SYNTHESIS OF 7-METHYL-3-BETA-D-RIBOFURANOSYLWYE, THE PUTATIVE STRUCTURE FOR THE HYPERMODIFIED NUCLEOSIDE ISOLATED FROM ARCHAEBACTERIAL TRANSFER-RIBONUCLEIC-ACIDS

The Vilsmeier-Haack reaction of 3-(2,3,5-tri-0-acetyl-/f-D-ribofuranosyl)wye (7c) followed successively by reduction with sodium borohydride and catalytic hydrogenolysis afforded the 7-methyl derivative 12c, which provided the title compound 12a on deprotection. Compound 12c was more effectively produced by direct hydrogenolysis of the 7-formyl derivative 8c, especially by use of Pearlman’s catalyst. Similar treatment of l-benzyl-7-formylwye (14) led to a better synthesis of 7-methylwye (lb), the fluorescent base isolated from Archaebacterial transfer ribonucleic acids. Although hydrogenolysis of the 6-formyl compound 11 took place smoothly even over ordinary palladium on charcoal to afford 12c, this route had a bottleneck in the step of transformation of 8c into 11. Compound 12a proved to be highly sensitive to acidic hydrolysis at the glycosyl bond and the rate determined in 0.1 n hydrochloric acid at 25 °C was virtually the same as that of 3-/M>ribofuranosylwye (7a). © 1990, The Pharmaceutical Society of Japan. All rights reserved.