoimmune, radiation damage caused by, or other factors of inflammatory diseases.
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Paragraph 0187; 0188; 0189
(2018/07/15)
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- π-Conjugate Fluorophore-Tagged and Enzyme-Responsive l -Amino Acid Polymer Nanocarrier and Their Color-Tunable Intracellular FRET Probe in Cancer Cells
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The present investigation accounts one of the first example of enzyme-responsive and π-conjugate-tagged l-amino acid amphiphilic polymer and their fluorescence resonance energy transfer (FRET) probes for color-tunable intracellular bioimaging in cancer ce
- Saxena, Sonashree,Jayakannan, Manickam
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p. 2594 - 2609
(2017/08/18)
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- ARYL LACTAM KINASE INHIBITORS
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The present disclosure is generally directed to compounds which can inhibit AAK1 (adaptor associated kinase 1), compositions comprising such compounds, and methods for inhibiting AAK1.
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Page/Page column 275
(2015/11/02)
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- Synthesis and reactivity of 4-oxo-5-trimethylsilanyl derived α-amino acids
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A Lewis-acid promoted one-carbon homologation of an aspartic acid semialdehyde with trimethylsilyldiazomethane has led to the efficient synthesis of two silicon-containing α-amino acids. The use of trimethylaluminium or catalytic tin(II) chloride gave nov
- Reid, Caroline M.,Fanning, Kate N.,Fowler, Lindsay S.,Sutherland, Andrew
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p. 245 - 251
(2015/02/02)
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- Aryl vinyllactam serinekinase inhibitor
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The present disclosure is generally directed to compounds which can inhibit AAK1 (adaptor associated kinase 1), compositions comprising such compounds, and methods for inhibiting AAK1.
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Paragraph 0476
(2016/10/09)
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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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supporting information
p. 474 - 482
(2015/01/30)
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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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Page/Page column
(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 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 00158; 00159
(2013/08/28)
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- BENZIIMIDAZOLE AND IMIDAZOPYRIDINE DERIVATIVES AS SODIUM CHANNEL MODULATORS
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The invention relates to benzimidazole and imidazopyridine derivatives, to their use in medicine, to compositions containing them, to processes for their preparation and to intermediates used in such processes. More particularly the invention relates to new Nav1.8 modulators of formula (I) or pharmaceutically acceptable salts thereof, wherein R1, R2, R3, R4, R5, R6, R7. X and Y are as defined in the description. Nav1.8 modulators are potentially useful in the treatment of a wide range of disorders, particularly pain.
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Page/Page column 168
(2013/08/15)
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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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- The synthesis of a chiral β-amino acid derivative by the Grignard reaction of an aspartic acid equivalent
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A novel synthetic route to chiral β-amino acid derivative has been developed by a Grignard reaction of 2,4,5-trifluo- rophenyl magnesium bromide with the Weinreb amide derivative of L-aspartic acid. The aspartic equivalent was synthesised from L-aspartic
- Liu, Feng,Yu, Wansheng,Ou, Wenhua,Xu, Xiaojiong,Ruan, Libo,Wang, Xiaoke,Li, Yiming,Peng, Xijiang,Tao, Xiaohu,Mao, Jun,Wan, Jiaomei,Pan, Xianhua
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experimental part
p. 517 - 519
(2010/12/25)
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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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- Efficient and selective cleavage of the t-butoxycarbonyl group from di-t-butylimidodicarbonate using catalytic bismuth(III) bromide in acetonitrile
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Di-t-butylimidodicarbonates can be chemoselectively and efficiently deprotected to the corresponding mono-BOC-protected amines in high yields using a catalytic amount of bismuth(III) bromide in acetonitrile at room temperature. This method is mild and compatible with the presence of a wide range of functional and other protecting groups in the substrates, such as TBDMS, MOM and mono-BOC or Cbz-protected amines, etc. The method has advantages of ease of operation and use of nontoxic and inexpensive catalyst.
- Zheng, Jianlong,Yin, Biaolin,Huang, Wenming,Li, Xiaopeng,Yao, Hequan,Liu, Zhaogui,Zhang, Jiancun,Jiang, Sheng
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scheme or table
p. 5094 - 5097
(2009/12/01)
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- A practical method for selective cleavage of a tert-butoxycarbamoyl N-protective group from N,N-diprotected α-amino acid derivatives using montmorillonite K-10
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A new, practical, and mild procedure for the selective cleavage of a tert-butoxycarbonyl group (Boc) in N-Boc-N-acyl-diprotected amines is described. When applied to α-amino acids, complete integrity of the stereochemistry was observed. The use of N,N-di-Boc-α-amino-δ- and γ-hydroxy esters provided both δ- and γ-lactones in very good yields. The method is based on the use of Montmorillonite K-10 either in CH 2Cl2 at room temperature or in toluene at 65°C and is compatible with the presence of a large range of functional and other protecting groups in the substrates. In most cases virtually pure samples are obtained after filtration and removal of solvents. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Hernandez, J. Nicolas,Crisostomo, Fernando R. Pinacho,Martin, Tomas,Martin, Victor S.
