Calixarene synthesis

Chiral groups may be attached to both the narrow and the wide rims of the calixarene skeleton I (or even to the bridges14) and this may be done by chemical modification of the calixarene or by the use of appropriate chiral phenols for the calixarene synthesis. With resorcarenes II chiral groups may be introduced at the hydroxy groups or at the 2-position between the OH-functions. Their attachment at the bridges (CHR ) was also realized. 

ZINKE ZIEGLER Synthesis of Calixarenes Synthesis of calixarenes (a basket-llke macrocycHc compound)... 

The Petrolite method for calixarene synthesis also leads to dihomooxacalix[4]arenes, as represented by the p-tert-butyl compound 9. Proton-NMR spectra and TLC data indicate that the mixture obtained from p-terf-butylphenol and paraformaldehyde contains appreciable amounts of 9, but it is difficult to obtain a pure sample of 9 from this mixture 23,2, 28>. Compound 9 is much more readily accessible by the thermally-induced dehydration of the (u. v(hydroxymethyl)tetramer 46 which can be readily prepared by the convergent synthesis outlined in Scheme 5 followed by bis hydroxymethylation 62), as shown in Scheme 6. Other oxacalixarenes can also be obtained by thermally-induced dehydration. For example, 2,6-6 (hydroxymethyl)-phenols (42) yield hexahomotrioxacalix[3]arenes (43)28,62,101 > j cfroxymethyl)... 

Calixarenes Synthesis and Historical Perspectives, p. 1.53 Cation-n Interactions, p. 214 Crown Ethers, p. 326... 

L. K. Novel spherancl-type calixarenes—Synthesis, conformational studies, and isomer separation. Chem. Ber. 1993. 126. 1435. 

As well as those thiaphanes mentioned in Section 2.2 as intermediates in [2n -and [m.nlphane syntheses, there are oxa- and azaphanes like 26,27 and 28, which are named homooxa- and homoazacalixarenes because they were first obtained through the Petrolite procedure of calixarene synthesis in 1962 [31, 32]. The compounds were first characterised in 1979, and in 1983 Gutsche [35] described detailed syntheses based on inter- or intra-annular thermally-induced dehydration of bis(hydroxymethyl)aromatic building blocks. 

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