A tandem Mannich addition–palladium catalyzed ring-closing route toward 4-substituted-3(2H)-furanones

• Jubi John,
• Eliza Târcoveanu,
• Peter G. Jones and
• Henning Hopf

Beilstein J. Org. Chem. 2014, 10, 1462–1470, doi:10.3762/bjoc.10.150

• the usual spectroscopic methods (see Supporting Information File 1) and also by X-ray structure determination [43] for furanones 7 (product formed by the reaction of 1b with 2b) and 10 (product formed by the reaction of 1d with 2a) (Figure 3). We believe that the mechanism of the present furanone

Tandem Cu-catalyzed ketenimine formation and intramolecular nucleophile capture: Synthesis of 1,2-dihydro-2-iminoquinolines from 1-(o-acetamidophenyl)propargyl alcohols

• Gadi Ranjith Kumar,
• Yalla Kiran Kumar,
• Ruchir Kant and
• Maddi Sridhar Reddy

Beilstein J. Org. Chem. 2014, 10, 1255–1260, doi:10.3762/bjoc.10.125

• for supervising the X-ray data collection and structure determination of 9j reported in this paper. We gratefully acknowledge the financial support by CSIR-Network project 'BSC0102' (CSIR-CDRI-THUNDER) and by DST under the 'Fast Track Proposal Scheme for Young Scientists'. CDRI Communication No. 8678.

Copper–phenanthroline catalysts for regioselective synthesis of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and of pyrrolo[1,2-a]phenanthrolines under mild conditions

• Rupankar Paira,
• Tarique Anwar,
• Maitreyee Banerjee,
• Yogesh P. Bharitkar,
• Shyamal Mondal,
• Sandip Kundu,
• Abhijit Hazra,
• Prakas R. Maulik and
• Nirup B. Mondal

Beilstein J. Org. Chem. 2014, 10, 692–700, doi:10.3762/bjoc.10.62

• -least-squares methods on F2. Programs: APEX2 (Bruker AXS Inc., Madison, Wisconsin, USA) for data collection, SAINT (Bruker AXS Inc., Madison, Wisconsin, USA) for cell refinement and data reduction, SHELXTL (Bruker AXS Inc., Madison, Wisconsin, USA) for structure determination, refinements and molecular

Self-assembly of metallosupramolecular rhombi from chiral concave 9,9’-spirobifluorene-derived bis(pyridine) ligands

• Rainer Hovorka,
• Sophie Hytteballe,
• Torsten Piehler,
• Georg Meyer-Eppler,
• Filip Topić,
• Kari Rissanen,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 432–441, doi:10.3762/bjoc.10.40

• {[(dppp)2Pd2{(S)-6}2](OTf)2}2+, 2482.5 {[(dppp)2Pd2{(S)-6}2](OTf)3}+ and {[(dppp)4Pd4{(S)-6}4](OTf)6}2+. Crystal structure determination: Data for the X-ray crystallographic analysis of [(dppp)2Pd2{(R)-3}2][(dppp)2Pd2{(S)-3}2](OTf)8 derived from (rac)-3 and [(dppp)Pd(OTf)2] were collected on a SuperNova

Four-component reaction of cyclic amines, 2-aminobenzothiazole, aromatic aldehydes and acetylenedicarboxylate

• Hong Gao,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 2934–2939, doi:10.3762/bjoc.9.330

• the different reactivity of piperidine, pyrrolidine and morpholine in this reaction is not very clear. The structures of the prepared 2-pyrrolidinones 1a–1n were fully characterized by 1H and 13C NMR, HRMS, IR spectra, and were further confirmed by single crystal structure determination of compound 1f

• -olates 2f–2h in good yields (Table 2, entries 6–8). The prepared piperidinium and morpholinium 2-pyrrolidinon-3-olates 2a–2h are very stable compounds. Their structures were fully characterized by 1H and 13C NMR, HRMS, IR spectra, and were also confirmed by single crystal structure determination of

Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones – First evidence for the 1,3-oxathiole–thiocarbonyl ylide interconversion

• Valerij A. Nikolaev,
• Alexey V. Ivanov,
• Ludmila L. Rodina and
• Grzegorz Mlostoń

Beilstein J. Org. Chem. 2013, 9, 2751–2761, doi:10.3762/bjoc.9.309

• precipitate was separated by filtration and washed with dichloromethane (2 × 1–2 mL). The solvents from the filtrate were evaporated and the reaction products from the residue were isolated by recrystallization or chromatography. X-ray crystal-structure determination of 3a. All measurements were performed on

