Benzyl 2-acetamido-6-O-(2-acetamido-2-deoxy-4,6-O-isopropylidene-β-d-glucopyranosyl)-2-deoxy-3,4-O-isopropylidene-α-d- galactopyranoside (2) was obtained by acetalation of its parent disaccharide with 2,2-dimethoxypropane in hot N,N-dimethylformamide and in the presence of 4-toluenesulfonic ac...
3- O-(2-Acetamido-2-deoxy-β-d-glucopyranosyl)-α-d-galactopyranose (10, “Lacto-N-biose II”) was synthesized by treatment of benzyl 6-O-allyl-2,4-di-O-benzyl-β-d-galactopyranoside with 2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-α-d-glucopyrano)[2,1-d]-2-oxazoline (5), followed by selective O-d...
Methyl β-d-galactopyranoside was transformed into methyl 2-O-benzyl- (5, 24%) and 2-O-benzyloxymethyl-4,6-O-benzylidene-β-d-galactopyranoside (8, 60%) in two and four steps respectively. Compounds 5 and 8 were then transformed into the corresponding 3-O-methyl, 3-C-methyl, and 3-deoxy derivati...
Benzoylation of benzyl 4,6-O-benzylidene-β-d-galactopyranoside (1) with one equivalent of benzoyl chloride in pyridine-dichloromethane solution yields preferentially the 3-benzoate 3. Under alkaline conditions, benzoate 3 can be converted, in high yield, into the 2-benzoate 5, thus providingg a...
2-O-Benzoyl-3,6-di-O-benzyl-4-O-(chloroacetyl)-, 4-O-acetyl-2-O-benzoyl-3,6-di-O-benzyl-, and 2-O-benzoyl-3,4,6-tri-O-benzyl-α-d-galactopyranosyl chloride were converted into the corresponding 2,2,2-trifluoroethanesulfonates, and these were treated with allyl 2-O-benzoyl-3,6-di-O-benzyl-α-d-ga...
Benzyl β-D-galactopyranoside was converted into the crystalline 3,4-O-isopropylidene derivative (2), which was selectively benzoylated to give crystalline benzyl 6-O-benzoyl-3,4-O-isopropylidene-β-D-galactopyranoside (8. The structure of 8 was established by various reactions, which included t...
A lectin was isolated from the tuberous rhizome of Keampferia rotunda by using different chromatographic methods with the molecular weight of 21 ± 1 kDa. The lectin contained highest percentage of leucine and lowest percentage of tryptophan residues as determined by LC–MS. The lectin agglutina...
The LAC4 gene of Kluyveromyces lactis encoding for β-galactosidase was overexpressed in the yeast Arxula adeninivorans to produce the enzyme, which can be used for the synthesis of β-d-galactosides. These compounds play a major role as precursors for the synthesis of glycolipids and glycoprote...
Allyl 6-O-benzyl-3,4-O-isopropylidene-α-d-galactopyranoside (1) was used to prepare a series of 2-O-benzoyl-3,6-di-O-benzyl-α-d-galactopyranosyl halides carrying either a second benzoyl group (11, 17a) or a selectively removable, temporary protecting group (17b-d) at position 4. In one synthet...
Isopropylidenation of p-nitrophenyl β-d-galactopyranoside under kinetic control afforded the 4,6-acetal (2). The structure of 2 was established by 1H- and 13C-n.m.r. spectroscopy, and confirmed by methylation, and hydrolysis to 2,3-di-O-methyl-d-galactose. Selective benzoylation of 2 with benzo...
The 2,3,4- (9) and 2,4,6-tribenzyl (19) ethers of 1-thio-β-d-galactopyranose were prepared from the corresponding O-benzylated normal (1-hydroxyl) sugars 4 and 15 via the sequence: normal sugar → diacetate → O-acetylglycosyl bromide → O-acetyl-glycosyl ethylxanthate → 1-thio sugar. 2,3,4-Tr...
Both protective and pre-spacer features of 4-(2-chloroethoxy)phenyl (CEP) aglycon, which belong to the class of Janus aglycons, were engaged in a benzyl-free synthesis of oligosaccharide fragments of polysaccharides from rhizobacterium Azospirillum brasilense sp7. Introduction of α-1,4-linked L...
6-O-Acetyl-2-O-benzoyl-3,4-di-O-benzyl-α-d-galactopyranosyl chloride (8) was prepared from 1,6-anhydro-2-O-benzoyl-3,4-di-O-benzyl-β-d-galactopyranose via the corresponding 1,6-di-O-acetyl derivative 7. The glycosyl chloride 8 was converted into the 1-O-tosyl derivative (9) which was allowed t...
Regioselective preparation of methyl 3,6-di-O-benzyl-β-d-galactopyranoside, methyl 2,4-di-O-benzyl-β-d-galactopyranoside, and methyl 3,4-di-O-benzyl-β-d-galactopyranoside by the stannyl method is described.
Two series of related donor–acceptor conjugated heterocyclic azo dyes based on the thienylpyrrole system, functionalized with benzothiazol-2-yl (5–6) or benzothiazol-6-yl acceptor groups (7) through an NN bridge, have been synthesized by azo coupling using 1-alkyl(aryl)thienylpyrroles (1) and ...
Vesicular Glutamate Transporters (VGLUTs) allow the loading of presynapic glutamate vesicles and thus play a critical role in glutamatergic synaptic transmission. VGLUTs have proved to be involved in several major neuropathologies and directly correlated to clinical dementia in Alzheimer and Par...
Two series of novel thermally stable second-order nonlinear optical (NLO) heterocyclic azo dyes 4–5 have been designed and synthesized. The two series of compounds were based on different combinations of acceptor groups (thiadiazole or arylthiadiazole electron-deficient heterocycles) linked to ...
A series of pyrazolone-based full heterocyclic and half heterocyclic hydrazone dyes as well as aniline modified hydrazone-azomethine dyes has been successfully synthesized and spectrally characterized. UV–Vis spectral comparisons indicate that the aniline modified hydrazone-azomethine dyes show...
A series of heterocyclic azo dyes were dispersed in poly(methyl methacrylate) (PMMA) matrix and the photochromic properties of the coloured films studied by UV–Vis spectroscopy. Visible irradiation of the coloured films lead to a fast decrease in the colour intensity due to the trans–cis photo...
The synthesis and single crystal X-ray structures of two fluorinated azo pigments and their nonfluorinated analogues derived from N-acetoacetanilide and N,N′-(1,4-phenylene) bis-(acetoacetamide) as coupling components were described. These two kinds of pigments existed in the ketohydrazone and ...
About|Contact|Cas|Product Name|Molecular|Country|Encyclopedia
Message|New Cas|MSDS|Service|Advertisement|CAS DataBase|Article Data|Manufacturers | Chemical Catalog
©2008 LookChem.com,License: ICP
NO.:Zhejiang16009103
complaints:service@lookchem.com Desktop View