9-(1,1-Dimethyl-3-oxobutyl)adenine

The title compound, C11H15N5O, crystallizes with two independent molecules in the asymmetric unit, both of which contain essentially planar imidazole and pyrimidine rings [maximum deviations = 0.002 (2) and 0.026 (2) Å, respectively, for the first molecule, and 0.001 (2) and 0.025 (2) Å for the second]; the dihedral angles between the rings are 2.1 (2) and 1.7 (2)° in the two molecules. The crystal structure is stabilized by intermolecular N—H⋯N hydrogen bonds, defining chains along a, which are further linked by weak intermolecular π–π contacts [centroid centroid distance = 3.7989 (16) Å] into planes parallel to (01).

The title compound, C 11 H 15 N 5 O, crystallizes with two independent molecules in the asymmetric unit, both of which contain essentially planar imidazole and pyrimidine rings [maximum deviations = 0.002 (2) and 0.026 (2) Å , respectively, for the first molecule, and 0.001 (2) and 0.025 (2) Å for the second]; the dihedral angles between the rings are 2.1 (2) and 1.7 (2) in the two molecules. The crystal structure is stabilized by intermolecular N-HÁ Á ÁN hydrogen bonds, defining chains along a, which are further linked by weak intermolecularcontacts [centroid centroid distance = 3.7989 (16) Å ] into planes parallel to (011).

Comment
Adenine and adenine derivatives have drawn great attention of biochemists and organic synthetic chemists in recent years because of its good active biologic quality. Especially in the respects of antivirus and restraint of cancer cells (Jeffery et al., 2000). They are found in a variety of biologically active molecules (Bayes et al., 2003). The title compound was a new purine alkaloid, isolated from the mycelium of Ganoderma Capense (Lloyd) Teng obtained by submerged fermentation (Yu et al., 1990). The Ganoderma Gapense (Lloyd) Teng is a famous traditional Chinese medicine, and the content of the title compound was very poor, only 8 × 10 -5 from the corresponding mycelium. Herein, we report the synthesis and crystal structure of the title compound.
The title compound crystallizes with two independent but closely similar molecules per asymmetric unit (Fig 1). Both contain nearly planar imidazole and pyrimidine rings are essentially planar, with maximum deviations of 0.002 (2) In the crystal, molecules are linked by intermolecular N-H···N hydrogen-bonds (Table 1) to form an infinite one-dimensional zigzag chain running alomg a (Fig.2), in turn connected by π-π contacts involving the N3-C4, N6-C14 N8-C15 rings, defining two-dimensional layers parallel to (011).

Experimental
The title molecule was prepared according to literature procedure (Jiang et al., 1995). The compound was dissolved in a minimal amount of DMSO and the solution was then placed in a chamber saturated with dichloromethane at room temperature, covered and allowed to crystallize for two weeks. The resulting pale yellow crystals were collected by filtration, and a suitable crystal was selected for structural determination.

Refinement
All H atoms were placed in calculated positions, with N-H = 0.86 and C-H = 0.93, 0.96 or 0.97 Å, and included in the final cycles of refinement using a riding model, with U iso (H) = 1.2U eq (C).  Fig. 1. View of the title compound without the hydrogen atom-labeling scheme. Displacement ellipsoids are drawn at the 30% probability level.  supplementary materials sup-9