[{"from": "human", "value": "Provide a brief overview of this molecule. [C][S][=Branch1][C][=O][=Branch1][C][=O][O].[C][=C][Branch1][#C][N][C][=Branch1][C][=O][C][=C][Ring1][#Branch1][N][C][=N][Ring1][Branch1][N]"}, {"from": "gpt", "value": "The molecule is the mesylate salt form of dezaguanine, a purine nucleoside analogue with antineoplastic and antiviral activities.  By competing with guanine, dezaguanine gets incorporated into DNA and inhibits DNA synthesis, thereby inducing cell death."}]