Vilsmeier-haack reactoin of glycals-a short route to C-2-formyl glycals☆
TL;DR: A short and straightforward route has been accomplished for the synthesis of C-2-formyl glycals by a Vilsmeier-Haack reaction of glycals.
About: This article is published in Tetrahedron Letters.The article was published on 1991-07-29. It has received 52 citations till now. The article focuses on the topics: Glycal.
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TL;DR: In this paper, β-enaminals were successfully synthesized in good to excellent yields by the reaction of C2-formyl glycals with primary amines, which led to unexpected reductive cleavage of allyl ether.
6 citations
TL;DR: Findings confirm that carbohydrate fused pyrano[3,2-c]pyranones are better candidates for anticancer activity.
Abstract: Pyrano[3,2-c]pyranone is an important structural motif present in many natural products exhibiting diverse biological activities. Two series of carbohydrate fused pyrano[3,2-c]pyranone derivatives (n = 20) were efficiently synthesized starting from 2-C-formyl galactal and 2-C-formyl glucal, reacting with various 4-hydroxycoumarins in a very short reaction time (10 min) under microwave assisted conditions. The anticancer activity of these synthesized pyrano[3,2-c]pyranones was determined in detail through cellular assays against MCF-7 (breast), MDA-MB-231 (breast) and HepG2 (liver) cancer cell lines. The newly synthesized pyrano[3,2-c]pyranones were screened for their cell-viability and anti-proliferative activity against MCF-7, MDA-MB-231 and HepG2 cell lines. Compounds 12, 13 and 14 exhibited high growth inhibitory potencies selectively against MCF-7 cells with half-maximal inhibitory concentration (IC50) values of 19.9, 14.5 and 10.9 μM respectively. Compounds 12, 13, 14, 15 and 19 inhibited the growth of MDA-MB-231 cells (breast) by 43, 44, 37, 31 and 45% respectively. However, no inhibitory effect was observed for these compounds in the human liver cancer cell line (HepG2) and normal cell lines (HEK293, human embryonic kidney cells). Mechanistic studies showed that these compounds alter the cell morphology and cause G2/M arrest in MCF-7. Further studies showed that compounds 12, 13 and 14 significantly inhibited cell migration which was accompanied by altered microtubule distribution. An enhanced accumulation of these compounds in cells was observed as compared to the 4-hydroxycoumarins precursor in the intracellular uptake assay. These findings confirm that carbohydrate fused pyrano[3,2-c]pyranones are better candidates for anticancer activity.
5 citations
TL;DR: In this paper, reaction of 1,5-anhydro-2-deoxy-2,formyl-3,4,6-tri-O-methyl-D-lyxo-hex-1-enitol with various nucleophiles under Lewis acid catalysis led to stereoselective C-3 substitution.
Abstract: Reaction of 1,5-anhydro-2-deoxy-2-formyl-3,4,6-tri-O-methyl-D-lyxo-hex-1-enitol 1 and its arabino epimer 3 with various nucleophiles under Lewis acid catalysis led to stereoselective C-3 substitution.
5 citations
27 Oct 2017
5 citations
TL;DR: 2-Deoxy-2-C-alkyl glycal derivative is a suitable glycosyl donor to prepare 2-deoxy-1,5-anhydro-d-arabino-hex-1-enitol, mediated through haloglycosylation and a subsequent dehalogenation.
Abstract: A method to convert 2-hydroxy glycol ester to the corresponding corresponding 2-deoxy-2-C-alkyl glycol in a facile manner, through key reactions including (i) C-allylation at C-1, (ii) Wittig reaction, and (iii) Cope rearrangement of a 1,5-diene derivative, is reported. The alpha-anomer of the 1,5-diene derivative underwent Cope rearrangement to afford 2-deoxy-2-C-glycal derivative, whereas the beta-anomer was found to be unreactive. Employing this sequence, was transformed to 3,4,6-tri-O-benzyl-2-deoxy-2-C-alkyl-1,5-anhydro-D-arabino-hex-1-enitol. 2-Deoxy-2-C-alkyl glycol derivative is a suitable glycosyl donor to prepare 2-deoxy-2-C-alkyl glycosides, mediated through haloglycosylation and a subsequent dehalogenation. A number of 2-deoxy-2-C-alkyl glycosides, with both glycosyl and nonglycosyl moieties at the reducing end, are thus prepared from the glycol.
