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Search for "amino groups" in Full Text gives 165 result(s) in Beilstein Journal of Organic Chemistry.

Synthesis and conformational preferences of short analogues of antifreeze glycopeptides (AFGP)

  • Małgorzata Urbańczyk,
  • Michał Jewgiński,
  • Joanna Krzciuk-Gula,
  • Jerzy Góra,
  • Rafał Latajka and
  • Norbert Sewald

Beilstein J. Org. Chem. 2019, 15, 1581–1591, doi:10.3762/bjoc.15.162

Graphical Abstract
  • amino groups of the resin were o-NBS protected by treatment of 4-nitrobenzenesulfonyl chloride (o-NBS-Cl) and sym-collidine in NMP (Scheme 1A, b). Subsequently the resin was N-methylated by Mitsunobu reaction (Scheme 1A, c). Triphenylphosphine (PPh3) was dissolved in dry THF and methanol and shaken with
  • Fmoc-Sieber-PS resin was N-methylated. Firstly, the Fmoc group was cleaved with 20% piperidine in DMF from the resin linker (3 × 10 min shaking). After washing the resin three times with DCM, DMF and 1-methyl-2-pyrrolidone (NMP), the free amino groups of the resin were o-NBS protected. A mixture of 4
  • –1.2 equiv) were pre-activated with HATU (2.8 equiv) in DMF and added to the reaction vessel, followed by HOAt (2.25 equiv) and DIEA (2.75 equiv) in DMF. Coupling was carried out at room temperature for 3 hours. After final Fmoc deprotection, the amino groups of peptides were acetylated using acetic
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Published 16 Jul 2019

Synthesis of dipolar molecular rotors as linkers for metal-organic frameworks

  • Sebastian Hamer,
  • Fynn Röhricht,
  • Marius Jakoby,
  • Ian A. Howard,
  • Xianghui Zhang,
  • Christian Näther and
  • Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1331–1338, doi:10.3762/bjoc.15.132

Graphical Abstract
  • groups are known to exhibit the highest electron-withdrawing effect among the uncharged small functional groups [54]. As electron-donating substitutents, amino groups exhibit the strongest effects, especially if tris-alkyl substituted. However, we chose alkoxy substituents for our design, because
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Published 18 Jun 2019

N-doped carbon dots covalently functionalized with pillar[5]arenes for Fe3+ sensing

  • Jia Gao,
  • Ming-Xue Wu,
  • Dihua Dai,
  • Zhi Cai,
  • Yue Wang,
  • Wenhui Fang,
  • Yan Wang and
  • Ying-Wei Yang

Beilstein J. Org. Chem. 2019, 15, 1262–1267, doi:10.3762/bjoc.15.123

Graphical Abstract
  • stretching vibration of C–N at 1433 cm−1 in CCDs was obviously increased because the abundant amino groups of CN-dots reacted with carboxylic acid groups of the CP[5] macrocycles. Powder X-ray diffraction (PXRD) patterns (Figure 1e) of CCDs show the characteristic peaks of CN-dots and CP[5], further
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Published 07 Jun 2019

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

  • Shahien Shahsavari,
  • Dhananjani N. A. M. Eriyagama,
  • Bhaskar Halami,
  • Vagarshak Begoyan,
  • Marina Tanasova,
  • Jinsen Chen and
  • Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

Graphical Abstract
  • removed with an acid in each synthetic cycle. The exo-amino groups of nucleosides dA, dC and dG are protected with acyl groups, the nascent ODN is anchored to a solid support via a base- or nucleophile-cleavable linker, and in the most widely used phosphoramidite technology the phosphate groups are
  • electrophilic ODN synthesis technology, the phosphoramidite monomers 3a–c and the linker 4 (Figure 1) were needed. The construction of linker 4 was reported previously [40]. The synthesis of 3a–c is shown in Scheme 2. The reagent 5 needed for protecting the exo-amino groups of nucleobases was prepared in two
  • protections, which contained a tertiary butyl carbamate moiety, were not completely stable under the acidic conditions needed for de-tritylation in each synthetic cycle. Once the protection was lost, in the coupling step, incoming phosphoramidites would react with the free amino groups, and branched ODNs
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Published 20 May 2019

