Sugar chemistry without protecting groups-III. A facile chemical synthesis of 6-O-acyl-D-glycopyranoses and methyl-6-O-acyl-d-glycopyranosides.
作者:Krystyna Baczko、Daniel Plusquellec
DOI:10.1016/s0040-4020(01)80906-6
日期:——
Regioselective acylation of non protected glycopyranosides was performed using 3- acylthiazolidine-2-thiones 1 and the novel 3-acyl-5-methyl-1,3,4-thiadiazole-2(3H)-thiones 2 as the acylating reagents, yielding 6-O-acylated derivatives in high yields. Acylation of free α-D-glucose and α-D-galactose using the same conditions lead to the 6-O-acylglycoses. This reaction is compared with our previous synthesis
of sucrose fatty acid esters to undergo intramolecular migrations in organic medium and the regioselectivity of some transesterifications of sucrose were investigated by HPLC, in situ NMR spectroscopy and preparative methods. Extensive acylation on secondary positions of the glucose moiety followed by migrations is general for base catalysed transesterification. The stability of 3‐ and 6‐O‐acyl derivatives
unprotected sucrose in N,N-dimethylformamide and the appropriate 3-acylthiazolidine-2-thiones 6 or 3-acyl-5-methyl-1,3,4-thiadiazole-2(3H)-thiones 7. A selective ionization of the free sugar by sodium hydride or triethylamine, followed by acylation with 6, gave 2-O-acylsucroses which were subjected in situ to intramolecular isomerizations using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or an aqueous solution
Sugar chemistry without protecting groups: a novel regioselective synthesis of 6-O-acyl-D-glucopyranoses and methyl-6-O-acyl-α--glucopyranosides
作者:Daniel Plusquellec、Krystyna Baczko
DOI:10.1016/s0040-4039(00)96390-1
日期:1987.1
hydroxyl groups of α--glucose and methyl-α--glucoside were selectively esterified by treating the free sugars with -acylthiazolidine-2-thiones, thus affording respectively 6--acyl--glucopyranoses and methyl-6--acyl-α--glucopyranosides in high yields. This new reaction is compared with our previous synthesis of 1--acyl-β--glucopyranoses from β--glucose and interpreted in terms of anomeric effect.
1,5-Anhydro-D-fructose substituted with a hydrophobic group for use as anti-oxidant and/or emulsifier
申请人:——
公开号:US20020102342A1
公开(公告)日:2002-08-01
The present invention provides a derivatised anhydrofructose comprising a hydrophobic group linked (directly or indirectly) to a C of an anhydrofructose moiety.