Enriching calixarene functionality with 1,3-diketone groups

Abstract

Acylation of magnesium enolates of acetophenones with the calixarene-based 1-acylbenzotriazoles was systematically studied to access scarcely available cone and 1,3-alternate calix[4]arenes having the synthetically/receptor valuable 1,3-diketone groups linked to the...

Building Triazolated Macrocycles from Bis-Propargylated Calix[4]arenes and Bis-Azidomethylated Azobenzene or Stilbene

“…Indeed, both spectra contained mainly the broadened and highly shape-distorted signals from the huge oligomers/polymers, while signals of just minor intensities might be assigned to the desired bis(calixarenes) or at least to small cyclic oligomeric products of CuAAC (Figure 4). To improve the solubility of the CuAAC reaction products and, perhaps, to facilitate their separation using column chromatography, the calixarene dipropargyl ether 1 was replaced with the dipropargyl ether 7 [42] having additional ester functionalities. Similar to the above cases, equimolar CuAAC reactions between calixarene 7 and bis(azides) 2 or 4 conducted under the CuI/Et3N catalysis were completed within 24 h. However, huge linear or cyclic polymeric/oligomeric compounds appeared to be the major product of the reactions, as it was concluded from the 1 H NMR spectra of the product mixtures obtained after the removal of copper salts.…”

“…The obtained data confirmed the biscalixarene molecular structure of this compound having two Due to the extremely low content of the non-polymeric products in the mixtures, their chromatographic separation was attempted for only the CuAAC between calixarene 7 and bis(azide) 2 (Scheme 3). In this case, a single non-polymeric product of moderate purity was obtained in 3% yield (see middle trace in Figure 4 for the 1 H NMR spectrum of the separated product), which was the desired bis(calixarene) To improve the solubility of the CuAAC reaction products and, perhaps, to facilitate their separation using column chromatography, the calixarene dipropargyl ether 1 was replaced with the dipropargyl ether 7 [42] having additional ester functionalities. Similar to the above cases, equimolar CuAAC reactions between calixarene 7 and bis(azides) 2 or 4 conducted under the CuI/Et3N catalysis were completed within 24 h. However, huge linear or cyclic polymeric/oligomeric compounds appeared to be the major product of the reactions, as it was concluded from the 1 H NMR spectra of the product mixtures obtained after the removal of copper salts.…”

“…Commercial reagents were used as received. Compounds 1 [39], 2 [40], 3 [41] and 7 [42] were synthesized by the reported procedures.…”