Synthesis of 2,1-benzisoxazole-3(1H)-ones by base-mediated photochemical N–O bond-forming cyclization of 2-azidobenzoic acids

• Daria Yu. Dzhons and
• Andrei V. Budruev

Beilstein J. Org. Chem. 2016, 12, 874–881, doi:10.3762/bjoc.12.86

• cyclization products such as 2,1-benzisoxazole-3(1H)-one (2a) and 2-oxo-3-carboxy-3H-azepine (3a) has been reported [30]. The structure of benzisoxazole 2a was determined by IR, 1H and 13C NMR spectroscopy and by comparison of its mass spectrum with the corresponding spectrum from the NIST library (NIST

Elucidation of a masked repeating structure of the O-specific polysaccharide of the halotolerant soil bacteria Azospirillum halopraeferens Au4

• Elena N. Sigida,
• Yuliya P. Fedonenko,
• Alexander S. Shashkov,
• Nikolay P. Arbatsky,
• Evelina L. Zdorovenko,
• Svetlana A. Konnova,
• Vladimir V. Ignatov and
• Yuriy A. Knirel

Beilstein J. Org. Chem. 2016, 12, 636–642, doi:10.3762/bjoc.12.62

• , one- and two-dimensional 1H and 13C NMR spectroscopy. The following masked repeating structure of the O-specific polysaccharide was established: →3)-α-L-Rhap2Me-(1→3)-[β-D-Glcp-(1→4)]-α-D-Fucp-(1→2)-β-D-Xylp-(1→, where non-stoichiometric substituents, an O-methyl group (~45%) and a side-chain glucose

• to 2-O-methylation. Hence, Rha and Rha2Me occupied the non-reducing end in compounds 1 and 2, respectively (Scheme 1). The isolated higher-molecular mass compounds were separated by reverse-phase HPLC and demonstrated by 1H and 13C NMR spectroscopy (data not shown) to be dimeric by-products resulted

• . halopraeferens Au4 by Smith degradation (1 and 2) and solvolysis with CF3CO2H (3).a Gro indicates glycerol. 1H and 13C NMR chemical shifts of the OPS from A. halopraeferens Au4.a Supporting Information Supporting Information File 238: 1H and 13C NMR spectroscopy data of the O-specific polysaccharide and of the

Cu(I)-catalyzed N,N’-diarylation of natural diamines and polyamines with aryl iodides

• Svetlana P. Panchenko,
• Alexei D. Averin,
• Maksim V. Anokhin,
• Olga A. Maloshitskaya and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2015, 11, 2297–2305, doi:10.3762/bjoc.11.250

• described in the literature [29][33][34][35], it was possible to analyze the reaction mixtures by 1H and 13C NMR spectroscopy and in some cases the products were isolated by column chromatography on silica gel. For example, in the proton NMR spectrum of compound 9 two signals are observed in the aliphatic

Copper-mediated synthesis of N-alkenyl-α,β-unsaturated nitrones and their conversion to tri- and tetrasubstituted pyridines

• Dimitra Kontokosta,
• Daniel S. Mueller,
• Dong-Liang Mo,
• Wiktoria H. Pace,
• Rachel A. Simpson and
• Laura L. Anderson

Beilstein J. Org. Chem. 2015, 11, 2097–2104, doi:10.3762/bjoc.11.226

• of N-alkenyl-α,β-unsaturated nitrones 8 to pyridines 9, two mechanistic experiments were evaluated (Scheme 4). The conversion of nitrone 8ae to pyridine 9ae was monitored by 1H and 13C NMR spectroscopy. Surprisingly, after heating 8ae for 4 h at 140 °C in DMSO-d6, a 1:1:1 mixture of isoxazoline 15ae

Qualitative evaluation of regioselectivity in the formation of di- and tri-6-O-tritylates of α-cyclodextrin

• Keisuke Yoshikiyo,
• Yoshihisa Matsui and
• Tatsuyuki Yamamoto

Beilstein J. Org. Chem. 2015, 11, 1530–1540, doi:10.3762/bjoc.11.168

• ,6C-di-O-trityl-α-CD’s. Keywords: 1H and 13C NMR spectroscopy; quantitative analysis; regioselectivity; tritylation; ultra-fast liquid chromatography (UFLC); Introduction Regioselective modification and deprotection on the primary hydroxy side of cyclodextrins (CDs) are of great importance in

