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1.19 * 0.10, and not sensibly a function of acidity (0.05-1.00 N), showing that deuterons are favored over protons by 20 % inside the molecular cavity.The equilibrium and rate constants of the isomerization of the 17.7.71 and 18.8.81 ammonium ions are not influenced by the nature of the counterion; however, this is no longer so when the hydrocarbon chains contain nine or more methylenes due to a remarkable kind of ion pairing in the larger ammonium ions.* (4) C.

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While 2,3,5-tri-O-benzoyl-D-ribose shows little if any mutarotation in chloroform or aqueous dioxane, methylation studies and comparisons between its rotation and those of some closely related substances (both to be published in the near future) appear to justify the tentative conclusion that it belongs to the /3-D-series.Acetylation of 2,3,5-tri-O-benzoyl-D-ribose in pyridine at a low temperature afforded in 88% yield crystalline l-O-acetyl-2,3,5-tri-O-benzoyl-D-ribose [m.p. 130-131°( cor.); [ ]'20 +44.2°(CHCU)].Similarly, benzoylation at low temperature gave in 89% yield D-ribofuranose tetrabenzoate [m.p. 121-122°( cor.); [a]20D +17.0 (CHC1*)]; the same substance was also obtained through the benzoylation of D-ribose in pyridine at 100°although the yield in this case (11%) was low owing to the difficulty of separating the product from /3-D-ribopyranose tetrabenzoate which is formed simultaneously.2,3,5-Tri-O-benzoyl-D-ribose has been used for the synthesis of benzyl d-D-ribofuranpside tribenzoate;it is possible that it may prove of general utility for the synthesis of ribofuranosides.