Photoswitchable precision glycooligomers and their lectin binding

• Daniela Ponader,
• Sinaida Igde,
• Marko Wehle,
• Katharina Märker,
• Mark Santer,
• David Bléger and
• Laura Hartmann

Beilstein J. Org. Chem. 2014, 10, 1603–1612, doi:10.3762/bjoc.10.166

• ligands (Figure 1): Starting from an ethylenediamine functionalized trityl resin (0.0125 mmol), the first building block, i.e., TDS (8 equiv) was attached via activation with PyBOP/HOBt (8 equiv/4 equiv) and DIPEA (16 equiv) in DMF and subsequent coupling for 1 hour. After a washing step, the terminal

• ethylenediamine linker and used as resin for solid phase synthesis. 0.0125 mmol of resin were swollen in DCM for 15 min. The initial coupling to the ethylenediamine linker was performed with a 0.1 mmol building block solution (8 equiv, TDS, EDS or AZO) in DMF (0.5 mL), followed by the addition of a 0.1 mmol PyBOP

Biantennary oligoglycines and glyco-oligoglycines self-associating in aqueous medium

• Svetlana V. Tsygankova,
• Alexander A. Chinarev,
• Alexander B. Tuzikov,
• Nikolai Severin,
• Alexey A. Kalachev,
• Juergen P. Rabe,
• Alexandra S. Gambaryan and
• Nicolai V. Bovin

Beilstein J. Org. Chem. 2014, 10, 1372–1382, doi:10.3762/bjoc.10.140

• solvents were bought from Merck and Sigma–Aldrich. Activated esters BocGlyONSu and BocGly2ONSu were prepared as described earlier [9] from glycine or glycylglycine (Acros). Ethylenediamine and 1,10-diaminodecane were supplied from Sigma-Aldrich, and diamine NH2(CH2CH2O)3CH2CH2NH2 (1) was synthesized from

Molecular recognition of surface-immobilized carbohydrates by a synthetic lectin

• Melanie Rauschenberg,
• Eva-Corrina Fritz,
• Christian Schulz,
• Tobias Kaufmann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 1354–1364, doi:10.3762/bjoc.10.138

• previously [39]. Fluorescein-labeled FITC-HisHis was obtained by labeling of Cys-His-Cys with fluorescein isothiocyanate, which was achieved by using an Fmoc-protected oligo(ethylene glycol) spacer synthesized in four steps from commercially available ethylenediamine (see Supporting Information File 1). The

Flow synthesis of phenylserine using threonine aldolase immobilized on Eupergit support

• Jagdish D. Tibhe,
• Hui Fu,
• Timothy Noël,
• Qi Wang,
• Jan Meuldijk and
• Volker Hessel

Beilstein J. Org. Chem. 2013, 9, 2168–2179, doi:10.3762/bjoc.9.254

• each other which resulted in higher values for enzyme retention. For the indirect method, however, the epoxy groups were converted into aldehyde groups. These groups can only react with nucleophiles such as amino groups. During treatment of Eupergit with ethylenediamine, a coupling of two adjacent

• method the enzyme was separated from the support by a spacer element. This was formed by the reaction of ethylenediamine and glutaraldehyde. This reaction reduces the probability of blocking the active site of the enzyme which would provide higher activity retention. For the direct method, our results

• , Germany). L-threonine, β-nicotinamide adenine dinucleotide disodium salt (NADH) were purchased from AppliChem GmbH (Darmstadt, Germany). Glycine, benzaldehyde, pyridoxal-5’-phosphate (PLP), Eupergit CM, 2-mercaptoethanol, 25% glutaraldehyde solution in water, ethylenediamine and other reagents were all

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• ethylenediamine complex of lithium acetylide in a 1:1 THF/DMSO solvent mixture at 0 °C allowed the terminal alkyne to be accessed in 84% yield without rearrangement to the internal alkyne. Silyl protection afforded alkyne 50, which was prone to decomposition upon extended storage, even at −20 °C. Hydrozirconation

Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors

• Rahat Javaid,
• Shin-ichiro Kawasaki,
• Akira Suzuki and
• Toshishige M. Suzuki