A new and convenient synthetic way to 2-substituted thieno[2,3-b]indoles

• Roman A. Irgashev,
• Arseny A. Karmatsky,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2015, 11, 1000–1007, doi:10.3762/bjoc.11.112

• unequivocally by X-ray crystallography analysis, thus supporting the data of 1H and 13C NMR spectroscopy (Figure 2). The Lawesson’s reagent appears to act firstly as a source of hydrogen sulfide to reduce the C=C double bond in compound 10a, and secondly, as the thiation agent to form thieno[2,3-b]indole 12a by

Synthesis and characterization of the cyanobenzene-ethylenedithio-TTF donor

• Sandrina Oliveira,
• Dulce Belo,
• Isabel C. Santos,
• Sandra Rabaça and
• Manuel Almeida

Beilstein J. Org. Chem. 2015, 11, 951–956, doi:10.3762/bjoc.11.106

• formation of insoluble dcdb-TTF. The CNB-EDT-TTF 3 electron donor is thermally stable, not sensitive to oxygen and soluble in common solvents such as CH2Cl2, CHCl3 and AcOEt. The molecular structure and purity of the isolated compound after column chromatography were confirmed by 1H and 13C NMR spectroscopy

Multivalent polyglycerol supported imidazolidin-4-one organocatalysts for enantioselective Friedel–Crafts alkylations

• Tommaso Pecchioli,
• Manoj Kumar Muthyala,
• Rainer Haag and
• Mathias Christmann

Beilstein J. Org. Chem. 2015, 11, 730–738, doi:10.3762/bjoc.11.83

• structures were confirmed by 1H and 13C NMR spectroscopy and the functionalization degrees of 4a–c were determined by correlating the aromatic with the polyglycerol backbone protons (for details see Supporting Information File 1). The synthesis of modified imidazolidin-4-one 5 started with (S)-tyrosine

Synthesis and chemosensing properties of cinnoline-containing poly(arylene ethynylene)s

• Natalia A. Danilkina,
• Petr S. Vlasov,
• Semen M. Vodianik,
• Andrey A. Kruchinin,
• Yuri G. Vlasov and
• Irina A. Balova

Beilstein J. Org. Chem. 2015, 11, 373–384, doi:10.3762/bjoc.11.43

• of mass-average molecular weights () [17][19][25]. Therefore in order to avoid using of new unusual terms the oligomers obtained were named PAEs. The structure of oligomers 10a,b was confirmed by 1H and 13C NMR spectroscopy, FTIR spectra and CHN-elemental analysis. In FTIR spectra of compounds 10a,b

(CF₃CO)₂O/CF₃SO₃H-mediated synthesis of 1,3-diketones from carboxylic acids and aromatic ketones

• JungKeun Kim,
• Elvira Shokova,
• Victor Tafeenko and
• Vladimir Kovalev

Beilstein J. Org. Chem. 2014, 10, 2270–2278, doi:10.3762/bjoc.10.236

• following reaction with hydrazine hydrate gave the pyrazoles 6a–d in 62–76% yield. The products were identified by 1H and 13C NMR spectroscopy, microanalysis and by spectral comparison with the known compounds. The molecular structures of compounds 3с, 3u, 4a, 6b were confirmed by X-ray diffraction [26

Investigations of thiol-modified phenol derivatives for the use in thiol–ene photopolymerizations

• Sebastian Reinelt,
• Monir Tabatabai,
• Urs Karl Fischer,
• Norbert Moszner,
• Andreas Utterodt and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1733–1740, doi:10.3762/bjoc.10.180

• ). Besides FTIR, 1H and 13C NMR spectroscopy, elemental analysis and mass spectrometry was conducted for detailed characterization of all products 10a,b, 14a–c and 17. Mechanical properties of 10a,b, 14a–c and 17 employed in thiol–ene photopolymerizations. In this study we measured the flexural strength

Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: new multivalent galectin-3 ligands

• Silvia Bernardi,
• Paola Fezzardi,
• Gabriele Rispoli,
• Stefania E. Sestito,
• Francesco Peri,
• Francesco Sansone and
• Alessandro Casnati

