Influence of cyclodextrin on the solubility of a classically prepared 2-vinylcyclopropane macromonomer in aqueous solution

• Helmut Ritter,
• Jia Cheng and
• Monir Tabatabai

Beilstein J. Org. Chem. 2012, 8, 1528–1535, doi:10.3762/bjoc.8.173

• vinylcyclopropane end group and a poly(N-isopropylacrylamide) (poly(NiPAAm)) chain was obtained from amidation of 1-ethoxycarbonyl-2-vinylcyclopropane-1-carboxylic acid (4) with an amino-terminated poly(NiPAAm) 3 as an example. This macromonomer 5 showed an LCST effect after complexation of the vinyl end group with

• ß-cyclodextrin in water. Via radical ring-opening copolymerization of 5 and NiPAAm a graft copolymer 8 with a clouding point of 32 °C was synthesized. The branched unsaturated polymer was treated with ozone to cleave the double bonds of the main chain. Keywords: branched poly(NiPAAm); cloud point

• in literature about the behavior of vinylcyclopropane-containing macromonomers. Thus, in this paper we are going to report our findings about the preparation and characterization of a new type of macromonomers based on a 2-vinylcyclopropane derivative bearing a thermoresponsive poly(NiPAAm) moiety as

Chiral recognition of ephedrine: Hydrophilic polymers bearing β-cyclodextrin moieties as chiral sensitive host molecules

• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 1516–1519, doi:10.3762/bjoc.7.177

• in the host–guest system, the LCST rises to 35 °C for polymer 2, which is 3 °C higher than the value for pure poly(NIPAAM). The increase of LCST takes place because the hydrophobic phenyl ring of ephedrine is incorporated into the CD cavity, and the hydrophilic OH and amino groups are located in the

Chiral recognition of macromolecules with cyclodextrins: pH- and thermosensitive copolymers from N-isopropylacrylamide and N-acryloyl-D/L-phenylalanine and their inclusion complexes with cyclodextrins

• Sabrina Gingter,
• Ella Bezdushna and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 204–209, doi:10.3762/bjoc.7.27

• ). However, the presence of D- or L-Phe significantly affects the LCST value of pure poly(NIPAAm) (32 °C), since the hydrophilic/hydrophobic balance of the polymer is changed [17][18]. As noted above, incorporation of the hydrophobic phenylalanine moieties into the polymer reduces the LCST to 25 °C for the

• %, N 7%, H 6.5%, 2L C 64.2%, N 5.7%, H 6%. Synthesis of poly(NIPAAm-co-D- or L-phenylalaninacrylamide) 3D, 3L 6.2 g (54 mmol) of N-isopropylacrylamide (NIPAAm) were dissolved in 5 mL of dimethylformamide. In each of two 100 mL flasks was placed 0.3 g (1.4 mmol) 2D/2L dissolved in 3 mL of DMF. Then 68

Calix[4]arene-click-cyclodextrin and supramolecular structures with watersoluble NIPAAM-copolymers bearing adamantyl units: “Rings on ring on chain”

• Bernd Garska,
• Monir Tabatabai and
• Helmut Ritter

Beilstein J. Org. Chem. 2010, 6, 784–788, doi:10.3762/bjoc.6.83

• supramolecular complex formation with poly(NIPAAM) bearing attached adamantyl units was investigated by dynamic light scattering (DLS) and turbidity measurements. Keywords: β-cyclodextrin; calix[4]arene; click chemistry; poly(NIPAAM); Introduction Supramolecular interactions of macrocycles with different types

• at pH 12 (17.5 nm), it can be supposed, that due to deprotonation intermolecular electrostatic repulsion takes place which decreases the agglomeration in the system. The turbidity point of copolymer 5 in water, 29 °C, is significant lower than that of the unmodified poly(NIPAAM) at 34 °C, which can

• ). The temperature shift relative to the cloud point of poly(NIPAAM) itself, can be explained by the inclusion of the hydrophobic adamantyl units of 5 by the CD moiety of 4, which, in principal, should increase the cloud point temperature. In contrast to this, the unavoidable presence of the hydrophobic

Free radical homopolymerization of a vinylferrocene/cyclodextrin complex in water

• Helmut Ritter,
• Beate E. Mondrzik,
• Matthias Rehahn and
• Markus Gallei

Beilstein J. Org. Chem. 2010, 6, No. 60, doi:10.3762/bjoc.6.60

• MALDI-TOF which indicated a mass of 6172.7 [M+Na]+. Very recently a paper was published, reporting the expected LCST properties of the copolymer consisting of N-allylferrocenecarboxamide and N-isopropylacrylamide (poly(NiPAAM/FCN)) [26]. However, in this instance the copolymer was prepared by a