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Diester intrabridging of p-tert-butylcalix[8]arene and unexpected formation of the monospirodienone derivative
No full textMethylation of p-tert-butylcalix[8]arene. Products obtained in the presence of weak bases
No full textMethylation of p-tert-butylcalix[8]arene with Mel in the presence of K2CO3 or CsF in acetone or THF/DMF has been investigated. Depending on the experimental conditions, different CH2Cl2-soluble derivatives and Variable amounts of a material insoluble in common organic solvents are formed. The composition of the reaction mixture was determined by exhaustive benzylation which originates soluble, more tractable compounds. With both bases methylation mainly follows the so-called alternate alkylation route, proximal substitution also occurring to some extent, a behaviour similar to benzylation under comparable conditions. The CH2Cl2-soluble portion of the methylation mixtures, when obtained under appropriately chosen conditions, is enriched in a particular component and thus convenient procedures are now available for the preparation of mono-, 1,3-di-, 1,2,4-tri-, 1,2,3,4-tetra-, and heptamethoxy derivatives of p-tert-butylcalix[8]arene
Synthesis of p-tert-butyl-5,5’-bicalix[4]arene and access to 5,5’-bicalix[4]arenes functionalized at the upper rim
No full textMethylation of p-tert-butylcalix[8]arene. Products obtained in the presence of strong bases
No full textMethylation of p-tert-butylcalix[8]arene with Mel in the presence of strong bases (NaH, BaO/Ba(OH)(2), or Cs2CO3) in THF has been investigated. Composition of the reaction mixtures differs remarkably from those obtained using weak bases and described in a preceding paper. Several previously unreported methylated products [two dimethoxy- (2(1,5) and 2(1,4)), a trimethoxy- (3(1,2,5)), a tetramethoxy- (4(1,2,3,6)), two pentamethoxy- (5(1,2,3) and 5(1,2,4)), and three hexamethoxy- (6(1,2), 6(1,3), and 6(1,4))] have been isolated. In many cases the substitution pattern was assigned unambiguously on the basis of spectroscopic evidence only, while in others chemical correlation with known compounds was required
Sintesi di 5,5’bicalix[n]areni p-solfonati idrosolubili e studi preliminari delle loro capacità complessanti
No full textAlkali cation “conformational templation” in 1,5-bridged calix[8]arenes: a single crystal X-ray proof
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