Cyclic 8-bromo-inosine-5'-diphosphate ribose (8-Br-N1-cIDPR) was cleanly degraded at acidic pH by N9 ribosyl scission and subsequent pyrophosphate cleavage to give 8-bromo-N1-ribosyl hypoxanthine 5'-monophosphate (8-Br-N1-IMP), a novel class of mononucleotide, as the sole product.
