7322-42-1Relevant academic research and scientific papers
Intramolecular glycosidation by click reaction mediated spacer generation followed by spacer cleavage
Kumar, Amit,Geng, Yiqun,Schmidt, Richard R.
, p. 6846 - 6851 (2013/03/13)
2-O-Propargyl-substituted glycosyl donors and O-(2-azidobenzyl)-substituted acceptors having a vicinal hydroxy group readily underwent the click reaction. Intramolecular glycosidation with N-iodosuccinimide/trifluoromethansulfonic acid as the activating system afforded β-(1-3)- and α-(1-2)-linked disaccharides as part of 14-membered macrocycles. Descriptors for these reactions are proposed that consider the donor and acceptor attachment sites and the stereochemistry of the functional groups. Investigation of the influence of 2-O-linked 1-aryl-1,2,3-triazol-4-ylmethyl groups, as contained in the spacer, on the anomeric selectivity exhibited no anchimeric assistance. In addition, it was shown that the spacer group can be readily cleaved under Birch reduction conditions. The 1,2,3-triazole-forming click reaction was employed to generate glycosyl donor-spacer-acceptor constructs. Upon glycosidation, 14-membered macrocycles were obtained with high anomeric selectivity. Spacer cleavage was performed under Birch reduction conditions. Copyright
Efficient Intramolecular Glycosylation Supported by a Rigid Spacer
Mueller, Matthias,Huchel, Ursula,Geyer, Armin,Schmidt, Richard R.
, p. 6190 - 6201 (2007/10/03)
The m-xylylene moiety was employed as rigid spacer in intramolecular glycoside bond formation. Fifteen-membered macrocycle formation starting from 6-O-linked donor and 6- and 4-O-linked acceptor (5a,b, 6b) led exclusively to β(1-4)- and β(1-6)-linked compounds 7β and 8β, respectively, which gave cellobioside and gentiobioside derivatives. The glycosylation yields could be improved by 14-membered macrocycle formation. In the four cases studied, the donor was 6-O-linked to the spacer. For the acceptor linkage to the spacer and the accepting hydroxy group, relative D-/L-threo- and D-/L-erythro-arrangements were chosen. Standard glycosylation conditions led in three cases (13, 14, 23) only to β-linkage in high yield (16β, 17β, 25β). For the transformation of 24, having a D-erythro-arrangement in the acceptor moiety, the α-anomer 26α was preferentially obtained. Limitation of the conformational space of the donor and the acceptor as in 31, which is stereochemically identical with 24, led to the corresponding α-glycoside 32α in 87% yield. Synthesis of a pseudo mirror image of 23 [having 6-(D)/3-(D-threo)-arrangement], namely 35, having 3(L)/6-(L-threo)-arrangement of the donor and acceptor moieties, expectedly gave only α-glycoside 36α in very high yield. Thus, the efficiency and versatility of this conceptual approach to intramolecular glycoside bond formation is exhibited.
Template directed cyclo-glycosylation: Effect of the anchoring sites of the spacer and temperature in the regio-and stereo-selectivity of the glycosylation
Valverde, Serafin,Gomez, Ana M.,Lopez, J. Cristobal,Herradon, Bernardo
, p. 1105 - 1108 (2007/10/03)
The anchoring sites of the spacer and the reaction temperature have a remarkable effect on the regio-and stereo-selectivity of intramolecular macrocyclic glycosylation reactions of several template linked monosaccharides leading to macrocyclic disaccharides and thence to disaccharides.
A NOVEL OBSERVATION ON KOENIGS-KNORR CONDENSATION OF 2,3,4,6-TETRA-O-ACETYL-α-D-GLUCOPYRANOSYL BROMIDE WITH METHYL 4,6-O-BENZYLIDENE-α-D-GLUCOPYRANOSIDE
Temeriusz, Andrzej,Piekarska, Boguslawa,Radomski, Jan,Stepinski, Janusz
, p. 141 - 147 (2007/10/02)
As a result of condensation between methyl 4,6-O-benzylidene-α-D-glucopyranoside and bromo-2,3,4,6-tetra-O-acetyl-α-D-glucopyranose in 1,2-dichloroethane in presence of silver carbonate, after removal of functional groups, the following substances were ob
