XXIX. Part of a letter from Matthew Guthrie, M. D. of Petersburgh, to Dr. Priestley, F. R. S. on the antiseptic regimen of the natives of Russia

doi:10.1098/rstl.1778.0030

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“…The title compound was prepared according to Guthrie & Smith (1968). Both base-and acid-catalysed acetylation gave the same product; colourless, 8-9 mm long, 2-3 mm thick columns were crystallized from ethanol (m.p.…”

Section: Methodsmentioning

confidence: 99%

Structure of the unstable monoclinic 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose

Czugler¹,

Kàlmán²,

Kovács³

et al. 1981

Acta Crystallogr Sect B

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The unstable A form of 1,2,3,5-tetra-O-acetyl-fl-Dribofuranose, C13H1809 (m.p. = 330-331 K), crystallizes in the monoclinic system, a = 12.649 (2), b = 5.582 (2), c = 11.078(2) A,/3 = 97.92(1) °, space group P2~, Z = 2, D e = 1.364 Mg m -3. Final R = 0.045 for 1142 reflexions. To shed light on the spontaneous and irreversible transition of form A into * Dedicated to Professor Geza Schay (first director of CRIC) on his 80th birthday. the stable orthorhombic form B (m.p. 358 K) the present structure determination of A is compared with that of B reported by James & Stevens [Cryst. Struct. Commun. (1973), 2, 609-612] and Poppleton ]Acta Cryst. (1976), B32, 2702-2705]. Neither the bonding of the molecules nor the puckering of the furanose rings reveals significant differences. However, two of the four acetyl moieties exhibit torsional parameters [C(4) IntroductionThe structural dimorphism of 1,2,3,5-tetra-O-acetylfl-D-ribofuranose (I) was discovered when Zinner (1950) found that the title compound, obtained by direct acetylation of D-ribose, showed a considerably higher melting point (355 K) than had been found by Howard, Lythgoe & Todd (1947) and Bredereck & Hoepfner (1948) (331 and 329 K, respectively). Davoll, Brown & Visser (1952) also prepared crystals which melted in the range 329-331 K, but repetition of the procedure described by Bredereck & Hoepfner (1948) yielded a sample melting at 358 K. The identical molecular structure of the higher-melting crystals (hereafter B) with that of the lower-melting product (hereafter A) was proved by preparative methods. When crystals of A were exposed to the air in a laboratory inoculated with B their melting points rose to 358 K while the crystals rapidly became opaque and A could not be prepared thereafter. Their structural dimorphism was suggested by Farrar (1952) who pointed out that both forms exhibit the same specific rotation in chloroform. Patterson & Groshens (1954), who determined the lattice parameters and space group of both crystals (A: monoclinic P2~, Z = 2, B: orthorhombic P2~2121, Z = 4), corroborated Farrar's conclusions. They also observed rapid and irreversible phase transformations of A into B catalysed by the presence of B crystals. Since then, no comparative structural studies of A and B have been reported, presumably because of fruitless attempts to prepare the unstable A (Poppleton, 1976). Accordingly, the crystal structure of B could only be determined to date (James & Stevens, 1973;Poppleton, 1976). IAcO OAcRecently, whilst preparing ribofuranosyl derivatives, we have synthesized the title compound and obtained crystals which melt at 331 K. Its optical rotation in chloroform was identical to that of the higher melting B. Since we have invariably grown A in several experiments it seemed worthwhile to determine its crystal structure by X-ray diffraction and compare it with that of B. ExperimentalThe title compound was prepared according to Guthrie & Smith (1968). Both base-and acid-catalysed acetylation gave the same product; colourless, ...

