alyzed galactose or lactose with 2-bromotetradecanoic acid. Second, these products
were chemically dimerized with dicarboxylic acids, and after deprotection by tri-
fluoroacetic acid, in the case of 1,2 : 3,4-di-O-isopropylidene-D-galactopyranose
and lactose tetra-acetal esters, the desired gemini products were obtained in reason-
able overall yields. Additionally, a trimeric sugar ester surfactant was prepared in a
similar fashion in just one step by reacting 6-O-(2-bromotetradecanoic) methyl-a-D-
glucoside with 1,3,5-tris (4-carboxy butyloxy)-benzene.
17.2.4 Protease-mediated catalysis in organic solvents
Beside lipases, proteases were also used successfully for the regioselective acylation
of sugars and related compounds in anhydrous organic solvents. The most common
solvents employed in these processes are dimethylformamide and pyridine (Table 5).
As for the regioselectivity of acylation of sucrose, several proteases of the subtilisin
family catalyze selectively the acylation of the primary 1’-OH in the fructose ring
(Figure 4), which is frequently demonstrated in the literature (Carrea et al., 1989;
Soedjak and Spradlin, 1994; Plou et al., 1995; Rich et al, 1995; Polat et al., 1997).
With lipases as catalysts, the preferred acylation position is the 6-hydroxyl group
17.2 Lipase- and protease-catalyzed esterification of lipids 375
Figure 4. Scheme of the protease-catalyzed synthesis of sucrose-monolaurate.