title: Alkali-catalyzed isomerization of some nitrogen-bridged furanosyl uracils to the corresponding pyranosyl cyclonucleosides.
abstract: With a view to examine the possibility of introducing an "up" amino residue into the sugar moiety of uracil nucleosides through 2,3'-N-cyclonucleosides, 2,3'-imino and 2,3'-substituted imino-1-(5'-O-benzoyl-beta-D-lyxofuranosyl)uracils, 2a4, 2b5 and 2c-f, were synthesized and debenzoylated correspondingly to 3a4, 3b5 and 3c-f. Hydrolysis of 3a,c,d,e with one to one mixture of 6N-NaOH and EtOH allowed the isolation of the corresponding 2,3'-N-bridged lyxopyranosyl nucleosides 4 in optically active, crystalline form. This is the first example of furanosyl to pyranosyl conversion in the field of pyrimidine cyclonucleosides.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D007536:Isomerism; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship; D014498:Uracil / Q000031:analogs & derivatives*
chemical_list: D014498:Uracil