Beilstein J. Org. Chem. 2013, 9, 1156–1163, doi:10.3762/bjoc.9.129

• demonstrates the robustness of the present catalytic reactors. Experimental Materials and reagents Reagent-grade formic acid (HCO2H, 98%), p-nitrophenol, palladium acetate [Pd(CH3COO)2], silver nitrate (AgNO3), disodium ethylenediamine tetraacetate (EDTA–Na2), ammonia (NH3, 28%), hydrazine monohydrate, nitric

A one-pot catalyst-free synthesis of functionalized pyrrolo[1,2-a]quinoxaline derivatives from benzene-1,2-diamine, acetylenedicarboxylates and ethyl bromopyruvate

• Mohammad Piltan,
• Loghman Moradi,
• Golaleh Abasi and
• Seyed Amir Zarei

Beilstein J. Org. Chem. 2013, 9, 510–515, doi:10.3762/bjoc.9.55

• -diaminobenzene, dialkyl acetylenedicarboxylates, and ethyl bromopyruvate forms pyrrolo[1,2-a]quinoxaline derivatives in good yields. Ethylenediamine also reacts under similar conditions to produce new pyrrolo[1,2-a]pyrazine derivatives. Keywords: acetylenedicarboxylates; benzene-1,2-diamine; ethyl bromopyruvate

• react with ethyl bromopyruvate (3) to generate the intermediate 6. This intermediate undergoes a series of cyclization and elimination reactions to generate the product 4a. We then investigated the reaction between ethylenediamine (8) and activated acetylenic compounds in the presence of ethyl

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

• -tetrazole)6]X2 complexes, which are nearly regular octahedral [50]. Another possibility to fulfill the condition for thermal spin crossover to occur is the coordination of a hexadentate system, such as the mixed aliphatic/heterocyclic tetrakis(2-pyridylmethyl)ethylenediamine) [51] or the completely

Amino-substituted diazocines as pincer-type photochromic switches

• Hanno Sell,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2013, 9, 1–7, doi:10.3762/bjoc.9.1

• should be suitable as molecular pincers. To demonstrate this property we studied the binding of ethylenediamine to the two isomers of the acetamido derivative 5 (Figure 5). We carried out 1H NMR titrations of cis-5 as well as of the photostationary mixture of cis-5 and trans-5 upon irradiation with light

• of a wavelength of 405 nm with ethylenediamine in acetonitrile. The spectra showed a significant chemically induced shift (CIS) of the acetamide protons of both isomers upon addition of ethylenediamine. Equilibrium analysis with respect to the CIS binding isotherms by means of nonlinear least-squares

• methods (for details see Supporting Information File 1) [18][19] yielded a binding constant for the 1:1 ethylenediamine complex of the cis isomer of Ka,cis = 0.88 ± 0.03 M−1. For the corresponding complex of the trans isomer a slightly lower binding constant of Ka,trans = 0.61 ± 0.05 M−1 was determined in

New efficient ligand for sub-mol % copper-catalyzed C–N cross-coupling reactions running under air

• Per-Fredrik Larsson,
• Peter Astvik and
• Per-Ola Norrby

Beilstein J. Org. Chem. 2012, 8, 1909–1915, doi:10.3762/bjoc.8.221

• mono-methylating ethylene amines were ineffective for the ethylenediamine motif; hence, there is an opportunity for further ligand synthesis development. Experimental General: All the experiments were carried out under inert atmosphere (nitrogen). DMEDA, iodobenzene and dodecane were distilled over

Enaminones in a multicomponent synthesis of 4-aryldihydropyridines for potential applications in photoinduced intramolecular electron-transfer systems

• Nouria A. Al-Awadi,
• Maher R. Ibrahim,
• Mohamed H. Elnagdi,
• Elizabeth John and
• Yehia A. Ibrahim

Beilstein J. Org. Chem. 2012, 8, 441–447, doi:10.3762/bjoc.8.50

• % yield by microwave irradiation with R-1-phenylethylamine in this three-component reaction. The bis(dihydropyridines) 5a,b were obtained in 75–92% yield with ethylenediamine and 1,3-diaminopropane as the primary amines, respectively. The 4-(1-naphthyl)dihydropyridines 6a–f and 4-(phenanthren-9-yl

