Alkenyl glycerol ethers

The alkyl glycerol ethers, alkenyl glycerol ethers and monoglycerides can occur as a- and j8-isomers diglycerides may be symmetrical (a,a -) or asymmetrical (a,jS-). 

FIGURE 10-9 Ether lipids. Plasmalogens have an ether-linked alkenyl chain where most glycerophospholipids have an ester-linked fatty acid (compare Fig. 10-8). Platelet-activating factor has a long ether-linked alkyl chain at C-l of glycerol, blit C-2 is ester-linked to acetic acid,... 

Schwartz (1972) also noted the detection of about 70 glycerol-l-alkyl ethers in milk fat. Saturated ethers, both odd and even from C-10 through C-18, were found, with traces of ethers up to C-25 present. Fifty-five unsaturated ethers were separated, but only the A-9, A-9, 12, and A-9, 12,15 compounds were tentatively identified. In addition, Schwartz isolated over 50 bound aldehydes probably derived from the glycerol-l-alkenyl ethers (phosphorus free). 

Diol lipids have recently been detected in maize oil (seed oil from Zea mays) with the help of chromatographic methods [12]. It was evident that adsorption TLC was not capable of separating the esters and alkenyl ether esters of diols from the corresponding glycerol derivatives [12] (see also [22] and [9]). Using TLC, it was nevertheless possible to fractionate the products of alkaline methanolysis of the triglycerides of maize oil into three fractions methyl esters, alkenyl ethers and polyhydric alcohols. The alcohols could be separated and identified as their acetates by gas chromatography [12]. 

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