Synthesis and characterization of novel bioactive 1,2,4-oxadiazole natural product analogs bearing the N-phenylmaleimide and N-phenylsuccinimide moieties

• Catalin V. Maftei,
• Elena Fodor,
• Peter G. Jones,
• M. Heiko Franz,
• Gerhard Kelter,
• Heiner Fiebig and
• Ion Neda

Beilstein J. Org. Chem. 2013, 9, 2202–2215, doi:10.3762/bjoc.9.259

• underwent a cyclodehydration reaction, delivering aniline 1 with 59% yield after purification. The structure of compound 1 was confirmed by X-ray structure determination (Figure 3 and Figure 4). It crystallizes with two molecules in the asymmetric unit, which differ in the relative orientation of the rings

• -butylamidoxime and 4-nitrobenzonitrile under mild conditions. The results are summarized in Table 1. The optimized yield was 93% (Scheme 3) which makes this route more practical than the amidoxime route presented in Scheme 2 with a yield of only 59%. The structure of compound 2 was confirmed by X-ray structure

• determination (Figure 5 and Figure 6). The interplanar angle in compound 2 is only 3° and the molecules are linked to ribbons parallel to the b axis by two C–H···O interactions. Imide derivatives have been found to possess a broad spectrum of biological activities. A variety of methods have been reported for

Sequential Diels–Alder/[3,3]-sigmatropic rearrangement reactions of β-nitrostyrene with 3-methyl-1,3-pentadiene

• Peter A. Wade,
• Alma Pipic,
• Matthias Zeller and
• Panagiota Tsetsakos

Beilstein J. Org. Chem. 2013, 9, 2137–2146, doi:10.3762/bjoc.9.251

• where ternary adduct 12a,b is formed. Consistent with the presence of these zwitterions, the related open-chain adduct 13 was a minor product obtained from the reaction of Z-diene 1b and β-nitrostyrene in dichloromethane solution. Nitronic ester structure determination Structure assignments for nitronic

Synthesis of enantiomerically pure (2S,3S)-5,5,5-trifluoroisoleucine and (2R,3S)-5,5,5-trifluoro-allo-isoleucine

• Holger Erdbrink,
• Elisabeth K. Nyakatura,
• Susanne Huhmann,
• Ulla I. M. Gerling,
• Dieter Lentz,
• Beate Koksch and
• Constantin Czekelius

Beilstein J. Org. Chem. 2013, 9, 2009–2014, doi:10.3762/bjoc.9.236

• confirmed by crystal structure determination of intermediate 6, based on the known auxiliary configuration (see Supporting Information File 1). Hydrophobicity of L-5-F3-Ile We investigated the relationship between side chain volume and hydrophobicity of L-5-F3Ile. Since size and hydrophobicity are known to

Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step

• James C. Anderson,
• Andreas S. Kalogirou,
• Michael J. Porter and
• Graham J. Tizzard

Beilstein J. Org. Chem. 2013, 9, 1737–1744, doi:10.3762/bjoc.9.200

• [56]. Further stereochemical proof was provided by a single crystal X-ray structure determination of 2·HCl (vide infra). We presumed again that the primary amine of 21 would be more nucleophilic towards a keto acid derivative 5. In order to obtain a piperazinone of the desired connectivity (23) a keto

• recording of NMR spectra in D2O, but again the chemical shifts were inconsistent with those reported. Single crystal X-ray structure determination of 2 proved unambiguously the assigned structure obtained from spectroscopic data (Figure 1) [59]. Conclusion The rapid synthesis of r-3,c-5-diisobutyl-c-6

Palladium-catalyzed synthesis of N-arylated carbazoles using anilines and cyclic diaryliodonium salts

• Stefan Riedmüller and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2013, 9, 1202–1209, doi:10.3762/bjoc.9.136

• byproducts from the crude reaction mixture. After a systematic structure determination by one- and two-dimensional NMR techniques as well as mass spectrometry, we elucidated the two byproducts as the two regioisomers 2'-bromo-N-(4-fluorophenyl)biphenyl-2-amine (7a, 12%) and 2'-bromo-N-(4-fluorophenyl

Facile synthesis of functionalized spiro[indoline-3,2'-oxiran]-2-ones by Darzens reaction

• Qin Fu and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2013, 9, 918–924, doi:10.3762/bjoc.9.105

