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
Abstract We describe a new synthetic route to amphiphilic derivatives of naphthalene disulfonic acid which have been found to be active against HIV-1 and HIV-2. The compounds were obtained in good yield by a new efficient acylation of amino-naphthalene disulfonic acid using N-acyl-thiazolidine-2-thiones as acylating agents.
Chimie des sucres sans groupements protecteurs - I - esterification regioselective de l'hydroxyle anomere du lactose, du maltose et du glucose
作者:Daniel Plusquellec、Fabienne Roulleau、Francoise Bertho、Martine Lefeuvre、Eric Brown
DOI:10.1016/0040-4020(86)80009-6
日期:1986.1
Et3N, afforded high yields of the corresponding reactive amides –, -thioesters – and aryl esters – and –, respectively. The esters -, - and – reacted with excess β-lactose in pyridine, to give the corresponding β-esters, – resulting from esterification of the anomeric hydroxyl of the sugar. The amides , – gave the α-lactosyl esters ,–. The amide and the esters ,, reacted with β-maltose, thus affording