Supramolecular structures based on regioisomers of cinnamyl-α-cyclodextrins – new media for capillary separation techniques

• Gabor Benkovics,
• Ondrej Hodek,
• Martina Havlikova,
• Zuzana Bosakova,
• Pavel Coufal,
• Milo Malanga,
• Eva Fenyvesi,
• Andras Darcsi,
• Szabolcs Beni and
• Jindrich Jindrich

Beilstein J. Org. Chem. 2016, 12, 97–109, doi:10.3762/bjoc.12.11

• capillary electrophoresis. The influence of the addition of 2-O-Cin-α-CD and 3-O-Cin-α-CD to the background electrolyte (BGE) and its impact on the effective mobilities of eighteen selected analytes were tested. Nine analytes were in the form of cations (aniline, antipyrine, L-histidine, DL-tyrosine, DL

Bromotyrosine-derived alkaloids from the Caribbean sponge Aplysina lacunosa

• Qun Göthel,
• Thanchanok Sirirak and
• Matthias Köck

Beilstein J. Org. Chem. 2015, 11, 2334–2342, doi:10.3762/bjoc.11.254

• activities, including antiviral [2], antibiotic [3][4][5], Na+/K+ ATPase inhibition [6][7][8], anti-HIV [9][10], antifungal [11], histidine-H3 antagonist [12], cytotoxic [13][14], and antimalarial activities [15][16][17]. During our investigation of the chemical constituents of Aplysina lacunosa (Aplysinidae

Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

• Paul P. Kelly,
• Anja Eichler,
• Susanne Herter,
• David C. Kranz,
• Nicholas J. Turner and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2015, 11, 1713–1720, doi:10.3762/bjoc.11.186

• histidine were not among the active site residues of the parent (or wild type) enzyme but appeared in several of the new variants, thus introducing a thiol, polar or basic group where previously none existed. More bulky aromatic side chains in libraries I and II were often substituted for smaller side

Multivalency as a chemical organization and action principle

• Rainer Haag

Beilstein J. Org. Chem. 2015, 11, 848–849, doi:10.3762/bjoc.11.94

• ], peptide–polymer interactions [17][18][19][20] tripodal-catecholates [21] and polycatechol–surface interactions [22] as well as multivalent organocatalyts [23]. Finally, multivalent dendritic poly(arginine/histidine)-siRNA complexes are evaluated regarding their transfection efficiency [24]. In the future

Multivalent dendritic polyglycerolamine with arginine and histidine end groups for efficient siRNA transfection

• Fatemeh Sheikhi Mehrabadi,
• Hanxiang Zeng,
• Mark Johnson,
• Cathleen Schlesener,
• Zhibin Guan and
• Rainer Haag

Beilstein J. Org. Chem. 2015, 11, 763–772, doi:10.3762/bjoc.11.86

• , arginine (Arg) and histidine (His). To investigate the effects from introducing Arg and His to dPG, the resulting polyplexes of amino acid functionalized dPG-NH2s (AAdPGs)/siRNA were evaluated regarding cytotoxicity, transfection efficiency, and cellular uptake. Among AAdPGs, an optimal vector with (1:3

• residues (His) are important for safe and efficient siRNA transfection, this study indicates that AAdPGs containing higher degrees of His display lower cytotoxicity and more efficient endosomal escape. Keywords: arginine; dendritic polyglycerolamine; histidine; multivalent vector; siRNA delivery

• biomedical purposes [6] such as anti-inflammatory [10] and anticancer therapy [11][12]. Previously a number of cationic polymers like chitosan [13][14][15], PEI [16], and PAMAM [17] have been post-modified with histidine (His) or arginine (Arg) groups. The introduction of histidine groups has been beneficial

Articulated rods – a novel class of molecular rods based on oligospiroketals (OSK)

• Pablo Wessig,
• Roswitha Merkel and
• Peter Müller

Beilstein J. Org. Chem. 2015, 11, 74–84, doi:10.3762/bjoc.11.11

• aim we chose metal cations as triggers and imidazole moieties as chelating groups at the ARs. The chelating event should be monitored by the influence on the [4 + 4] cycloaddition of anthracene. The synthesis of such a fourfold functionalized AR is based on the natural amino acid L-histidine. In the

• first step histidine methylester hydrochloride (40) is acylated with anthracene-9-acetic acid to give 41. After saponification of the ester the potassium salt of the corresponding acid 42 was treated with 32c affording the articulated rod 43 in quantitative yield (Scheme 10). The stretched–folded

Synthesis of modified cyclic and acyclic dextrins and comparison of their complexation ability