• structures of the spiro compounds 5a–p were also established by spectroscopic methods and were confirmed by single-crystal X-ray structure determination of compound 5o (Figure 3). 1H NMR spectra showed that a mixture of cis/trans isomers existed in most samples with a large range of different cis/trans

Direct alkenylation of indolin-2-ones by 6-aryl-4-methylthio-2H-pyran-2-one-3-carbonitriles: a novel approach

• Sandeep Kumar,
• Ramendra Pratap,
• Abhinav Kumar,
• Brijesh Kumar,
• Vishnu K. Tandon and
• Vishnu Ji Ram

Beilstein J. Org. Chem. 2013, 9, 809–817, doi:10.3762/bjoc.9.92

• filtered, washed with water, and dried. The isolated product was purified by silica gel column chromatography using hexane/chloroform as eluent to afford products 10a and 10b (the analytical data and spectra are given in Supporting Information File 1 and Supporting Information File 2). Structure

• determination Intensity data for the yellow colored crystals of 8y and 5 were collected at 298(2) K on an OXFORD CrysAlis diffractometer system equipped with a graphite-monochromated Mo Kα radiation source, λ = 0.71073 Å. The final unit cell determination, scaling of the data, and corrections for Lorentz and

Ring-opening reaction of 2,5-dioctyldithieno[2,3-b:3',2'-d]thiophene in the presence of aryllithium reagents

• Hao Zhong,
• Jianwu Shi,
• Jianxun Kang,
• Shaomin Wang,
• Xinming Liu and
• Hua Wang

Beilstein J. Org. Chem. 2013, 9, 767–774, doi:10.3762/bjoc.9.87

• compounds including the X-ray structure determination of 3i. Supporting Information File 108: X-ray crystallographic data file of 3i. Acknowledgements This research was supported by the National Natural Science Foundation of China (21270255, 51273055, 20972041, 50803015) and the Program for Innovation

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

• , Mössbauer spectroscopy, crystal-structure determination and heat-capacity measurements [23][27][28]. In the following we shall briefly discuss the main molecular changes that accompany LS↔HS conversions in iron(II) compounds and their detection with suitable physical methods. As will be shown in many

Regioselective synthesis of 7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione derivatives: A new drug-like heterocyclic scaffold

• Nikolay T. Tzvetkov,
• Harald Euler and
• Christa E. Müller

Beilstein J. Org. Chem. 2012, 8, 1584–1593, doi:10.3762/bjoc.8.181

• the case of C5-thionation, the 13C NMR signal for this carbon atom is shifted from about 176 to 208–209 ppm. In addition, the C4 signal is shifted from ca. 62 to 71 ppm upon thionation. The structure determination of the condensed key products 24 and 25 was carried out by heteronuclear correlation NMR

Design of a novel tryptophan-rich membrane-active antimicrobial peptide from the membrane-proximal region of the HIV glycoprotein, gp41

• Evan F. Haney,
• Leonard T. Nguyen,
• David J. Schibli and
• Hans J. Vogel

Beilstein J. Org. Chem. 2012, 8, 1172–1184, doi:10.3762/bjoc.8.130

• ellipticity according to Wallace and Janes [42]. NMR structure determination The solution structures of gp41w-4R, gp41w-KA and gp41w-FKA were determined in the 4:4:1 cosolvent mixture of CDCl3:methanol-d3:H2O previously used by our group to study the NMR solution structures of other AMPs [19][20][43]. NMR

Synthesis of new pyrrole–pyridine-based ligands using an in situ Suzuki coupling method

• Matthias Böttger,
• Björn Wiegmann,
• Steffen Schaumburg,
• Peter G. Jones,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2012, 8, 1037–1047, doi:10.3762/bjoc.8.116

• otherwise stated. X-Ray structure determination: Data collection and reduction: Crystals were mounted in inert oil on glass fibres and transferred to the cold gas stream of the diffractometer (Oxford Diffraction Xcalibur). Measurements were performed with monochromated Mo Kα radiation (λ = 0.71073 Å). No

The use of glycoinformatics in glycochemistry

• Thomas Lütteke

Beilstein J. Org. Chem. 2012, 8, 915–929, doi:10.3762/bjoc.8.104

• a fully assigned spectrum or to glycan structure determination [150]. GlycoWorkbench also facilitates upload of primary data into EUROCarbDB [24]. Furthermore, it enables user-defined residues, which is important when chemically synthesized glycans are to be analyzed. Such glycans may contain highly

