PROPERTIES OF UNUSUAL PHOSPHOLIPIDS - III - SYNTHESIS, MONOLAYER INVESTIGATIONS AND DSC STUDIES OF HYDROXY OCTADECA(E)NOIC ACIDS AND DIACYLGLYCEROPHOSPHOCHOLINES DERIVED THEREFROM

Diacylglycerophosphocholines containing (R)-3-, (R)-12-, (R)-17-hydrox y octadeca(e)noic acids and the corresponding racemates were synthesiz ed and purified to homogeneity. The influence of the position of the h ydroxy group on the monolayer packing properties of these fatty acids and their phosphatidylcholines was studied by Langmuir techniques and xy-octadec-cis-9-enyl]-sn-glycero-3-phosphocholine displayed the large st lift-off area (330 Angstrom(2)/molecule). This result was in line w ith the thermotropic phase behavior of these phospholipids, as measure d by differential scanning calorimetry (DSC): the gel-to liquid-crysta lline phase transition temperature (T-m) passed through a minimum of - 15.1 degrees C for y-octadec-cis-9-enyl]-sn-glycero-3-phosphocholine. (C) 1997 Elsevier Science Ireland Ltd.