Calixarene Esters and Ethers

The phenolic OH groups of the calixarenes are readily converted to ester and ether moieties. The acetates of many of the calixarenes have been prepared, the earliest 

Still another calixarene derivative of interest and utility is the trimethylsilyl ether. The hexa-trimethylsilyl ealix[6]arenes and octa-trimethylsilyl calix[8]arenes can be prepared 23) by using standard trimethylsilylating agents such as hexamethyldisilazene and chlorotrimethylsilane. The tetra-trimethylsilyl ethers of the calix[4]arenes, however, do not form under these conditions and require the use of the very reactive N,0-i (trimethylsilyl (acetamide 109). 

The formation of calixarene esters and ethers can be complicated by the problem of incomplete derivatization, as noted above, and also by the fact that conformational fixing generally occurs in the case of the calix[4]arenes. The consequences of the latter are discussed in Section 5.2. 

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