145852-76-2

Upstream product

• 100-39-0 benzyl bromide 
• 2873-29-2 D-glucal triacetate 
• 13265-84-4 D-glucal 
• 791790-13-1 3-O-benzyl-4,6-O-p-methoxybenzylidene-D-glucal 
• 356067-96-4 1,5-anhydro-3-O-benzyl-2-deoxy-4-O-(4-methoxybenzyl)-D-arabinohex-1-enitol 
• 913258-73-8 (2R,3S,4R)-4-Benzyloxy-2-benzyloxymethyl-3-(4-methoxy-benzyloxy)-3,4-dihydro-2H-pyran 
• 312623-79-3 (4aR,8R,8aS)-2-(4-methoxyphenyl)-4,4a,8,8a-tetrahydropyrano[3,2-d][1,3]dioxin-8-ol 

Downstream Products

• 163228-32-8 (3aS,4R,6S,7R,7aR)-6-((2R,3S,4R)-4-Benzyloxy-2-benzyloxymethyl-3,4-dihydro-2H-pyran-3-yloxy)-7-hydroxy-4-triisopropylsilanyloxymethyl-tetrahydro-[1,3]dioxolo[4,5-c]pyran-2-one 
• 165524-87-8 4-O-acetyl-1,5-anhydro-3,6-di-O-benzyl-2-deoxy-D-arabino-hex-1-enitol 
• 162128-74-7 (3aS,4R,6S,7R,7aS)-6-((2R,3S,4R)-4-Benzyloxy-2-benzyloxymethyl-3,4-dihydro-2H-pyran-3-yloxy)-4-triisopropylsilanyloxymethyl-7-((2S,3S,4R,5R,6S)-3,4,5-tris-benzyloxy-6-methyl-tetrahydro-pyran-2-yloxy)-tetrahydro-[1,3]dioxolo[4,5-c]pyran-2-one 
• 1279711-36-2 3,6-di-O-benzyl-4-deoxy-D-glucal 
• 1279711-53-3 methyl 3,6-di-O-benzyl-4-deoxy-1R-D-galactopyranose 
• 1279711-67-9 C₂₀H₂₂O₄ 
• 895140-72-4 (2R,3S,4R)-4-Benzyloxy-2-benzyloxymethyl-3-[(2S,3R,4S,5S,6R)-4,5-bis-benzyloxy-6-benzyloxymethyl-3-((2S,3S,4R,5R,6S)-3,4,5-tris-benzyloxy-6-methyl-tetrahydro-pyran-2-yloxy)-tetrahydro-pyran-2-yloxy]-3,4-dihydro-2H-pyran 
• 385421-81-8 n-pentenyl 4,6-di-O-benzyl-3-O-levulinyl-2-O-pivaloyl-β-D-galactopyranosyl-(1->4)-3,6-di-O-benzyl-2-O-pivaloyl-β-D-glucopyranoside 
• 385421-82-9 n-pentenyl 4,6-di-O-benzyl-2-O-pivaloyl-β-D-galactopyranosyl-(1->4)-3,6-di-O-benzyl-2-O-pivaloyl-β-D-glucopyranoside 
• 385421-76-1 dibutyl 3,6-di-O-benzyl-4-O-levulinyl-2-O-pivaloyl-β-D-glucopyranosyl phosphate 
• 253683-26-0 dibutyl 4-O-tert-butyldimethylsilyl-3,6-di-O-benzyl-2-O-pivaloyl-β-D-glucopyranoside phosphate 

Relevant academic research and scientific papers

Microwave-assisted regioselective benzylation: An access to glycal derivatives with a free hydroxyl group at C4

D-glucal, D-galactal, and their 6-O-TBDMS derivatives were benzylated in a two-step procedure under microwave conditions. In the first step glycals were converted into dibutylstannylene acetal or tributyltin ether intermediates, which were next alkylated with benzyl bromide in the presence of Bu 4NBr. In all cases the 4-OH group stayed unsubstituted. Microwave-assisted benzylation contributes to a significant reduction of the reaction time in comparison with the classical synthesis, which requires several hours of heating. Supplemental materials are available for this article. Go to the publisher's online edition of Journal of Carbohydrate Chemistry to view the free supplemental file.

Stereoelectronic factors in the stereoselective epoxidation of glycals and 4-deoxypentenosides

Glycals and 4-deoxypentenosides (4-DPs), unsaturated pyranosides with similar structures and reactivity profiles, can exhibit a high degree of stereoselectivity upon epoxidation with dimethyldioxirane (DMDO). In most cases, the glycals and their corresponding 4-DP isosteres share the same facioselectivity, implying that the pyran substituents are largely responsible for the stereodirecting effect. Fully substituted dihydropyrans are subject to a "majority rule", in which the epoxidation is directed toward the face opposite to two of the three groups. Removing one of the substituents has a variable effect on the epoxidation outcome, depending on its position and also on the relative stereochemistry of the remaining two groups. Overall, we observe that the greatest loss in facioselectivity for glycals and 4-DPs is caused by removal of the C3 oxygen, followed by the C5/anomeric substituent, and least of all by the C4/C2 oxygen. DFT calculations based on polarized-π frontier molecular orbital (PPFMO) theory support a stereoelectronic role for the oxygen substituents in 4-DP facioselectivity, but less clearly so in the case of glycals. We conclude that the anomeric oxygen in 4-DPs contributes toward a stereoelectronic bias in facioselectivity whereas the C5 alkoxymethyl in glycals imparts a steric bias, which at times can compete with the stereodirecting effects from the other oxygen substituents.

