Synthesis and Biological Activities of C (5)‐N‐Spin‐Labeled Uridines and Related Derivatives

Abstract Direct introduction of a N‐atom in one step at C (5) of 5‐hydroxyuridine (4a) or 5‐hydroxy‐2′‐deoxyuridine (4b) by certain primary amines led to the synthesis of two novel C(5)‐N‐spin‐labeled nucleoside analogs and to several C(5)‐N‐aryl adducts. Substitution by 4‐amino‐2,2,6,6‐tetramethylpiperidinooxyl (3) at C(5) of 4a or 4b led to the spin‐labeled nucleosides 5‐[(1‐oxyl‐2,2,6,6‐tetramethyl‐4‐piperidinyl)amino]uridine and ‐2′‐deoxyuridine ( 2a and 2b , respectively). The analogous C(5)‐substituted aniline adducts 5‐anilino uridine (5a) and 5‐anilino‐2′‐deoxyuridine (5b) and the p ‐toluidine adducts 5‐( p ‐toluidino)uridine (6a) and 5‐( p ‐toluidino)‐2‐deoxyuridine (6b) were also prepared. In addition, results of the antiviral and antimetabolic activity of some of these analogs are reported.