Carbohydrate fatty acid polyesters

A one-stage procedure involving sodium catalysed transesterification between raffinose undeca-acetate and methyl esters of long-chain fatty acids (derived, for example, from salad oil) has been employed to produce raffinose fatty acid polyesters in excellent yields (>96%) their physical properties are described as similar to those of analogous sucrose polyesters." Certain carbohydrate esters of fatty acids, e.a.. sucrose mono-laurate, -palmitate, and -stearate, have been found to enhance the activity of thiabendazole, a fungicide used against Penicillium dioitatum infections of citrus fruit. The mechanism of this action remains to be clarified. ... 

Plants were probably the first to have polyester outerwear, as the aerial parts of higher plants are covered with a cuticle whose structural component is a polyester called cutin. Even plants that live under water in the oceans, such as Zoestra marina, are covered with cutin. This lipid-derived polyester covering is unique to plants, as animals use carbohydrate or protein polymers as their outer covering. Cutin, the insoluble cuticular polymer of plants, is composed of inter-esterified hydroxy and hydroxy epoxy fatty acids derived from the common cellular fatty acids and is attached to the outer epidermal layer of cells by a pectinaceous layer (Fig. 1). The insoluble polymer is embedded in a complex mixture of soluble lipids collectively called waxes [1], Electron microscopic examination of the cuticle usually shows an amorphous appearance but in some plants the cuticle has a lamellar appearance (Fig. 2). 

The 10-undecenoic acid motif has also been attached to isosorbide in the preparation of a fatty acid-/carbohydrate-based monomer [131]. ADMET polymerization in the presence of C3 and C4 produced fully renewable unsaturated polyesters (Scheme 18). Most importantly, the transesterification of these polyesters with MeOH, and subsequent analysis by GC-MS of the products, allowed for the quantification of double-bond isomerization during ADMET in a very simple manner. This strategy was then extended to fatty acid-based ADMET polyesters synthesized in the presence of indenylidene metathesis catalysts [132]. With these studies, the knowledge on the olefin isomerization in ADMET reactions was widened, and it is now possible to almost completely suppress this undesired side reaction. 

Initially, it was expected that the use of fatty acids was the most interesting way to produce and control these materials composition, once the polyester composition reflects the carbon chain length from the offered source. When the main source is nonanoic acid, for example. Pseudomonas oleovorans produces PHAmcl composed of 3-hydroxynonanoate predominantly. However, it was discovered in the 90s that a group of Pseudomonas accumulates PHAmcl from carbohydrates. When produced from carbohydrates, PHAmcl presents 3-hydro)ydecanoic acid (HD) as the main constituent and other... 

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