(E)-9-(But-2-en-1-yl)-6-chloro-9H-purine

The asymmetric unit of the title compound, C₉H₉ClN₄, contains two mol­ecules. In the crystal, the mol­ecules are ordered in a chain-like fashion along the a axis, and form layers offset relative to the C plane by approximately 30°. This ordering does not, however, appear to be directed by classical hydrogen bonding.The allylic side chains of both independent mol­ecules are disordered, with occupancies of 0.870 (4) and 0.934 (3) for the major components. The disorder components represent two possible spatial orientations of the atoms around the C=C double bond.