- FeCl3 mediated arylidenation of carbohydrates
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Glycosides and thioglycosides based on monosaccharides in reaction with benzaldehyde dimethylacetal or p-methoxybenzaldehyde dimethyl acetal undergo FeCl3-catalyzed (20 mol %) regioselective 4,6-O-arylidenation producing the corresponding acetals in high yields. FeCl3 also mediates acetalation of glycosides and thioglycosides of cellobiose, maltose, and lactose affording the corresponding 4′,6′-O-benzylidene acetals, which were isolated after their acetylation in situ with acetic anhydride and pyridine. The combined yields (two steps) of these final products are also high (61-84%). The procedure is applicable to a wide variety of functional groups including -OBn.
- Basu, Nabamita,Maity, Sajal K.,Roy, Soumik,Singha, Shuvendu,Ghosh, Rina
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experimental part
p. 534 - 539
(2011/04/27)
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- Chemical synthesis using enzymatically generated building units for construction of the human milk pentasaccharides sialyllacto-N-tetraose and sialyllacto-N-neotetraose epimer
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α,2-3- and α,2-6-sialylated lactosaminide precursor structures obtained by various enzymatic procedures could be used for glycosylations employing triflic acid/N-iodosuccinimide. Easily accessible selectively protected lactoside derivatives served as acce
- Schmidt, Dirk,Thiem, Joachim
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scheme or table
(2010/07/18)
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- CHEMICAL MODIFICATION OF METHYL β-CELLOBIOSIDE
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Treatment of methyl β-cellobioside (1) with α,α-dimethoxytoluene in N,N-dimethylformamide in the presence of p-toluenesulfonic acid gave a high yield of methyl 4',6'-O-benzylidene-β-cellobioside (6), which was transformed into methyl 2,3,2',3',4',6'-hexa-
- Takeo, Ken'Ichi,Fukatsu, Toshiya,Yasato, Tetsushi
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