Pentostatin: C~11~H~16~N~4~O~4~. Mw: 268.27. (1) Imidazo[4,5-d][1,3]diazepin-8-ol, 3-(2-deoxy-β-D-erythro-pentofuranosyl)-3,6,7,8-tetrahydro-, (R)-; (2)(R)-3-(2-Deoxy-β-D-erythro-pentofuranosyl)-3,6,7,8-tetrahydroimidazo[4,5-d][1,3]diazepin-8-ol. CAS-53910-25-1 (1977).