Novel (2-amino-4-arylimidazolyl)propanoic acids and pyrrolo[1,2-c]imidazoles via the domino reactions of 2-amino-4-arylimidazoles with carbonyl and methylene active compounds

  • Victoria V. Lipson,
  • Tetiana L. Pavlovska,
  • Nataliya V. Svetlichnaya,
  • Anna A. Poryvai,
  • Nikolay Yu. Gorobets,
  • Erik V. Van der Eycken,
  • Irina S. Konovalova,
  • Svetlana V. Shiskina,
  • Alexander V. Borisov,
  • Vladimir I. Musatov and
  • Alexander V. Mazepa

Beilstein J. Org. Chem. 2019, 15, 1032–1045, doi:10.3762/bjoc.15.101

Graphical Abstract
  • cyclic or acyclic CH acids the C5 reaction centre in the 2-amino-4-arylimidazoles possesses higher nucleophilicity than both the exo- and endocyclic amino groups. Regarding the short reaction times of novel Yonemitsu-type reactions that has been achieved without application of any catalyst we assume that
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Published 06 May 2019

Oxidative radical ring-opening/cyclization of cyclopropane derivatives

  • Yu Liu,
  • Qiao-Lin Wang,
  • Zan Chen,
  • Cong-Shan Zhou,
  • Bi-Quan Xiong,
  • Pan-Liang Zhang,
  • Chang-An Yang and
  • Quan Zhou

Beilstein J. Org. Chem. 2019, 15, 256–278, doi:10.3762/bjoc.15.23

Graphical Abstract
  • , Scheme 9) [62]. In this transformation, many substituted MCPs 1 with alkyl groups, Ts-protected amino groups, or halogens were tolerated well and gave the desired products 31 in good yields. Moreover, the product 31a could go through a further oxidation to afford two different products in the presence of
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Published 28 Jan 2019

Synthesis of mono-functionalized S-diazocines via intramolecular Baeyer–Mills reactions

  • Miriam Schehr,
  • Daniel Hugenbusch,
  • Tobias Moje,
  • Christian Näther and
  • Rainer Herges

Beilstein J. Org. Chem. 2018, 14, 2799–2804, doi:10.3762/bjoc.14.257

Graphical Abstract
  • derivatives [18][19]. Towards the synthesis of S-diazocines (Figure 1), two general approaches could be derived from the well investigated azobenzene preparation methods: a) Reductive coupling of two nitro groups or b) oxidative coupling of two amino groups [20]. To cleanly form N=N bonds by reduction of
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Published 07 Nov 2018

Novel solid-phase strategy for the synthesis of ligand-targeted fluorescent-labelled chelating peptide conjugates as a theranostic tool for cancer

  • Sagnik Sengupta,
  • Mena Asha Krishnan,
  • Premansh Dudhe,
  • Ramesh B. Reddy,
  • Bishnubasu Giri,
  • Sudeshna Chattopadhyay and
  • Venkatesh Chelvam

Beilstein J. Org. Chem. 2018, 14, 2665–2679, doi:10.3762/bjoc.14.244

Graphical Abstract
  • in high chemical yield and purity by strategically introducing differentially protected dibasic amino acids such as lysine whose α- and ε-amino groups are protected as base labile Fmoc and trifluoroacetyl (Tfa) protecting groups, respectively. The whole concept is successfully illustrated using
  • position of the fluorescent tag and chelating core would lie outside the surface of the protein tunnel. Moreover, differentially protected α- and ε-amino groups of the amino acid lysine (Lys), Fmoc-Lys-(Tfa)-OH, is also introduced in the peptide chain. The main purpose of this exercise is to connect the
  • of bioconjugates 13 and 17 [panels (x) and (xii)], confirming the specificity of the synthesized bioconjugates. Thus, we have developed a novel strategy to synthesize targeted fluorescent tagged bioconjugates by introducing differentially protected α- and ε-amino groups of lysine amino acid
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Published 18 Oct 2018

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

  • Vladimir A. Burilov,
  • Guzaliya A. Fatikhova,
  • Mariya N. Dokuchaeva,
  • Ramil I. Nugmanov,
  • Diana A. Mironova,
  • Pavel V. Dorovatovskii,
  • Victor N. Khrustalev,
  • Svetlana E. Solovieva and
  • Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

