Methylation 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.
Methylation of p-tert-butylcalix[8]arene. Products obtained in the presence of weak bases
NERI, Placido
1996-01-01
Abstract
Methylation 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