• Kata Tuza,
• László Jicsinszky,
• Tamás Sohajda,
• István Puskás and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2014, 10, 2836–2843, doi:10.3762/bjoc.10.301

• applied for the native compounds. The guest candidates were chlorpheniramine, histidine, ibuprofen, camphoric acid, and chrysanthemic acid. Most of the guest compounds were racemates in order to detect enantiorecognition ability if there is any. In most cases the maltooligomers and the cyclodextrin

• interactions than the corresponding maltooligomers. It can be observed, that the hydroxypropylated CDs and the corresponding acyclodextrins possessed similar affinity towards the analyte. In the case of histidine, none of the investigated hosts showed detectable affinity. The highest stability was determined

Versatile synthesis of amino acid functionalized nucleosides via a domino carboxamidation reaction

• Vicky Gheerardijn,
• Jos Van den Begin and
• Annemieke Madder

Beilstein J. Org. Chem. 2014, 10, 2566–2572, doi:10.3762/bjoc.10.268

• functionalities on the nucleoside. As proof of principle and with the catalytic serine–histidine–aspartate catalytic triad of serine proteases in mind, we illustrate the preparation of three different nucleosides equipped with three functional amino acids containing hydroxy, imidazole, amine and carboxylate

• assembly of the desired chain without DNA damage. In the current study, we have chosen to couple three amino acids, which contain functional groups commonly used in SELEX approaches to modify DNA or RNA, to 5-iodo-2’-deoxyuridine. We describe the direct and linker-less introduction of histidine, serine and

• . For the introduction of histidine onto the nucleoside as shown in Scheme 1, we chose to protect the free 3’ and 5’-hydroxy groups with tert-butyldimethylsilyl (TBDMS) groups 1 to avoid side reactions during the next step, the carboxamidation reaction [48]. While protected histidine is commercially

Oxidative phenylamination of 5-substituted 1-hydroxynaphthalenes to N-phenyl-1,4-naphthoquinone monoimines by air and light “on water”

• Julio Benites,
• Juan Meléndez,
• Cynthia Estela,
• David Ríos,
• Luis Espinoza,
• Iván Brito and
• Jaime A. Valderrama

Beilstein J. Org. Chem. 2014, 10, 2448–2452, doi:10.3762/bjoc.10.255

• such as singlet oxygen [20], we examined the effect of histidine, a well-known singlet oxygen scavenger [21], on the formation of iminoquinone 6 from 1,5-DHN (1) and 4-hydroxyphenylamine. When the experiments were performed under standard conditions by using sunlight or green LEDs in the presence of

• histidine, compound 6 was obtained in 69 and 62% yield, respectively. By comparing these results to that observed in the absence of histidine, it may be suggested that singlet oxygen is involved in the oxidative coupling reaction to produce compound 6. In addition, experiments on the oxidative coupling

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

Flow synthesis of a versatile fructosamine mimic and quenching studies of a fructose transport probe

• Matthew B. Plutschack,
• D. Tyler McQuade,
• Giulio Valenti and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 2022–2027, doi:10.3762/bjoc.9.238

• , methionine and histidine. As expected, the amino acids lacking functionality known to quench fluorophores (alanine, glutamine and lysine) did not quench NBDM at concentrations as high as 50 mM. Interestingly, tyrosine did not quench NBDM fluorescence even at concentrations as high as 2 mM (solubility limit

• for tyrosine). Methionine and histidine, however, did quench NBDM via a dynamic mechanism (Figure 4). Carbohydrate–carbohydrate and carbohydrate–aromatic ring interactions are well-known [29][30]. Based on these interactions, we hypothesized that abnormal fluorescence behavior may be exhibited at high

• fitted using a polynomial fit (order = 2) with direct weighting. Comparison of quenching 2 µM NBDM, as measured by fluorescence intensity of methionine and histidine. Each data set was plotted in OriginPro 8.6 and fitted using a linear fit with direct weighting. Batch synthesis of NBDM. a) NaNO2

True and masked three-coordinate T-shaped platinum(II) intermediates

• Manuel A. Ortuño,
• Salvador Conejero and
• Agustí Lledós

Beilstein J. Org. Chem. 2013, 9, 1352–1382, doi:10.3762/bjoc.9.153

• [93]. The corresponding crystallographic structures show the platinum coordinated to a histidine residue of the protein and two ligands (Cl− [92] or NH3 [93]). However, in both situations the fourth ligand was not fully detectable, so that the authors suggested the participation of a coordinating

Synthesis and evaluation of cell-permeable biotinylated PU-H71 derivatives as tumor Hsp90 probes

