L. Denapoli et al., IMPROVED SYNTHESIS OF ISOGUANOSINE AND 6-SUBSTITUTED XANTHOSINE DERIVATIVES, Journal of the Chemical Society. Perkin transactions. I, (1), 1995, pp. 15-17
Isoguanosine 1 was obtained in 76% overall yield starting from 2',3',5
'-tri-O-acetylxanthosine 3 in a reaction involving the chloro derivati
ve 4 and the N-(purin-6-yl) pyridinium salt derivative 8 which also pr
oved to be new and valuable synthetic intermediates in the obtainment
of C-6-substituted xanthosine derivatives.