GLYCERYL ETHERS 395 



property. The specific rotation, [alsJci, in chloroform, was found to be 

 +2.6° (cone, 0.95), while the similar value for batyl acetate in the same 

 solvent has been reported to be —8.5° (cone, 2.63). Since optical activity 

 could exist only when the higher alcohol was attached to the a-carbon of 

 glycerol, this would soom to nfford an indisputable proof of the a-ether 

 structure. Under such conditions, the synthetic octadecyl glyceryl ether 

 would be a racemic product which would possess somewhat different 

 physical properties than the optically active natural form. Such an 

 hypothesis offers an adequate explanation for the slight discrepancy in 

 mixed melting point between the natural and the synthetic products. 



The optical properties were further investigated by Baer and Fischer,'"'^ 

 who synthesized batyl and chimyl alcohol with /( — )-acetoneglycerol. 

 The synthetic and the natural products were identical, and hence it is con- 

 cluded that these glyceryl ethers belong to the d-series. Although selachyl 

 alcohol was not synthesized in the original work, it was also assigned to the 

 d-series because of its close relationship to batyl alcohol. The terminology 

 for the optical isomers conforais to an earlier recommendation of Baer and 

 Fischer-* ^'^ that the principle used for the classification of a-monoglycerides 

 and glj^cerophosphates be followed. 



The reaction used for the synthesis of the glyceryl ethers is indicated in 

 the following equation : 



H-C-ONa H,C-OR 



CH. /0-CH CH. /0-CH H,C-OR 



/C I " yC I ► HOCH + (CH3)2C0 



CH; ^O-CH^ CH^ ^0-CH^ H^COH 



However, more recently Baer, Rubin, and Fischer^^^ have synthesized the 

 d-, Z-, and c?Z-isomers of selachyl alcohol by the following reaction : 



CHjONa HjCOCieHj, 



HjC^^ /OCH HjCx yOCH 



,C I + C,eH„0 SGjC.H, ► .C | 



Na salt of 01eyl-/> OleyW(-)-, d(+)-, or 



Z( — )-, (/( + )-, toluene dZ-acetoneglycerol 



or dl-a,cetone- sulfate 



glycerol 



HzCO-CHjs 



► HOCH 



I 

 HjCOH 



rf-Selachyl 

 alcohol 



«» K. Baer and H. O. L. Fischer, ./. Biol. Chem., I40, 397-410 (1941). 



*"> K. Baer and H. O. L. Fischer, /. Biol. Chem., 128, 475-489, 491-500 (1939). 



*" E. Baer, L. J. Rubin, and H. O. L. Fischer, ./. Biol. Chem., 15.5, 447-457 (1944). 