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p. 5050 - 5058
(2008/03/18)
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- New approaches for the synthesis of isotopically labelled guanidine-derived amino acids and noradrenaline reuptake inhibitors
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A new approach for the stereoselective synthesis of guanidine-derived amino acids, L-arginine and (+)-blastidic acid, has been devised which allows the selective incorporation of isotopic labels in both the side chain of the amino acid as well as the guanidine unit. A new asymmetric synthesis of the (S,R)-diastereomer of reboxetine, an antidepressant, has also been completed which allows the specific incorporation of radiolabelled iodine for SPECT imaging. Copyright
- Bischoff, Roland,Hamilton, Deborah J.,Jobson, Nicola K.,Sutherland, Andrew
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p. 323 - 326
(2008/02/05)
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- A chiral pool approach toward the synthesis of thalidomide metabolites
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A synthetic strategy toward the glutarimide-derived metabolite of thalidomide, 5′-hydroxythalidomide (5′-OH THD, 2) was developed which utilizes aspartic acid as a "chiral pool"-type starting material. The synthesis incorporates a Henry reaction as the key carbon-carbon bond-forming step followed by a tandem reduction-cyclization of the intermediate nitroalcohol in forming the heterocyclic core of 5′-OH THD.
- Luzzio, Frederick A.,Duveau, Damien Y.,Figg, William D.
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p. 321 - 334
(2008/04/18)
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- Chirality transfer in the aza-[2,3]-Wittig sigmatropic rearrangement
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The aza-[2,3]-Wittig sigmatropic rearrangements of substrates derived from enantiomerically pure alanine, valine and serine with phenyl and ester anion stabilising groups were investigated for their efficiency in chirality transfer. It was found that a me
- Anderson, James C.,Gair Ford,Whiting, Matthew
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p. 3734 - 3748
(2007/10/03)
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- Ceric ammonium nitrate (CAN) mediated esterification of N-Boc amino acids allows either retention or removal of the N-Boc group
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Reaction of N-Boc amino acids with ceric ammonium nitrate in an alcohol as the solvent at room temperature resulted in the esterification of N-Boc amino acids with Boc group retention. When the reaction was conducted at reflux temperature, esterification was accompanied with simultaneous removal of the Boc group. Both reactions gave the desired products in good yields.
- Kuttan, Ashani,Nowshudin, Shiek,Rao
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p. 2663 - 2665
(2007/10/03)
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- A flexible approach for the synthesis of selectively labelled L-arginine
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A simple and efficient synthesis of L-arginine has been achieved in 12 steps and 24% overall yield. Regioselective reduction and functional group manipulation of the β-side chain of aspartic acid allowed the preparation of an ornithine derivative, which was then guanylated with a bis-protected 1-guanyl-pyrazole and deprotected to give L-arginine. This approach allows the flexible incorporation of stable isotopes and this is demonstrated using potassium 13C-cyanide, which has resulted in the preparation of 5-13C-L-arginine.
- Hamilton, Deborah J.,Sutherland, Andrew
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p. 5739 - 5741
(2007/10/03)
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- Reactivity of chiral α-amidoalkylphenyl sulfones with stabilized carbanions. Stereoselective synthesis of optically active 1-aminopyrrolizidine
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Metal enolates and functionalized allylzinc reagents react with optically active α-amidoalkylphenyl sulfones to give N-carbamoylamino derivatives with variable levels of anti diastereoselectivity. Zinc enolates provide comparable results with respect to l
- Giri, Nicola,Petrini, Marino,Profeta, Roberto
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p. 7303 - 7308
(2007/10/03)
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- A new selective cleavage of N,N-dicarbamoyl-protected amines using lithium bromide
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A mild and new procedure for the selective cleavage of an alkoxycarbonyl group (Boc, CBz) in N,N-dicarbamoyl-protected amino compounds is described. The method is based on the use of lithium bromide in acetonitrile and is compatible with a large range of other functionalities present in the substrates. Compared with other reported methodologies, the procedure is particularly useful for the Cbz-selective cleavage in N,N-Ts,Cbz-diprotected amines. A rationalization of the selectivity supported by ab initio calculations is also presented.
- Hernandez, J. Nicolas,Ramirez, Miguel A.,Martin, Victor S.
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p. 743 - 746
(2007/10/03)
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- Synthesis of thymine derivatives of 4-hydroxyvaline
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A synthetic route to thymine derivatives of (2S,3R)- and (2S,3S)-4-hydroxyvaline has been developed starting from commercially available L-aspartic acid.
- Abraham, Achamma,Howarth, Nicola M.
