2-Amino-7-chloro-2 `-deoxytubercidin

Abstract

In 4-chloro-7-(2-de-oxy-beta-D-erythro-pento-furanos-yl)-7H-pyr-rolo-[2,3 -d]-pyrimidine-2,4-diamine, C11H14ClN5O3, the conformation of the N-glycosylic bond is between anti and high-anti [chi = -102.5 (6)degrees]. The 2'-deoxy-ribofuranosyl unit adopts the C3'-endo-C4'-exo (T-3(4)) sugar pucker (N-type) with P = 19.6 degrees and tau(m) = 32.9 degrees [terminology: Saenger (1989). Landolt-Bornstein New Series, Vol. 1, Nucleic Acids, Subvol. a, edited by O. Madelung, pp. 1-21. Berlin: Springer-Verlag]. The orientation of the exocyclic C4'-C5' bond is ap (trans) with a torsion angle gamma = 171.5 (4)degrees. The compound forms a three-dimensional network that is stabilized by four inter-molecular hydrogen bonds (N-H center dot center dot center dot O and O-H center dot center dot center dot N) and one intra-molecular hydrogen bond (N-H center dot center dot center dot Cl).