Tribenzotriquinacenes bearing three peripheral or bridgehead urea groups stretched into the 3-D space

• Jörg Tellenbröker and
• Dietmar Kuck

Beilstein J. Org. Chem. 2011, 7, 329–337, doi:10.3762/bjoc.7.43

• to give apparently identical EI mass spectra. In all of these cases, loss of a methyl radical is, by far, the dominating primary fragmentation process. However, 1H and 13C NMR spectroscopy allowed us to unequivocally assign the isomers. The C3-symmetry of compound 10 is reflected by the relatively

Effects of anion complexation on the photoreactivity of bisureido- and bisthioureido-substituted dibenzobarrelene derivatives

• Heiko Ihmels and
• Jia Luo

Beilstein J. Org. Chem. 2011, 7, 278–289, doi:10.3762/bjoc.7.37

• analysis. All products were fully characterized by 1H and 13C NMR spectroscopy, mass spectrometry, and elemental analysis. The solubility of the dibenzobarrelene derivatives 1e–g is very low in most organic solvents (e.g., <5 mg/l in acetonitrile at 20 °C). In contrast, the 3,5-bis(trifluoromethyl)phenyl

Michael-type addition of azoles of broad-scale acidity to methyl acrylate

• Sławomir Boncel,
• Kinga Saletra,
• Barbara Hefczyc and
• Krzysztof Z. Walczak

Beilstein J. Org. Chem. 2011, 7, 173–178, doi:10.3762/bjoc.7.24

• , when DIPEA was used as a base, this regioisomer was obtained in ca. 10% yield, as determined by 1H NMR spectroscopy. The structures of all the products were established by means of 1H and 13C NMR spectroscopy. It is worth noting that in none of the reactions polymerisation or hydrolysis of methyl

The catalytic performance of Ru–NHC alkylidene complexes: PCy₃ versus pyridine as the dissociating ligand

• Stefan Krehl,
• Diana Geißler,
• Sylvia Hauke,
• Oliver Kunz,
• Lucia Staude and
• Bernd Schmidt

Beilstein J. Org. Chem. 2010, 6, 1188–1198, doi:10.3762/bjoc.6.136

• H (37.4 mg, 2.5 mol %). The solution was heated to the appropriate temperature (80 °C or 110 °C) for 20 h, then cooled to ambient temperature and the solvent evaporated. The crude product was analyzed by 1H and 13C NMR spectroscopy. Analytically pure samples were obtained by column chromatography on

Synthesis and crystal structures of multifunctional tosylates as basis for star-shaped poly(2-ethyl-2-oxazoline)s

• Richard Hoogenboom,
• Martin W. M. Fijten,
• Guido Kickelbick and
• Ulrich S. Schubert

Beilstein J. Org. Chem. 2010, 6, 773–783, doi:10.3762/bjoc.6.96

• . 1H and 13C NMR spectroscopy and elemental analysis, the chemical structures of the TetraTos and HexaTos were verified by MALDI-TOF MS, revealing only the desired mass peak corresponding to full tosylation (Figure 2). The absence of residual hydroxyl groups is of major importance for the use of these

Synthesis, electronic properties and self-assembly on Au{111} of thiolated (oligo)phenothiazines

• Adam W. Franz,
• Svetlana Stoycheva,
• Michael Himmelhaus and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2010, 6, No. 72, doi:10.3762/bjoc.6.72

• chloride [53] to the lithio species at low temperature, albeit the thiofunctionalized derivative 2c was obtained in only 15% yield. The structures of the (oligo)phenothiazinyl thioacetates 2 and 4 were unambiguously supported by 1H and 13C NMR spectroscopy, mass spectrometry and elemental analysis

The development and evaluation of a continuous flow process for the lipase- mediated oxidation of alkenes

• Charlotte Wiles,
• Marcus J. Hammond and
• Paul Watts

Beilstein J. Org. Chem. 2009, 5, No. 27, doi:10.3762/bjoc.5.27

• remove any acetic acid (1) and residual urea (8). The organic layer was then dried using MgSO4, filtered and concentrated in vacuo to afford the target epoxide. The reaction products were then analysed by GC-MS, 1H and 13C NMR spectroscopy and the spectroscopic data compared with those reported within

• products were then analysed by GC-MS, 1H and 13C NMR spectroscopy and the spectroscopic data compared with those reported within the literature. General procedure for the optimisation of olefin epoxidation under continuous flow To optimise a continuous flow epoxidation, a gas-tight syringe (2.5 ml) was

• then analysed by GC-MS, 1H and 13C NMR spectroscopy in order to characterise the epoxide and determine product purity. Enzyme stability To confirm the Novozym® 435 (4) was sufficiently stable to be used for the continuous flow synthesis of epoxides over extended periods of operation, two experiments

N-1 regioselective Michael- type addition of 5-substituted uracils to (2-hydroxyethyl) acrylate

• Sławomir Boncel,
• Dominika Osyda and
• Krzysztof Z. Walczak

Beilstein J. Org. Chem. 2007, 3, No. 40, doi:10.1186/1860-5397-3-40

• of the product was confirmed by 1H and 13C NMR spectroscopy. See Figure 1 in Supporting Information File 1 for the assignment of particular protons in NMR spectrum of the model ester-conjugated nucleoside. Conclusion In summary, a simple and efficient method of N-1 alkylation of uracil rings using

Trapping evidence for the thermal cyclization of di-(o-acetylphenyl)acetylene to 3,3'-dimethyl- 1,1'-biisobenzofuran

• Charles P. Casey,
• Neil A. Strotman and
• Ilia A. Guzei

Beilstein J. Org. Chem. 2005, 1, No. 18, doi:10.1186/1860-5397-1-18

• 13C NMR spectroscopy as well as by HRMS. X-ray quality crystals of meso-3 were obtained by slow diffusion of pentane into CH2Cl2 solution. In the X-ray crystal structure, meso-3 adopts a Ci symmetric conformation (Figure 1). Isolation of DMAD adducts meso-3 and rac-3 provides strong evidence for the

• solution was degassed. After three days of stirring under N2, the excess DMAD was evaporated under vacuum (3 × 10-2 torr). Preparative TLC gave DMAD adducts meso-3 and rac-3 as white powders in 60% and 22% yields, respectively (Scheme 6). Both compounds were characterized spectroscopically through 1H and