5090-05-1Relevant academic research and scientific papers
Galactosylation of thiol group by beta-galactosidase.
Nakano,Shizuma,Kiso,Kitahata
, p. 735 - 740 (2007/10/03)
beta-Galactosidase catalyzed beta-galactosylation not only of a hydroxyl group but also of a thiol group in the condensation reaction of D-galactose and 2-mercaptoethanol. The thio-galactosylation product was confirmed as 2-hydroxyethyl S-beta-D-galactoside on the bases of fast atom bombardment mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance spectorometry. Aspergillus oryzae beta-galactosidase hydrolyzed p-nitrophenyl S-beta-D-galactoside most rapidly among several beta-galactosidases and produced the thio-galactosylation product most efficiently. The Penicillim multicolor enzyme was as effective as the A. oryzae enzyme. However the enzymes from Escherichia coli, Saccharomyces fragilis, Kluyveromyces lactis, and Bacillus circulans galactosylated hydroxyl groups predominantly to produce O-galactoside. The thio-galactoside was synthesized most effectively at a 2-mercaptoethanol concentration of about 1.25 M. Galactose concentration at 0.8-2.8 M did not affect the synthetic yield of the thiogalactoside so greatly.
Preparation and reactions of 2-chloroethyl 1-thio-β-D-glycopyranosides derived from D-galactose, D-glucose, and 2-acetamido-2-deoxy-D-glucose
Cerny, Miloslav,Trnka, Tomas,Budesinsky, Milos
, p. 1489 - 1500 (2007/10/03)
Chloroethyl 1-thio-β-D-glycopyranosides of the D-galacto and D-gluco configurations 5a-5c were prepared by alkylation of the corresponding 1-thio-β-D-hexopyranoses 3a-3c with 1-bromo-2-chloroethane followed by deacetylation. The starting 1-thio-β-D-hexopyranoses were obtained from the acetylated glycopyranosyl halides via isothiouronium salts. It was demonstrated that the chloroethyl thioglycosides 5a-5c undergo hydrolysis in aqueous solutions to give the 2-hydroxyethyl thioglycosides 6a-6c and reducing hexoses and that this hydrolysis proceeds via episulfonium salts. The hydrolysis was monitored by 1H and 13C NMR spectroscopy. In 1% aqueous solutions of sodium carbonate containing phenol or aniline, the thioglycosides 5a-5c provide, in addition to the above hydrolysis products, also the phenoxyethyl and phenylaminoethyl thioglycosides 9a, 10a and 9b, 10b, respectively.
