Front Matter

(Tina Sui) #1
Lang et al. (1999) also amidated sophorolipids, but they used lactonic-SL as feed-

stock. Depending on theN-alkylation grade of the amine (branched alkyl chain,

dialkylation), the reaction had to be performed differently. In the case of primary

N-alkylated amines only catalytic amounts of ammonium chloride were necessary

for successful conversions. The longer the alkyl chain, the faster was the reaction.

The formation of theN,N-diethyl amide was only possible if diethyl amine was

predeprotonized withn-butyl lithium.

17.4.2 Enzymatically modified sophorolipids, enzymatically

modified

Thus, to date, physiological variables during fermentations have provided routes to

the variation of sophorolipid composition, but have not led to well-defined pure

compounds. An alternative strategy to the tailoring of sophorolipid structure during

thein vivoprocessing step is to develop methods for the regioselective modification

of sophorolipids after microbial formation.

382 17 Enzymatic Synthesis and Modification of Glycolipids

Figure 7. Conversion of mono- or diacetylated 17-L-([2’-O-b-D-glucopyranosyl-b-D-glucopyrano-
syl]-oxy)-octadecanoic acid into acid amides by the reaction with amine compounds in a methylene
chloride solvent in the presence ofN-methyl-2-chloro-pyridinium iodide and tributylamine (Ishigami,
1994).

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