SYNTHESIS OF QUINAZOLINE C-NUCLEOSIDES - A NEW CLASS OF 6 6 BICYCLIC PURINE-LIKE ANALOGS/

The quinazoline C-nucleoside congeners of adenosine (1) and inosine (2 ) have been obtained by radical-induced addition of 4-bromobulyronitri le to C-ribosyl acrylonitrile 10. A base-catalyzed Ziegler-Thorpe cycl ization of the dinitrile thus obtained (II) followed by aromatization with DDQ afforded key intermediate 6-ribosylated anthranilonitrile 14 and its alpha-isomer. Annulation of a pyrimidine ring onto 14 or onto the corresponding o-amino-amide followed by deblocking with MeOH/HCl f inally gave 1 or 2 respectively.