Formation of epoxide-amine oligo-adducts as OH-functionalized initiators for the ring-opening polymerization of ε-caprolactone

• Julia Theis and
• Helmut Ritter

Beilstein J. Org. Chem. 2010, 6, 938–944, doi:10.3762/bjoc.6.105

• two very weak signals, which were difficult to discern, at 2.81 and 2.66 ppm, corresponding to the CH2 of the epoxide group. MALDI-TOF MS measurements (Figure 2) definitely indicated the formation of an oligomer homologous series of epoxide-amine addition products of 1 and 3. The amino alcohol

• repetitive unit (green) has a molecular mass of 463.56 g/mol and the molecule with the highest assignable molecular mass is the n = 13 oligomer with [M + Na+] = 6049 m/z. Furthermore, the mass to charge ratios (m/z) of the repetitive unit containing epoxide (blue) and amine (red) end groups were observed

• oligomeric initiator. This oligomer can be obtained in a one-pot microwave assisted heterogeneous catalytic transfer hydrogenation, starting from 4-nitroanisole (2) in the presence of the diglycidyl ether of bisphenol A (1). Product 4 consists of oligomers because of some side reactions. The hydroxy groups

EPR and pulsed ENDOR study of intermediates from reactions of aromatic azides with group 13 metal trichlorides

• Giorgio Bencivenni,
• Riccardo Cesari,
• Daniele Nanni,
• Hassane El Mkami and
• John C. Walton

Beilstein J. Org. Chem. 2010, 6, 713–725, doi:10.3762/bjoc.6.84

• )-cyclohexa-2,5-dienone) and much dark-coloured polymer [31]. The EPR spectrum showed the radical cation of Variamine blue (11b+•) plus broad signals which we attributed to oligomer and/or polymer radical cations (Scheme 2). When anhydrous AlCl3 in DCM – instead of the gallium halide – was added to a solution

• eventually polyaniline type polymers X[C6H4NH]nC6H4NH2. Some polymer radical cation was always observed by EPR spectroscopy, but whether dimer or trimer or oligomer dominated the spectrum depended on a delicate balance between solvent, metal halide and other factors. Reactions of 2-methoxy- and 3

• , such that coupling takes place with the anilinium cation instead. Trimer 18+• could be produced by coupling of 17+• with more 13a followed by a similar sequence of steps. The trimer could then grow into oligomer and polymer by a succession of such coupling reactions. In general, the aromatic azides

RAFT polymers for protein recognition

• Alan F. Tominey,
• Julia Liese,
• Sun Wei,
• Klaus Kowski,
• Thomas Schrader and
• Arno Kraft

Beilstein J. Org. Chem. 2010, 6, No. 66, doi:10.3762/bjoc.6.66

• , so that specific 1:1 complexation is favored (Figure 4). In order to investigate this assumption, the sodium methacrylate polymer S20CH15 was titrated as a short oligomer (MW 3000 g mol−1) and an average-size polymer (MW 12000 g mol−1). Direct comparison produced a drastic difference: No binding

Polar tagging in the synthesis of monodisperse oligo(p-phenyleneethynylene)s and an update on the synthesis of oligoPPEs

• Dhananjaya Sahoo,
• Susanne Thiele,
• Miriam Schulte,
• Navid Ramezanian and
• Adelheid Godt

Beilstein J. Org. Chem. 2010, 6, No. 57, doi:10.3762/bjoc.6.57

• synthetic routes have emerged: The repeating unit by repeating unit approach (Scheme 1a) with desilylation and coupling of the (functionalized) arylethyne with 1-iodo-4-(2-trimethylsilylethynyl)benzene as the two repeating steps [6][9][20][21][22][23][24]. The oligomer grows slowly repeating unit by

• : (1) The type of MnO2 used for the removal of the HOM group, (2) carbometalation, a side reaction when using hydroxymethyl as an alkyne protecting group, (3) purity of 1,4-dihexyl-2,5-diiodobenzene, and (4) polar tags in the side chains of building blocks to reduce the number of steps in oligomer

Synthesis, characterization and photoinduced curing of polysulfones with (meth)acrylate functionalities

• Cemil Dizman,
• Sahin Ates,
• Lokman Torun and
• Yusuf Yagci

Beilstein J. Org. Chem. 2010, 6, No. 56, doi:10.3762/bjoc.6.56

• determined using polystyrene standards. Thermal gravimetric analysis (TGA) was performed on Perkin–Elmer Diamond TA/TGA with a heating rate of 10 °C min under nitrogen flow. Preparation of the oligomers General procedure for the synthesis of polysulfone oligomer Bisphenol A (40 g, 175 mmol), bis(p

• washed several times with water in order to remove the remaining salts and impurities. Finally, the polymer was washed with methanol and dried in a vacuum oven at 60 °C for about 12 h to give PSU-2000 oligomer (42.2 g). IR (ATR, cm−1): 3435 (-OH), 3200–3000 (Ar), 2975 (-CH3 sym-), 2945 (-CH3 asym-), 1322

• followed by excess acryloyl chloride (1.15 mL, 14.3 mmol) dissolved in 5 mL CH2Cl2 which was added slowly to the reaction flask over a 10 min period. The reaction mixture was stirred for 24 h then filtered to remove the salts formed and poured into methanol to precipitate the acrylate oligomer. The

(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties

• José L. Jiménez Blanco,
• Fernando Ortega-Caballero,
• Carmen Ortiz Mellet and
• José M. García Fernández

Beilstein J. Org. Chem. 2010, 6, No. 20, doi:10.3762/bjoc.6.20

• other) exhibit a well defined repeating turn secondary structure stabilised by inter-residual hydrogen bonds, whereas the epimeric α-D-arabinofuranose oligomer 12 (with the C-2 and C-5 substituents in trans relative disposition) do not show any secondary structure in solution [34]. NMR and IR studies on