SYNTHESIS AND NMR CONFORMATIONAL STUDIES OF P-TERT-BUTYLDIHOMOOXACALIX[4]ARENE DERIVATIVES

The tetramethyl (2) and tetraethyl (3) ethers, and the tetraacetate (4 ) derivatives of the p-tert butyldihomooxacalix[4]arene were prepared. The mobility of these compounds studied by temperature-dependent H-1 NMR spectroscopy. For the tetraacetate derivative, at room temperature , 1,2- or 1,3-alternate conformations are suggested. Those conformatio ns were confirmed by NOE difference and COSY spectra for the tetraethy l ether derivative in CDCl3 at -20 degrees C.