Help ethanolamine

The use of solvent mixtures helps to combine the chemical and physical effects of absorption. This mainly involves the following systems methanol and ethanolamines (Lurgi Amisol processes), sulfolane and diisopropyiamine (Shdl Sulfmol process). 

The reactions may be run on a large scale but is advisable to cool the reaction to 0 "C or 25 "C since the reduction may become exothermic. Usually an excess of organoborane is used since the bimolecular process becomes very slow towards the end of the reduction. Excess organoborane is destroyed by the addition of a low-boiling aldehyde such as acetaldehyde. This helps prevent contamination of the desired product with isopinocampheol. The borane component may be removed by precipitation as an ethanolamine complex or by an oxidative workup using hydrogen peroxide and base. Alternatively, these two steps may be combined, with the majority of the borane removed with ethanolamine and any remaining boron components removed by oxidation. 

Recently, two groups independently reported a membrane-bound enzyme activity in bovine brain that catalyzes the formation of an amide bond between the carboxyl group of arachidonic acid and the amino group of ethanolamine in an ATP- and CoA-independent manner (Devane and Axelrod, 1994 Kruszka and Gross, 1994). This activity was reported to be sensitive to inhibition by DTNB (Kruszka and Gross, 1994) and PMSF (Devane and Axelrod, 1994). It is possible that the cottonseed NAPE synthase enzyme and the bovine microsomal enzyme share a common mechanism. Future work with the purified enzyme should help to clarify the precise mechanism of this unusual enzyme activity. 

To test this hypothesis, the incorporation of [Me- U] and [ S] sulfocholine into PSC has now been studied in N. alba. In addition, to help explain why alba contains no nitrogenous phospholipids while photosynthetic diatoms, like Nltzschla angularls, contain PC and phosphatidylethanolamine (PE) [4], the incorporation of labelled sulfocholine, choline, serine and ethanolamine into the phospholipids of these two diatoms was compared. 

In studies with acylation of diethanolamine, it was found that direct acylation of diethanolamine to amide is more selective in hexane than in dioxane [50]. As diethanolamine is highly viscous, an increase in temperature was important to reduce the viscosity and promote the reaction. O-acylation does not take place in hexane but is favoured in dioxane rather than A-acylation. Excess of the amine helped to increase the conversion to amide. The transacylation approach resulted in higher reaction rates and selectivities in both the solvents. Lipase-catalysed synthesis of secondary-amide surfactant (A-methyl lauroylethanolamide) in acetonitrile was also favoured in the presence of a molar excess of amine (A-methyl ethanolamine) [51]. 

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