Improved double epimerisation of (D)-glucose into (D)-gulose and the synthesis of (D)-xylo-imidazolopiperidinose

Siendt, Hervé; Tschamber, Théophile; Streith, Jacques

doi:10.1016/s0040-4039(99)01003-5

Cited by 5 publications

(6 citation statements)

References 12 publications

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“…As outlined in Scheme , d ‐glucose was initially transformed into 1,2:5,6‐di‐ O ‐isopropylidene‐α‐ d ‐ ribo ‐hexofuranos‐3‐ulose ( 11 ) by a two‐step procedure consisting of the formation of 1,2:5,6‐di‐ O ‐isopropylidene‐ d ‐glucose, followed by oxidation of the unprotected hydroxy group with PDC (pyridinium dichromate) . Reaction of 3‐keto derivative 11 with acetic anhydride under basic conditions provided enol acetate 12 in 69 % yield . Subsequent cis ‐stereoselective hydrogenation of this compound gave gulose derivative 13 exclusively in 79 % yield .…”

Section: Resultsmentioning

confidence: 99%

Reversal of Stereoselectivity in Cycloadditions of Five‐Membered Cyclic Nitrones Derived from Hexoses

et al. 2017

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Two five‐membered cyclic nitrones derived from hexoses, a newly synthesized d‐allo‐configured nitrone and an already known d‐talo‐configured nitrone, have been examined in 1,3‐dipolar cycloaddition reactions with vinyl acetate, allyl benzoate, methyl acrylate, acrylonitrile, and vinylene carbonate. The reactions of the d‐allo‐configured nitrone proceeded preferentially through the expected exo‐anti transition state, but all the cycloadditions of the d‐talo‐configured nitrone surprisingly showed high exo‐syn selectivity. This reversal of stereoselectivity has been explained by 3D analysis of the preferred conformations of the nitrones, obtained from X‐ray data. The structures were further inspected using CONFLEX, PM5, and DFT calculations. All these methods revealed that the dioxolane substituents attached to C‐5 of both nitrones had opposite spatial locations.

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Section: Resultsmentioning

confidence: 99%

Reversal of Stereoselectivity in Cycloadditions of Five‐Membered Cyclic Nitrones Derived from Hexoses

et al. 2017

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“…16,17 We followed the literature procedure and obtained compound 3 starting from 1,2:5,6-di-O-isopropylidene-a-D-glucofuranose by inversion of configuration in the 3-position and followed by acetylation. 16,17 We followed the literature procedure and obtained compound 3 starting from 1,2:5,6-di-O-isopropylidene-a-D-glucofuranose by inversion of configuration in the 3-position and followed by acetylation.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of N-methyl-d-ribopyranuronamide nucleosides

2008

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a b s t r a c tThe synthesis of N-methyl-D-ribopyranuronamide nucleosides is described. The key route is the rearrangement of a 1,2-O-isopropylidene protected furanose sugar with a carboxamide function in the 4-position to a ribopyranuronamide ring. The Lewis acid catalyzed condensation of adenine and thymine nucleobases with the per-O-acetylated N-methyl-D-ribopyranuronamide sugar is used to give the target nucleosides as a mixture of the a and b anomers. The mixture was separated and the final compounds were obtained by deacetylation in basic conditions.

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“…In order to prepare a 2-unsubstituted imidazole, formamide must be employed, while the 1,3-bifunctional electrophiles could be represented by various haloketones [16][17][18] or hydroxyketones [20]. Sugar based hydroxyketones or hydroxyaldehydes and their application as suitable 1,3-bifunctional electrophiles are also well known [20][21].…”

Section: Resultsmentioning

confidence: 99%

“…The condensation may be enhanced by microwave irradiation [22] as well. Nevertheless, the most used method for imidazole ring construction involves a condensation of the α-bromoketones with formamidine in liquid ammonia [16][17][18][19][20][21].…”

Section: Resultsmentioning

confidence: 99%

Facile Synthesis of Optically Active Imidazole Derivatives

et al. 2007

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Five optically active imidazole derivatives have been synthesized via a facile 4-step reaction sequence starting from commercially available and inexpensive N-Cbz amino acids. While microwave assisted condensation was unsuccessful, the condensation of the corresponding α-bromoketones with formamidine acetate in liquid ammonia was revealed to be a useful method for the synthesis of such imidazole derivatives. The derivatives thus prepared are structurally-related to histamine.

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Improved double epimerisation of (D)-glucose into (D)-gulose and the synthesis of (D)-xylo-imidazolopiperidinose

Cited by 5 publications

References 12 publications

Reversal of Stereoselectivity in Cycloadditions of Five‐Membered Cyclic Nitrones Derived from Hexoses

Reversal of Stereoselectivity in Cycloadditions of Five‐Membered Cyclic Nitrones Derived from Hexoses

Synthesis of N-methyl-d-ribopyranuronamide nucleosides

Facile Synthesis of Optically Active Imidazole Derivatives

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