Polycondensation of bis(cyanoacetate) and a,10bdihydrobenzofuro[2,3‐b]benzofuran‐2,9‐dicarbaldehyde via knoevenagel reaction: Synthesis of donor–acceptor polymers containing shoulder‐to‐shoulder main chains

Abstract

Compound 5a,10b-dihydrobenzofuro [2,3-b]benzofuran-2,9-dicarbaldehyde (II) was prepared by two-step reactions from p-cresol and glyoxal. The bis(cyanoacetate) monomers (III) were prepared in a high yield by reacting ethyl cyanoacetate with the appropriate diol in the presence of tetra-n-butyl titanate. The polymers from II and III were synthesized by Knoevenagel polycondensation that was first carried out in anhydrous THF and followed by a solid-state polycondensation, and main-chain polymers with good glass transition temperatures in high yield were obtained. The polymerization of II and III afforded polymers IV, which exhibited good solubility in most organic solvents. The structure of all the monomers and polymers were characterized by conventional spectroscopic methods. The synthesized polymers contain acceptor groups (cyanide and carbonyl) and a donor group (benzodihydrofuran) in their main chain.

Small Molecule Inhibitors of Dynamin I GTPase Activity: Development of Dimeric Tyrphostins

“…However, replacement of the amide linkage with the corresponding esters (Scheme ) maintained a moderate level of inhibition, which again was dependent upon the spacer length (Table , analogues 90 − 93 ). Presumably the reduction in inhibition is a result of the less favorable H-bonding characteristics of the ester “O” compared with the amide “NH” 3 Synthesis of Ester Based Linker Analogues of 9 a a Cf.…”

Natural source, bioactivity and synthesis of benzofuran derivatives

“…It is found that the shoulder-toshoulder arrangement of the NLO chromophore introduced a backbone polymer with a large off-diagonal tensor component (Scheme 9). 113,114…”

Conjugated Polymer Photovoltaic Materials

“…Many functional groups, such as aldehyde, ester, nitryl, hydroxy and carboxy, have no obviously negative effects on the coupling reaction, so that this reaction has been widely used for preparation of PPVs. Cyano-substituted PPV can be readily prepared by the Knoevenagel polycondensation reaction between equimolar amounts of a terephthaldehyde derivative and a 1,4-diacetonnitrile-benzene derivative [39]. The condensation reaction takes place upon addition of excess potassium tertbutoxide or tetrabutylammonium hydroxide in THF/tert-butanol mixture at 50°C.…”

“…PPV and its derivatives can be synthesized via various methods, including the Wessling precursor method [36], Gilch method [37], Heck coupling reaction [38], Knoevenagel polycondensation [39], etc. With the Wessling method, the PPV precursor can be synthesized by the reaction of bis-(sulfonium halide) salts of pxylene with a base (NaOH) in water or alcohol solution, and then the precursor solution is spin-cast on ITO substrate, PPV film being formed by heat treatment at 180-300°C under vacuum.…”