Two benzylated hydroxyglycals derived from d-fructofuranose

Zissis, Emmanuel; Ness, Robert K.; Fletcher, Hewitt G.

doi:10.1016/s0008-6215(00)84943-5

Cited by 6 publications

(4 citation statements)

References 12 publications

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“…0.14 k J m ~l -~. ~~a In the cases of the exocyclic alkenes (3), (5), (7), and (9), Jr,2 values in the range 3-5 Hz again indicate the significance of the conformation (V4) with all the ring ester substituent groups axial; that is, with favourable anomeric effects. I n solution, tetra-0-acetyl-and -benzoyl-p-n-xylopyranose, which are related to these alkenes by loss of C-6, oscillate rapidly between both chair conformations,m the ' all axial ' lC, form representing roughly one-third and one-half of the equilibria, respectively, at room temperature (Jl,z 6.7 and 5.1 Hz, respectively, acetone solution).…”

Section: F02me C02mementioning

confidence: 97%

“…by substitution of the acyloxy-groups at that position, and the other vinylic carbon atotn (C-5) and C-6 were shielded by 7 and 5 p.p.m., respectively. Introduction of the 5,B-double bond to the pentaesters [compounds (3), ( F ) , (7), and (9)] caused only small changes for the resonances for C-l-C-4 which, with minor exceptions, were shielded relative to those resonances for yenta-0-acetyl-and -benzoyl-pn-glucose. Tliis is again consistent with a disturbance of the equilibria involving both chair conformations in favour of the lC, forms.…”

Section: F02me C02mementioning

confidence: 99%

“…Evaporation of the solvent from the extracts gave a light coloured oil ( View Article Online C,,H,,O,, requires C, 49.5; H, 5.2%); 6 2.08-2.16 (15 H, 5Ac),4.61 (2H,s,H-6and-6'),5.12(1H,t, J l , 2 = J 2 . 3 = 3 Hz, H-2), 5.46 (1 H, dd, J1,3 1 Hz, H-3), and 6.20 (1 H , dd, 1,2,3,4-Tetra-O-benzoyl-6-deoxy-P-~-xylo-hex-5-enopyvnnose (7).-Aqueous copper(r1) sulphate (0.6 g in 5 ml) and zinc dust (9 g) were added to a solution of sodium acetate (12 g) in aqueous acetic acid (60 nil, 1 : 1). A solution of penta-O-benzoyl-5-bromo-~-~-glucopyranose (2) (6 g) in acetone (350 ml) was then slowly added and the mixture was stirred at room temperature for 48 h. The solids and most of the organic solvents were removed and the aqueous system was extracted with chloroform ( x 3).…”

Section: F02me C02mementioning

confidence: 99%

“…22 Introduction of the exocyclic metliylene group apparently favours the lC, conformation because the coupling constants are reduced to ca. 5 Hz for the acetates (3) and ( 5) and 3-4 Hz for the benzoates (7) and (9), suggesting that for the former the equilibria contain ca. 50% of each chair, and for the latter the ' all-axial ' form dominates by ca.…”

Section: F02me C02mementioning

confidence: 99%

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Unsaturated carbohydrates. Part 22. Alkenes from 5-bromohexopyranose derivatives

Blattner¹,

Ferrier²,

Tyler³

1980

J. Chem. Soc., Perkin Trans. 1

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Base-catalysed elimination of hydrogen bromide from 5-bromo-P-D-glucopyranose penta-acetate and pentabenzoate gives predominantly the endocyclic products, whereas treatment with zinc-acetic acid affords a means of obtaining the exocyclic 6-deoxy-5-enose esters. All eight alkenes obtainable from these two bromo-compounds are reported together with their 'H and 13C n.m.r. spectra. Unsaturated compounds derived from penta-0benzoyl-5-bromo-a-D-glucopyranose and acetylated 5-bromouronates are also reported. The conformations of all the alkenes are discussed and,-in one case, the influences of the anomeric and allylic effects can be compared.

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Section: F02me C02mementioning

confidence: 97%

Section: F02me C02mementioning

confidence: 99%

Section: F02me C02mementioning

confidence: 99%

Section: F02me C02mementioning

confidence: 99%

See 2 more Smart Citations

Unsaturated carbohydrates. Part 22. Alkenes from 5-bromohexopyranose derivatives

Blattner¹,

Ferrier²,

Tyler³

1980

J. Chem. Soc., Perkin Trans. 1

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Darstellung ungesättigter Kohlenhydrate durch Esterpyrolyse, IV. Thermische cis‐Eliminierungen aus vollständig acetylierten Aldo‐ und Ketofuranosen

