59891-26-8Relevant articles and documents
Crystallization, polymorphism, and binary phase behavior of model enantiopure and racemic 1,3-Diacylglycerols
John Craven,Lencki, Robert W.
, p. 1566 - 1572 (2011)
1,3-Diacylglycerols (1,3-DAG) are components in many natural, commercial, and food systems. These compounds are always asymmetric, and diacid forms are chiral. To understand what effect this has on their crystallization behavior, model enantiopure (1-decanoyl-3-palmitoyl-sn-glycerol) and racemic (1,3-decanoyl-palmitoyl-rac-glycerol) 1,3-DAG were prepared and characterized. In addition, binary phase diagrams were prepared to investigate their phase behavior and the racemate's crystalline tendency. The major finding for this work is eutectic phase behavior was seen for blends of opposite enantiomers indicating racemic mixtures form conglomerates (mechanical mixtures of enantiopure crystals) in the solid phase. Differential scanning calorimetry melting curves of the racemic mixture display marked polymorphism, whereas, the pure enantiomer did not. This can be understood from a structural perspective since chain-end matching and hydrogen-bond optimization (via orientation of glycerol) are simultaneous for enantiopure, but are multistage for racemic DAG. Thus, there are critical differences between the crystallization behavior of enantiopure and racemic 1,3-DAG, and future physical analysis of these compounds should reflect this finding.
Preparation of diacid 1,3-diacylglycerols
Craven, R. John,Lencki, Robert W.
, p. 1281 - 1291 (2011/08/21)
A complete methodology (including synthesis, purification and analysis) for the preparation of 1,3-DAG is described. For a successful synthesis project, the strengths and weaknesses of each particular process should be taken into account and measures taken to offset or balance potential weaknesses. To this end, we describe some of the challenges associated with: chemically and enzymatically catalyzed acylglycerol syntheses; recrystallization and flash chromatography for purification of partial acylglycerols; and thin-layer chromatography (TLC) separation of DAG. For this work, 1-MAG intermediates and subsequent diacid 1,3-DAG were prepared using non-enzymatic methods, whereas, monoacid 1,3-DAG were prepared by enzymatic methods. It was not always possible to obtain pure samples of target compounds-in recrystallizations this is due to solid solution formation and co-crystallization and in chromatographic separations it is due to co-elution of components with similar Rf. Furthermore, TLC Rf of DAG is determined by two main factors: acyl chain length and positional isomerism. Interestingly, while the role of positional isomerism is well-known, the role of acyl chain length in these separations has only recently come to light.