Beilstein J. Org. Chem. 2014, 10, 1672–1680, doi:10.3762/bjoc.10.175

• formation of the tetraazidocalixarene derivative 12 (1 h, 75% yield). The CuAAC conjugation reaction was carried out following exactly the same procedure as for compound 9 and allowed the isolation of 13 in very high yields (81%). Glycoconjugates 9 and 13 were fully characterized by 1H and 13C NMR

• spectroscopy, which displayed the disappearance of the alkyne protons and the appearance of the typical broad signal of 1,4-disubstituted triazole protons at 7.75–7.85 ppm (CD3OD/CDCl3). ESIMS (+) analyses showed peaks for the [M + 2Na]2+ and [M + 3Na]3+ adducts, which indicates the conjugation of all four

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

• without purification. NMR spectra were recorded with a 300 or 400 MHz spectrometer for 1H NMR, 75 or 100 MHz for 13C NMR spectroscopy. Chemical shifts are reported relative to tetramethylsilane in CDCl3 or to residual signals of undeuterasted solvent CDCl3/DMSO-d6 for 1H and 13C NMR spectroscopy

Cuevaenes C–E: Three new triene carboxylic derivatives from Streptomyces sp. LZ35ΔgdmAI

• Jing-Jing Deng,
• Chun-Hua Lu,
• Yao-Yao Li,
• Shan-Ren Li and
• Yue-Mao Shen

Beilstein J. Org. Chem. 2014, 10, 858–862, doi:10.3762/bjoc.10.82

• for 48 h for antifungal activity and at 37 °C for 24 h for antibacterial activity and examined for the presence of a zone of inhibition. Cuevaenes A–E (1–5) isolated from Streptomyces sp. LZ35. Selected NOESY correlations of compounds 1, 3 and 4, 5. 1H and 13C NMR spectroscopy data for compounds 3, 4

Rapid pseudo five-component synthesis of intensively blue luminescent 2,5-di(hetero)arylfurans via a Sonogashira–Glaser cyclization sequence

• Fabian Klukas,
• Alexander Grunwald,
• Franziska Menschel and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 672–679, doi:10.3762/bjoc.10.60

• 2 mmol scale. The structural assignments of all furans 2 were unambiguously supported by 1H and 13C NMR spectroscopy, mass spectrometry, and combustion analysis (HRMS in case of 2j and 2m). Due to the poor solubility of some compounds all spectra were recorded in DMSO at room temperature, whereas

Tuning the interactions between electron spins in fullerene-based triad systems

• Maria A. Lebedeva,
• Thomas W. Chamberlain,
• E. Stephen Davies,
• Bradley E. Thomas,
• Martin Schröder and
• Andrei N. Khlobystov

Beilstein J. Org. Chem. 2014, 10, 332–343, doi:10.3762/bjoc.10.31

• °C, and anhydrous benzyl alcohol (1.4 mL) added dropwise over 15 min. After the addition of the alcohol was completed, the reaction mixture was warmed up to room temperature and stirred for 1.5 h. The resulting mixture was analysed by 1H and 13C NMR spectroscopy and found to be a mixture of the

A simple, enaminone-based approach to some bicyclic pyridazinium tetrafluoroborates

• František Josefík,
• Markéta Svobodová,
• Valerio Bertolasi and
• Petr Šimůnek

Beilstein J. Org. Chem. 2013, 9, 1463–1471, doi:10.3762/bjoc.9.166

• procedure (method C) with the other ones see Table 1. The methodology failed only in the case of compound 4i (Table 1, entry 10), which was too unstable and decomposed upon an attempt of its isolation. The pyridazinium salts prepared were characterized by means of 1H and 13C NMR spectroscopy and elemental

Diastereoselective synthesis of nitroso acetals from (S,E)-γ-aminated nitroalkenes via multicomponent [4 + 2]/[3 + 2] cycloadditions promoted by LiCl or LiClO₄

• Leandro Lara de Carvalho,
• Robert Alan Burrow and
• Vera Lúcia Patrocinio Pereira

Beilstein J. Org. Chem. 2013, 9, 838–845, doi:10.3762/bjoc.9.96

• respective carbonylated isoxazolines and, therefore, causing a decrease in yield. These last compounds could be identified through 1H and 13C NMR spectroscopy. The signals at 9.5 ppm, and 201 and 159 ppm revealed the presence of an aldehyde function and a sp2 carbon bond of an isoxazoline ring (spectra not