Graphical Abstract
  • amino groups in the ethylenediamine fragment (pK2 = 9.08 and pK3 = 9.97 for the diethylenetriamine conjugated acid [48]). Thus, stabilization of the monocationic form prevents the formation of a dicationic species. The premicellar aggregates of the lipophilic dicationic macrocycle 10b demonstrate a
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Published 31 Jul 2018

Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril

  • Mohammad A. Alnajjar,
  • Jürgen Bartelmeß,
  • Robert Hein,
  • Pichandi Ashokkumar,
  • Mohamed Nilam,
  • Werner M. Nau,
  • Knut Rurack and
  • Andreas Hennig

Beilstein J. Org. Chem. 2018, 14, 1961–1971, doi:10.3762/bjoc.14.171

Graphical Abstract
  • applicable to pH-sensitive fluoresceins, cyanines or rhodamines, in which protonation and deprotonation of suitably positioned amino groups can also modulate their fluorescence properties. It can also be used to design dyes which reduce their fluorescence upon binding, e.g., when electron-poor groups are
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Published 30 Jul 2018

An amine protecting group deprotectable under nearly neutral oxidative conditions

  • Shahien Shahsavari,
  • Chase McNamara,
  • Mark Sylvester,
  • Emily Bromley,
  • Savannah Joslin,
  • Bao-Yuan Lu and
  • Shiyue Fang

Beilstein J. Org. Chem. 2018, 14, 1750–1757, doi:10.3762/bjoc.14.149

Graphical Abstract
  • 10.3762/bjoc.14.149 Abstract The 1,3-dithiane-based dM-Dmoc group was studied for the protection of amino groups. Protection was achieved under mild conditions for aliphatic amines, and under highly reactive conditions for the less reactive arylamines. Moderate to excellent yields were obtained
  • collection of transformations to be carried out on the protected substrates that are unattainable using any known protecting groups. Keywords: amine; carbamate; dM-Dmoc; oxidation; protecting group; Introduction In multistep organic synthesis, amino groups usually have to be protected [1]. Protecting
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Published 13 Jul 2018

Recent applications of chiral calixarenes in asymmetric catalysis

  • Mustafa Durmaz,
  • Erkan Halay and
  • Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

Graphical Abstract
  • . The low enantioselectivities obtained were mainly attributed to the high flexibility of catalytic amino groups of N,O-type enantiomers. Suzuki–Miyaura cross–coupling and Tsuji–Trost allylic substitution reaction Manoury et al. described the synthesis of ferrocene-bearing enantiomerically pure
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Published 08 Jun 2018

The first Pd-catalyzed Buchwald–Hartwig aminations at C-2 or C-4 in the estrone series

  • Ildikó Bacsa,
  • Dávid Szemerédi,
  • János Wölfling,
  • Gyula Schneider,
  • Lilla Fekete and
  • Erzsébet Mernyák

Beilstein J. Org. Chem. 2018, 14, 998–1003, doi:10.3762/bjoc.14.85

Graphical Abstract
  • ]. Classical nitration methods have, however, many drawbacks concerning elevated reaction temperatures, long reaction times, and poor yields. The introduction of amino or substituted amino groups onto ring A of estrone is fascinating from both organic chemical and biological points of view. Certain ring A
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Published 04 May 2018

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

  • Eirinaios I. Vrettos,
  • Gábor Mező and
  • Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

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Published 26 Apr 2018

Phosphodiester models for cleavage of nucleic acids

  • Satu Mikkola,
  • Tuomas Lönnberg and
  • Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

Graphical Abstract
  • transfer from the attacking 2´-OH to non-bridging phosphoryl oxygen. Primary amines are, in turn, used to mimic the action of the ε-amino group of lysine. Both guanidine and primary amino groups are basic functions that at physiological pH are present as guanidinium and ammonium ions. These ions tend to
  • were compared to the reactions of UpU [86] and 4´-hydoxymethyl-UpT (12b) [87]. The pKa values for the mono- and diammonium ions of 12a were determined to be 7.2 and 5.8, respectively. At pH 3–5, i.e., under conditions where both amino groups were protonated, both the cleavage and 3´,5´→2´,5
  • range 7.5–8.5, where both amino groups still are deprotonated, the behavior of 12a, however, differs from that of UpU or 12b; another pH-independent cleavage occurs [86]. This reaction is one order of magnitude faster than the pH-independent cleavage of 12a at pH 3–5, i.e., when both amino groups are
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Published 10 Apr 2018

