189182-99-8

Upstream product

• 19249-03-7 triethylene glycol di-(p-toluenesulfonate) 
• 155341-38-1 25,26-dihydroxy-27,28-mono(crown-4)calix[4]arene 
• 248590-47-8 25,26,27,28-tetrakis(hydroxy)calix[4]arene 

Relevant academic research and scientific papers

1,2-bridged calix[4]arene monocrowns and biscrowns in the 1,2-alternate conformation

The condensation of 1,2-di[(2-pyridylmethyl)oxy]calix[4]arenes 1 (R = (t)Bu, H) with glycol ditosylates 2a-e in anhydrous toluene in the presence of (t)BuOK has led to a mixture of 1,2-alternate and cone 1,2-calix[4]arene crown conformers 3 and 4, respectively. Similarly, the reaction of 1,2- bridged calix[4]arene crown-4 5 with tri- to pentaethylene glycol ditosylates 2a-c has produced 1,2-alternate and cone calix[4]arene biscrown conformers 6 and 7, respectively. The distribution of conformers depends on the para- substituent at the upper rim and the length and bulkiness of the ditosylates. The best yields of the 1,2-alternate conformer (up to 51%) are observed in the absence of (t)Bu groups and with the longer polyether chain. The conformational features of 3 and 6 have been deduced by NMR spectroscopy and by X-ray crystallography. X-ray analysis of 25,26-27,28-biscrown-4- calix[4]arene (6a) shows that there are two independent molecules in the asymmetric unit, both in the 1,2-alternate conformation.

Water-soluble para-sulfonated 1,2;3,4-calix[4]arene-biscrowns in the cone conformation

Water-soluble 1,2;3,4-calix[4]arene-biscrowns (14)-(18) have been synthesized in two or three steps via chlorosulfonation. Cs+-ligand interactions were studied in aqueous media by 1H NMR.