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

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

• (Scheme 37). Also, a condensation reaction between ethylenediamine and acetic acid catalysed by γ-Al2O3 at high temperatures gives 2-methylimidazole (187) in approximately 90% yield [56]. Elz and Heil [57] prepared the 1,2,3,9-tetrahydro-4H-carbazol-4-one (140) by the reaction of phenylhydrazine (138

Identification and synthesis of impurities formed during sertindole preparation

• I. V. Sunil Kumar,
• G. S. R. Anjaneyulu and
• V. Hima Bindu

Beilstein J. Org. Chem. 2011, 7, 29–33, doi:10.3762/bjoc.7.5

• sertindole. Sertindole (1), process related impurities and metabolites. Reagents and conditions: i) K2CO3, CuBr, ethylenediamine, DMF 130–135 °C; ii) CH3COOH, CF3COOH, 100–110 °C; iii) PtO2/H2, methanol, 30–35 °C; iv) K2CO3, KI, methylisobutyl ketone (MIBK),110–115 °C. Reagents, conditions (and yields): i

• , conditions (and yields): i) 12, K2CO3, Cu(II)Br, ethylenediamine, DMF, 130–135 °C, (51%); ii) 14, CH3COOH, CF3COOH, 100–105 °C (57%); iii) (a) pH adjusted to 6–7; (b) PtO2/H2, MeOH, 30–35 °C; (c) column chromatography (33.3%); iv) 16, K2CO3, KI, MIBK, reflux (64.3%). Reagents, conditions (and yield): i) (a

Redox-active tetrathiafulvalene and dithiolene compounds derived from allylic 1,4-diol rearrangement products of disubstituted 1,3-dithiole derivatives

• Filipe Vilela,
• Peter J. Skabara,
• Christopher R. Mason,
• Thomas D. J. Westgate,
• Asun Luquin,
• Simon J. Coles and
• Michael B. Hursthouse

Beilstein J. Org. Chem. 2010, 6, 1002–1014, doi:10.3762/bjoc.6.113

• hindrance by the aromatic units towards the formyl group, compound 21 [4] was reacted with ethylenediamine in the presence of a catalytic amount of acetic acid (Scheme 5). The Schiff base product 22 was obtained in 62% yield as a pale brown crystalline solid. Although highly strained and buckled TTF

• , 109.4, 104.4, 98.9, 56.0, 55.7, 37.1 and 19.5; νmax (KBr)/cm−1 1650, 1610, 1503, 1294, 1208 and 1033. N,N’-Bis{5-[bis(2,4-dimethoxyphenyl)methyl]-2-thioxo-[1,3]dithiole-4-ylmethylene}ethan-1,2-diamine (22) Compound 21 (0.50 g, 1.12 mmol) was dissolved in methanol (50 cm3). Ethylenediamine (0.06 g, 1.12

• ), 2,4-dimethoxybenzaldehyde (1 equiv), then repeat, −78 °C, THF; (ii) HClO4, CH2Cl2, rt. Reagents and conditions: (i) ethylenediamine, AcOH, MeOH; (ii) P(OEt)3, 120 °C, 3 h. Reagents and conditions: (i) P(OEt)3, reflux; (ii) Hg(OAc)2, CH2Cl2/AcOH; (iii) NaOEt, THF, reflux, then Bu4NBr and NiCl2·6H2O, rt

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

Concise methods for the synthesis of chiral polyoxazolines and their application in asymmetric hydrosilylation

• Wei Jie Li,
• Zun Le Xu and
• Sheng Xiang Qiu

Beilstein J. Org. Chem. 2010, 6, No. 29, doi:10.3762/bjoc.6.29

• C21H27N3O3: C, 68.27; H, 7.37; N, 11.37. Found: C, 67.98; H, 7.63; N, 11.56. (+)-N,N,N′,N′-Tetrakis{[4-(R)-ethyloxazolin-2-yl]methyl}ethylenediamine (6) Ethylenediaminetetraacetic acid (1.17 g, 4.0 mmol), (R)-2-amino-1-butanol (1.57 g, 17.6 mmol) and toluene (40 mL) were added to a three-neck flask with a

