SYNTHESIS OF THE NEW PHOSPHORUS CONTAINING CHOLESTERYL ESTERS BY ACYLATION OF PHOSPHONIUM SALTS

Abstract

The process of acylation of alkylidenephosphoranes, which contain different functional groups in molecules, the dependence of the reaction on the conditions, the pH level, the nature of the reagents etc have been investigated. The possibility of introducing of cholesterol fragment into the ylid molecule and application of the reaction for obtaining of the new cholesterol-containing derivatives that can have practically valuable properties (particularly liquid crystals) and cn be used as initial compounds for further obtaining of new unsaturated cholesterol derivatives with extended structural fragments have been investigated. The interaction of phosphorylides with cholesteryl chloroformate, which leads to the formation of alkylidene phosphoranes with a cholesteryl fragment have been studied, conditions and features of this reaction in one-phase and two-phase systems, with application of the different bases, have been established. A number of new acylated phosphorus ylides containing various aliphatic and aromatic structural fragments, including ones of some known biologically active compounds have been obtained. It is shown that the problem of insufficient stability of some alkylidenephosphoranes can be solved by application of phosphonium salts as initial compounds without intermediate isolation of the corresponding ylides in the individual state. To avoid the re-ylidation process, the reaction was carried out in the presence of triethylamine (onephase system) or sodium hydroxide (two-phase system). This method has significant advantages over those known from literary sources as it does not require an applisation of such expensive and exigent for experimental conditions reagents as organometallic compounds. Some of the obtained acylated phosphorus ylides contain structural fragments, which make further studies of their biological activity promising. The behavior of some obtained compounds indicates the formation of a mesophase during melting, that can be a sign of liquid crystal properties.