Glycal glycosylation and 2-nitroglycal concatenation, a powerful combination for mucin core structure synthesis

(Chemical Equation Presented) A 3,4-O-unprotected galactal derivative having bulky 6-O-TIPS protection (compound 2) could be regioselectively 3-O-glycosylated with O-(galactopyranosyl) trichloroacetimidates; depending on the protecting group pattern stere

Conversion of D-Glucals into L-Glycals and Mirror-Image Carbohydrates

(Equation presented) L-Glycals can be prepared in seven steps from readily available D-glucals, enabling the facile construction of mirror-image carbohydrates such as the L-lactosamine derivative shown above.

Design, synthesis and biological activity of carbohydrate-containing peptidomimetics as new ligands for the human tachykinin NK-2 receptor

Enantiopure cycloadducts between glycals and alkyl or aryl heterodienes were selected as small, rigid, nonpeptide molecules able to superimpose to the structure of the cyclopeptide tachykinin NK-2 antagonist 1. The presence of three aromatic groups in the pyranose ring resulted essential for NK-2 affinity, while an increase in activity was shown by the corresponding sulfoxides.

Novel Bicylic Donors for the Synthesis of 2-Deoxy-β-Glycosides

Novel bicyclic glycosyl donors have been prepared by the cycloaddition reaction of glycals with 3-thiono-2,4-pentanedione 17 followed by methylenation of the resulting ketone. Treatment of the heterocyclic donors with triflic acid in the presence of a variety of alcohol acceptors leads to the formation of β-glycosides in good yields and with excellent stereoselectivities. Desulfurization of the C-2 carbon-sulfur bonds gives the corresponding 2-deoxy-β-glycosides. This method has been extended to the synthesis of glycosidic linkages found in the aureolic acid antibiotics. Tetra-N-butylammonium triflate proved to be a useful additive in these glycosylation reactions, suggesting an important role for triflate anion in stabilizing intermediates which are formed.

Novel Heterocycloaddition Reaction of Glycals

Diacyl thione species 1 has been generated and reacted in situ with both pyranoid and furanoid glycals to form novel [4 + 2] cycloadducts. Factors such as protecting groups and configuration of substituents in the glycals along with medium effects were varied to discover influences on face selectivity and reactivity. A qualitative correlation of reactivity with the HOMO-LUMO gap between the glycal (HOMO) and the heterodienic species (LUMO) is observed. In one example, the isolation of byproducts suggests that the cycloaddition may in fact be stepwise.

Synthesis of Asialo GM1. New insights in the application of sulfonamidoglycosylation in oligosaccharide assembly: Subtle proximity effects in the stereochemical governance of glycosidation

The total synthesis of asialo GM1 (1a) has been accomplished. Using related chemistry, the methyl glycoside of the asialo compound (1b) has also been synthesized. These kinds of compounds have been identified as potential ligands for bacterial and viral infection sites. A simpler structure, which has also been identified for its infection attracting structure in the context of glycopeptides and glycolipids (methyl glycoside 2), has also been synthesized. The key common phase in the syntheses involves the sulfonamidoglycosidation reaction which is used to create a β-linkage leading to a ga1NAc residue joined to the C4 hydroxyl group of a galactose unit either as a monosaccharide (see compound 2) or as C4' in the context of a lactosyl moiety. During the course of these studies there was encountered an unusual 'proximal hydroxyl' directing effect. Thus, when C4 on the galactose ring of an azaglycosylating donor bears a free hydroxyl (see, for instance, compound 13), β-glycoside formation predominates. When this hydroxyl group is blocked, the process tends in the direction of α-glycoside formation (see compound 32). These findings were explained as arising from a critical intramolecular hydrogen bond between the C4 axial hydroxyl of the galactose donor and its proximal pyranosidal ring oxygen. This interaction stabilizes conformations from which β-glycosidation predominates.

Microbial biotransformations of a synthetic immunomodulating agent, HR325

The microbial biotransformation of HR325 [2-cyano-3-cyclopropyl-3-hydroxy-N-(4'-trifluoromethyl-3' -methylphenyl)propenamide], a synthetic immunomodulating agent, has been investigated in order to be compared with animal metabolism and to prepare some metabolites which are difficult to obtain by chemical methods. Several fungal strains are able to completely metabolize this drug. Mortierella isabellina NRRL 1757 only achieves a benzylic hydroxylation on the aromatic methyl group, affording in high yield the corresponding hydroxymethyl derivative. In addition, other strains, such as Cunninghamella elegans ATCC 26269 or Beauveria bassiana ATCC 7159 can cleave both cyclopropyl and cyano groups in a new unknown oxidative biochemical reaction, which can be mimicked by m-chloroperbenzoate oxidation. The resulting cyanohydrin is hydrolyzed and reduced to a primary alcohol. In B. bassiana, the final incubation product is a β-4-O-methylglucoside derivative of this alcohol, and has been fully characterized by independent synthesis. The different metabolic patterns of HR325 in the three fungal strains are discussed, and a mechanistic hypothesis about the oxidative cleavage of the right part of the molecule is proposed. The production of microbial metabolites is compared to animal metabolism in terms of structure and efficiency.

Total synthesis and proof of structure of a human breast tumor (globo-H) antigen

The total synthesis of the Hakomori MBr1 antigen, heavily expressed on human breast tumors, is related. The construction involved the assembly of four glycals: (17 (twice), 18, 20, and 26) and an L-fucose derivative, 34. The sensitivity of the stereochemi