Monosaccharide mit stickstoffhaltigem Ring, XIII. Synthese und Reaktionen von Keto‐piperidinosen

Paulsen, Hans; Sangster, Ian; Heyns, Kurt

doi:10.1002/cber.19671000314

Cited by 121 publications

(45 citation statements)

References 18 publications

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“…General Procedure 2: β-Galactosidase-catalysed glycosylation with 2-acetamido-2-deoxy--glucopyranose (14) as acceptor: Glycosyl donor (150 µmol) and 2-acetamido-2-deoxy--glucopyranose (14) (300 mg, 1.36 mmol, 9 equiv.) were dissolved in 50 m sodium acetate buffer (4 mL) pH 5.0 at 55°C.…”

Section: Resultsmentioning

confidence: 99%

“…As uniform acceptor substrates 2-acetamido-2-deoxy--glucopyranose (14) as well as allyl 2-acetamido-2-deoxy-α--glucopyranoside (15) were used in the enzymatic glycosylation. Reactions with compound 15 were performed at room temperature for 3 days, while reactions with GlcNAc (14) required 3 h at 55°C.…”

Section: β-Galactosidase Catalysed Glycosylationmentioning

confidence: 99%

“…Most previously described glycomimetics [12] contain carba- [13] or azasugars, with the ring-oxygen substituted by carbon or nitrogen, [14,15] or as in the C-glycosides having carbon instead of the anomeric oxygen. [16] Here it was envisaged to have nitrogen as a flexible bridging atom between two non-anomeric positions to arrive at a novel class of glycomimetics, not described so far.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Novel Di‐ and Trisaccharide Mimetics with Non‐Glycosidic Amino Bridges

2007

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Synthesis of novel di‐ and trisaccharides using enzymatic glycosylation, Dess–Martin oxidation and reductive amination allows rapid access to the target structures. Thus, a novel class of glycomimetics was obtained having nitrogen inserted as bridging atom between two non‐anomeric positions. Novel di‐ and trisaccharide mimetics were designed using N‐acetylglucosamine as a basis structure. A third monosaccharide unit was attached via an unnatural sugar–sugar bond without participation of the anomeric center. Their synthesis, proceeding via oxidation, glycosylation and reductive amination, required only a few steps, thus allowing rapid access to the target structures. Generation of the novel pseudo‐disaccharide was achieved by Dess–Martin oxidation and a subsequent reductive amination. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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Section: Resultsmentioning

confidence: 99%

Section: β-Galactosidase Catalysed Glycosylationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis of Novel Di‐ and Trisaccharide Mimetics with Non‐Glycosidic Amino Bridges

2007

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“…The key intermediate of this approach is the imine 75, which is easily prepared in eight steps from l-sorbose (an inexpensive sugar) in 64 % overall yield (Scheme 6). 2,3;4,6-Di-O-isopropylidene-α-lsorbofuranose (71) was obtained in one step from l-sorbose in 80 % yield as reported earlier by Paulsen et al [44] A judicious four-step protection-deprotection procedure gave the fully protected furanose 73 (91 % yield from 71), which was subsequently subjected to cleavage of the trityl group upon treatment with HBr in glacial AcOH. The resulting hydroxymethyl group was then oxidized by treatment with DM periodinane in DCM to afford the aldehyde 74 on a large scale (approx.…”

Section: Chiral-pool Starting Materials: Carbohydratesmentioning

confidence: 99%

Recent Advances in the Total Synthesis of Piperidine Azasugars

et al. 2005

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Since the discovery of nojirimycin, a glycosidase inhibitor, polyhydroxylated piperidines (also called azasugars: the ring O‐atom of a carbohydrate is replaced by nitrogen) have attracted considerable attention and have been the target of numerous synthetic strategies during the last decade. The efficient synthesis of naturally occurring azasugars and their analogs is of considerable importance due to their potential glycosidase inhibitor properties. Some of them have been widely investigated as candidates for drugs to treat a variety of carbohydrate‐mediated diseases such as diabetes, viral infections, including HIV, cancer metastasis, hepatitis, and Gaucher’s disease. This microreview focuses on recent syntheses of azasugars. In addition, the biology of these compounds is briefly considered. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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“…My co-worker, I. Sangster, converted the Reichstein intermediate of vitamin C synthesis, 2,3-0-isopropylidine-a-L-sorbofuranose, into a 6-amino-6-deoxy-Lsorbose [27]. He found that in concentrated hydrochloric acid solution this aminosugar formed an ammonium salt in which the sorbose is in the furanose form with oxygen in the ring.…”

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confidence: 99%

The Early Days of Monosaccharides Containing Nitrogen in the Ring

Paulsen

1998

Iminosugars as Glycosidase Inhibitors

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The history of the first synthesis of monosaccharides with nitrogen in the ring as well as the discovery of their very strong inhibitory effect on glycoside-cleaving glycosidases much later is a fascinating chapter in carbohydrate chemistry [1,2]. Early attempts to replace the oxygen in pyranoses or furanoses by another hetero atom were made with sulfur. In 1961, the laboratories of J. C. Schwarz [3] and L. W. Owen [4] as well as of R. L. Whistler [5] succeeded independently and simultaneously in synthesizing 5-thio-o-xylopyranose, which contains sulfur instead of oxygen in the ring. The chemical properties of these sulfur-containing saccharides were very similar to those of the oxygen analogs. This is not surprising, since sulfur is divalent and, like oxygen, found in the second main group of the periodic table. The sulfur-containing sugars showed mutarotation and could be converted into the corresponding glycosides. R. L. Whistler then studied this substance class in detail [2]. Apart from sulfur-containing six-membered rings, sulfur-containing five-membered rings and also the corresponding sulfur-containing nucleosides could be synthesized [6]. The thio compounds did show one peculiarity; the sulfur in the ring could be oxidized to sulfoxides and sulfones.At that time we were interested in finding out whether the ring oxygen of pyranoses could also be replaced by nitrogen. The reactions in this case were not predictable, because nitrogen is trivalent and also has basic properties. Aldimines were also possible cyclization products. We first synthesized 5,6-diacetamidol,2-0-cyclohexylidene-5,6-dideoxyhexofuranoses of the n-gluco-and L-idoform, since it could be expected that the 5 -aminosugars would give an appropriate ring closure with nitrogen. Deblocking of the compounds under the required acidic conditions yielded, however, the 2-aminomethyl-5-hydroxypyridine in both cases [7]. This result showed that although a saccharide with nitrogen in the ring had apparently been formed as the intermediate product, it had been converted into the pyridine derivative under the acidic conditions with elimination of three water molecules. With this result the race was on to isolate the nitrogen-containing saccharides that had so far only been identified as intermediate products.We were more successful with 5-acetamido-l,2-O-cyclohexylidene-5-deoxy-Dxylofuranose. It could be deblocked under milder acidic conditions and we were able to isolate the crystalline 5-acetamido-5-deoxy-o-xylopypranose in 1962 [8].Jniinosugfirs ns Glycosidase Inhibitors: Nojirimycin and Beyond. Edited by Arnold E. Stiitz

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Monosaccharide mit stickstoffhaltigem Ring, XIII. Synthese und Reaktionen von Keto‐piperidinosen

Cited by 121 publications

References 18 publications

Synthesis of Novel Di‐ and Trisaccharide Mimetics with Non‐Glycosidic Amino Bridges

Synthesis of Novel Di‐ and Trisaccharide Mimetics with Non‐Glycosidic Amino Bridges

Recent Advances in the Total Synthesis of Piperidine Azasugars

The Early Days of Monosaccharides Containing Nitrogen in the Ring

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