247049-50-9Relevant academic research and scientific papers
Syntheses of novel types of calix [6]bis-crowns and related compounds
Chen,Li
, p. 340 - 343 (2001)
The syntheses of novel types of p-tert-butylcalix[6]bis-crowns and related compounds is described. By reacting p-tert-butylcalix[6]-1,4-crown-4 with ethylene glycol ditosylate or polyethylene glycol ditosylates using NaH as a base in DMF, p-tert-butylcalix[6]-2,3-ethylene-1,4-crown-4, p-tert-butylcalix[6]-1,4-crown-4-2,6-crown-3, monotosyloxyethoxyethyl-p-tert-butylcalix[6]-1,4-crown-4, p-tert-butylcalix[6]-1,4-crown-4-2,5-benzocrown-4 and p-tert-butylcalix[6]-1,4-crown-4-2,6-crown-5 were obtained in reasonable yields under selective conditions.
Molecular design and synthesis of a calix[6]crown-based lithium- selective ionophore
Chen, Yuanyin,Yang, Fafu,Gong, Shuling
, p. 4815 - 4818 (2000)
Several 1,4-bridged calix[6]arene tetraesters were prepared from 1,4-p- tert-calix[6]crown-4's by etherifying with ethyl bromoacetate. It was found that the 1,4-p-tert-calix[6]crown-4 tetraethylester (3a) and the 1,4-p-tert- calix[6]benzocrown-4 tetramethylester (4b) exhibit very high selectivity toward lithium and sodium ions, respectively. The ion selectivity is very sensitive to the structure of polyoxyethylene spacer and the R in the ester moiety. (C) 2000 Elsevier Science Ltd.
Synthesis and characterization of p-tert-butylcalix[6]-1,4-crown-4-2,6-crown-5, p-tert-butylcalix[6]-1,4-benzocrown-4-2,3-crown-5
Chen, Yuan-Yin,Li, Hai-Bing
, p. 1208 - 1209 (2000)
Two new types of calix[6]-bis-crowns, p-tert-butylcalix[6]-1,4-crown-4-2,6-crown-5 and p-tert-butylcalix[6]-1,4-benzo-crown-4-2,3-crown-5, have been synthesized and characterized. The conformation of p-tert-butylcalix[6]-1,4-crown-4-2,6-crown-5 may be (u,
Synthesis of doubly bridged p-tert-butyl-calix[6]arene containing hard and soft ion binding sites
Chen,Chen
, p. 9079 - 9082 (2000)
A conformationally preorganized, C(s)-symmetrical p-tert-butyl-calix[6]-1,4-crown-4-2,6-dioxo-diazacrown-4 with hard and soft ion binding sites at the lower rim is synthesized. The binding sites may complex alkali metal ions or transition metal ions selectively. (C) 2000 Elsevier Science Ltd.
Synthesis of p-tert-butylcalix[6]-1,4-2,5-bis-crowns
Chen, Yuanyin,Yang, Fafu,Lu, Xueran
, p. 1571 - 1574 (2007/10/03)
The synthesis and complexation properties of the first example of p- tert-butylcalix[6]-1,4-2,5-bis-crowns are reported. Their complexation abilities and selectivities are different from that of analogous calix[6]crown. Compound 2b exhibits high complexat
Selective bridging of p-tert-butylcalix[6]arene with polyethylene glycol ditosylates
Li, Jiansen,Chen, Yuanyin,Lu, Xueran
, p. 10365 - 10374 (2007/10/03)
A convenient method for preparing various p-tert-butylcalix[6]crowns and related compounds has been developed. By refluxing p-tert-butylcalix[6]arene with ethylene glycol ditosylate or polyethylene glycol ditosylates using K2CO3 as a base in acetonitrile, 1,2-ethylenecalix[6]arene, 1,3-and 1,4- calix[6]crown-3, 1,3-and 1,4-calix[6]crown-4, 1,4-calix[6]benzocrown-4, 1,2- and 1,3-calix[6]crown-5 were obtained selectively. A rather flattened (o, o, o, o, o, o) conformation, adopted by the constrained 1,4-calix[6]crown-3 at ambient temperature, was observed for the first time.
