(1'R,2'S,3'R)-1-[2,3-Dihydroxy-4-hydroxymethyl-4-cyclopenten-1-yl]uracil 2,4(1H,3H)-Pyrimidinedione, 1-[4,5-dihydroxy-3-(hydroxymethyl)-2-cyclopenten-1-yl]- AIDS-114538 AIDS114538 Cyclopentenyl uracil NSC375574