Optical rotatory dispersion and absolute configuration. V. The absolute configuration of natural plasmalogen.

PLAWALOGENS are a group of aldehydogenic substances widely distributed in nature in both the animal and plant kingdom. 4 Their chemical structure is that of a c&l(alk-l’enyl) ether of a 2-acyl-3glycerylphosphate (I) where R” may be derived from choline, ethanolamine or serine. Hydrogenation and acid hydrolysis8 yielded chimyl and batyl alcohols (IIa and IIb), while enzymic hydrolysis followed by alkaline saponification8 atforded a cis-1-alkenylglycerol (III), the fatty aldehydes from which were shown to be almost completely saturated and to consist mainly of the palmitic and stearic derivatives. The absolute configuration of the plasmalogens is of considerable biological and chemical interest in view of their possible biogenetic relationshipq” to the corresponding diacylphosphatides which could be reduced to the plasmalogens, possibly via a hemiacetal intermediate.qb However, some disagreement exists on the optical properties of the 1-alkenyl-3glycerylphosphates obtained by alkaline hydrolysis; thus specific rotations of [aIn -8~6”s” and +6*25”@’ are recorded for I-alkenyl-3-glycerylphosphorylethanolamine, and -7*85”s6 and “less than 2°“2b for I-alkenyl-3glycerylphosphorylcholine. No optical rotations have been reported either for the l-alkenyl(III) or for the I-alkyl-glycerols (II) obtained by hydrolysis and hydrogenation of plasmalogens.