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p. 675 - 677
(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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- Discovery of N-hydroxy-2-(2-oxo-3-pyrrolidinyl)acetamides as potent and selective inhibitors of tumor necrosis factor-α converting enzyme (TACE)
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New inhibitors of tumor necrosis factor-α converting enzyme (TACE) were discovered using an N-hydroxy-2-(2-oxo-3-pyrrolidinyl)acetamide scaffold. The series was found to be potent in a porcine TACE (pTACE) assay with IC50s typically below 5 nM.
- Duan, James J.-W.,Lu, Zhonghui,Xue, Chu-Biao,He, Xiaohua,Seng, Jennifer L.,Roderick, John J.,Wasserman, Zelda R.,Liu, Rui-Qin,Covington, Maryanne B.,Magolda, Ronald L.,Newton, Robert C.,Trzaskos, James M.,Decicco, Carl P.
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p. 2035 - 2040
(2007/10/03)
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- Indium-mediated facile cleavage of the t-butoxycarbonyl group from di-t-butylimidodicarbonate
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Di-t-butylimidodicarbonates are selectively and efficiently deprotected to the corresponding mono-BOC protected amines in high yields using indium or zinc metal in refluxing methanol. Simple BOC and CBz protected amines are unaffected by these conditions.
- Yadav,Reddy,Reddy, K.Srinivasa,Reddy, K.Bhaskar
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p. 1549 - 1551
(2007/10/03)
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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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p. 7599 - 7603
(2007/10/03)
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- The hydrolysis of primary amide groups in Asn/Gln-containing peptides
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Peptides Boc-Ala-Asn/Gln-OH and Boc-Asn/Gln-Ala-OH were saponified with barium hydroxide to corresponding Asp/Glu-containing peptides. Under the conditions of saponification, Boc-Asn-Ala-OH additionally afforded Boc-Asp-OH, isopeptide Boc-Asp(Ala)-OH, and Boc-NHSuc > Ala-OH, with the third being the key intermediate in these transformations. Boc-Asp(OMe)-Ala-OMe underwent similar transformations under treatment with diazomethane or triethylamine. Saponification with barium hydroxide was accompanied by a high epimerization of N-terminal amino acid residues, whereas the products of the diazomethane treatment of Boc-Asp(OMe)-Ala-OMe had a low degree of epimerization.
- Onoprienko,Yelin,Miroshnikov
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p. 361 - 368
(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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- Enantiospecific synthesis of α-amino acid semialdehydes: A key step for the synthesis of unnatural unsaturated and saturated α-amino acids
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The enantiospecific synthesis of unnatural unsaturated and saturated α- amino acids based on a Wittig type reaction is described. The versatile synthetic intermediates, L-glutamic and L-aspartic acid semialdehydes, are obtained from the corresponding N,N-di-Boc-diesters, by the selective reduction of the ω-ester with DIBAL under controlled conditions. The semialdehydes are chemically stable for a prolonged time and react with various phosphorous ylides, under controlled conditions, to produce the enantiomerically pure unsaturated α-amino acids in high yields. The method is equally applicable to homologated diesters obtained by the presented methodology providing unsaturated amino acids with variable unsaturated- positions and geometries. The corresponding saturated products can be obtained by simple hydrogenation.
- Padron, Jose M.,Kokotos, George,Martin, Tomas,Markidis, Theodoros,Gibbons, William A.,Martin, Victor S.
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p. 3381 - 3394
(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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- Diastereoselective reactions of Grignard reagents with chiral amino lactols derived from L-aspartic acid
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Nucleophilic additions to chiral amino lactols obtained from L-aspartic acid containing a chiral α-silyloxymethyl function by simple Grignard reagents exhibited high stereoselectivity to provide the corresponding optically active amino alcohols containing three contiguous stereogenic centers. The mechanistic origin of the asymmetric induction is rationalized based on chelation controlled models.
- Yoda,Nakagami,Takabe
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p. 169 - 172
(2007/10/02)
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- Aldehyde derivatives and their use as calpain inhibitors
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Aldehyde derivatives with a specific calpain inhibiting activity and a platelet-aggregation inhibiting effect with formula (I) or formula (II): wherein R1 represents an aromatic hydrocarbon group, a heterocyclic group, or a group of-X-R3 in which X represents O,-S(O)m-(m = 0, 1, or 2), and R3 represents an aromatic hydrocarbon group, a heterocyclic group, or an alkyl group; Z represents R?-Y-or R?O-CH(R?)-in which Y represents a 3-to 7-membered nitrogen-containing saturated heterocyclic group, or a single cyclic saturated hydrocarbon group, R? represents an alkyl group, an alkenyl group, an alkynyl group, an acyl group, a sulfonyl group, an alkoxycarbonyl group, a carbamoyl group, or a thiocarbamoyl group, R? represents hydrogen, an alkyl group, or an aromatic hydrocarbon group, and R? represents an acyl group, a carbamoyl group, a thiocarbamoyl group, or an alkyl group; and n is an integer of 1 to 5. wherein R?, R?, R?, and R1? are defined in the specification.
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