4 citations
References
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146 citations
TL;DR: The Tetrasaccharid Lycotetraose, das im Tomatin with Tomatidin verknupft ist, lies sich strukturell aufklaren, indem 1. Tomatin, 2. Glykosid (β 1-Tomatin) and 3. das xylosefreie Trisaccharide Triscarid (Lycotriose), letzteres nach katalytischer Hydrierung zum Lycotriit, with Methyljodid and Silber
Abstract: Das Tetrasaccharid Lycotetraose, das im Tomatin mit Tomatidin verknupft ist, lies sich strukturell aufklaren, indem 1. Tomatin, 2. das daraus durch Abspaltung von D-Xylose gewonnene Glykosid (β1-Tomatin) und 3. das xylosefreie Trisaccharid (Lycotriose), letzteres nach katalytischer Hydrierung zum Lycotriit, mit Methyljodid und Silberoxyd in Dimethylformamid permethyliert wurden. Aus den Spaltstucken der permethylierten Verbindungen, die kristallisiert erhalten wurden, ergibt sich fur die Lycotetraose die verzweigte Konstitution einer β-D-Glucopyranosyl(1 2Glucose)-β-D-xylopyranosyl(1 3Glucose)-β-D-glucopyranosyl(1 4Galaktose)-α-D-galaktopyranose und damit fur das Tomatin die Formel I. Auch aus Demissin last sich, unter Abspaltung von D-Xylose und des Aglykons, kristallisierte Lycotriose gewinnen.
110 citations
TL;DR: Three fluoro-substituted unsaturated sugars have been synthesized by transformations within the D-glucal and ethyl 2,3-dideoxy-α-D-erythro-hex-2-enopyranoside series.
Abstract: Three fluoro-substituted unsaturated sugars have been synthesized by transformations within the D-glucal and ethyl 2,3-dideoxy-α-D-erythro-hex-2-enopyranoside series. A number of the intermediate unsaturated sugars not previously described have been characterized. The advantages of the t-butyldimethylsilyl blocking group in such syntheses are described.
71 citations
TL;DR: The palladium-catalyzed couplings of the protected 1-(tributylstannyl)-D-glucal 1 and substituted aryl bromides provide the corresponding C-arylglucals and a dimer as mentioned in this paper.
Abstract: The palladium-catalyzed couplings of the protected 1-(tributylstannyl)-D-glucal 1 and substituted aryl bromides provide the corresponding C-arylglucals and a dimer
70 citations
TL;DR: In this article, it was shown that triacetyl glucal can be converted to 6-O-triphenylmethyl ether or 6 O-benzoyl ester to promote solubility in chloroform, and the derivatives are oxidized in that solvent in 12 h or less.
Abstract: Whereas the pseudo-axial 3-hydroxyl group of allal derivatives is known to be inert to manganese dioxide oxidation, the equatorial counterpart in glucal derivatives is shown to be readily oxidized. Thus glucal is converted to the 6-O-triphenylmethyl ether or 6-O-benzoyl ester to promote solubility in chloroform, and the derivatives are oxidized in that solvent in 12 h or less.Acetonation of glucal is readily accomplished in 45 min using 2,2-dimethoxypropane and p-toluenesulfonic acid in dimethylformamide; the product may be oxidized directly either with manganese dioxide or dipyridine chromium oxide. Thus it is possible to obtain 1–3-g quantities of the crystalline acetonated enone from triacetyl glucal (via deacetylation, acetonation, and oxidation) in 3–4 h.If the acetonation medium stands for 2 h methyl 2,3-dideoxy-4,6-O-isopropylidene-α-D-erythro-hex-2-enopyranoside is obtained. The mechanism of its formation in the reaction medium is discussed.
64 citations