Aminosugar-based immunomodulator lipid A: synthetic approaches

  • Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

Graphical Abstract
  • chemical structure of lipid A is based on the β(1→6)-linked 1-,4′-bisphosphorylated diglucosamine backbone which is typically tetra- till heptaacylated at the amino groups (positions 2 and 2’) and hydroxyl groups (positions 3 and 3’) by (R)-3-hydroxy- or/and (R)-3-acyloxyacyl fatty acids of variable
  • -benzyl ether. The liberated 4’-OH group was phosphorylated via phosphoramidite procedure to furnish 56. Next, both 2- and 2’-N-Troc groups were reductively cleaved using Zn in acetic acid and the resulting 2’- and 2-amino groups were acylated with (R)-3-dodecanoyltetradecanoic acid to give 57. Three
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Published 04 Jan 2018

Development of a fluorogenic small substrate for dipeptidyl peptidase-4

  • Futa Ogawa,
  • Masanori Takeda,
  • Kanae Miyanaga,
  • Keita Tani,
  • Ryuji Yamazawa,
  • Kiyoshi Ito,
  • Atsushi Tarui,
  • Kazuyuki Sato and
  • Masaaki Omote

Beilstein J. Org. Chem. 2017, 13, 2690–2697, doi:10.3762/bjoc.13.267

Graphical Abstract
  • trisubstituted (2 and 4) products in one synthetic operation. Next, the fluorescence profiles of these products were investigated. The results are summarized in Figure 1 and Table 2. The number of amino groups and TFPE groups introduced into compounds 1–4 significantly affected the fluorescence profiles in THF
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Published 14 Dec 2017

Metal-mediated base pairs in parallel-stranded DNA

  • Jens Müller

Beilstein J. Org. Chem. 2017, 13, 2671–2681, doi:10.3762/bjoc.13.265

Graphical Abstract
  • comprising one hydrogen bond only and in addition a destabilizing steric clash between two opposing amino groups (Scheme 1b). As a result, most reports on parallel-stranded DNA involving reversed Watson–Crick base pairs focus on A:T rich-sequences. The presence of interspersed G:C base pairs within a duplex
  • reported in PDB entry 2RVP [25]. Hydrogen-bonding patterns of various reversed Watson–Crick base pairs. a) A:T; b) G:C (steric clash between opposing amino groups indicated by red hemicycles); c) G:C in an alternative geometry; d) iG:C. R, R’ = DNA backbone. Various hydrogen-bonding patterns. a) T:A:T and
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Published 13 Dec 2017

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

  • Matthias Wünsch,
  • David Schröder,
  • Tanja Fröhr,
  • Lisa Teichmann,
  • Sebastian Hedwig,
  • Nils Janson,
  • Clara Belu,
  • Jasmin Simon,
  • Shari Heidemeyer,
  • Philipp Holtkamp,
  • Jens Rudlof,
  • Lennard Klemme,
  • Alessa Hinzmann,
  • Beate Neumann,
  • Hans-Georg Stammler and
  • Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

Graphical Abstract
  • side chain can be introduced using masked or protected functionalities. Side chains with amino groups were introduced masked as azide. For this purpose, the unprecedented intramolecular Huisgen reaction has to be suppressed. Electron-withdrawing substituents in the Cβ-position could not be used by this
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Published 15 Nov 2017

An efficient synthesis of a C12-higher sugar aminoalditol

  • Łukasz Szyszka,
  • Anna Osuch-Kwiatkowska,
  • Mykhaylo A. Potopnyk and
  • Sławomir Jarosz

Beilstein J. Org. Chem. 2017, 13, 2146–2152, doi:10.3762/bjoc.13.213

Graphical Abstract
  • the benzoyl group at the amino and the free hydroxy functions providing dibenzoyl derivative 14 in very good yield (94%, Scheme 2). The reduction of derivative 14 with LiAlH4 removed the benzoyl protection from both hydroxy and amino groups and surprisingly, no reduction of the benzoyl located at the
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Published 16 Oct 2017

