Xanthosine

 ( Nucleosides ) 

Xanthosine is a nucleoside derived from xanthine and ribose. It is the biosynthetic precursor to 7-methylxanthosine by the action of 7-methylxanthosine synthase. 7-Methylxanthosine in turn is the precursor to theobromine (active alkaloid in chocolate), which in turn is the precursor to caffeine, the alkaloid in coffee and tea.

• Xanthosine monophosphate
• Xanthosine diphosphate
• Xanthosine triphosphate