Ester hydrolysis copper-catalyzed reactions

Complexes of metal + ligand + protein or DNA can also catalyze the Diels Alder cycloaddition or oxidations with hydrogen peroxide. Copper complexes bound to DNA catalyzed the Diels-Alder cycloaddition with up to 99% ee [15, 16], Cu(phthalocyanine) complexed to serum albumin also catalyzed the enantioselective (98% ee) Diels-Alder reaction, but only with very high catalyst loading (10 mol%) and only with pyridine-bearing dienophiles (presumably to complex the copper) [17]. Achiral Cr(III) complexes or Mn(Schiff-base) complexes inserted into the active site of apomyoglobin variants catalyzed the sulfoxidation of thio-anisole with up to 13 and 51% ee, respectively [18, 19]. A copper phenanthroline complex attached to the adipocyte lipid-binding protein catalyzed the enantioselective hydrolysis of esters and amides [20]. 

In the beginning, we have focused on copper complexes that catalyze the hydrolysis of carboxylic esters, and at a later stage of the project, oxidation reactions by O2 or H2O2. Figure 3.4 summarizes the newly synthesized fluorophore-labeled chelators, and their properties are briefly discussed below. A significant advantage of the DNA-linked chelators is that they can be readily combined with both a reporter fluorophore and a functionality for surface immobilization by hybridization with a complementary DNA strand that is 3 terminally functionalized with, for example, tetramethylrhodamine (TMR) and 5 -functionalized with biotin for interaction with surface-bound streptavidin. 

Other factors can have an impact on the oxidative stability of fatty oils and/or esters, such as, water, metals and light, etc. The presence of water can cause hydrolysis reactions and damage the fuel quality. Moreover, water can be dispersed in the biodiesel by mono-, di-glycerides and glycerol (co-products of the esterification). These compounds can play the role of emulsifier [3]. Furthermore, the presence of metals, even trace levels, can catalyze the oxidation reaction. Copper [30] has the... 

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