et al. 1982

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Die thermische cis-Eliminierung der anomeren Acetylgruppe in vollstlndig acetylierten Furanosen bleibt nicht auf der Stufe des Hydroxyglycals stehen, sondern fiihrt unter Eliminierung eines weiteren Molekiils Essigsaure zu substituierten Furanen. So liefern b-o-Ribofuranosetetraacetat 1 und PD-Galactofuranosepentaacetat 3 die Furane 2 bzw. 4. Auch a-D-Fructofuranosepentaacetat 5 ergibt den Furanabkommling 6. Daneben werden jedoch die E-und 2-Isomeren 7 und 8 mit exocyclischer Doppelbindung gebildet. Weitere Umlagerung dieser Produkte wird nicht beobachtet. Preparation of IJnssturated Carbohydrates by Ester Pyrolysis, IV l). -Thermal cis Eliminations from Completely Acetylated Aldo-and KetofuranosesThermal cis elimination of the anomeric acetyl group in completely acetylated furanoses does not yield the expected hydroxyglycals but gives by further elimination of another molecule of acetic acid substituted furans. Thus, b-D-ribofuranose tetraacetate 1 and P-D-galactofuranose pentaacetate 3 give the furans 2 or 4, respectively. a-D-Fructofuranose pentaacetate 5 equally yields the furan derivative 6. But in this case the E and 2 isomers 7 and 8 with exocyclic double bond are also formed. Further rearrangement of these products is not observed.In den vorangehenden Arbeiten ' v 2 ) konnten wir zeigen, dal3 vollstandig acetylierte Aldo-und Ketopyranosen thermisch selektiv die anomere Acetylgruppe unter Bildung einfach ungesattigter Verbindungen eliminieren. Voraussetzung hierfur ist ein a-H-Atom in cis-koplanarer Anordnung zur Acetoxygruppe, um die notwendige Geometrie des Ubergangszustandes der Eliminierung zu ermdglichen3). Es wurden daher auch Furanosederivate entsprechender Struktur der Pyrolyse in der von uns entwickelten Hochdruck-Hochtemperatur-Str~mungsapparatur4~ unterworfen. Uber diese Untersuchungen, deren Ergebnisse zum Teil von den bisher erhaltenen abweichen, wird im folgenden berichtet .Pyrolyse der 1 ,2,3,5-Tetra-O-acetyl-~-D-ribofuranose5) (1) und der 1,2,3,5,6-Penta-U-acetyl-~-D-galactofuranose (3)Wird das Tetraacetat 1 in Iproz. Ldsung in Aceton bei einer Temperatur von 340°C und einer Verweilzeit von 0.8 min durch den Reaktor4) gepumpt, so wird neben der Ausgangssubstanz lediglich eine weitere Verbindung beobachtet. Diese kann in uber

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Synthesis of (3S, 4S)- and (3S, 4R)-4-Amino-3-hydroxy-6-methylheptanoic Acid, and Their N-(Acetyl-l-valyl-l-valyl) Derivatives

Kinoshita¹,

Hagiwara²,

Aburaki³

1975

Bulletin of the Chemical Society of Japan

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Natural (−)(3S,4S)-4-amino-3-hydroxy-6-inethylheptanoic acid (10a) present in pepstatins, specific inhibitors of acid proteases, and its (+) (3S,4R) diastereomer (10b) were synthesized starting from 3-deoxy-1,2-O-isopropylidene-α-d-erythro-pentodialdo-1,4-furanose (1) through highly stereoselective and stereospecific routes. The partial pep tide of pepstatin Ac, N-(acetyl-l-valyl-l-valyl)-(3S,4S)-4-amino-3-hydroxy-6-methylheptanoic acid (15a) and its (3S,4R) diastereomer (15b) were synthesized via azide-coupling of the t-butyl esters of 10a and 10b with acetyl-l-valyl-l-valine azide, respectively. Compound 15a inhibited proteolysis by pepsin, however, the diastereomer 15b showed no inhibition against pepsin.

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Two benzylated hydroxyglycals derived from d-fructofuranose

Cited by 6 publications

References 12 publications

Unsaturated carbohydrates. Part 22. Alkenes from 5-bromohexopyranose derivatives

Unsaturated carbohydrates. Part 22. Alkenes from 5-bromohexopyranose derivatives

Darstellung ungesättigter Kohlenhydrate durch Esterpyrolyse, IV. Thermische cis‐Eliminierungen aus vollständig acetylierten Aldo‐ und Ketofuranosen

Synthesis of (3S, 4S)- and (3S, 4R)-4-Amino-3-hydroxy-6-methylheptanoic Acid, and Their N-(Acetyl-l-valyl-l-valyl) Derivatives

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