Syntheses of 3,4- and 1,4-dihydroquinazolines from 2-aminobenzylamine

  • Jimena E. Díaz,
  • Silvia Ranieri,
  • Nadia Gruber and
  • Liliana R. Orelli

Beilstein J. Org. Chem. 2017, 13, 1470–1477, doi:10.3762/bjoc.13.145

Graphical Abstract
  • required functionalization of both amino groups present in 2-ABA was achieved by different routes involving selective N-acylation and cesium carbonate-mediated N-alkylation reactions, avoiding protection/deprotection steps. The heterocycles were efficiently synthesized in short reaction times by microwave
  • -dihydroquinazolines, a heterocyclic framework quite unexplored. In addition to the heterocyclization itself, the preparation of the acyclic precursors for the synthesis of dihydroquinazolines remains challenging as in some cases it includes a selective N-functionalization of the amino groups of 2-ABA. For example
  • different nucleophilicity of both amino groups, the predictable formation of a hydrogen bond between the aromatic amino group (hydrogen bond donor) and the aliphatic NHR (hydrogen bond acceptor) could increase the nucleophilicity of the former and decrease the reactivity of the latter, favoring the chance
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Published 27 Jul 2017

Synthesis of oligonucleotides on a soluble support

  • Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

Graphical Abstract
  • protected nucleoside 3´-(2-cyanoethyl-N,N-dialkylphosphoramidite)s (1 in Scheme 1) or 3´-(H-phosphonate)s are usually preferred as building blocks [3] (2 in Scheme 1). The attacking 5´-OH apart, all other nucleophilic functionalities must be kept protected during the coupling. The primary amino groups of
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Published 12 Jul 2017

Switchable highly regioselective synthesis of 3,4-dihydroquinoxalin-2(1H)ones from o-phenylenediamines and aroylpyruvates

  • Juraj Dobiaš,
  • Marek Ondruš,
  • Gabriela Addová and
  • Andrej Boháč

Beilstein J. Org. Chem. 2017, 13, 1350–1360, doi:10.3762/bjoc.13.132

Graphical Abstract
  • monosubstituted o-phenylenediamines 11. In this case the amino groups usually have different reactivity and thus produce a mixture of regioisomeric products. If both regioisomers are needed, one can separate them [21]. Separation can be difficult to such an extent that some of the Cu(II) chelators were
  • the substituent in aryldiamine 11. If the nucleophilicity of the two amino groups in 11 are not differentiated enough, the obtained selectivity will be less synthetically useful. In that case, a different synthesis will be required, e.g., masking amino with the nitro group. The HOBt/DIC procedure
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Published 10 Jul 2017

Interactions between shape-persistent macromolecules as probed by AFM

  • Johanna Blass,
  • Jessica Brunke,
  • Franziska Emmerich,
  • Cédric Przybylski,
  • Vasil M. Garamus,
  • Artem Feoktystov,
  • Roland Bennewitz,
  • Gerhard Wenz and
  • Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

Graphical Abstract
  • measurements. Small-angle neutron and X-ray (SANS/SAXS) scattering experiments confirm the stiffness of the polymer chains with an apparent contour length of about 130 Å. Surface modification of planar silicon wafers as well as AFM tips was realized by covalent bound formation between the terminal amino groups
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Published 18 May 2017

Total synthesis of TMG-chitotriomycin based on an automated electrochemical assembly of a disaccharide building block

  • Yuta Isoda,
  • Norihiko Sasaki,
  • Kei Kitamura,
  • Shuji Takahashi,
  • Sujit Manmode,
  • Naoko Takeda-Okuda,
  • Jun-ichi Tamura,
  • Toshiki Nokami and
  • Toshiyuki Itoh

Beilstein J. Org. Chem. 2017, 13, 919–924, doi:10.3762/bjoc.13.93

Graphical Abstract
  • -dimethylaminopyridine (DMAP) to convert the amino groups into acetamide groups and to protect the hydroxy groups as acetyl groups. The 2-azido group of tetrasaccharide 8 was then reduced to a 2-amino group with 1,3-propanedithiol. Thus-obtained tetrasaccharide was treated with iodomethane (MeI) and N,N
  • structurally well-defined tetrasaccharide gave TMG-chitotriomycin after manipulations of the amino groups and global deprotection. Further investigations to improve the β-selectivity in the disaccharide synthesis and a large scale synthesis are in progress in our laboratory. Experimental General 1H and 13C NMR
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Published 16 May 2017
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