On the Isolation from Tissues of certain Pentose Derivatives

Abstract

In the tissues of animals, both normal and after insulin convulsions, there is present a substance which can be estimated as furfural by distillation with acid but it does not give rise to reducing sugar on acid hydrolysis, however mild; other evidence is given of the unstable nature of the substance. Isolation was attempted after methylation with methyl sulphate and soda at an early stage after extraction, followed by repeated methylation with methyl iodide. A liquid was obtained, soluble in water and ether, boiling pt. 118-122[degree]C. at 13 mm. pressure. The values for C-, H- and OMe approximate to those required for a trimethyl methylpentoside. Reducing sugar of undetermined nature was liberated on hydrolysis. ([alpha])Hg. green =+17.6[degree]. A stable pentose derivative was regularly present in the extracts before methylation. This was obtained crystalline, in a yield of 2.5 mgm. per kgm. fresh tissue. M.P. 65-66[degree]C. ([alpha]) Hg. green = -108.8[degree]. The substance is soluble in water and alcohol, and d-ribose is liberated on acid hydrolysis; it is probably methyl or ethyl riboside. Reasons are given for believing that the compound is present as such in the tissues. Tests with arabinose showed no condensation with alcohol under the experimental conditions.