Synthesis of 1-monoglycerides having C11-20 branched chain fatty acids and their hemolysis effects.

Ci4~ i6 branched chain fatty acids have other biological effects, such as platelet aggregation inhibition effect reported by Omura et al.3) On such research background, we have prepared a homologous series of 1-monoglycerides derived from C1 1 ^,20 isoor owtewo-branched chain fatty acids to examine their biological effects. The synthetic scheme adopted here is shown in Fig. 1. Racemic 1,2-isopropylidene-glycerol was esterified with the appropriate isoor anteiso-bmnchQd chain fatty acids in carbon tetrachloride in the presence of 4-(dimethylamino)pyridine (DMAP) and A^TV'-dicyclohexyl-carbodiimide (DCC) to afford 1 ,2-isopropylidene3-acyl-glycerols (I)4). During hydrolysis of the protecting ketal group, acyl migration may occur to yield 2-acylglycerols especially at higher reaction temperature. The following deprotection therefore was performed by the procedure of Kodali5), in which I on silica gel were exposed to hydrogen chloride (HC1) gas at -75°C for about 10 minutes. The reaction mixture was extracted three times with 50-ml portions of 30% (v/v) methanol in chloroform at 0°C. The combinedorganic extracts were washed with 50-ml of water before concentration