5-Iodo-1-(2,3,6-trideoxy-.alpha.-L-hex-2-enopyranos-4-ulosyl) uracil 5-Iodo-1-(6-methyl-5-oxo-5,6-dihydro-2H-pyran-2-yl)-2,4(1H,3H)-pyrimidinedione AIDS-136601 AIDS136601 NSC638461