The anomers of 8-aza-7-deaza-2 `-deoxy-adenosine

Abstract

The structures of 4-amino-1-(2-deoxy-beta-D-erythro-pentofuranosyl)-1H-pyrazolo[3,4-d]py rimidine, (I), and 4-amino-1-(2-deoxy-alpha-D-erythro-pentofuranosyl)-1H-pyrazolo[3,4-d]p yrimidine, (II), both C10H13N5O3, have been determined. The sugar puckering of both compounds is C-2'-endo-C-3'exo (T-2'(3')) (S-type sugar). The N-glycosidic torsion angle chi(1) is in the anti range [-106.3 (2)degrees for (I) and 111.5 (3)degrees for (II)] and the crystal structure is stabilized by hydrogen bonds.