Fatty acid vinyl esters as acylating agents: A new method for the enzymatic synthesis of monoacylglycerols

Abstract

Lipase-catalyzed synthesis of monoacylglycerols (MAG) was performed by transesterification reactions between fatty acid vinyl esters and either glycerol (1) or 1,2-O-isopropylidene-rac-glycerol (2), without solvents or in the presence of npentane. Vinyl decanoate, vinyl laurate, vinyl stearate and vinyl palmitate have been converted to the corresponding monoacylglycerols. As expected for the reaction with 1, a mixture of mono-, di-and triacylglycerols was synthesized. The highest concentrations of MAG were achieved with vinyl stearate (30% 2-MAG and 15% 1-MAG). The reactions of fatty acid vinyl esters with the protected glycerol (2) led to the corresponding protected 3-monoacylglycerols with 100% conversion after short reaction times. The subsequent cleavage of these acetonides was performed by four different methods. The fastest cleavage was found with trifluoroacetic acid as catalyst, whereas the highest concentration of MAG (100%) was obtained for the boric acid-catalyzed hydrolysis of the acetonides. JAOCS 72, 193-197 (1995).

Kinetics of enzymatic synthesis of isopropylidene glycerol esters by goat pregastric lipase

“…Enol esters have also been used as acyl donors which shift the position of the equilibrium because they cause irreversible tautomerization of the vinyl alcohol or isopropenyl alcohol by-product. In a short reaction time, 100% conversion of long-chain fatty-acid vinyl esters was achieved (12,13).…”

Synthesis of polyfunctional glycerol esters: Lipase‐Catalyzed esterification of glycerol with diesters

“…Acylation of the isopropylidene derivative of glycerol has been widely used for the synthesis of monoacylglycerols (8)(9)(10). Our initial studies with isopropylidene glycerol were carried out in hexane solvent at 60°C using Lipozyme TM as the catalyst and dimethyl sebacate as the acyl donor.…”

“…The latter strategy, however, deals with substrates that often have very different solubility characteristics, which often inhibits their reaction with each other. A number of publications have addressed this problem by devising different methods to modify the solubility of glycerol, for example by adsorption onto inert supports (5-7), use of the isopropylidene protecting group (8)(9)(10), or complexation with phenyl boronic acid (PBA) (11,12). Other approaches to overcoming the glycerol solubility limitation include carrying out the reaction with substrates in biphasic systems (13), by microemulsion (14), or by addition of water to the reaction media (15).…”

Synthesis of regioisomerically pure triacylglycerols containing n ‐3 very long‐chain polyunsaturated fatty acids

“…The reaction can be performed at lower temperatures to minimize acyl migration [43]. Bornscheuer and Yamane [45] used this technique for regiospecific synthesis of sn-1(3)-monoacylglycerol (MAG). They found that transesterification of FA vinyl ester and isopropylidene glycerol in pentane produced MAG in higher yield and in shorter time compared to direct esterification with free acids or transesterification with FA esters.…”