The regioisomeric 1H(2H)-pyrazolo[3,4-d]pyrimidine N-1- and N-2-(2 `-deoxy-beta-D-ribofuranosides)

Abstract

In the title regioisomeric nucleosides, alternatively called 1-(2-deoxy-beta-D-erythro-furanosyl)-1H-pyrazolo[3,4-d]pyrimidine, C10H12N4O3, (II), and 2-(2-deoxy-beta-D-erythro-furanosyl)-2H-pyrazolo[3,4-d]pyrimidine, C10H12N4O3, (III), the conformations of the glycosylic bonds are anti [-100.4 (2)degrees for (II) and 15.0 (2)degrees for (III)]. Both nucleosides adopt an S-type sugar pucker, which is C2'-endo-C3'-exo (T-2(3)) for (II) and 3'-exo (between E-3 and T-4(3)) for (III).