Stereoselective, nitro-Mannich/lactamisation cascades for the direct synthesis of heavily decorated 5-nitropiperidin-2-ones and related heterocycles

• Pavol Jakubec,
• Dane M. Cockfield,
• Madeleine Helliwell,
• James Raftery and
• Darren J. Dixon

Beilstein J. Org. Chem. 2012, 8, 567–578, doi:10.3762/bjoc.8.64

• studentship (to D.M.C), a postdoctoral fellowship (to P.J.), and a Leadership Fellowship (to D.J.D.). We thank Dr Edward Cleator of MSD for useful discussion, Andrew Kyle and Katherine Bogle for X-ray structure determination and the Oxford Chemical Crystallography Service for use of the instrumentation.

Intramolecular carbenoid ylide forming reactions of 2-diazo-3-keto-4-phthalimidocarboxylic esters derived from methionine and cysteine

• Marc Enßle,
• Stefan Buck,
• Roland Werz and
• Gerhard Maas

Beilstein J. Org. Chem. 2012, 8, 433–440, doi:10.3762/bjoc.8.49

• by NMR comparison with the corresponding alanine-derived ring system, for which a structural proof was furnished by X-ray crystal-structure determination [18]. Due to the symmetry of the dimers, the NMR spectra display signals for only half of the total number of carbon and hydrogen nuclei

Double N-arylation reaction of polyhalogenated 4,4’-bipyridines. Expedious synthesis of functionalized 2,7-diazacarbazoles

• Mohamed Abboud,
• Emmanuel Aubert and
• Victor Mamane

Beilstein J. Org. Chem. 2012, 8, 253–258, doi:10.3762/bjoc.8.26

• use of the palladium-catalyzed double N-arylation of electron-rich anilines as the key reaction, the diazacarbazoles were regioselectively generated. Crystal structure determination shows that these molecules interact mainly through π–π stacking. The reported synthesis should widen the use of

• 2a. Functionalized diazacarbazoles 12a–c from bipyridine 2b. Double N-arylation of 2a with aromatic amines 6 catalyzed by a palladium–XPhos complex.a Supporting Information Supporting Information File 48: Characterization data and NMR spectra of all compounds, including X-ray structure determination

Valence isomerization of cyclohepta-1,3,5-triene and its heteroelement analogues

• Helen Jansen,
• J. Chris Slootweg and
• Koop Lammertsma

Beilstein J. Org. Chem. 2011, 7, 1713–1721, doi:10.3762/bjoc.7.201

• , by the hydrolysis of ethyl-1H-azepine-N-carboxylate with potassium hydroxide and subsequent protonation [82]. Because 1H-azepine is highly unstable and rapidly undergoes a [1,3]-H shift to 3H-azepine, only an X-ray structure determination at −78 °C of an N-substituted derivative was reported by Vogel

Functionalization of anthracene: A selective route to brominated 1,4-anthraquinones

• Kiymet Berkil Akar,
• Osman Cakmak,
• Orhan Büyükgüngör and
• Ertan Sahin

Beilstein J. Org. Chem. 2011, 7, 1036–1045, doi:10.3762/bjoc.7.118

• , 310.2 [M − 2Br + Na + 2H]+, 271.0, 254.0, 227.1 [M − 3Br + Na + H]+, 149.1; Anal. Calcd for C14H5Br3O2: C, 37.79; H, 1.13; found: C, 37.79; H, 1.31. Crystallography For crystal structure determination, single crystals of compounds 7 and 17 were used for data collection on a four-circle Rigaku R-AXIS

Gold-catalyzed propargylic substitutions: Scope and synthetic developments

• Olivier Debleds,
• Eric Gayon,
• Emmanuel Vrancken and
• Jean-Marc Campagne

Beilstein J. Org. Chem. 2011, 7, 866–877, doi:10.3762/bjoc.7.99

• equivalent of hydroxylamine was obtained. By using 2.1 equivalents of the Cbz- or PhSO2-protected hydroxylamines, compounds 24a–c were isolated in 67–79% yields as single diastereomers. Determination of the structures of 24 was a challenging task and could only be determined by an X-ray crystal structure

• determination on compound 24b [63]. Efforts to regenerate isoxazolines 23a from 24a by acidic treatment, under various conditions, were unsuccessful in our hands. Notably, in the presence of 37% aqueous HCl in refluxing methanol, the transacetalized product 25 was isolated in 68% yield (Scheme 13). The desired