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

•  1). The structures of the products were confirmed by 1H and 13C NMR spectroscopy, as well as X-ray crystallography (Figure 2). As in the parent system 1 the amino and acetamido derivates 4 and 5 are thermodynamically most stable in their cis form. Photochromic Properties trans-Azobenzene exhibits a

Binaphthyl-anchored antibacterial tripeptide derivatives with hydrophobic C-terminal amino acid variations

• John B. Bremner,
• Paul A. Keller,
• Stephen G. Pyne,
• Mark J. Robertson,
• K. Sakthivel,
• Kittiya Somphol,
• Dean Baylis,
• Jonathan A. Coates,
• John Deadman,
• Dharshini Jeevarajah and
• David I. Rhodes

Beilstein J. Org. Chem. 2012, 8, 1265–1270, doi:10.3762/bjoc.8.142

• achieved by exposure to trifluoroacetic acid, followed by trifluoroacetate/chloride ion exchange on treatment with an excess of HCl in diethyl ether, and finally evaporation to afford the salts 2a–g in good overall yields. The structures of the final compounds were supported by 1H and 13C NMR spectroscopy

Synthesis of mesomeric betaine compounds with imidazolium-enolate structure

• Nina Gonsior,
• Fabian Mohr and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 390–397, doi:10.3762/bjoc.8.42

• compounds were evaluated by 1H and 13C NMR spectroscopy by using a Bruker Avance DRX 500 spectrometer at 500.13 MHz for proton and 125.77 MHz for carbon. With DMSO-d6 as solvent, chemical shifts were referenced to the solvent values at δH = 2.51 ppm and δC = 39.52 ppm. C, H and N elemental analysis was

A ferrocene redox-active triazolium macrocycle that binds and senses chloride

• Nicholas G. White and
• Paul D. Beer

Beilstein J. Org. Chem. 2012, 8, 246–252, doi:10.3762/bjoc.8.25

• good yield; however, attempts to cyclise under analogous conditions to those used to produce 3 were unsuccessful, resulting in decomposition of the ferrocene motif. All new compounds were characterised by 1H and 13C NMR spectroscopy and high-resolution ESI mass spectrometry, as well as by 19F and 31P

Pseudo five-component synthesis of 2,5-di(hetero)arylthiophenes via a one-pot Sonogashira–Glaser cyclization sequence

• Dominik Urselmann,
• Dragutin Antovic and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1499–1503, doi:10.3762/bjoc.7.174

• moderate to good yield (Figure 1). The structural assignments of all thiophenes 2 were unambiguously supported by 1H and 13C NMR spectroscopy, mass spectrometry, and combustion analysis. Due to poor solubility no NMR spectra of compounds 2m, 2n and 2o could be recorded, yet, the assignment of the molecular

Nano copper oxide catalyzed synthesis of symmetrical diaryl sulfides under ligand free conditions

• K. Harsha Vardhan Reddy,
• V. Prakash Reddy,
• A. Ashwan Kumar,
• G. Kranthi and
• Y.V.D. Nageswar

Beilstein J. Org. Chem. 2011, 7, 886–891, doi:10.3762/bjoc.7.101

• identity and purity of the product was confirmed by 1H and 13C NMR spectroscopy. Synthesis of symmetrical aryl sulfides catalyzed by copper oxide nanoparticles. Screening of copper sources for the cross-coupling reaction between iodo benzene and potassium thiocyanate.a Nano CuO catalyzed C–S cross-coupling

Synthesis of cross-conjugated trienes by rhodium-catalyzed dimerization of monosubstituted allenes

• Tomoya Miura,
• Tsuneaki Biyajima,
• Takeharu Toyoshima and
• Masahiro Murakami

Beilstein J. Org. Chem. 2011, 7, 578–581, doi:10.3762/bjoc.7.67

• dimerized product (13% NMR yield) and unidentified compounds (Table 1, entry 1). The structure of the minor dimerized product was determined to be (E)-10,11-dimethyleneicos-8-ene (3a) by 1H and 13C NMR spectroscopy. Thus, the two isomeric dimers, one identical to the isomer obtained by the palladium