ISSN:
0947-3440
Schlagwort(e):
D-Galacturonic acid derivatives
;
Regioselective deacetylation
;
1,2-O-Isopropylidene derivatives of D-galacturonic acid
;
Lipases
;
Enzyme catalysis
;
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
A number of D-galacturonic acid derivatives (1, 3, 7 and 9) have been selectively deacetylated in enzyme-catalyzed reactions. The 2-O-acetyl groups were selectively hydrolyzed from 2,3,4-tri-O-acetyl-β-D-galactopyranurono-6,1-lactone (1), and methyl [methyl (3) and benzyl (7) 2,3,4-tri-O-acetyl-β-D-galactopyranosid]uronates, affording the specifically deacetylated products in good to excellent yields. The methyl 1,2,3,4-tetra-O-acetyl-α-D-galactopyranuronate (9) was hydrolyzed at the anomeric position in 48% yield using the acylase from Aspergillus melleus (E1), whereas the lipases from wheat germ (E5 and E7) catalyzed the selective cleavage of the acetyl groups in both the 1- and 2-O-positions, furnishing the methyl 3,4-di-O-acetyl-D-galactopyranuronate (12) in 46% isolated yield. The latter compound was obtained in nearly quantitative yield by selective enzymatic deacetylation at the 2-O-position of 7, followed by hydrogenolytic cleavage of the anomeric O-benzyl group. Isopropylidenation of 12 furnished the hitherto unknown methyl 3,4-di-O-acetyl-1,2-O-isopropylidene-α-D-galactopyranuronate (13).
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jlac.199719970720
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