Convergent syntheses of Le^X analogues

• An Wang,
• Jenifer Hendel and
• France-Isabelle Auzanneau

Beilstein J. Org. Chem. 2010, 6, No. 17, doi:10.3762/bjoc.6.17

• group (NaCNBH3, HCl·Et2O) to yield acceptor 6. The triacetate 15 was also converted in seven steps to acceptor 5. The phthalimido group was first removed (ethylenediamine, EtOH) and the free amine acetylated. Zemplén deacetylation was followed by conversion of the triol to the 4,6-benzylidene acetal 18

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides

• Ana Maria Castilla,
• M. Morgan Conn and
• Pablo Ballester

Beilstein J. Org. Chem. 2010, 6, No. 5, doi:10.3762/bjoc.6.5

• amide groups (ΔΔG0 (ethylenediamine-succinamide) = −2.35 kcal/mol). The calculated stability constants are, in general, lower than the values expected for a complex that can be stabilized by an array of not adjacent four hydrogen bonds in chloroform solution (K ≈ 104 M−1). The stability constant values

• for the hydrogen-bonding pattern DAAD instead of ADAD when n = 2 (ΔΔG0 (succinamide-ethylenediamine) = −0.92 kcal/mol) but selects the hydrogen-bonding pattern ADAD when n = 1 (ΔΔG0 (Gly-malonamide) = −0.90 kcal/mol). Surprisingly, linear receptors 15 and 17 exhibited higher levels of

Prediction of reduction potentials from calculated electron affinities for metal-salen compounds

• Sarah B. Bateni,
• Kellie R. England,
• Anthony T. Galatti,
• Handeep Kaur,
• Victor A. Mendiola,
• Alexander R. Mitchell,
• Michael H. Vu,
• Benjamin F. Gherman and
• James A. Miranda

Beilstein J. Org. Chem. 2009, 5, No. 82, doi:10.3762/bjoc.5.82

• condensation of the appropriate substituted salicylaldehyde with ethylenediamine. The reaction was allowed to reflux for 2 h before the crude salen ligand was recrystallized in 95% ethanol. Each salen ligand was characterized by IR and NMR spectroscopy. Second, the appropriate metal acetate and the salen

(−)-Complanine, an inflammatory substance of marine fireworm: a synthetic study

• Kazuhiko Nakamura,
• Yu Tachikawa and
• Daisuke Uemura

Beilstein J. Org. Chem. 2009, 5, No. 12, doi:10.3762/bjoc.5.12

• Discussion Our synthesis started from the known compound 3 [5][6] that could be derived from (R)-malic acid, (R)-2, in three steps (1. BH3·SMe2; 2. cat. TsOH, Et2CO; 3. TsCl, pyridine) (Scheme 1). The resultant tosylate 3 was treated with lithium acetylide ethylenediamine complex to give the terminal

• complanata (body length 10 cm). Total synthesis of complanine. Keys: a) 1. BH3·SMe2 (71%); 2. cat. TsOH, Et2CO (59%); 3. TsCl, pyridine (80%) [5][6]; b) lithium acetylide ethylenediamine complex (1.2 equiv), DMSO, rt, 3 h (51%); c) 1-iodopent-2-yne (2.0 equiv), EtMgBr (1.6 equiv), CuI (cat.), THF, 0 °C to rt

Hydrogenation of aromatic ketones, aldehydes, and epoxides with hydrogen and Pd(0)EnCat™ 30NP

• Steven V. Ley,
• Angus J. P. Stewart-Liddon,
• David Pears,
• Remedios H. Perni and
• Kevin Treacher

Beilstein J. Org. Chem. 2006, 2, No. 15, doi:10.1186/1860-5397-2-15

• that different side reactions can take place like aromatic ring hydrogenation, as well as hydrogenolysis of the produced alcohol to the hydrocarbon derivative. [5][6] Some of these problems have been circumvented by adding ethylenediamine, [7] although this can make isolation of the product and