5-P-a-D-ribose 1-di-P
5-phosphoribosyl diophosphate
5-P-ribosyl 1-pirophosphate
PRPP

C5H13O14P3

It's a biphosphorylated ribose (at two different positions).

Synthesis of tryptophan (3D)
Synthesis of histidine (3D)
Pyrimidine synthesis (3D)
Purine Ribonucleotides synthesis (3D)