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Section: Methodsmentioning

confidence: 99%

Structure of the unstable monoclinic 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose

Czugler¹,

Kàlmán²,

Kovács³

et al. 1981

Acta Crystallogr Sect B

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“…80-83°C [ref. [30] 81-83°C]. 3 mmol) in Ac 2 O (15 mL) 1,2,3,5-tetra-O-acetyl-β--ribofuranose (5) (6.0 g, 18.9 mmol) was added.…”

Section: 235-tetra-o-acetyl-β-l-ribofuranose (4)mentioning

confidence: 99%

Reaction Kinetics and Mechanism of Sulfuric Acid‐Catalyzed Acetolysis of Acylated Methyl L‐Ribofuranosides

et al. 2009

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The mechanism of the sulfuric acid‐catalyzed acetolysis of methyl 2,3,5‐tri‐O‐acetyl‐ and methyl 2,3,5‐tri‐O‐benzoyl‐L‐ribofuranosides and the accompanying anomerization of both the starting material and the 1,2,3,5‐tetra‐O‐acetyl‐ and 1‐O‐acetyl‐2,3,5‐tri‐O‐benzoyl‐L‐ribofuranoses formed was investigated. The progress of the reactions was followed by 1H NMR spectroscopy and the rate constants for the reactions were determined for a proposed kinetic model. The role of H+ and Ac+ as the catalytically active species was clarified, proving that the anomerization of the acylated methyl furanosides is activated by protonation, while, on the contrary, the anomerization of the 1‐O‐acetyl ribofuranoses is activated by the acetyl cation. The anomerization of the acylated methyl furanosides was verified to be activated on the ring oxygen leading to endocyclic CO‐bond rupture while the 1‐O‐acetyl ribofuranoses are activated on the acetyloxy group on C(1) leading to exocyclic cleavage.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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“…On the other hand in the present work with an "epimerizing mixture", acetolysis of the isopropylidene derivative of the same heptose yielded the ido isomer as the major product. A preparation of 1,2,3,5-tetra-0-acetyl-P-D-ribofuranose by acetolysis of a methyl ribofuranoside mixture has been described (14). In one variation -, the ratio of acetic acid to acetic anhydride was 1.5 to 2 while in the other it was 30 to 7.…”

Section: Introductionmentioning

confidence: 99%

“…I ) An observation relating to furanoses is that acetolysis of the 1,2-0-isopropylidene derivatives of D -g l u~~f u r a n~~e triacetate and D-xylofuranose diacetate leaves the sugars in the furanose form with little or no conversion to pyranose acetate taking place ( I , 13). A recent synthesis of 1,2,3,5-tetra-0-acetyl-P-D-ribofuranose from methyl D-ribofuranoside takes advantage of the stability of the acetylated furanose structure in an acetolysis medium (14). It appeared possible that if free sugars were dissolved in an acetolyzing medium, tautomerization might occur with the formation of relatively large amounts of furanoses.…”

Section: Introductionmentioning

confidence: 99%

Epimerization of Monosaccharides Under Acetolysis Conditions

Sowa¹

1971

Can. J. Chem.

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Monosaccharides with a cis-configuration at C-2 and -3 readily undergo inversion at C-2 in an acetolysis medium composed of acetic acid, acetic anhydride, and sulfuric acid. The acetolysis-inversion reaction has been carried out with 2,3;5,6-di-0-isopropylidene-D-gulofuranose, 2,3;6,7-di-0-isopropylidene-D-glycero-D-gulo-heptose, 2,3-0-isopropylidene-D-ribose, D-ribose, and D-mannose using chromatography for isolation of the deacetylated epimeric products. The reaction requires a medium with a high concentration of acetic acid (ca. 90%) and appears to take place only with furanose structures. Inversions observed with the unsubstituted pyranoses D-ribose and D-mannose probably occur because of tautomerization to furanose forms. The epimerization proceeds in the direction which yields a smaller number of cis-oriented groups at C-2, -3, and -4 of the furanose forms of monosaccharides.

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XXIX. Part of a letter from Matthew Guthrie, M. D. of Petersburgh, to Dr. Priestley, F. R. S. on the antiseptic regimen of the natives of Russia

Cited by 3 publications

References 0 publications

Structure of the unstable monoclinic 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose

Structure of the unstable monoclinic 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose

Reaction Kinetics and Mechanism of Sulfuric Acid‐Catalyzed Acetolysis of Acylated Methyl L‐Ribofuranosides

Epimerization of Monosaccharides Under Acetolysis Conditions

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