| abstract |
Compounds of the formula ##STR1## wherein R is a phenyl or cyclohexyl group which may be substituted by halogen, lower alkyl or lower alkoxy, or their acid addition salts, are produced in good yield by reacting a compound of the formula ##STR2## wherein R 1 , R 2 and R 3 , independently of each other, are a hydroxyl group which may be proctected, which is prepared in 2 or 3 steps from 5-amino-1-β-D-ribofuranosylimidazole-4-carboxamide, with a compound of the formula n n R--N═C═N--R.sup.4 n n wherein R has the same meaning as defined above and R 4 is hydrogen or the same group as R, and, if necessary, subjecting the resulting compound to a treatment for removal of protective groups on its hydroxyl groups. |