A wheel surprise: Reaction of resorcinol and 1,5‐pentanedial in ethanol at 80 °C for 48 h in the presence of HCl surprisingly afforded a soluble cyclic oligomer in high yield (83 %) under thermodynamic control. Single‐crystal X‐ray analysis revealed a waterwheel‐like structure with a large hydrophobic hole through the center (see picture). A carboxylic ester derivative of the compound was shown to be highly selective for Rb+ ions.
Eine überraschende Ringbildung ist das Resultat der Reaktion von Resorcin mit 1,5‐Pentandial in Ethanol bei 80 °C in Gegenwart von konz. HCl. Das lösliche cyclische Oligomer, das binnen 48 h in hoher Ausbeute (83 %) unter thermodynamischer Kontrolle entsteht, hat laut Röntgenstrukturanalyse eine wasserradähnliche Struktur mit einem großen hydrophoben Hohlraum in der Mitte (siehe Bild). Ein Carbonsäureester‐Derivat erwies sich als hoch selektiv für Rb+‐Ionen.
Reaction of resorcinol and 1,4-butanedial [(CH 2 ) 2 (CHO) 2 ] in the presence of concentrated HCl in ethanol at 80°C for 48 h afforded a soluble polymer (CRA-polymer) in quantitative yield under thermodynamic control. Single X-ray crystal analysis revealed that the precursor product had cyclic structure, and TOF mass spectroscopy of CRA-polymer revealed a ladder structure with calixresorcinarene moieties in the main chain. The photoinduced deprotection reaction of CRA-polymer derivative (CRA-polymer-BOC) containing tertbutyloxycarbonyl groups were examined in the film state in the presence of photoacid generator to produce the alkaline developable CRA-polymer with release of isobutylene and carbon dioxide.
We have examined the synthesis of cyclic oligomers with pendant norbornadiene (NBD) moieties based on the calixarenes [p-tert-butylcalix[8]arene (BCA), p-methylcalix[6]arene (MCA), calix[4]resorcinarene (CRA), 2,8,14,20-tetradecylcalix[4]resorcinarene (CRA10), and 2,8,14,20-tetrakis(p-hydroxyphenyl)calix[4]resorcinarene (CRAph)]. The photochemical valence isomerization of the obtained calixarene derivatives containing NBD moieties proceeded very smoothly to afford the corresponding quadricyclane (QC) moieties, and it was found that the large refractive-index changes (Δn’s = 0.028–0.061) before and after photo-isomerization.
The synthesis and photoinduced deprotection reaction of calix[4]resorcinarene derivatives with pendant acetal moieties were examined. C-methyl[(methoxymethylcarbonyl)oxy]calix[4]resorcinarene (CRA-Acetal) and C-4-hydroxyphenyl[(methoxymethylcarbonyl)oxy]calix[4]resorcinarene (CRAph-Acetal) were prepared from C-methylcalix[4]resorcinarene (CRA) and C-4-hydroxyphenylcalix[4]resorcinarene (CRAph). The synthesized CRA-Acetal and CRAph-Acetal had good solubilities, good film-forming properties, and high thermal stabilities. The photoinduced deprotection reaction of CRA-Acetal and CRAph-Acetal was examined in the presence of bis[4-(diphenylsulfonio)phenyl]sulfide (DPSP) as a photo-acid generator in the film state upon UV irradiation. It was found that the deprotection reaction of acetal groups of CRA-Acetal and CRAph-Acetal proceeded smoothly without further heating to produce the corresponding calixarene derivatives, CRA-COOH and CRAph-COOH with carboxylic acid groups.
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