Synthesis of 5-Thiomethylribose

Abstract

THERE has been isolated from yeast¹, crude oryzanine² and impure cozymase³ an unusual nucleoside which on acid hydrolysis yields adenine and a thiomethyl-sugar. Falconer and Gulland⁴ claim to have demonstrated that the thiomethyl-sugar and adenine are combined at the 9-position of the base. The thiomethyl-sugar has been the subject of several investigations; thus Suzuki et al.^2,5 and Levene and Sobotka⁶ have shown that the thiomethyl group is retained during osazone formation, thereby excluding positions 1 and 2 of the sugar as the sites where it is combined. The thiomethyl-sugar could be readily reduced to a thiomethylpentitol, which on oxidation with lead tetra-acetate yielded 0.9 mol. of formaldehyde⁷, indicating that position 3 in the sugar cannot be the combining position of the thiomethyl group. Satoh and Makino⁸ adduced further evidence which excluded also the C₄ of the pentose as the site of the thiomethyl substituent. Previously, Wendt⁷, using titration data obtained by the Willstätter–Schüdel method, had shown that the thiomethyl-sugar obtained by acidic hydrolysis of the nucleoside was an aldose. Hence all the available evidence indicated that the derivative was a 5-thiomethylpentose.