• Tony Taldone,
• Anna Rodina,
• Erica M. DaGama Gomes,
• Matthew Riolo,
• Hardik J. Patel,
• Raul Alonso-Sabadell,
• Danuta Zatorska,
• Maulik R. Patel,
• Sarah Kishinevsky and
• Gabriela Chiosis

Beilstein J. Org. Chem. 2013, 9, 544–556, doi:10.3762/bjoc.9.60

• clinical trials, has been the ATP-competitive inhibitors that bind to the N-terminal nucleotide binding pocket [4][5]. Hsp90 belongs to the family of GHKL (G = DNA gyrase subunit B; H = Hsp90; K = histidine kinases; L = MutL) ATPases, which is distinguished by a unique bent shape of its nucleotide binding

Photoinduced electron-transfer chemistry of the bielectrophoric N-phthaloyl derivatives of the amino acids tyrosine, histidine and tryptophan

• Axel G. Griesbeck,
• Jörg Neudörfl and
• Alan de Kiff

Beilstein J. Org. Chem. 2011, 7, 518–524, doi:10.3762/bjoc.7.60

• Axel G. Griesbeck Jorg Neudorfl Alan de Kiff University of Cologne, Department of Chemistry, Organic Chemistry, Greinstr. 4, D-50939 Köln, Germany; Fax: +49(221)470 5057 10.3762/bjoc.7.60 Abstract The photochemistry of phthalimide derivatives of the electron-rich amino acids tyrosine, histidine

• and tryptophan 8–10 was studied with respect to photoinduced electron-transfer (PET) induced decarboxylation and Norrish II bond cleavage. Whereas exclusive photodecarboxylation of the tyrosine substrate 8 was observed, the histidine compound 9 resulted in a mixture of histamine and preferential

• cysteine and S-methyl cysteine derivatives [8]. Other proteinogenic amino acids that, in principle, should also be able to show bielectrophoric behavior with aromatic side chains similar to phenylalanine are tyrosine, histidine and tryptophan. The photochemistry of the phthalimide derivatives of these

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

• histidine and possessing inherent catalyst and acid–base functionality. An imidazole ring is also a component of the biogenic amine histamine. It is interesting to note that the imidazole ring does not however appear in the most common H1 and H2 antagonists, presumably due to its metabolic vulnerability

Achiral bis-imine in combination with CoCl₂: A remarkable effect on enantioselectivity of lipase-mediated acetylation of racemic secondary alcohol

• K. Arunkumar,
• M. Appi Reddy,
• T. Sravan Kumar,
• B. Vijaya Kumar,
• K. B. Chandrasekhar,
• P. Rajender Kumar and
• Manojit Pal

Beilstein J. Org. Chem. 2010, 6, 1174–1179, doi:10.3762/bjoc.6.134

• ., serine, histidine, and aspartate) at the active site of CAL-B increases the nucleophilicity of the serine residue. This then interacts with the carbonyl group of the vinyl acetate to form the “acyl-enzyme intermediate” T-1 (Scheme 4) which finally transfers the acyl group to the substrate alcohol 4 via T

Differences between β-Ala and Gly-Gly in the design of amino acids-based hydrogels

• Andreea Pasc,
• Firmin Obounou Akong,
• Sedat Cosgun and
• Christine Gérardin

Beilstein J. Org. Chem. 2010, 6, 973–977, doi:10.3762/bjoc.6.109

• networks as a result of intimate interactions between gelator molecules. Keywords: amino acid; histidine; hydrogel; peptide-based surfactant; soft matter; supramolecular; Introduction Hydrogels continue to attract much interest due to their versatile applications in tissue engineering, biosensing, drug

• amphiphiles, we have recently shown that Gly-Gly-His and β-Ala-His-amphiphiles act as efficient hydrogelators [10]. The histidine moiety seems to play a key role in hydrogel formation, developing not only π-π stacking interactions but also by H-bonding; by replacing histidine by phenylalanine no hydrogel

En route to photoaffinity labeling of the bacterial lectin FimH

• Thisbe K. Lindhorst,
• Michaela Märten,
• Andreas Fuchs and
• Stefan D. Knight

Beilstein J. Org. Chem. 2010, 6, 810–822, doi:10.3762/bjoc.6.91

• , FimHtr, which resembles the adhesin domain of the complete FimH, was used [24]. FimHtr comprises of amino acids 1-160 of FimH and is terminated by a histidine tag His6. FimHtr has the same carbohydrate binding properties as FimH. Mass spectrometric analysis of FimHtr revealed m/z = 17839 (calcd. m/z

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32