Search results for "Anomer"
showing 4 items of 24 documents
Carbohydrates as Stereodifferentiating Auxiliaries
2017
Carbohydrates are inexpensive natural products. Although they contain numerous functional groups and stereogenic centers in one molecule, carbohydrates were recognized as stereodifferentiating auxiliaries much later than other classes of natural products as for example amino acids or terpenes. Apart from their polyfunctional nature carbohydrates are characterized by the anomeric and exo-anomeric effects which have distinct influence of the spatial orientation of substituents linked to the anomeric position. Based on these stereochemical properties carbohydrates were used as stereodifferentiating auxiliaries in numerous diastereoselective reactions, such as aldol addition, alkylation reactio…
Stereoselective synthesis of glycosides and anomeric azides of glucosamine
1992
The β-azide of O-acetyl protected N-acetyl glucosamine is efficiently accessible via a phasetransfer-catalyzed reaction of the corresponding glycosyl chloride with sodium azide. The azido group revealed to be a useful anomeric protection for modifications of the protecting group pattern of the glucosamine unit. Exchange of the O-acyl groups by 4-methoxybenzylidene and 4-methoxybenzyl (Mpm) protection delivered regioselectively blocked glucosaminyl azide derivatives. In contrast, the N-phthaloyl protected glucosaminyl azide was obtained quantitatively from the corresponding glycosyl fluoride via a boron trifluoride-promoted reaction with trimethylsilyl azide. N-Phthaloyl glucosaminyl fluorid…
ChemInform Abstract: Stereoselective Synthesis of Glycosides and Anomeric Azides of Glucosamine.
2010
The β-azide of O-acetyl protected N-acetyl glucosamine is efficiently accessible via a phasetransfer-catalyzed reaction of the corresponding glycosyl chloride with sodium azide. The azido group revealed to be a useful anomeric protection for modifications of the protecting group pattern of the glucosamine unit. Exchange of the O-acyl groups by 4-methoxybenzylidene and 4-methoxybenzyl (Mpm) protection delivered regioselectively blocked glucosaminyl azide derivatives. In contrast, the N-phthaloyl protected glucosaminyl azide was obtained quantitatively from the corresponding glycosyl fluoride via a boron trifluoride-promoted reaction with trimethylsilyl azide. N-Phthaloyl glucosaminyl fluorid…
The fate of implant after endoscopic injection of dextranomer/hyaluronic acid in vesicoureteral reflux: time to partial reabsorption and stabilization
2020
Summary Background/introduction Vesicoureteral reflux (VUR) potentially leads to renal damage, scarring, and eventually end-stage renal disease. Endoscopic treatment is well tolerated in children, it has reduced costs, and it effectively prevents urinary tract infections (UTIs), while avoiding long term antibiotics use. Objective With the aim to investigate the time needed to reach the stabilization of the dextranomer/hyaluronic acid (Dx/HA) implants and to identify cut-off heights to ensure the success of the procedure, the authors analyzed ultrasonographic (US) intra-operative appearance of the mounds following endoscopic treatment for VUR and repeated the measurements during serial posto…