6-Mercapto-9-(2,3-O-isopropylidene-β-D-ribofuranosyl)purine is a chemically modified nucleoside derivative. Its structure consists of a purine base (6-mercaptopurine) linked to a ribofuranose sugar moiety, where the 2' and 3' hydroxyl groups are protected by an isopropylidene (acetonide) group. This protection enhances the compound's stability and alters its solubility profile, making it a valuable intermediate in synthetic chemistry. This compound is primarily used as a key synthetic precursor in medicinal chemistry and biochemistry research. Its main application lies in the synthesis of various thiopurine nucleoside analogs, which are investigated for their potential therapeutic activities. Most notably, it serves as a crucial intermediate in the synthesis of the immunosuppressive and anti-leukemic drug 6-Thioguanosine (6-TG). The protected ribose moiety allows for selective further functionalization of the nucleobase or the sugar ring, facilitating the development of novel nucleoside-based pharmaceuticals. As a thiopurine derivative, it requires careful handling due to its potential biological activity. It is typically used in controlled research settings for the preparation of more complex bioactive molecules targeting nucleotide metabolism pathways.