Methylation studies on various uracil derivatives and on an isomer of uridine isolated from ribonucleic acids

1. 1. Various uracil derivatives including uridine and the recently isolated isomer of uridine were methylated with dimethylsulfate and the course of the reaction followed by isolating chromatographically and characterizing spectrophotometrically the products which were formed after various time intervals. 2. 2. The methylation products of the isomer of uridine indicate that the 1, 2, 3 and 6 positions are not involved in glycosidic linkage and that the C-4 is much less likely than the C-5 to be the point of attachment of the sugar moiety, thus indicating that the isomer of uridine is 5-ribosyluracil.