7-Deaza-2,8-diazaadenosine.

Area of Science:

• Crystallography
• Structural Chemistry
• Molecular Biology

Background:

• Nucleoside analogs are crucial in medicinal chemistry.
• Understanding the precise three-dimensional structure of nucleosides is vital for drug design.
• Pyrazolo[3,4-d][1,2,3]triazine derivatives represent a class of compounds with potential biological activity.

Purpose of the Study:

• To elucidate the detailed molecular structure and conformation of 4-amino-7-(beta-D-ribofuranosyl)-7H-pyrazolo[3,4-d][1,2,3]triazine.
• To characterize the glycosylic bond, sugar pucker, and C4'-C5' bond conformation.
• To investigate the intermolecular interactions, specifically hydrogen bonding, that stabilize the crystal structure.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the atomic arrangement.
• Analysis of torsion angles (chi, P, tau(m), gamma) to describe molecular conformation.
• Identification and analysis of hydrogen bond networks (N-H...O, O-H...N, O-H...O).

Main Results:

• The N-glycosylic bond exhibits a high anti torsion angle (chi = -83.2 degrees).
• The ribofuranose moiety adopts an S-type sugar pucker (C2'-endo-C1'-exo, (2)T(1)) with specific pseudorotation parameters (P = 152.4 degrees, tau(m) = 35.0 degrees).
• The C4'-C5' bond conformation is +sc (gauche,gauche) with gamma = 52.0 degrees, and the compound forms a 3D network via hydrogen bonds.

Conclusions:

• The determined structure provides a precise conformational description of this pyrazolo[3,4-d][1,2,3]triazine nucleoside analog.
• The observed hydrogen bonding network is key to the compound's solid-state stability.
• This structural data can inform the design of related nucleoside analogs for potential therapeutic applications.