1-(5'-Phosphoribosyl)-5-aminoimidazole 1-(5-Phospho-D-ribosyl)-5-aminoimidazole 25635-88-5 5'-Phosphoribosyl-5-aminoimidazole 5-Amino-1-(5-phospho-D-ribosyl)imidazole AIR Aminoimidazole ribotide C03373